Cryogenic Liquid Manifold- Application Guide

8/3/2019 Cryogenic Liquid Manifold- Application Guide

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Cryogenic Liquid Manifolds

Applications Guide

Continuing Education Publication


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Wondering how to keep informed aboutchanges in medical gas?

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Cryogenic Liquid Manifolds Applications Guide3

Notes on Using this Book:

This book is presented as a service to users of cryogenic gas liquid manifolds to assist in understanding thesedeceptively simple devices.

Third Edition November 2010Replaces an earlier edition dated February 2005

Notes

This book in both print and electronic versions is Copyright 2010 BeaconMedaes and Mark Allen. All Rights areReserved, and no reproduction may be made of the whole or any part without permission in writing. Distributionof the Electronic version is permitted only where the whole is transmitted without alteration, including this notice.

Comments on this book or on any aspect of medical gases are welcome and encouraged.Please send to [email protected]


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4Cryogenic Liquid Manifolds Applications Guide

Contents

Table of Contents

Introduction 5Some terms used in this booklet.

Liquid, glorious liquid 5

What makes liquid a good choice for manyfacilities?

What is cryogenic liquid 5The basics of cryogenic liquid gases. What theyare and how they act.Cylinders versus Containers 6How cryogenic liquids are stored and how theircontainers behave.

The unexpected 9

Why liquid manifolds sometimes dont seemto work as expected.

When is a liquid manifold not a good idea .. 12The limits to liquid manifolds.

Other Options 13The limits to liquid manifolds.

Annexes

Annex A 14Container DataRepresentative data on containers and cylinders.

Annex B 15Safe work practicesWorking with cryogenic containers and cryo-gens require some special practices.

Annex C 17Alarms and Alarm ResponseWith a liquid manifold comes some extra

alarms and some extra actions when theyring.

Annex D 19A Typical Liquid Manifold RoomAn example layout of a typical manifoldroom.

Annex E 21DimensionsThe dimensions necessary to lay out amanifold.

Annex F 24SignageThese are the signs required to be posted onthe door of a manifold room.

Annex G 28Oxygen Depletion MonitoringInformation about these safety monitoringdevices and conned space rules.

Annex H 30

Using Bulk and MiniBulk Sources with theLifeline ManifoldImplementation of the Lifeline manifold as abulk station control is very feasible. Here aresome guidelines to be observed.

Annex I 32Manifolds located outdoorsThis is the NFPA 50 Table referenced in NFPA99.

Annex J 33Sizing a ManifoldData here will allow the selection of a manifoldbased on type and size.


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Introduction

Introduction

This booklet is intended to help the user or specierof a liquid manifold and to a lesser extent a bulk gassystem understand how that system works and whatare some of the pitfalls of using one.

In this booklet we will use NFPA parlance for Cylinders(meaning high pressure cylinders containing gas) andContainers (meaning a cryogenic liquid containercontaining liqueed gas at supercold temperatures).We will also speak of the Primary header as the one inservice, the Secondary header as the one on standby,and the Reserve Header as the one which will servethe system only if both the primary and secondaryrun empty.Liquid, glorious liquid

Medical facilities are always searching for ways to save

money. One of those golden opportunities may befound by installing or converting to liquid manifoldsfor some of the gas delivery systems.

Liquid manifolds are very attractive for two simplereasons: Liquid is much less expensive to purchase than gasin cylinders (in most localities) when calculated ona volume of gas basis. The potential savings can beconsiderable. Although portable liquid containers are individuallyheavy, each one may contain as much gas as 17-25

cylinders. The labor involved with changing a coupleof liquid containers is nothing when contrasted withchanging that many cylinders.

To give an example, one facility reported their costs fora cylinder of nitrogen to be $6.50. They paid $2.30 permonth for demurrage (rental) on a cylinder. A containerof liquid nitrogen cost them $51.05, and demurragewas $25.00 per month. Although the liquid containeris clearly more expensive, it contained 21.5 times asmuch gas equivalent as the gas cylinder. The liquidcontainer must also be changed less often, saving labor.The facility used a $10.00/hour labor rate. So for this

facility, a cubic foot of gas delivered from cylinders costapproximately 2.8 cents. A cubic foot of gas deliveredby liquid costs 1 cent. Thats a big savings.

