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P L U SPreventing cross-contamination of drinking waterProtecting solar collectors from extreme temperatures

the magazine for plumbing engineers, designers, specifi ers, code offi cials, contractors, manufacturers, master plumbers, and plumbing professionals

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Solar Thermal System DesignPart 2: How to Overcome Freezing and StagnationOne area of solar thermal system design that deserves close consideration is the detrimental effects of extreme weather conditions—freezing and high-temperature stagnation—on solar collectors. This article discusses the pros and cons of glycol antifreeze, drainback, and direct water systems as freeze prevention methods, as well as how to prevent overheating and stagnation.

W. Hollis Fitch III

Get the Lead OutDid you know that products certified to NSF 61: Drinking Water System Components already conform to the new federal “Reduction of Lead in Drinking Water Act?” NSF 61 has limited the weighted average lead content to 0.25 percent in products and materials that come into contact with drinking water since it was adopted in 1988. Using booster systems as an example, this article explains how to specify products that will conform to federal and state lead-free requirements.

William “Skip” Roberts

10

FEATURES

GETTING TECHNICAL4 Hydronics for Plumbing Engineers What’s the Pressure?

6 Lessons Learned If Not You, Who? 8 Legal Pipeline The “Partial Performance” Exception to the Statute of Frauds

PERSPECTIVES28 Peer to Peer Empowering Africa’s Poor with Sustainable Sanitation

P l u m b i n g S y S t e m S a n d d e S i g nVOLUME 10, NUMBER 2 • MARCH 2011

CONTINUING EDUCATIONSanitary Drainage Systems34 Continuing Education Questions35 Continuing Education Answer Sheet

and Application Form

ASPE REPORT30 From the President’s Pen32 From the Executive’s Desk33 Society News33 New Members

READER SERVICES36 Classifieds36 Advertisers Index

The Official PublicaTiOn Of The american SOcieTy

Of Plumbing engineerS

CONTENTS

Plumbing Systems & Design™ is published by the American Society of Plumbing Engineers, Inc., 2980 S. River Road, Des Plaines, Illinois 60018, 847-296-0002, fax 847-296-2963, e-mail: [email protected], www.aspe.org. No charge for subscriptions to qualified individuals. Annual rate for subscriptions to nonqualifying individuals outside North America: $175.00 USD. POSTMASTER: Change of address should be sent to Plumbing Systems & Design, 2980 S. River Road, Des Plaines, Illinois 60018. Plumbing Systems & Design is an official publication of the American Society of Plumbing Engineers. Statements of fact, material, and opinion contained in contributed articles are the responsibility of the authors alone and do not imply an opinion or official position by the officers, staff, or members of the American Society of Plumbing Engineers. ©2011, American Society of Plumbing Engineers. All data and other information are provided with the understanding that the publisher is not engaged in rendering legal, consulting, engineering, or other professional services. All rights reserved; material may not be reproduced without written permission. ISSN 1548-5897

ADVERTISING SALES REPRESENTATIVENew England, Mid-Atlantic, & Virginia RegionsM.J. Mrvica Associates, Inc.(856) [email protected]

PUBLISHERAmerican Society of Plumbing Engineers

TECHNICAL EDITORSKarl Atteberry, PE, LEED APThomas J. Breu, PE, CPD, LEED APEsteban Cabello, PE, CPD, FASPEDale J. Cagwin, PE, CFEIJohn DeLeo, CPDPaul DiGiovanni, PERichard Ellis, CPD, CET, FASPE

EXECUTIVE PUBLISHERDavid R. Jern | [email protected]

MANAGING EDITORGretchen Pienta | [email protected]

GRAPHIC DESIGNERRachel Boger | [email protected]

Daniel Fagan, PE, CPDDoug Page, PE, LEED APJeffrey Ruthstrom, CPDMark Tanner, CPDPatrick Whitworth, CPD, FASPEJames Zebrowski, PE, CPD, FASPEStephen Ziga, CPD, SET

www.psdmagazine.orgE-mail: [email protected]

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By roy c.e. ahlgren

“What’s the pressure?” sounds like an easy question. The pressure is the number you read on a pressure gauge, and pressure gauges are installed throughout a typical hydronic system to help monitor system performance and identify problems. They are installed at the boiler, on the suction and discharge of a pump, and across the coils in an air handler.

While it’s easy to determine the pressure at any of these points, to determine if the system is operating properly, you also must know what a particular gauge is supposed to read. A pressure gauge in a closed hydronic system always reads the sum of as many as three “layers.”

What’s the Pressure?hydronicS for Plumbing engineerS

4 Plumbing Systems & Design MARCH 2011 WWW.PSDMAGAZINE.ORG

FIRST LAYER: STATIC PRESSUREIf the pump is turned off in a closed system, the water will not flow, and the pressure gauges read the static pressure. (Note: Gravity-induced flow could occur when the pump is off if a significant temperature difference exists from the top to the bottom of the system.)

Pressure is the force exerted over an area, and a column of water exerts a force proportional to its density and its height. Water density is determined by the concentration and type of additives such as treatment chemicals and antifreeze. It also is affected by temperature. Like most things, water expands and becomes less dense as it is heated.

For example, if you consider water with no additives at a temperature of 60°F, a column 2.3 feet high will exert a pres-sure of 1 pound per square inch (psi). Using this fact, you can derive the following rule of thumb: With the pump off, the expected gauge reading should be at least the height of the system above that gauge in feet divided by 2.3, plus the gauge reading at the top of that column.

SECOND LAYER: OPERATING PRESSUREOf course, 60°F water isn’t very useful in heating a building, so you must raise its temperature. Thus, the water expands, adding another static layer to the pressure gauge reading.

As the water heats and expands, so does the system piping. The net expansion could be defined as the expansion of the water minus the expansion of the piping as both heat up to the operating temperature. In a typical heating system, the net expansion might be 3.5 to 4 percent, which means that a system that had only 100 gallons of cold water now has 104 gallons of hot water.

Pressure is the force exerted over an area, and a column of water exerts a force proportional to its density and its height.

MARCH 2011 Plumbing Systems & Design 5

The air cushion trapped in the compression tank absorbs the net expansion, and as the volume of air decreases, its pressure increases according to Boyle’s law, which states that at a fixed temperature, pressure and volume are inversely proportional (while one doubles, the other halves). Every gauge in the system will register this increase in static pres-sure because the water isn’t flowing. If you want to achieve the required flow rate, the pump must create and maintain a differential pressure.

THIRD LAYER: PUMP HEADThe pump applies work to a pound of liquid at the suction nozzle, discharging it at a higher pressure. This differ-ential pressure acting on the water, which is essentially incompressible, overcomes friction in all of the system’s components, providing the flow required to move enough heat to keep the people inside the building comfortable. The pressure effect of the pump is reduced by friction, so the pressure layer caused by the pump will be smaller as it overcomes friction in pipes, fittings, coils, and so on.

At the point where the compression tank connects to the system (the point of no pressure change), the pump effect is zero. That’s why it’s a good idea to install the compression tank near the pump suction. By the time the liquid returns to the pump suction nozzle, all of the pump head is used up-that is, it has been converted to thermal energy by the system friction.

SO WHAT’S THE PRESSURE? The answer depends on several things:

Where the gauge is located: Is it at the top or the bottom of the •

system?

When the reading is taken: Is the system hot or cold?•

Is the pump on or off?•

How far is the gauge from the pump and the point of no pres-•

sure change?

Roy Ahlgren is a consultant to the hydronics industry. He served as chair of the ASHRAE Technical Committee on Hydronic and Steam Systems and was the director of the Bell & Gossett Little Red Schoolhouse. For more information or to comment on this article, e-mail [email protected].

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By J. Joe Scott ii, cPd, FaSPe

If Not You, Who?

Many changes have occurred in our indus-try in the past 30 years. Ouch, that hurts: I just realized that I have been designing plumbing systems for quite a while. While I may not be designing as many plumbing systems as I did in my early career, a mentor once told me that you need to remember where you came from because the past will help lead you into the future.

What have I learned during my many years of experience that I could pass on to younger plumbing engineers? Several things come to mind, but mostly I have learned that you need to be diligent in your quest for

knowledge and patient when dealing with others. I also have learned that giving back is very rewarding and should become part of your career. You never know what impact you will have on another person and what that impact may mean on a larger basis in the future.

Another lesson is to always strive to increase your knowledge so that you can teach someone else about what you just learned. If you have the desire to teach others about what you know, then you actu-ally will discover more in the process than you would if you were just learning for your

own sake. I have found that if I research a subject with the intention to teach someone else about it, then I will learn it better. For instance, when I was studying for a particu-lar accreditation exam, I was struggling to keep the information straight in my head. Once I stopped trying to learn what I needed just to take the test and started studying so I could teach someone else to take the test, the knowledge began to fall into place. Thankfully, I passed the test, but the passing of the test was not as significant as realizing that I needed to fundamentally change the way I was studying. It seems as though you

in a few short days you can: • Mingle with plumbing engineers from across the country • Identify what design methods you need to increase your skill set• Discover innovative ideas to take back to the office• Find out what industry segments will be hot in the next year• Pick the brains of experts working in the field• Grow your knowledge…and your career

NEW This Year! Networking Roundtable DiscussionsPartake in a lively conversation on the latest plumbing engineering issues with your peers from across the country.

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Oct. 27–30, 2011OrlandO, FlOrida


Joe Scott is senior plumbing designer for Cannon Design in St. Louis. To comment on this article or for more information, e-mail [email protected].

When dealing with a troubled economy such as the current one, anything we can do to help one another will be benefi cial.

Join ASPE for this four-part CPD review series, which will help you prepare to take the 2011 CPD Exam, being held April 15 or 16.

Don’t miss this valuable opportunity to receive helpful tips on what to study to successfully take the 100-question CPD Exam.

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*Deadline: To receive this manual in time for the first webinar, you must register for the four-part series by March 16, 2011. No refunds or rebates will be offered if you are unable to attend any of the scheduled webinars.

ASPE Webinars are 1 hour in length. Starts at 1pm CST.

C

ERTIFIED in PLUMBING DESIGN

• Am

e r ica n Society of Plumbing Eng ineers

•CPD

have to give your thoughts and knowledge away to make room for additional knowl-edge. I could be wrong, but that is what works for me.

What does that mean to you? Mentoring is a subject that does not get enough atten-tion, but it is imperative if we are going to teach the younger designers and engineers about what we do. Several years ago, Ken-neth G. Wentink, PE, asked me to be part of the team working on the Domestic Water

Heating Design Manual. While working on the manual, I was posed with a question that helped me understand that I had something to off er my peers. You have the same poten-tial to impact our industry, but the decision to do so lies only with you.

Th us, I will ask you the same questions that Donald L. Sampler, PE, FASPE, asked me: If not you, who? If not now, when? Th ose questions made me realize that I needed to do what I could to make the Domestic Water Heating Design Manual as good as possi-ble—quite a task for a young designer who was certain that many others knew more about hot water than I did. In fact, there are still many others who know more about hot water than I do.

Please look at the other people in your offi ce and determine what you can do to help them learn something today that will assist them with their careers tomorrow. When dealing with a troubled economy such as the current one, anything we can do to help one another will be benefi cial.

You also need to keep ASPE in the fore-front. Many of us have been part of this

Society for a while and owe much of our success to other ASPE members for helping us learn to be better designers. Go to local meetings and work with your peers to make a diff erence in your chapter. Together we can exchange information and help each other learn more about the plumbing systems that are evolving every day. By sharing our expe-riences, we may be able to keep someone from making a mistake that could cause a problem.

For those of you who are just getting into the industry, seek one of us old guys out. We want to see you succeed more than you know. You may have to put up with some war stories along the way, but that is how many of us learned what we know. Experience: You can’t trade it for anything except time.

By SteVen nudelman

The handshake has been in the news a lot lately. Competi-tors from around the world descended on New York City in January to try to win the World’s Longest Handshake competition. To win the competition, which took place outdoors in often below-freezing temperatures, contestants attempted to shake hands for 24 to 30 hours straight (with time taken for reasonable restroom breaks) to set a new Guinness World Record.

While this competition required a certain level of physical strength and determination, the casual (one-time) handshake often is not quite as intense. Indeed, the handshake dates back to ancient Greece, where it was used to show that a person came in peace without a weapon in his hands. Nowadays, the handshake is part of everyday culture, used upon greeting, departing, offering congratulations, and/or expressing agree-ment. This last gesture is the focus of this article.

LEGAL FORCE OF A HANDSHAKEBusinesspeople often shake hands to consummate an agreement, but the real question is whether the handshake has any legal significance to the parties. Generally speak-ing, the answer is no. While a handshake may serve as some tangential indicia of assent or a mutual meeting of the minds of two contracting parties, it is not dispositive as to whether the parties actually have an enforceable contract. Nevertheless, reasonable people continue to shake hands at the end of business deals—not only as a matter of custom or tradition, but because they believe that the gesture enhances the enforceability of the parties’ agreement.

Unfortunately, this belief does not square with the funda-mentals of contract law, and the purpose of this article is to correct this misperception about the business handshake. To undertake this task, let’s examine the opinion of the Superior Court of Delaware in Sunstar Ventures, LLC v. Tigani, No. 08C-04-042, 2009 Del. Super. LEXIS 439 (Del. Sup. Ct. April 30, 2009).

Sunstar Ventures, LLC v. Tigani In the spring of 2007, Mr. John Hynansky and Mr. Christo-pher Tigani allegedly made an oral agreement, sealed with a handshake, pursuant to which (a) Mr. Tigani agreed to

The “Partial Performance” Exception to the Statute of Frauds

legal PiPeline


buy Mr. Hynansky’s home for $5 million; (b) Mr. Tigani’s corporation, NKS, would lease warehouse space owned by Mr. Hynansky’s limited liability company, Sunstar; and (c) Mr. Hynansky would give Mr. Tigani a Porsche automobile worth more than $100,000. Under the parties’ agreement, Mr. Tigani was to take immediate possession of the home, lease it for a period of time, make renovations (subject to limited approval by Mr. Hynansky), and eventually close on the pur-chase before July 2009. Mr. Tigani was to make three princi-pal payments of $500,000 prior to the transfer of the home, and the $3.5 million balance would be paid at closing.

No Written AgreementMr. Tigani took possession of the home and started reno-vating, even though the parties never had a formal, written agreement (which was supposed to be drafted by their attorneys). As of March 2008, the parties still did not have a written agreement, and Mr. Hynansky sent Mr. Tigani an e-mail that read, in pertinent part: “I’ve been trying to com-municate with you and finalize our agreement for the last eight months to a year. I have again tried to communicate with you to finalize our agreement over the past week or so, specifically the last two days. … I trusted you; therefore, I let you work on MY HOUSE and tear it apart without a final signed contract, something I’ve never done before, and since you have possession of the house you no longer feel the necessity or the obligation to keep our original terms. … This it to inform you that I leave for Ukraine Monday, March 24th. THIS IS YOUR NOTIFICATION THAT IF OUR AGREEMENT IS NOT FINALIZED PRIOR TO MY TRIP, ON SUBSTANTIALLY THE TERMS THAT WE SHOOK HANDS ON, I AM CANCELLING THE AGREEMENT. Sincerely, John Hynansky.”

In response, Mr. Tigani sent Mr. Hynansky an e-mail stat-ing that the contract terms “do not work for me” and express-ing “regret that we are unable to come to terms.” Two weeks later, Sunstar and Mr. Hynansky filed a complaint against Mr. Tigani and NKS alleging breach of contract and a few other causes of action (that are beyond the focus of this article). In sum, Mr. Hynansky alleged that Mr. Tigani breached the parties’ contract involving the sale of Mr. Hynansky’s home

The application and impact of laws can vary widely based on the specific facts involved. Nothing in this column should be considered legal advice, recommendations, or an offer to perform services. The reader should not act upon any information provided in this column, including choosing an attorney, without independent investigation or legal representation. As such, this column should not be used as a substitute for consultation with an attorney.


and lease of warehouse space because Mr. Tigani failed to make the payments due for rent. In response, Mr. Tigani filed a motion to dismiss the complaint on the grounds that (a) there was no meeting of the minds on the material terms of the agreement, and (b) the contract violates the statute of frauds (which requires a signed writing to have an enforce-able agreement).

Motion to Dismiss the ComplaintAs it relates to the first branch of Mr. Tigani’s motion, the Court found that the material terms of the contract were sufficiently pleaded in the complaint. As the Court explained, “Even if aspects of the agreement are obscure, the agreement will be enforceable if the Court is able to ascertain the terms and conditions on which the parties intend to bind themselves. Indeed, an agreement may be enforceable where some of its terms are left to future deter-mination. While the Complaint does not state all the details of the contract with complete certainty, at this stage of the proceedings … the Complaint has sufficiently pled that the parties agreed to the material terms.”

The second branch of Mr. Tigani’s motion was a much closer call. According to the Delaware Statute of Frauds (as well as the statutes of frauds in most states), contracts for the sale of real estate must be reduced to writing and properly signed by the parties to be charged to be enforceable. This would seem to doom Mr. Hynansky’s complaint because it is undisputed that the parties lacked a written agreement. However, an exception to the statute of frauds exists (in Dela-ware and in most other states) when evidence of actual part performance of an oral agreement exists. Here, the Court found, as Mr. Hynansky alleged, there was “substantial par-tial performance” by Mr. Tigani since he took possession of Mr. Hynansky’s home and began making physical modifica-tions to it.

Thus, the Superior Court found that Mr. Hynansky’s com-plaint survived a motion to dismiss because it pleaded a claim for breach of contract, and, notwithstanding the lack of a written agreement for the sale of real estate, the parties had a potentially enforceable agreement (subject to the proofs and evidence that are adduced later as discovery proceeds and the matter heads to trial).

Steven Nudelman is a partner at the law firm of Greenbaum, Rowe, Smith and Davis LLP in Woodbridge and Roseland, New Jersey. He is a member of the firm’s Litigation Department and its Construction, Green Building, and Dispute Resolution Practice Groups. He may be reached at 732-476-2428 or [email protected]. To comment on this article, e-mail [email protected].

BACK TO THE HANDSHAKEWhile the opinion in Sunstar thoroughly examined the breach of contract claim, a defamation counterclaim (over some statements that Mr. Hynansky allegedly made about Mr. Tigani in a newspaper article), and other business tort claims, the Court was notably silent about the significance of the handshake. Indeed, after referring to the parties’ agreement as a “handshake agreement” in the begin-ning of the opinion, the Court said nothing else about the handshake. As suggested in the beginning of this article, the handshake played no role whatsoever in the enforce-ability of the parties’ agreement. More significant was the parties’ conduct following their oral agreement. The Court gave great weight to Mr. Tigani’s act of taking possession of the property and, as Mr. Hynansky conceded, tearing the place down as part of the renovations. This conduct gave rise to the “partial performance” exception to the statute of frauds, which otherwise mandates that certain agree-ments, such as agreements to transfer real estate, be in writing to be enforceable as a matter of law.

Plumbing engineers enter into business agreements all the time, and not all of them result in a writing signed by both parties to the transaction. (Indeed, unlike contracts for the transfer of real estate, not every kind of business agree-ment is required to be in writing under the statute of frauds.) While it is always preferable to have a signed writing as evidence of a contractual agreement—regardless of whether it is required under the statute of frauds or not—sometimes under the circumstances this is not immediately possible. Under those circumstances, and if the law requires a writ-ten agreement, think “partial performance.” Consider what kind of conduct has been done in furtherance of the parties’ agreement. After all, it is this conduct, not the act of shaking hands, that has the potential to salvage a claim that other-wise would not be enforceable due to the lack of a signed written agreement.


Get the Lead OutHow NSF 61 Helps Engineers Conform with New Lead Laws

BY WILLIAM “SKIP” ROBERTS

“Get the lead out.” When I first saw this phrase, I immediately thought about my days as a youth. My coaches and teachers told me to “get the lead

out” all the time. Today, the meaning is quite different. California, Vermont, Washington, D.C., and Chicago are leading the way in mandating less lead in their potable water streams, and President Obama recently signed the “Reduction of Lead in Drinking Water Act,” which sets a federal standard for the level of permissible lead in plumb-ing fixtures that carry drinking water, with the allowable lead content going from the past federal level of as much as 8 percent to 0.25 percent. This legislation (to take effect January 4, 2014) now makes the federal law consistent with the California lead-free legislation (AB 1953) passed in 2006, amends the definition of “lead-free” in the Safe Drinking Water Act (SDWA), and makes the federal require-ment consistent with the lead content requirements of NSF 61: Drinking Water System Components.

However, a surprising fact is that 36 states already require products in the potable water stream to be certified to NSF 61, and 10 others mention this standard in their administra-tive codes. Many of these states have had this mandate in place since the early 1990s due to the passing of the SDWA, which mandates the removal of harmful materials such as lead and chemicals from our drinking water.

NSF INTERNATIONAL BACKGROUNDYou may ask: What is NSF? Why are its standards impor-tant? The National Sanitation Foundation was founded


at the School of Public Health, University of Michigan, in 1944, and issued its first food safety standards in 1952. The organization is dedicated to public health, public safety, and environmental protection through testing and the issuance of standards focused on food, water, indoor air, and the environment.

In response to the passing of the Safe Drinking Water Act, NSF created a water treatment and distribution systems program. The SDWA covers all products that come in contact with drinking water from source to tap.

What Does “Source to Tap” Mean?Let’s define this before moving forward. To a municipality, “source to tap” means the water system from the treatment plant to the water meter in front of any building, whether it is a home, office building, or manufacturing plant. To a plumbing engineer designing the potable water system in any of these buildings, “source to tap” means the system from the water meter to the furthest fixture in the building.

NSF 61 certification covers all of the components found in the potable water stream.