At this rate, the facility estimated a cost of $4,312 forthis gas per year for the manifold. With a liquid system,they could cut this to $2,018, saving 53% or $2,294.Replacing the manifold cost about $6,000, so it waseasily within the 3 year payback required.

Liquid is an option for oxygen, nitrogen, nitrous oxide,

carbon dioxide, and argon systems. Taken together, thetotal savings can be very interesting indeed.

Many facilities realize these savings and operate theirliquid manifolds with little trouble, but others ndthem frustrating to operate and the cost savings elusiveor invisible. The facility who actually loses money on

a liquid conversion is not unheard of either. What isthe secret?

Cryogenic liquid containers, unlike cylinders, takemore management than simply changing the empties.Under the best of circumstances (when the container isclean and new) they will perform pretty close to theirspecied limits, but even then they do have limits.When one is used to dealing with cylinders, whichare quite straightforward, containers can come as asurprise. They can seem cranky, uneven, and wasteful.When a container is old and has suered the travails oftransportation, being dropped o trucks and handcarts,

and being generally maltreated, these symptoms canbe greatly exaggerated.

Facilities who succeed with liquid systems understandhow the containers work and that they need tobe managed to be at their best. They are howeverreasonably intuitive if you understand how cryogenicliquids behave.

What is cryogenic liquid

In accordance with the laws of materials, almost

every material will vaporize into a gas above sometemperature, and cooled below that temperature willbe a liquid. Medical gases are typically in the vaporstate at standard room temperatures but behave inevery respect in accordance with these rules.

So, if for instance we cool standard air, we should beable to change it from a gas to a liquid. And so wecan - but we have to cool it quite a lot - to minus 194degrees C (minus 318 degrees F). Because the productis at such extremely low temperatures, it is referred toas a cryogenic liquid.

Cooling air to minus 194 degrees C oers a challengeand an opportunity. Oxygen (which is about 21% ofstandard air) liquees at minus 182 degrees C, andnitrogen (78% of standard air) liquees at minus 196degrees C.

Keeping air mixed as a liquid is a problem if youwant liquid air but an opportunity if you only wantliquid oxygen or liquid nitrogen. Careful control ofthe temperature allows air to be separated into itsconstituent gases. This is how almost all oxygen or


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Cylinders vs. Containers

nitrogen used in a medical facility is produced.

Cylinder gas is typically that same liqueed gas allowedto warm back into vapor state and packaged in cylinders.

A cubic meter of oxygen gas (equivalent to 1,000 liters or35.3 cubic feet) at 70F and 1 atmosphere pressure will

occupy a cube 1 meter (3 feet) on each side. Pressurizedin a cylinder to 2,200 psig, the same gas will occupy 6.6liters or a space 188 millimeters on each side. Cooledto liquid state, the same amount of gas will occupy1.16 liters, or a cube 105 millimeters on a side. Thisdierence means that for the same size of container wecan store 1.8 times as much gas.

However, since cryogenic liquids can be stored at lowpressures, the containers do not need to be as strong,and thus can be made in much larger capacities. Oneexample of a small liquid container will hold about114,000 liters of gas equivalent, and large ones can run

into millions of liters. By comparison, a typical cylinderused on a medical system is capable of storing about6,700 liters of usable gas.

Holding more, the containers need to be changed lessoften, resulting in labor savings.

Containers holding cryogenic liquids are thus a superbway to store gases in volume. However, there are limitson the eective use of containers, which we will discussbelow.

Cylinders versus Containers

While safely storing gas in cylinders at 2,200 psig (andsometimes higher pressures) is not a trivial matter,safely storing and transporting a cryogenic liquidat these incredibly low temperatures is even morechallenging. Cryogenic containers are specificallydesigned for two functions: To safely insulate the cryogenic liquid and ensure

the user is largely protected from the extreme cold.This allows the liquid to be transported and stored.

To allow the user to withdraw the liquid either as

liquid or as gas for use.