NSF Standards DevelopmentNSF certification standards are developed by a group of organizations including NSF, the American Water Works Association (AWWA), Water Research Foundation, U.S. Environmental Protection Agency (EPA), and Health Canada. The group establishes balanced committees of participants to set standards for both the United States and Canada. Committee members include government officials, utility district officials, inspectors, and manufac-turers. NSF standards are re-evaluated on an annual basis, and most certifying agencies are inspected on a quarterly or semiannual basis.

Drinking Water StandardsThe NSF drinking water standards cover products and materi-als that come into contact with drinking water (NSF 61) and drinking water treatment chemicals (NSF 60). This article discusses plumbing materials (governed by NSF 61), includ-ing pipes and fittings, joining and sealing materials, paints and coatings, process media, endpoint devices (e.g., drinking fountains and faucets), and mechanical devices such as pro-cess equipment, water meters, valves, and booster systems.

The acceptance criteria for the above items are based on regulated contaminants, with the most prominent being lead, and more than 600 unregulated potential risk values have been identified. Components containing these contaminants, when part of the potable water stream, can leach chemicals into the drinking water and cause health problems.

CONFORMANCE RESPONSIBILITYThe Safe Drinking Water Act was originally passed in 1974 and then amended in 1986 and 1996. This act sets the basic minimum requirements for drinking water quality and the monitoring of that water, and each state is responsible for

enforcing the requirements. As of this writing, 46 states have legislation responding to the SDWA.

Each state has its own special way of ensuring confor-mance to the SDWA. Most states pass the responsibility to cities, municipal utility districts, and others responsible for local enforcement. Cities and counties either have their own plumbing codes or use nationally recognized standards as published by the International Plumbing Code (IPC) and the Uniform Plumbing Code (UPC). Some states, such as Kansas and Mississippi, adopted the SDWA in its original form and mandate the use of the IPC. Many others vary the legal language, but require NSF 61-Certified products in the potable water stream. Texas is the only state that specifies pump stations in its administrative language. California has gone the extra mile and requires another certification by an independent third party.

What Is an Independent Third Party?In 29 CFR, the U.S. Occupational Health and Safety Admin-istration (OSHA) defines a third-party certifier, or a nation-ally recognized testing laboratory, as “an organization which is recognized by OSHA ... and which tests for safety, and lists or labels or accepts, equipment or materials.” Some of the parties that can certify to NSF standards are the American National Standards Institute (ANSI), NSF, International Association of Plumbing and Mechanical Officials (IAPMO), Underwriters Laboratories (UL), and Canadian Standards Association (CSA). Other organiza-tions offer similar certificates.

WHY NSF 61?Why is NSF 61 certification necessary for products utilized for potable water?

It ensures that the products meet water utility requirements.•

It forms the basis for regulatory acceptance.•

It signifies testing and evaluation by an independent third-party •

agency that certifies to NSF standards.

It simplifies and unifies requirements.•

It evaluates products to the most current regulatory require-•

ments as regulations change.

It adds credibility in the marketplace for plumbing equipment.•

FOCUS ON BOOSTER SYSTEMSA booster system (see Figure 1) must be certified as a com-plete system, with all passageway components assessed and certified to the NSF 61 standard. The components include coatings, pipes, valves, pumps, gaskets, headers, and fittings.

Booster ComponentsMany coating materials by different manufacturers are certified to NSF 61 and must have a label attesting to that certification. The coating thickness is determined by the pipe diameter.

Pipes must have documentation as to the suitability of the metallurgy, but they don’t necessarily need a label. The most


commonly used pipe for boosters is 304 stainless steel, but 316 and 316L stainless steel are acceptable for applications below 120°F. Also, any steel pipe with an approved NSF 61 coating material is acceptable. Type L and Type K copper pipe are acceptable, but Type M is not.

The valves used on booster systems are wafer check valves, butterfly valves, pressure-regulating valves, and ball valves. If they have a label certifying them as NSF 61, then they are acceptable.

Pumps are a very interesting part of this equipment. Many pump companies advertise that they are NSF acceptable; however, some of their products are certified to NSF 50: Rec-reational Water Facility Components. The difference is that NSF 50 regulates swimming pool and spa components, while NSF 61 governs potable water system components. While the water in swimming pools may not be toxic, most people do not intentionally drink it. Thus, pumps for drinking water must be certified to NSF 61, not NSF 50.

The most interesting component is the smallest: the gasket. Booster system manufacturers can use only three acceptable gasket materials: EDPM (ethylene propylene diene monomer rubber), NBR (nitrile butadiene rubber), and SBR (styrene butadiene rubber). Buna and PTFE (poly-tetrafluoroethylene) are not acceptable. The bladder tank can be made of buna, but buna cannot be used as the gasket material. Manufacturers also must buy the gasket material in sheet form. Pre-cut gaskets cannot be used.

HOW TO FIND LABELED PRODUCTSThe label (see Figure 2) is the key element. If a product does not have an NSF 61 label, it is not certified for drinking water systems. The manufacturing facilities for labeled products and systems have been inspected and approved, and the products and systems themselves have been tested and evaluated. The components used in the test become frozen and cannot be changed due to product availability problems unless another test is performed and the new component is accepted for use by the certifying agency.

A common problem every engineer faces is finding suppli-ers that carry this label. NSF and some certifying agencies offer a product listing search on their websites, but you must know the manufacturer’s name first. The best way to ensure certifi-cation is to ask the supplier to provide a current copy of their certificate. If they have a current certificate, they are certified.

While the NSF 61 certificate is the only requirement in most states, California now requires an additional certificate commonly known as “AB 1953” or, officially, “California Health and Safety Code Section 116875,” which certifies that the product will not impart more than 0.25 percent lead by volume into the potable water stream.

This requirement also is mandated by the “Reduction of Lead in Drinking Water Act” as well as the “Assistance, Quality, and Affordability Act of 2010,” which was passed last spring. However, NSF 61 limits the weighted average of lead content in plumbing products to 0.25 percent, so products that are NSF 61 Certified already conform to the new law.

Figure 1 Booster pump system

Figure 2 NSF 61-Certified label (bottom white label) and California

AB 1953-certified label (middle white label)


KNOWLEDGE SETS YOU FREENow that you have read this, you should be more knowl-edgeable about NSF 61 and can start writing specifi cations requiring NSF 61 for potable water. Unfortunately, while I have presented this same information to many state government offi cials and city inspectors, only one of them expressed interest in enforcing the low-lead requirement. One state representative told me that most specifi cations already have a requirement to meet state and federal guide-lines, but many state guidelines use old plumbing codes that do not have an NSF 61 requirement. When was the last time one of your jobs was red-tagged due to valves or pipes without an NSF 61 label?

We all want drinking water that will not harm the drinker. Remember “sick” buildings in the 1980s and 1990s? At that time, California discovered water wells with high concentra-tions of lead, as well as brass and bronze pipes with lead-based parts that were in drinking water systems. Changes were made throughout the industry because of those discov-eries. However, while many states have a low-lead require-ment on their books, they do not strictly enforce it. Plumbing inspectors have not been looking for NSF 61 equipment under Section 6 in either the IPC or the UPC. Th e UPC did not mention NSF 61 valves until the 2009 version.

Safe drinking water has been on the federal government’s agenda since 1974. While most states attempted to follow the SDWA and adopted rules for its residents to follow, most man-ufacturers did not get involved until California mandated NSF 61 and “lead free” with AB 1953. Once that law was in place and enforcement was on the horizon, a trickle-down eff ect started to occur. To remain competitive, most manufacturers of drinking water system components reworked their products to conform to the lead-free requirement.

Now, however, we have federal legislation requiring NSF 61 and lead-free plumbing products, so we can start ridding our cities of all old potable water system components. Th e legislation aff ects new and replacement equipment, so, for instance, if a building needs additional pressure or fl ow for its drinking water supply, a new NSF 61 booster system should be installed, even if it will be placed in an old pipe scheme.

If you want to fi nd out if your state currently requires NSF 61-Certifi ed products in the potable water stream, look under NSF or National Sanitation Foundation in the state administrative code.

Why Should Engineers Specify NSF 61? Th at question is on every plumbing engineer’s lips or at least in their mind. Th e answer is: It’s the law! More impor-tantly, we want our families and friends to be able to drink from the tap without fear of harm.

ACKNOWLEDGEMENTTh anks to the Association of State Drinking Water Admin-istrators (ASDWA), I have a list of most of the state rules regarding drinking water systems. Please contact me at the e-mail in my bio for a copy.

Skip Roberts began his career in the pump industry with Aurora Pump Co. 30 years ago and has worked for various pump manufacturers as a salesman and market manager as well as a regional sales manager. He joined Tigerflow Systems Inc. in 2004, where he is involved with fire pump packaged systems, nonpotable booster systems, and potable booster systems. He is available to speak on the topic of NSF 61 and can be reached at skip.roberts@tigerfl ow.com. To comment

on this article, e-mail [email protected].

HELPFUL LINKS

NSF International: nsf.org

American Water Works Association: awwa.org

Water Research Foundation: waterresearchfoundation.org

U.S. Environmental Protection Agency: water.epa.gov/drink/

Safe Drinking Water Act: water.epa.gov/lawsregs/rulesregs/sdwa/index.cfm

Occupational Health and Safety Administration: osha.gov

American National Standards Institute: ansi.org

International Code Council: iccsafe.org

International Association of Plumbing and Mechanical Offi cials: iapmo.org

Underwriters Laboratories: ul.com

Canadian Standards Association: csa.ca

Association of State Drinking Water Administrators: asdwa.org

Solar Thermal


Solar Thermal Part 2:

How to

Overcome

Freezing and

Stagnation

System DesignPart 1 of this series on solar thermal

system design in the January/Febru-ary 2011 issue of Plumbing Systems &

Design discussed solar thermal system appli-cations and compared flat plate collectors and evacuated tube collectors. This article discusses two of the most important con-siderations for solar thermal system design: freezing and stagnation.

Solar thermal systems have been used for centuries. However, in the mid-1970s, U.S. government incentives provided a much-needed boost to solar thermal systems and generated a great deal of interest, research, and review of large-scale test installations. When the incentives ended in the early 1980s, the solar thermal industry came to a standstill in the United States, and advances in technology and understanding also stagnated. Today, solar thermal engineers have to dust off the white papers and books of the 1970s to get back up to speed, since little new information has been published since then.

One area that needs review is consideration of the detrimental effects of extreme weather conditions—freezing and high-temperature stagnation—on solar collectors. While freez-ing has been addressed in the past, the new evacuated tube collectors offer a different opportunity that should be explored. On the other hand, stagnation conditions largely have been ignored by the industry, which has led to many premature failures.

FREEZE PREVENTION METHODSSince flat panel collectors by design incor-porate a large, flat sheet of glass as a cover, they exhibit an inherently low R value, or thermal resistance. This means that flat panel collectors are quite susceptible to freezing as temperatures decrease. In fact, freeze-related damage has been the single largest problem the solar thermal industry has faced, and it is the cause of the major-ity of system damage, loss of service, poor reputation, and loss of investment to date.

by W. HOllIS FITcH III


In an effort to combat the damage caused to flat plate collectors by freezing, the industry adopted two solutions: using glycol antifreeze as the heat-transfer fluid (see Figure 1) or installing drainback systems to drain the exposed panels and piping of water during cold weather. It is essential to use one of these options when installing flat panel collectors, or the system inevitably will freeze at some point (unless the project is located in the tropics, of course). It is not practical to circulate hot water through such systems, since the heat loss from flat panels is prohibitive and would extend the payback beyond the design life of the collectors.

It is important to note that while both options help reduce the possibility of freez-ing, they both also present a host of other problems that need to be addressed as part of the design, operation, and maintenance of the system.

Glycol AntifreezeIn the case of glycol antifreeze as the heat-transfer medium, the problems are as follows:

Glycol is not stable at elevated temperatures; it •

breaks down over time and must be replaced.

If a solar thermal system stagnates, which hap-

pens from time to time, the higher tempera-

tures cause much faster breakdown. As a side

effect of this breakdown, glycolic acid is pro-

duced, which can etch copper piping, collector

components, heat exchangers, pumps, and

valves. A preventative maintenance program

should be put in place when glycol is used to

ensure that the pH is measured regularly and

that the glycol/water solution is replaced every

one to three years. Even the safe propylene

glycols used in solar systems are considered

controlled substances and should not be dis-

posed into sanitary drains, but taken to proper

recycling stations.

Glycol fluids require closed-loop piping sys-•

tems (see Figure 1). This means that the heat

from the solar loop must be transferred to

the potable water system, usually through a

double-wall heat exchanger and dual pumps

or through double-wall heat exchanger bun-

dles in storage tanks. Besides the higher costs

associated with the extra components, the big-

gest issue is maintaining pressure in the closed

loop. If any leak occurs in the glycol loop, then

the pressure soon will drop to zero, which

will cause overheating at the collectors, pump

failure from cavitation, and overheating of the

glycol. If a glycol system is used, low-pressure

alarms should be installed to notify operations

personnel of loss of pressure so immediate

action can be taken. Maintenance personnel

also should receive training on using the cor-

rect proportions when refilling the system with

the glycol/water mix, so an accurate base pres-

sure is built up again.

If a closed-loop glycol system loses pump flow, •

overheating will occur at the collectors, and

in most cases temperatures will increase high

enough to allow the formation of steam. All

closed-loop systems must have both expansion

tanks to allow for normal increases in system

volume as temperatures rise as well as pres-

sure-relieving devices to handle steam buildup.

If accidental discharge occurs, then the system

must be recharged immediately, and many

authorities having jurisdiction and plumb-

ing codes do not allow relief valve discharge

of glycol to either the roof surface or city

drains. Instead, special capture tanks must be

installed. Such systems also should have high-

pressure and high-temperature alarms installed

to alert personnel of possible problems.

Another concern in very cold climates is the •

viscosity of glycol mixes. As the coldest outside

air temperatures decrease region to region,

a higher and higher percentage of glycol

must be used in the solar loop. Ultimately the

percentage is so high that viscosity becomes

a factor. In normal operation, a glycol-based

system is stopped during times of heavy cloud

cover and at night. If conditions are also very

Figure 1 Glycol loop with heat exchanger

Source: Solarhot USA

Figure 2 Drainback system

Source: Solarhot USA


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cold, the glycol will prevent freezing, but

the temperature of the glycol will approach

the outside air temperature. When the sun

eventually comes out, the glycol may be so

viscous that it will resist pumping, and it may

be several hours before the very low flow rates

allow the fluid to heat sufficiently. In northern

areas of the United States, solar systems are

designed to circulate the glycol during these

cold periods to try to minimize this problem,

with the understanding that stored heat will

be lost from the system.

Drainback Systems Due to the issues regarding the use of glycol, many solar installers favor drain-back systems (see Figure 2). However, it is considered impractical to use drainback systems when the array size is more than 10 collectors due to the mounting difficulties.

Drainback systems are also closed loop, but they are maintained at atmospheric pressure. All piping and collectors are mounted so that water will completely drain from the exposed piping and collectors when the solar pumps stop. If freezing occurs, the solar pumps stop, and the system drains to a small tank located inside the building.

When using this type of system, the fol-lowing should be kept in mind:

Usually distilled or treated water is used in •

the loop, but since the system is exposed to

atmosphere (and must be vented at all times),

evaporation loss occurs daily. The facility

Solar Thermal Flow Diagrams

Standalone Solar Hot Water SystemSingle W/H with Triple Solar Storage

Tanks

DHW-5 8B -

Figure 3 Direct water system

should have readily available means for adding

this treated water to the system, or scale will

become a problem. Scaling is accelerated in

drainback systems since the dry collectors

become quite hot when the sun comes out

until the system is completely filled.

Drainback systems rely on the sloping compo-•

nents to drain, and complete drainage provides

the only freeze protection. Thus, the engineer

and installer must eliminate low spots where

water can collect, since water in a low spot

may freeze in low-temperature conditions.

Also, correct drainage must be ensured by

installing at least one vacuum breaker in each

row of collectors and perhaps a few more if

exposed piping is extensive. The facility main-

tenance crew should inspect these vacuum

breakers for correct operation each fall and

replace any that have sticky operation.

Drainback systems rely on a temperature •

sensor to signal the pumps to stop in cold

conditions. Since so much depends on this

sensor, the engineer should consider redun-

dant sources, and these should be inspected,

calibrated, and tested after each cold spell.

Direct Water SystemsThese two freeze-protection choices have become so ingrained in the body of knowledge that many engineers don’t even consider using a direct potable water system. However, a look at the history of solar thermal systems shows that despite the implementation of glycol or drainback

strategies, the failure rate of solar systems due to freezing has been widespread. The reasons vary from the installer not under-standing the importance of overall system design to a lack of proper monitoring and control systems or because facility opera-tions personnel assumed that the use of glycol or drainback options made them invincible against freeze failure, when in fact such options present an even larger oversight and maintenance burden.

Evacuated tube collectors change this entire paradigm. Evacuated tube collectors, by their very design, do not contain any water in the absorber, and the absorber itself can freeze without any damage to the collector. The water in the header piping is subject to freezing temperatures, but it is enclosed com-pletely by insulation. While heat loss from a flat panel collector is significant in freezing conditions, heat loss from evacuated tube col-lectors is nearly zero in the exposed tubes and minimal (200–500 British thermal units per hour) in the header. This means that the engi-neer now has a third option besides glycol and drainback: circulation of water during freeze conditions, or a direct water system (see Figure 3).

Using direct water in the solar loop obvi-ates all of the issues described above for glycol and drainback systems. The engineer must be concerned with only two issues: scaling and ensuring circulation during freeze conditions. Both of these are easily addressed. Scaling can be prevented using softened water or can be corrected by des-caling, and due to the low delta T between the water and the heat source, scaling forms quite slowly (in years). Freezing can be pre-vented by sensing outdoor temperatures and circulating water through the solar loop at low flow rates.

It is true that the sensors may fail; how-ever, with correct design and redundancy, multiple sensors can be monitored by the control system and activate circulation. It is also possible that a power failure may accompany very cold conditions, and the engineer is advised to connect the solar pumps to emergency power sources when-ever using a direct water system. A small amount of heat is lost during circulation, but this is usually less than 5 to 10 percent of what can be produced by the system during an average day. In all cases, a direct water system should incorporate both a freeze


Figure 4 Heat dissipater

Source: Armstrong International

dribble valve and automatic and manual draindown provisions as a last resort option.

No antifreeze option is foolproof. The engineer must compare the pros and cons of each choice, and make an informed deci-sion based on the location and application. In most cases, the direct water system, when correctly designed and built, presents the least risk of failure and the lowest operations and maintenance burden.

DEAlING WITH STAGNATIONStagnation occurs when the solar loop fluid stops circulating. When that occurs, the collectors have no way to relieve the heat gain and quickly rise to the maximum tem-perature associated with their design and R value. These temperatures range from more than 300°F for well-made flat plate collec-tors to 430°F for uncontrolled evacuated tube collectors.

Following are the most common reasons for stagnation conditions, listed in order of frequency:

Purposeful solar pump shutdown to prevent •

overheating in the rest of the solar system

Solar pump failure (loss of power or mechani-•

cal failure)

Solar loop blockage (incorrect valve position, •

foreign material in piping, etc.)

Whatever the cause, stagnation should be avoided as much as possible due to the ther-mal stress damage that occurs to collectors, piping and components, and glycol fluids.

Solar pump failure and solar loop block-age can be overcome by careful tagging of valves, using high-temperature alarms, and using duplex pumps connected to emer-gency power sources to minimize accidental conditions.

Preventing OverheatingSolar thermal systems are designed to pro-vide just enough heat in the summertime

to satisfy the facility demand. However, from time to time there may be too much solar gain and/or too little load needed by the facility, and in these cases the solar storage tanks will eventually reach their high-temperature limit, typically between 180 and 200°F. At this point, steps must be taken to prevent more energy from entering the solar system. These can include:

Stopping the pumps—a cheap option that can •

damage the pumps (and unfortunately is a

common choice today)

Circulating fluid through a heat dissipater (see •

Figure 4)—a good, but potentially expensive,

engineering solution

Installing larger storage tanks—a somewhat •

inexpensive option, but effective for only one

or two days of low facility loads

Dumping the heat to a secondary load such as •

a swimming pool or HVAC system—another

somewhat inexpensive option, but requires

careful planning during design and not always

possible

Dumping the heat by draining the water—an •

inexpensive option, but wastes water

Covering the collectors—sometimes used for •

seasonal installations

Each of the above options prevents the system from overheating, and each has its pros and cons. The solar engineer is advised to examine the options early in the design process to select the best overall design.

cONclUSIONFreezing and stagnation are damaging conditions lurking at opposite ends of the thermometer. Like most engineering challenges, they can be overcome by a thor-ough understanding of solar components, system design, and operating conditions. A number of recognized solutions are avail-able, and each project will lend itself to a particular combination that balances both initial cost and overall life-cycle costs.

The last article in this series will discuss solar thermal system design and best practices.

Hollis Fitch is Chief Executive Officer of Cinco Solar Inc. in Spring Branch, Texas. For more information or to comment on this article, e-mail [email protected].

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BACK FLOWP r e v e n t i o n 1 0 1

by Raymond F. Parham, PE


June 1983, Calgary, Canada: Residents complained about

poor-tasting water. The city collected samples and found

detectable levels of E coli in the water system.

February 1979, Seattle, Washington: Residents

complained that their water was “gray-green and

slippery.”

1993, North Carolina: Clinic employees complained of a

bitter taste and a strong chemical odor in the clinic’s

water.

1991, Michigan: A homeowner found parasitic worms in

his water, along with rust and debris.

Summer 2011, Your House: You are refilling your pool after a partial pumpdown as part of a chemical cleaning treatment. You leave the end of the hose

submerged in the pool as you run some errands. While you are out, the house down the street catches fire, and the fire department hooks up a pumper truck to the hydrant next to your driveway. When you get home, you notice that the water level in your pool is significantly lower than when you left and that the water coming from the master bath-room showerhead has a distinctive odor.