Guage

Relief Valve

and Burst Disc

Fill Line &Liquid Tap

Vent

Gas Tap

Contents indicator

Pressure Builder Valve

Pressure Building Regulator

OuterVessel

Detail 6A Representative Portable Liquid Container

(Note: Containers vary in detail)


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To explain the basics of how these containers operate,we can look at a typical portable container as mightbe used with a Lifeline liquid manifold. This examplestands about 160 cm (62 inches) tall and is about 50cm (20 inches) in diameter. It contains some 180 litersof cryogenic liquid when full. Although we have chosento illustrate this particular container, all cryogenic

containers are similar and all have the basic itemsdescribed here, although details of construction varygreatly. (Please refer to Detail 6 and 7)

A tour through a cryogenic container must begin withthe vessel which will actually hold the liquid. Typicallymade of stainless steel, this inner vessel is placed insideof another vessel. The outer vessel is what yourelooking at when you see a cryogenic container.

If a cryogenic liquid is exposed to temperatures higherthan the boiling point of the cryogenic liquid, it willvery rapidly and possibly explosively convert into gas.

Preventing this heat leakage is critical to the eectiveuse of any container. To minimize heat leakage,

between the inner and outer vessels there is usuallysome form of insulation. Equally or more importantthe space between the two is evacuated to a very deepvacuum. Given the extreme temperature dierencebetween the inner and outer vessels, every moleculeleft in the space will transmit heat and increase the heatleak rate. The absence of anything which can conduct

heat between the vessels is essential in building afunctional cryogenic container.

Now with the two vessels in place and insulated, therst concern is to get the liquid into the inner vessel.For this, a Fill connection is typically run to the bottomof the inner container. This line can then be used bothas a ll line and a liquid withdrawal line.

To ll the container, you must resolve the basic physicswhich say you cant put something in without takingsomething out. (In the case of a liquid container, thisis something of an oversimplication, since it is actually

possible to ll the container by manipulation of theinterior temperature, actually using the cryogenic

Gas Tap

OuterVessel

Detail 7Inside a Representative Portable Liquid Container

(Note: Containers vary in detail)

InnerVessel

Internal Vaporizer

Pressure Builder

Pressure BuilderDischarge

Fill and Liquid Line

Vent Line

Note that the container is shown full ofliquid in this illustration. The color is notintended to be accurate.


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of the internal vaporizer and thus change to gas andexpand. That gas is then returned to the top of theinner vessel (the headspace) where it provides thenecessary volume and pressure to push out more liquid.The amount of gas made by this pressure buildingcircuit is determined by a special kind of regulatorwhich maintains the pressure of the headspace (the

space between the top of the vessel and the liquid).

It is very typical for the pressure builder, the internalvaporizer and the gas connection to be interconnected.This allows excess pressure in the headspace to bedrawn o and used, which is particularly importantwhen usage is low. The circuit functions so that ifthe headspace pressure rises, any gas drawn fromthe container comes rst from the headspace. Oncedemand exceeds the NER for the container and theheadspace pressure falls, the pressure builder willattempt to satisfy the demand. If the demand exceedsthe output of the pressure builder (which has quite

limited vaporization capacity), liquid will be drawninto the internal vaporizer and converted to gas there.

On any liquid container one can nd these same basicelements, albeit with variations suited to the capacityof the system. For example, on portable containers,the pressure builders vaporizer is mostly internal,on a bulk station it is usually external and can oftenbe seen on the bottom of the vessel. Large vesselsusually have a clearly labelled Top Fill and Bottom

liquid to condense the gas internally and reduce theinternal pressure by that means. This manipulationis an important step in lling large containers and isa one of the few dierences between small and largecontainers. Large containers will have separate top lland bottom ll connections to facilitate this.) A methodfor allowing something out is provided in the form of

a vent connection. To ll the container, open the ventand pump in the liquid, then close the vent. Simplyby making the vent tube a specic length, one can alsoprevent overlling the container.