The first four events are recorded on the website of Galves-ton County (Texas) Water Control and Improvement District #1. What do they have in common? All were caused by either the absence of proper backflow prevention or the failure of backflow devices. The Galveston County Water District fur-ther reports that more than 10,000 cross-connections from garden hoses occur every day in Texas.

LET’S LOOK AT THE DETAILS OF THESE CASESEach of these cases provides an example of a different form of cross-contamination.

Calgary, Canada: This is an example of internal contami-nation inside a building. It occurred at a veterinary clinic, which had treatment and cleanup areas for the care of ani-mals. Due to a lack of proper backflow prevention devices, wastewater from the cleanup areas was allowed to back-siphon into the domestic water system—hence the positive

test for E coli. The clinic was ordered to install proper devices on each fixture in the building.

Seattle, Washington: This is a case of improper backflow prevention, which allowed cleaning solutions from a car-wash to flow back into the public water supply. When a high-pressure pump that transferred final rinse water back to the initial scrubber cycle failed, the operators of the carwash used a hose from the domestic system to operate the scrub-ber system. When the pump was repaired, everyone forgot about the hose. Thus, when the pump operated, it filled the scrubber system, and the pump discharge pressure was high enough to pump the rinse water back out to the city water main. The carwash was required to install a backflow preven-ter on the water service.

North Carolina: The clinic used an x-ray developer for which several different chemicals were mixed as part of the developer process. Someone had submerged the end of the fill hose in the mixer, which created a cross-connection. Due to a pressure differential in the building, the mixer chemicals were siphoned back into the domestic water piping.

Michigan: The homeowner did not maintain the vacuum breaker on the lawn irrigation system. In another section of the city, a water main break drained the mains in the hom-eowner’s area, which created a vacuum in the feed to the irrigation piping, pulling water collected around a sprinkler back into the water service. Along with the water were vari-ous critters and debris. When the water main was fixed and

FLOW


the water was turned back on, the critters and debris ended up inside the house.

Your House: When the fire department hooked up to the hydrant, they pulled a vacuum on the water main to get more water to fight the fire. With the water main under a vacuum, the system will try to fill it. (Remember, nature abhors a vacuum!) In this case, the only source of relief was to pull

water from the pool, into the garden hose, back through the house, backwards through the water meter, and out into the city water main. Yes, the fire department has published pro-cedures that say they never go below 20 pounds per square inch (psi) at the suction of an engine-driven fire pump, but I have talked to many operators who say that when a fire is hot, they are going to get every drop of water that they can.

Figure 2 Double-check valve assemblySource: National Environmental Services Center, National Drinking Water Clearinghouse, Tech Brief on Cross Connection and Backflow Prevention, illustrations by Bethany Reed

Figure 1 Reduced-pressure principle backflow preventer schematicSource: National Environmental Services Center, National Drinking Water Clearinghouse, Tech Brief on Cross Connection and Backflow Prevention, illustrations by Bethany Reed

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BACKFLOW PREVENTION DEVICESLet’s take a look at the proper prevention of cross-contamina-tion and the use of backflow preventers. Most plumbing codes in the United States require proper backflow prevention.

For instance, Section 608: Protection of Potable Water Supply of the International Plumbing Code (IPC) deals with cross-connections. It says: “A potable water supply system shall be

designed, installed, and maintained in such a manner so as to prevent contamination from nonpotable liquids, solids, or gases being introduced into the potable water supply through cross-connections or any other piping connections to the system.”

Table 608.1 of the IPC provides a list of backflow preventer types and the applications for each type. Some of these types and the reference standards that cover their operation follow:

Figure 3 Vacuum breakerSource: National Environmental Services Center, National Drinking Water Clearinghouse, Tech Brief on Cross Connection and Backflow Prevention, illustrations by Bethany Reed

Figure 4 Barometric loopSource: National Environmental Services Center, National Drinking Water Clearinghouse, Tech Brief on Cross Connection and Backflow Prevention, illustrations by Bethany Reed

C

M

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CM

MY

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Revit Ad final.pdf 1 12/14/09 9:16 PM


Air gap, ASME A112.1.3•

Atmospheric-type vacuum breaker, ASSE 1001•

Anti-siphon fi ll valve for water closet tanks, ASSE 1002•

Hose connection vacuum breaker, ASSE 1011•

Backfl ow preventer with intermediate atmospheric vent, ASSE 1012•

Reduced-pressure principle backfl ow preventer, ASSE 1013•

Double-check backfl ow prevention device, ASSE 1015•

Vacuum breaker for wall hydrants, ASSE 1019•

Pressure vacuum breaker assembly, ASSE 1020•

Backfl ow preventer for beverage-dispensing equipment, ASSE 1022•

Dual-check backfl ow preventer, ASSE 1024•

Laboratory faucet backfl ow preventer, ASSE 1035•

Reduced-pressure detector for fi re protection, ASSE 1047•

Double-check detector for fi re protection, ASSE 1048•

Hose connection backfl ow preventer, ASSE 1052•

Spill-resistant vacuum breaker, ASSE 1056•

Note that ASSE off ers many other standards. Plumbing engineers should verify that their specifi cations include the proper reference for any backfl ow prevention device used on a project. Further, design engineers should review all devices submitted to verify that the proper devices are installed.

As you can see, various types of devices for diff erent types of hazards are available, with more complex devices required for the most dangerous types of potential contamination.

WHY DO WE NEED BACKFLOW PREVENTION?Plumbing designers and engineers must consider at least two levels of backfl ow prevention. Th e fi rst level is pro-

tection of the public water supply. Th e local water utility should have minimum standards for connection to the public water supply. For most connections, proper back-fl ow prevention is required, but for some reason, it is not required for single- and two-family residential buildings, except for irrigation systems. Th erefore, it is very important for all hose bibbs on houses to be provided with tamper-resistant vacuum breakers.

Th is level of protection generally is required to be a reduced-pressure principle backfl ow preventer for domestic service and a double-check valve assembly for fi re protection systems. Sometimes the local authority requires the fi re pro-tection service to include detector function on the backfl ow preventer. Th is function adds an external element designed to monitor for small usages of the fi re service to prevent unauthorized domestic use through the fi re service connec-tion, which generally is not metered.

Th e second level of backfl ow prevention is protection of the occupants in a building from internal contamination. As identifi ed above in the cases of the Calgary and North Carolina clinics, the water supplies for the occupants were compromised due to contamination sources inside the buildings. Th e public water supplies would have been pro-tected by backfl ow prevention devices on the water service, but that did not protect the building occupants from internal contamination.

Th is level of protection could be provided by any of the backfl ow devices listed above. In general, higher hazards

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require more levels of protection. The order of protection level, from highest down, is:

Air gap•

Reduced-pressure principle backflow preventer•

Double-check valve backflow preventer•

Vacuum breaker•

For some projects, a third level of backflow prevention is required to eliminate cross-contamination between pro-cesses or equipment. For example, Biosafety Level 4 (BSL 4) facilities are required to have a nonpotable water supply to the laboratories. However, each individual lab must be pro-vided with a reduced-pressure principle backflow preventer to prevent one lab from contaminating an adjacent lab and to provide a second level of protection for the public water supply. The same situation may exist in a research laboratory where the designer needs to provide vacuum breakers on all faucets and equipment, even if a nonpotable or laboratory domestic water system is provided separate from the potable water system in the building. You do not want one lab to con-taminate the research or processes in an adjacent lab.

PRINCIPLES OF BACKFLOW PREVENTIONThe two basic types of contamination are back-siphonage and back-pressure.

Back-siphonage occurs when the pressure in the distribu-tion piping is negative, and the system tries to eliminate the vacuum. As represented above, back-siphonage can occur when negative pressure in the piping main tries to pull water

back into the system. The negative pressure could be the result of elevation differences or pumps pulling a negative pressure on the main. Another possible cause that often is missed is the venturi effect at nozzles or orifices. One example that is observed frequently is a chemical-dispensing system on a mop sink faucet. The dispensing system uses a venturi to draw detergents and/or chemicals into the water stream as the custodial staff fills buckets or equipment. With-out the proper vacuum breaker on the faucet, it is very easy to draw the chemicals into the domestic water piping system.

Back-pressure situations arise when a pumping system is installed on the water system. As mentioned above in the case of the carwash, the discharge pressure of chemical or feed pumps often is higher than the domestic water system pressure. Another example of this type of potential contami-nation is a chemical treatment system for chilled water, heat-ing hot water, or steam systems.

HOW BACKFLOW PREVENTERS WORK

Air GapAir gaps are the perfect backflow preventers. Without pipes, you can’t have cross-connections. Air gaps are most commonly required for faucets, tank discharge, and break tanks. The plumbing codes generally require an air gap of at least two times the effective diameter of the discharging pipe above the flood rim of the fixture. For most fixtures, the flood rim is simply the lowest edge of the fixture. For


floor drains, it is generally the floor level, but the designer must be aware of sumps or similar areas where the floor drain is in a trench or in another area that could have a higher flood rim.

Reduced-pressure Principle Backflow PreventerThis type of device is generally abbreviated RPBP (reduced-pressure backflow preventer) or RPZ (reduced-pressure zone). RPBP devices have two spring-loaded check valves with an air vent between them (see Figure 1). This allows the device to protect against either back-siphonage or back-pressure situations, even upon failure of the check valves.

For example, in the case of back-siphonage and a failure of the first check valve, the air vent will open and allow air to flow into the water main in lieu of drawing water from down-

stream of the device. In the case of a back-pressure situ-ation, the device compares the pressure at the inlet to the pressure at the outlet. When the pressure at the outlet is higher or within 5 pounds per square inch gauge (psig) of the pressure at the inlet, the vent will open and allow water from the supply to flow out of the vent. Therefore, if the second check valve fails in a back-pressure situation, the backflow would also be out the vent. Note that anything that prevents either check valve from closing completely in a no-flow situ-ation will, by design, result in water flow out the vent.

Double-check Valve Assembly The double-check valve assembly simply has two swing check valves in series (see Figure 2). It does not have the same vent capabilities of the RPBP; thus, it can be used only for low-hazard applications. Low-hazard generally includes applications that do not involve chemicals.

Vacuum BreakerA vacuum breaker (see Figure 3) is allowed only in back-siphonage situations (or, in some cases, very low-head back-pressure situations). Vacuum breakers work by allowing air to be drawn into the device when the inlet is at a lower pressure than the outlet. You commonly see vacuum breakers on hose bibbs, mop sink faucets, and devices with hoses installed on them (e.g., bedpan washers and laboratory sinks).

Barometric LoopOne last concept of backflow prevention that is not used very often is the barometric loop (see Figure 4). This type of

backflow prevention can be used to prevent back-siphon-age when pumping water to an open storage vessel. As indi-cated in Figure 4, the piping system must include a change in elevation so the highest portion of the piping system is at least 35 feet above the flood level of the atmospheric tank.

How does this protect the public water supply? Think about the principle of drinking through a straw. Even with a perfect vacuum at the top of the straw, you can only draw water up to the height equal to atmospheric pressure, which is 14.92 psi or 34.5 feet of water.