Once liquid is in the inner vessel, the question of heatleakage arises. Since no insulation can be perfect, evena closed container will gradually boil o liquid to gas.The rate at which this happens is called the NormalEvaporation Rate (NER) for the container. Over time,the NER will cause the internal pressure to increase.Eventually, this gas must vent or the container willexplode. Two devices are installed to handle this: a

safety relief valve and a burst disc. The relief valve willopen and close at its set pressure to vent o excess gas.Should the relief valve fail or not be able to handlethe volume (as sometimes happens if the insulatingvacuum is lost), the burst disc will blow out and ventthe pressure.

Now with liquid inside the container, there needs tobe a way to draw gas o for use. This could of coursebe accomplished by drawing liquid through the ll lineas mentioned earlier. However, since what comes outof the liquid tap is a very, very cold liquid, it needs to

be converted to a gas before its usable.

External vaporizers are typically used with largercontainers and installations demanding large outputs(bulk gas installations are of this type). Externalvaporizers can also be used with portable containersunder some circumstances.

However, smaller containers also have a vaporizerinside the container. This allows a gas connection tobe provided on the container. This internal vaporizeris essentially a tube tacked to the inside of the externalvessel. It pulls heat from the outer skin of the container

and uses that heat to convert the liquid to gas.

There is one further basic physics challenge to usingliquid containers, and that is that you cannot drawliquid out of a closed container without replacing it withsomething. One could of course open the vent line, butthat would admit air and contaminate the gas insidethe container. Clearly that would be inappropriate, soinstead we rely on the fact that a little liquid makes alot of gas. Some liquid is drawn from the bottom of theinner vessel, allowed to pass through a small version


About the Normal Evaporation Rate (NER)

The NER for liquid containers will vary a great deal.In all the examples we have used an NER of 1.5% fornew and clean containers, but in fact this rate is notxed and is often very much higher. NER for a givencontainer will vary depending on several factors includ-ing the temperature of the liquid (nitrogen (-196C)has a higher NER in the same container than oxygen(-183C)), ambient temperature, condition of the con-tainer, exterior heat sources (for instance bulk tanks areusually painted white to reduce solar heating), whetherthe pressure builder is open or closed, etc.

Portable containers are subject to all sorts of abusewhich tends to increase their NER. If the container isdirty, dented or otherwise in less than prime condition,it is common to have a higher NER. As containers age,the vacuum between the inner and outer vessels alsotends to degrade and the NER will rise.BeaconMeds recommends that NER as low as 1.5%should be reliably expected only in xed containers andthat an NER of 3-5% be used when making calculationswith portable containers.


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The Unexpected

Fill connection, whereas portable cylinders typicallyhave only a liquid connection and a vent. Large tanksalso have a trycock to determine how full they are,whereas portable containers have only the vent lineand are often lled by weight.

The unexpected

Failures in systems sourced from liquid manifolds arenot typically a failure of the manifold itself. This willbe especially true with the Lifeline manifold which hasan enviable history of reliability. More typically, liquidmanifolds prove unsatisfactory because their operatorssimply do not understand their limitations and applythem incorrectly.

Some typical scenarios:A facility sees the opportunity to realize the hugecost savings liquid can oer. They attempt to convertan existing gas manifold simply by attaching liquid

containers. They nd: The manifold crashes, sometimes immediately,

sometimes later, because the pressure relationshipsin the manifold are set for high input pressures whichliquid containers do not always deliver.

The manifold crashes because of cryogenictemperatures on regulators not suited to theconditions.

The system crashes because of inadequate ows(portable liquid containers by themselves cannottypically output gas at cylinder rates).

They get no source alarms, but the area alarms go o

because the manifold cannot maintain pressure.

A facility installs a proper liquid manifold but still suersfrustration with their system. These frustrations mightinclude: The disturbing experience of walking into the

manifold room and nding the containers all hissingaway like theyve suddenly sprung leaks.

Attaching a completely unused container to themanifold and nding its actually empty. Then tryinganother container only to nd that theyre all empty!

Checking the manifold header pressure gaugesfaithfully once a shift and still having the secondary

in use and reserve in use alarms go o moments later- but all the gauges read just what they always do! Supplying the manifold with four full containers.

Left header in service, right header on standby. Themanifold never gives an alarm for Changeover untilboth the Changeover and Reserve in Use alarms goo simultaneously. Upon investigation, both headersare empty.