In the application of a barometric loop, let’s assume that the water main on the left side of Figure 4 is 50 feet below the flood rim of the open vessel. If that water main suffered a break, water would start flowing out, lowering the pressure, and the system would try to pull water out of the tank. Since the only way to pull water out of the tank is to lower the pressure at the top of the “straw,” you end up with a pressure of zero at a point 34.5 feet above the flood rim. What happens when you expose water to a pressure of zero? It boils! Thus, the public water supply on the left side of the figure is protected by a bubble of steam that would form at 34.5 feet of elevation. The water cannot be pulled over the top of the loop.

WHERE DO WE INSTALL BACKFLOW PREVENTERS?Although the number of permutations for applications of backflow preventers is almost endless, there are some very specific rules about what type of device to install for generic types of hazards. The type of device depends totally on the type of hazard (back-siphonage and/or back-pres-sure) and what is happening downstream of the backflow preventer.

For connections to the public water supply, the following list should be followed:

Single- and two-family homes: None required•

Irrigation systems without chemical injection: Vacuum breaker•

Fire protection systems: Double-check valve assembly•

Every other connection, without exception: Reduced-pressure •

principle backflow preventer

For clarity, except for single- and two-family homes, all connections to the public water supply must be protected.

The decision to install simplex or duplex backflow preven-ters is based solely on whether the facility can be without water if the backflow preventer fails or during testing. Since testing is supposed to be done every year and it requires the backflow preventer to be taken out of service, facilities that can’t tolerate a loss of domestic water should be provided with duplex parallel backflow preventers.

For hazards that are internal to buildings, the rule of thumb is if chemicals and/or pumps are involved, use an air gap or a reduced-pressure principle device. Examples of these types of situations include the following:

In general, any nonpotable system requires an RPBP to protect •

the building’s occupants. Typical systems may include HVAC

makeup connections for steam, heating hot water, chilled water,

and/or process cooling systems; laboratory hot/cold water sys-

tems to comply with National Institutes of Health (NIH) or owner

For more information on backflow preventers, consult the following resources:

American Backflow Prevention Association: www.abpa.org

American Society of Sanitary Engineering: www.asse-plumbing.org

American Water Works Association: www.awwa.org

IAPMO Backflow Prevention Institute: www.iapmodwbp.org

U.S. Environmental Protection Agency Cross-Connection Control Manual: water.epa.gov/aboutow/ogwdw/upload/2003_04_09_crossconnection_crossconnection.pdf


requirements; and industrial applications that have tanks or

pumps as part of the process (remember the carwash).

Fire protection systems that use non-food-grade antifreeze com-•

pounds must be protected. (While the codes no longer allow

these compounds to be used, you might run across this situation

in an existing facility.)

If chemicals and/or pumps are not involved, then vacuum breakers are the way to go. The choice between an atmo-spheric vacuum breaker and a pressure-type unit depends on what is happening downstream of the device. If the discharge of the backflow preventer does not have restric-tions or shutoff valves, then an atmospheric type is okay. Examples of this include vacuum breakers on mop sink fau-cets, laboratory sinks, irrigation systems, fixtures with hoses that can drop into the water, and hose bibbs. If the discharge of the unit does have restrictions or shutoff valves, then a pressure vacuum breaker should be used. Examples of this include bedpan washers, spray hoses for commercial kitch-ens, and water service to equipment that does not include internal air gaps (remember the x-ray processor).

THINGS TO REMEMBER ABOUT BACKFLOW PREVENTIONFrom personal experience and from listening to war stories from those who have been taught lessons the hard way, I have created a list of several things the designer should keep in mind when dealing with backflow prevention. Recognize that this list does not include every problem ever discovered about designing proper backflow prevention, and it does not predict where future problems may occur.

First of all, any backflow preventer that is designed with a vent or a port that will allow air into the unit cannot be installed in a pit or on a device that can be flooded. This seems intuitive, but I cannot tell you how many times I have seen an RPBP installed on a below-grade valve or in a meter pit. If that pit is flooded at the same time a back-siphonage situation occurs, groundwater will be drawn into the water piping. The same is true of a vacuum breaker. Make sure that the backflow preventer can’t be flooded.

Further, backflow preventers are subject to freezing. In cold climates, it is tempting to locate them indoors (more on that later). Several manufacturers make enclosures that include an insulated shell and an internal heater, which works very well in most areas of the country. In milder cli-mates, the local authority may allow a non-freeze device that bleeds water out of the unit when the outdoor temperature approaches freezing. This is like cracking the hose bibb on your house on nights that are below freezing. If the local authority will not allow this, the only option is to locate the backflow preventer in a heated area.

Finally, the backflow preventer must be protected from debris that could prevent a check valve from closing. This is especially true with an RPBP, but I recommend putting a strainer in front of all RPBP and double-check valve assembly devices. This will keep construction debris and other material from blocking the first check valve.

The designer also must protect the building from the backflow preventer. For backflow preventers with a vent that are installed indoors, the engineer must accommodate the total flow from the vent in an upset condition. Check the manufacturer’s literature for the maximum flow rate when the vent is fully open. Putting a 6-inch RPBP in a basement with a 4-inch floor drain will result in flooding if the vent opens. Putting the same RPBP in a mechanical room with a 25-gallon-per-minute (gpm) sump pump will flood the sur-rounding area if the vent opens. (Yes, this was learned from personal experience!) Make sure the facility can dispose of the 300 to 400 gpm that will result from a failure.

Backflow preventers without a vent, such as double-check valve assemblies, do not cause this problem. As an option, most backflow preventer manufacturers have an option for a flow switch in the vent discharge drain. If this switch senses water flow, a control valve in front of the backflow preventer will close, thus preventing flooding.

The engineer also needs to remember that non-pressure-type vacuum breakers will sporadically spit water in normal use. Most of these types of non-pressure vacuum breakers are not designed for a shutoff valve downstream of the device. If a valve is required, it must be on the inlet side of the device (consult the manufacturer’s installation instruc-tions), so do not install one of these devices above a ceiling or in a finished space.

BACKFLOW PREVENTER MAINTENANCEThe last element is proper maintenance of backflow pre-venters. While it is not the responsibility of the designer to verify proper operation of backflow devices, it is their responsibility to require proper certification of the devices at the end of construction. Do not accept any closeout documents without proper certification of all backflow preventers on the project. If a leaking backflow preventer is found during an existing building survey, bring it to the owner’s attention. The leak probably indicates that some-thing is wrong with the device that will prevent it from working properly.

In conclusion, proper backflow prevention is essential to protecting the public water supply. Keeping chemicals, animal wastes, and debris from the potable water supply will save lives and improve health.

Raymond F. Parham, PE, is a plumbing/fire protection engineer with Moses & Associates. He has more than 25 years of experience in mechanical design and building construction and has been a registered Professional Mechanical Engineer since 1986 and a registered Fire Protection Engineer since 1999. For more information or to comment on this article, e-mail [email protected].

By daVid auerbach

Empowering Africa’s Poor with Sustainable Sanitation

Peer to Peer


Allow me to paint a picture of the slums of Kenya: 10 million people are packed into extremely dense quarters and typically live on less than $2 per day. In the largest slum, Kibera, 1 million people live in about 3 square kilometers—an area roughly the size of Central Park in New York City. Unemployment is a major problem—40 percent is the most commonly cited statistic. The violence in Kenya three years ago came from this demo-graphic: unemployed, bored, and frustrated young men. Apart from two major roads, the thoroughfares are dirt streets littered with all kinds of waste. No sewage infrastructure is available. For privacy, people resort to a practice known as “flying toilets,” in which they defecate into a plastic bag in their own home and then throw the bag away. Another option is to walk to one of the few scattered sanitation centers, which is not always a safe alternative, especially at night. The government has not invested in sanitation systems in these slums for more than 20 years simply because the slums are illegally settled upon; therefore, the government claims it has no obligation to provide municipal services.

Let me paint another picture of the slums: They are communities full of people determined to survive. These people often move to the outskirts of cities from rural areas in search of a better chance to support their families. Some of the communities have been settled for decades. In Kibera, more than 250 youth groups with 15 to 25 people per group, mostly men aged between 17 and 35 who have lived in the slums all of their lives, are working hard to turn their neighborhoods into thriving communities. Some of the most entrepreneurial and practical people I’ve ever met live there.

I am part of a team of students at the Massachusetts Institute of Technol-ogy (MIT) who have started a company, Sanergy, with the belief that the latter picture can and will trump the former. At the center of our work is the provision of adequate sanitation. We came together in September 2009 and tried to determine the obstacles to the sanitation question. The facts around sanitation in the developing world are startling: 2.6 billion people lack access to basic sanitation; 2 million children die every year due to diarrheal-related diseases; and 10 percent of the global disease burden is due to a lack of sani-tation. Kenya’s slums, 80 percent of which are without proper sanitation, are at the center of this crisis.

It was difficult to know where to start. Clearly, if the question were simply one of providing more toilets, plenty of governments and charities could do that. We settled on two hypotheses:


We must take a systems-based approach, •

from providing dignified, appealing sanitation

options, to encouraging people to use the

toilets, to collecting the waste, to disposing of

waste effectively.

We also believe that sanitation must be •

thought of as an opportunity to generate

income for the community, rather than a

development problem that simply needs to be

solved.

Viewed through these lenses, we developed a model that creates jobs, opportunity, renew-able energy, and fertilizer, while addressing serious social and economic needs.

Our first major step was to build an easy-to-manufacture sanitation facility with local materials. With a team of engineers and designers from MIT and Nairobi University, we developed a $200 modular hygienic toilet (see Figure 1) that is prefabricated with local materials, yet has the durability and aesthet-ics of a permanent structure. Because the slums rarely have a sewage infrastructure, we built dry toilets. Each one of these toilets can be deployed on every block of housing, so approximately 15 families have ready access to sanitation a stone’s throw away.

The waste from an installed toilet diverts into two barrels, one for urine and one for feces. The barrels, which hold approximately 30 liters of waste (about 100 uses), are double-sealed to protect people from the

waste. Every day, a network of waste collec-tors retrieves the barrels using handcarts and wagons. This is an important step because, at present, it costs $200 for a dump truck to come into the slums to remove waste. The waste is taken to a centralized facility where it is converted into electricity and organic fertilizer, which helps address East Africa’s energy shortage and poor crop yields (see Figure 2).

However, to do all of this, we needed to build a network of sanitation operators in the slums. This is where the youth groups get involved. We have partnered with a non-profit called Carolina for Kibera, which was started a decade ago by University of North Carolina students and has done tremendous community development work in the slums. Through this partnership, we can identify youth groups to own (as a franchise partner) and operate the sanitation facilities. The low cost of each toilet means that the youths are able to access microfinance loans to finance the construction of the facility.

The youths operate the toilets as a for-profit business, charging small member-ship fees to users, selling complementary products and services, and selling ad space in the toilets (a truly captive audience!). In exchange, users gain access to a clean, safe, private toilet. (In the future, we aim to design a low-flow hot shower as an amenity.)

We believe that these youths have the abil-ity to attract and incentivize the local com-munity to use the toilets. They are far more effective salespeople for that community than we ever could hope to be.

We plan to scale our operations to 30 toilets this year and then to 660 toilets the following year. In time, if we are successful, we will be able to provide power for approxi-mately 10,000 homes in Kenya and 18,902 metric tons of organic fertilizer. At the same time, the provision of sanitation facilities will help cut down the incidence of diarrhea by 30 percent.

While at the 2010 ASPE Convention in Philadelphia last fall, I was struck by the number of ASPE members who said that regular people think plumbing engineers simply repair leaky faucets. It is our hope that the work of Sanergy demonstrates not only how critical the provision of adequate sanitation is to our daily lives, but also how it has the power to begin to change entire communities. Of course, we cannot do this alone, and we are always on the lookout for partners in our plumbing engineering com-munity.

David Auerbach is the co-founder of Sanergy, a graduate student at MIT’s Sloan School of Management, and a student member of ASPE. He can be reached at [email protected]. To comment on this article, e-mail [email protected].

Figure 1 Modular dry toilet Figure 2 Sustainable sanitation cycle


taking aSPe for grantedWILLIAM F. HUGHES JR., CPD, LEED AP, FASPE, 2010-2012 ASPE PRESIDENT

Over the years, I have heard many people question the value of ASPE, such as “What does being an ASPE member do for me?” and “Why should I become a member of ASPE? What is the value of being a member?”

With life moving at a fast pace and business as usual, we sometimes take things for granted. I, for one, know that I did. However, last year I was one of the many ASPE mem-bers who lost their job due to the economy. After 41 years of working for my previous employer, I was laid off due to a lack of work. With no new potential projects on the horizon, the fi rm could not even begin to guess when things would turn around. I found myself in a situation in which I never expected to be so late in my career.

What do I do? Where do I turn? Th ese are just some of the many questions I asked myself.

Shortly after being laid off , I received my copy of the Boston Chapter newsletter, and I then started to realize many of the values of being an ASPE member that I have taken for granted over the years. I realized that ASPE isn’t just about education on the latest feats of engineering and new technol-ogy relating to our fi eld. It is an organization that cares about its members’ livelihoods. One example is the Compassionate Dues Waiver program. Th anks to this program, I did not have to choose between paying my dues and paying my bills while I was unemployed.

A few years ago, the Boston Chapter announced that meals at monthly chapter meetings would be free for retired mem-bers and for unemployed members. When I fi rst heard this, I thought it was a great idea. It ensured that members in times of need did not miss out on the valuable information, net-working, and camaraderie at chapter meetings due to their current circumstances.

Th ese monthly dinner meetings were something I took for granted. I always attended the meetings on the second week of the month—sometimes not even knowing what the topic was. I just left my offi ce at 4 p.m., and then it was ASPE time until the meeting ended.

Last September, however, I didn’t leave my offi ce. I left my house. Walking into the meeting that night, I was instantly reminded of one of our greatest member benefi ts: networking. Th e bonds and friendships that I developed over the years with the individuals attending chapter meetings never felt more important to me than on that night. It was a time of need for me, and seeing those familiar faces, hearing them express their concern, and learning that they would let me know of

From the President’s Pen

www.aspe.org

ASP

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PORT

any job openings was a great feeling. Th e number of contacts I made at just this one meeting was a confi dence booster.

Over the years I had taken networking and being an ASPE member for granted, but I suddenly realized that this opportunity would not have happened if I had not become a member of ASPE. Being involved in your local chapter further increases these special bonds and relationships. Members who do not take advantage of these types of oppor-tunities cause the board of directors much frustration.

Th e experience of writing my resume revealed several more additional values of ASPE that I had been taking for granted. By listing all of my experiences with ASPE, my resume off ered many signs of personal commitment to a potential employer.

Th e fi rst item was the CPD after my name. Th is was one of the requirements for employment listed by several of the fi rms looking to hire plumbing engineers. After writing it thousands of times as part of my signature and taking it for granted, I fi nally saw its additional value—not only in the knowledge I gained from taking the test, but also for continu-ing with the recertifi cation process.

Other benefi ts of being an ASPE member that I included on my resume were the positions I have held on the chapter and national levels, the many educational programs pro-vided by ASPE that increased my knowledge, and the ASPE committees in which I have been involved or chaired.

Following the resume process, the next step was going on interviews, which also enlightened me about the value of having the CPD after my name. At the fi rm for which I am currently working, the CPD designation and its recertifi cation are important because they show that employees want to stay current with the most up-to-date information, changes in technology, and the development of new products.

My current fi rm also placed a great value on the Plumb-ing Engineering Design Handbook as a valuable tool for its staff —another member benefi t that I think we all take for granted. ASPE has developed many programs and publica-tions that we as a group often take for granted or do not value, but remember that they are there for you when you need them.

With the CPD exam taking place next month, now is an excellent time to take advantage of one of the many values of ASPE. It can only enhance you career. Who knows? You might learn something.

In the past, compliant and substandard couplings looked very similar.Now NSF® Certification makes it easy to tell the difference.

NSF-Certified couplings meet all industry standards.The NSF mark is proof of full compliance.

Anaco’s legendary quality is verified.Insist on NSF and Anaco.

Standing the test of time

www.aspe.org

ASP

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PORT


the aSPe Family —a Sometimes Forgotten Value

JIM KENDZEL, CAE, ASPE EXECUTIVE DIRECTOR

As I sit down to write this column, I have offi cially been the executive director/CEO of ASPE for 50 days. In that short time I have had the pleasure of participating in an ASPE board meeting as well as speaking to many members and chapter leaders. I would like to thank all of you who reached out to welcome me to ASPE and also thank all of those who took the time to discuss ASPE with me—its past, present, and future. Your candor, openness, and dedication to ASPE are greatly appreciated.

Th e Society recently lost a long-time devoted member of the ASPE family: Past President William P. Schaefer, PE, FASPE. In notifying ASPE leaders, both past and present, of Bill’s passing, I naturally referred to it in the context of ASPE losing a family member. When I received responses to my notice, it became evident that the word “family” was appro-priate. Th is led me to think about what family represents.

Since coming on board with ASPE, I have been trying to fi nd the right phrases, taglines, etc. to defi ne the value of ASPE and market that value to current and potential mem-bers. What automatically comes to mind are such services as professional development, certifi cation, technical publica-tions, and networking. I have to be honest in acknowledging that the concept of joining a family is seldom a value that comes to mind when I think of a society or association. As I ponder this concept, however, I realize that it could be one of the most signifi cant values one can gain by joining and participating in ASPE activities.

As I thought further about the contact I have had with ASPE members in the last 50 days, it became clear to me that family (although the actual word may not be used in discus-sion) is a very signifi cant value that members derive from the Society. We may use the more formal term “networking;” however, when you peel back the layers, what you realize is that our members may join ASPE for professional develop-ment or other tangible benefi ts, but over time what they truly grasp and grow into is the understanding that involvement in their professional society leads to so much more, includ-ing shared experiences, life-long friendships, and extended families.

I thought it might be helpful to look at some defi nitions of “society” to see if there is connection with the word “family”

From the Executive’s Desk

to further support my premise. Wikipedia provides the fol-lowing defi nition for society:

A group of people related to each other through persistent rela-•

tions such as social status, roles, and social networks

Webster’s Dictionary (for those traditionalists among us) provides the following:

A highly structured system of human organization for large-scale •

community living that normally furnishes protection, continuity,

security, and a national identity for its members

Th ese defi nitions contain some powerful phrases, includ-ing related, persistent relations, protection, continuity, secu-rity, and national identity. All of these represent value that is oftentimes diffi cult to measure or put into fi nancial terms when considering joining or maintaining membership with ASPE.

Of course, as we all know, along with the positive values of family are also the inherent negative aspects, including confl ict, miscommunications, breakups, etc. When you bring individuals who are passionate about their profession into a family of others who are just as passionate, disagreements and confl ict will occur. As with any healthy family setting, it is important to work through these issues in an open and transparent manner for the good of the family unit or society.

Th e good news is that everyone I have had the opportunity to speak with, including board members, chapter presidents, members, and staff , has expressed a great passion and hope for the long-term success of ASPE. As an executive director/CEO, I cannot ask for a greater gift than the one I have found in the true excitement and optimism of the ASPE member-ship. I have no doubt that, as with any family, ASPE will experience rough times along the way, and tough decisions will need to be made that may not satisfy all of the ASPE family. With such a strong core passion for who we are as a Society, I am confi dent that we will be able to come through those rough times even stronger than before and continue to move forward for the true benefi t of the plumbing engineer-ing profession.

On behalf of the entire ASPE membership, I pass along our deepest sympathy and prayers to the Schaefer family and also the knowledge that you will always be a part of our family. Our support is only a phone call away.


Welcome to all new Society members. When you choose a chapter affi liation, you have twice the advantage. not only can you be involved at the national level, you also can participate in chapter functions and programs. to all members, old and new, this is your Society. your involvement enhances the plumbing engineering fi eld as well as aSPe. Suggestions about how to make your Society more benefi cial to both fellow members and all involved in the industry are welcome.

new aSPe members

alabama chapternelson randolph Wesley douglas Sherer, Pe

baltimore chapterJames Steven Watkeys

boston chapterStephen david byron timothy John gillis cedric m. mukania, ge nathaniel Sharpe donald Scott tauer

british columbia chapterJohnathan Paul lea cannata dean conte lei Zhang

central Florida chapternathan michael hutchings mark r. Penoyar

central texas chaptereric lane

charlotte chaptermatthew Pesce, Pe daniel bryan Williams

chicago chapterthomas William buchanan daniel Paul cole andy cornell James g. Kendzel, mPh, cae david lynam

dallas/Ft. Worth chapterJack r. Stringer

denver chaptermarc d. graham, Pe Jack r. Smith

eastern michigan chapterthomas alec climie

houston chapterJoseph barrile randy Willis

Johnstown chaptermike Shaffer

los angeles chapteremil Jocson balceta, ge

member at large Stuart ryan degray hugh Staiger, Pe george randall Wandling, Pe

miami chaptermiguel esteban gonzalez, Pe

minnesota chaptergreg Korpi

montreal chaptercarlo giurini alexandre lupien denis martin Jacques Sasseville

new Jersey chaptergregory thomas Zimmerman

new orleans chapterryan Joseph torres

new york city chapterchris cardona christopher leong, Pe michael J. lonigro, Pe, ge

northern california chapterJaime Zaldivar, ge

omaha chaptertodd anthony bentzen cecily haggerty, ge layne andrew micek

orange county chapterJim cutter dindo Vicencio, Pe

overseas chaptermoataz mohamed abd el-latif,

ge yasser amer ahmed, ge ahmed abdelwahab atteya, ge mohammed el amin ahmed

hassanain, ge

Philadelphia chaptermark louis daniszewski, ge

Phoenix chapterrichard Sindair

Portland chaptereric marc ranger

Quebec chapterbastien thibault

raleigh chapterKendrick bedford cross michael P. dixon Jr., Pe

richmond chapterbenjamin doyle, ge melissa durrant Jason Weir, Pe

Seattle chapterthomas John hagensen harold Wayne Seale daniel Sung, Pe robert J. trebon

Southern nevada chapterrichard andrew ballard drew miller michael roscoe

St. louis chapterJohn g. benz rick bradbury

Washington, d.c., chapterhong niu

Western michigan chapterKevin Wendell moore

Past aSPe President and aSPe Fellow Passes away

aSPe charters its 62nd chapter: long islandexpansion in the northeast brings more networking and educational opportunities to area Plumbing engineers

Society News

Th e ASPE board of directors has approved a petition for char-ter to establish the Society’s 62nd North American chapter in Long Island, New York. Th e chapter’s board of directors is:

• President: Paul Freeman, PE• Vice President Membership/Legislative: Vincent

Falkowski, PE

• Vice President Technical/Education: Ed Hopkins, PE• Treasurer: Jon Ross• Affi liate Liaison: Mike Finnegan“Now the Long Island community has a local way to meet,

communicate, educate, and unite members of the plumbing industry,” says Long Island Chapter President Paul Freeman.

William P. Schaefer, PE, FASPE, of Syracuse, New York, a member of the Central New York Chapter, an ASPE board member from 1980–1990, and president of ASPE from

1988–1990, passed away on January 22. ASPE sends its con-dolences to the Schaefer family and to those who knew and worked with Bill during his long career.

34 Plumbing Systems & Design MARCH 2011

CONTINUING EDUCATION: Sanitary Drainage Systems

About This Issue’s Article

PSd

175

continuing education from Plumbing Systems & Design

ce Questions — “Sanitary drainage Systems” (PSd 175)The ultimate vertical speed a sheet of water attains while 1. falling down a stack is ________.

terminal lengtha. terminal velocityb. frictional velocityc. hydraulic jumpd.

________ is a phenomenon in which 2. water flowing along a building drain and sewer decreases slowly and then increases suddenly as the depth of flow increases and completely fills the cross-section of the drain.

terminal lengtha. terminal velocityb. frictional velocityc. hydraulic jumpd.

What is the residential drainage fixture unit load for a 1.6-gpf 3. gravity tank toilet?

2a. 3b. 4c. 5d.

1,200 fixture units require what size stack?4. 4 inchesa. 5 inchesb. 6 inchesc. 8 inchesd.

Which of the following is commonly used to compute flow in 5. piping?

hazen-Williams formulaa. darcy-Weisbach formulab. manning formulac. all of the aboved.

The minimum slope for a 2-inch horizontal drainage pipe is ____.6. 1/4 inch per foota. 1/8 inch per footb. 1/16 inch per footc. none of the aboved.

A typical ejector pump installation includes a ________.7. floata. companion flangeb. check valvec. all of the aboved.

A cleanout should be provided at every change of direction 8. greater than ________ degrees.

30a. 45b. 60c. 90d.

A small amount of ________ can be used to prevent the 9. evaporation of the water seal in an infrequently used drain.

greasea. vegetable oilb. peanut butterc. glued.

Which of the following is a type of cleanout outlet?10. no-huba. spigotb. inside caulkc. all of the aboved.

________ provides excellent corrosion resistance in domestic 11. sewage drainage systems.

cast irona. galvanized steelb. concretec. clayd.

The Sovent system uses what type of pipe material?12. coppera. cast ironb. PVcc. both a and bd.

Do you find it difficult to obtain continuing education units (CEUs)? Through this special section in every issue of PS&D, ASPE can help you accumulate the CEUs required for maintaining your Certified in Plumb-ing Design (CPD) status.

now online!The technical article you must read to complete the exam is located at www.psdmagazine.org. Just click on “Continuing Education” at the top of the page. The following exam and application form also may be down-loaded from the website. Reading the article and completing the form will allow you to apply to ASPE for CEU credit. If you earn a grade of 90 percent or higher on the test, you will be notified that you have logged 0.1 CEU, which can be applied toward CPD renewal or numerous regulatory-agency CE programs. (Please note that it is your responsibility to determine the acceptance policy of a particular agency.) CEU information will be kept on file at the ASPE office for three years.Note: In determining your answers to the CE questions, use only the material pre-

sented in the corresponding continuing education article. Using information from

other materials may result in a wrong answer.

the march 2011 continuing education article is “Sanitary drainage Systems,” chapter 1 from Plumbing Engineering Design Handbook, Volume 2.

the purpose of a sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment to an approved point of disposal. this chapter discusses the components of drain and waste systems (hori-zontal branches, vertical stacks, building drains, and build-ing sewers) and how to design a system according to the applicable code to carry away soiled water from individual fixtures rapidly without clogging the pipes, leaving solids in the piping, generating excessive pneumatic pressures at points where the fixture drains connect to the stack, or creating undue noise.

you may locate this article at psdmagazine.org. read the article, complete the following exam, and submit your an-swer sheet to the aSPe office to potentially receive 0.1 ceu.

WWW.PSDMAGAZINE.ORG


PS&D Continuing Education Answer SheetSanitary Drainage Systems (PSD 175)

Questions appear on page 34. Circle the answer to each question.

Q 1. A B C D Q 2. A B C D Q 3. A B C D Q 4. A B C D Q 5. A B C D Q 6. A B C D Q 7. A B C D Q 8. A B C D Q 9. A B C D Q 10. A B C D Q 11. A B C D Q 12. A B C D

Plumbing Systems & Design continuing education application FormThis form is valid up to one year from date of publication. The PS&D Continuing Education program is approved by ASPE for up to one contact hour (0.1 CEU) of credit per article. Participants who earn a passing score (90 percent) on the CE questions will receive a letter or certification within 30 days of ASPE’s receipt of the application form. (No special certificates will be issued.) Participants who fail and wish to retake the test should resubmit the form along with an additional fee (if required).1. Photocopy this form or download it from www.psdmagazine.org.2. Print or type your name and address. Be sure to place your ASPE membership number in the appropriate space.3. Answer the multiple-choice continuing education (CE) questions based on the corresponding article found on

www.psdmagazine.org and the appraisal questions on this form.4. Submit this form with payment ($35 for nonmembers of ASPE) if required by check or money order made payable to ASPE or credit

card via mail (ASPE Education Credit, 2980 S. River Road, Des Plaines, IL 60018) or fax (847-296-2963).

Please print or type; this information will be used to process your credits.

Name ________________________________________________________________________________________________________

Title _________________________________________________ ASPE Membership No. ____________________________________

Organization __________________________________________________________________________________________________

Billing Address ________________________________________________________________________________________________

City _________________________________________ State/Province ________________________ Zip ______________________

Country ______________________________________________ E-mail _________________________________________________

Daytime telephone ____________________________________ Fax ____________________________________________________

PE State _____________________________________________ PE No. _________________________________________________

Appraisal QuestionsSanitary Drainage Systems (PSD 175)

1. Was the material new information for you? ❏ Yes ❏ No

2. Was the material presented clearly? ❏ Yes ❏ No

3. Was the material adequately covered? ❏ Yes ❏ No

4. Did the content help you achieve the stated objectives? ❏ Yes ❏ No

5. Did the CE questions help you identify specific ways to use ideas presented in the article? ❏ Yes ❏ No

6. How much time did you need to complete the CE offering (i.e., to read the article and answer the post-test questions)?

I am applying for the following continuing education credits:

I certify that I have read the article indicated above.

Signature

Expiration date: Continuing education credit will be givenfor this examination through March 31, 2012.

Applications received after that date will not be processed.

❏ ASPE Member ❏ NonmemberEach examination: $25 Each examination: $35Limited Time: No Cost to ASPE Member

Payment: ❏ Personal Check (payable to ASPE) $❏ Business or government check $❏ DiscoverCard ❏ VISA ❏ MasterCard ❏ AMEX $

If rebilling of a credit card charge is necessary, a $25 processing fee will be charged.ASPE is hereby authorized to charge my CE examination fee to my credit card

Account Number Expiration date

Signature Cardholder’s name (Please print)


claSSiFiedS/adVertiSerS indeX

ADvERTISERS INDExAnaco ........................................................... 31

www.abifoundry.comArmstrong .................................................... IFC

www.armstronginternational.comBradford White .............................................. 17

www.bradfordwhite.comBradley ...........................................................5

www.bradleycorp.com/halo2011CISPI ............................................................ BC

www.cispi.orgDelta ..............................................................1

www.deltafaucet.com/professionalsGuardian ....................................................... 23

www.gesafety.com/revitHoeptner ........................................................4

www.freezeflow.comIAPMO .........................................................IBC

www.iapmo.orgKusel Equipment ........................................... 25

www.kuselequipment.comLiberty Pumps ............................................... 36

www.libertypumps.comSchier Products ............................................. 19

www.schierproducts.com/greatbasin.htmlZoeller ............................................................3

www.zoeller.com

Looking to Fill a Position?

Recruitment Advertising WorksPlace your ad into ASPE’s

Plumbing Systems & Design

Call 847.296.0002

University Mechanical Contractors, Inc. is seeking Commercial and Industrial Project

Managers for work in the Seattle area:Commercial Project Manager with a minimum of 15 years experience managing the self-performance of large ($20mm+) commercial mechanical contracting projects (HVAC/piping/plumbing/med gas). Hospital and data center project experience preferred. Salary range: $90-$115,000

Industrial Project Manager with a minimum of 10 years experience managing the self-performance of large industrial mechanical contracting projects. Wastewater treatment plant experience preferred. Salary range: $75-$100,000

Locally owned and operated (Mukilteo WA), University Mechanical Contractors, Inc. designs and builds complete mechanical systems for commercial and industrial projects. With over 90 years of experience, UMC is one of the largest mechanical contractors in Washington State, having performed commercial and industrial work in Oregon, Alaska, Nevada, California, and Hawaii. UMC has an excellent benefit package including medical/ dental/ vision/ life insurance coverage and 401K match. University Mechanical Contractors, Inc. is a Drug Free Workplace and an Affirmative Action, Equal Opportunity Employer. Learn about UMC at www.umci.com.

Email resume to [email protected]. Please reference this ASPE ad.

Need ENERGY STAR®

Certification?Manufacturers wishing to promote the energy-saving benefits of their products by labeling them as ENERGY STAR® qualified can apply to do so through IAPMO R&T, long recognized as a leader in third-party certification for its efficiency and commitment to customer service.

Energy Star Ad.indd 1 2/3/11 11:07:35 AM

NSF recently approved a new coupling inspection program in accordance with the current edition of CISPI 310. It holds couplings to the same level of rigorous standards as NSF Certified cast iron pipe and fittings. So look for the NSF Mark when choosing your next coupling to make sure your complete pipe system meets NSF Certification.

For more information go to www.nsf.org or www.cispi.org

Complete peace of mind comes with a system

that’s completely NSF Certified.

62675 CPF PS&D.indd 1 2/7/11 2:00 PM

WITH NSF 61 - ASPE · [email protected] PUBLISHER American Society of Plumbing Engineers...

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