Having the system crash because the new liquidmanifold cant deliver a ow rate the old cylindermanifold never had a problem with.

A daily examination of the manifold reveals theSecondary header is drawing down at a faster ratethan the Primary.

Having an employee die from asphyxiation in thecontainer storage room because he didnt know theventing nitrogen had displaced all the air in thatclosed room.

All of these are phenomena which can be traced tonormal liquid containers. As they will suggest, thesecan result in very serious problems. But to balancethe account, many facilities nd these systems entirelysatisfactory and never experience these problems orsucceed in preventing them from becoming serious bygood management.

As mentioned before, liquid containers all havea natural rate of heat leakage called the NormalEvaporation Rate. A clean, new container lled withoxygen will have a typical NER in the range of 1.5%

per day (but see sidebar About the NER). To seewhat this means, consider a container lled with 165liters of liquid oxygen. This would vaporize into about120,000 liters of gas. If we never touch this container,the pressure will gradually build up until the safetyvalve begins to bleed off the excess pressure (theexact pressure at which this will occur will vary withthe container rating). If we listen, well hear this asthe steady hiss of escaping gas. It is not a leak, but anormal phenomena. Each day, the container will vento about 1.5% of its contents when full. That is, 1.5%of 120,000 liters or 1,800 liters. This will not decline

as the container empties, but will continue essentiallyat this rate, day and night.If we leave this container alone for 30 days, it will be halffull. If we leave it for 60, it will essentially be empty.The same container lled with Nitrogen has an NER of2%, so it will last only 50 days. Note that we have notused any gas - this is simply loss due to the NER of thecontainer.

A t t a c h t h econtainer to amanifold with

t h r e e mo r ec o n t a i n e r sidentical tothe first. Wethen have theconfigurations h o w n i nDetail 9. Ifwe use no gaswhatever, theNER of these

Detail 9A Basic Liquid x Liquid Manifold

Primary/Secondary

Primary/Secondary


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The Unexpected

four containers lled with oxygen will require they vent7,200 liters of gas per day (1,800 x 4).

If the facility in our example uses 3,600 liters per day,the containers will only have to vent the other 3,600 -but they will vent as much as needed to absorb the NER.

There are other situations to consider as well. Forinstance, whatever amount the facility uses duringthe day, if they use none at night the containers willprobably be venting every morning. Although theirusage may be mathematically adequate, it is notsteady, whereas the heat leakage is essentially constant.To totally avoid loss of the gas, the draw from thecontainers must match or exceed the NER not as anaverage but on a nearly continuous basis.

This seems to present a problem, as no medical facility ever has entirely smooth demand.However, there is a degree of exibility designed

into the containers. A typical container hasa pressure builder pressure 50-100 psi lowerthan the relief valve setting. Under demand,the container will drop to the pressure builderpressure and hold at that pressure until empty. Ifthe demand stops, the pressure will build towardthe relief valve pressure at a rate determinedby the NER and how full the container is. Fullcontainers will reach the pop o pressure fasterthan nearly empty containers simply becausethey have less headspace to pressurize.

On a gas manifold, any gas drawn will come fromthe primary header until it is empty, at which timethe manifold switches, an alarm is initiated and themanifold draws from the secondary header. Howevera liquid manifold includes a code mandated featurecalled an economizer to reduce waste. The manifold rst draws o the container which has the highestpressure, and that will include the containers on thesecondary header. The manifold is designed to drawfrom the primary header only after the gas in excess ofthe NER is drawn away from both the primary and thesecondary headers. In using 3,600 liters/day, each ofthe four containers would contribute about 900 liters

to the demand and would vent about 900 liters2

.

So long as the demand remains below the NER of 7,200liters per day, the surprise is that all four containers

will empty at essentially the same rate. If your systemwere congured like Detail 9, the rst indication youwould get that the gas was running out would be theChangeover alarm, followed immediately (secondslater) by the system running empty.

Once the demand rises over the NER for the containers,

in our example 7,200 liters per day, the manifold willbegin to draw any additional gas preferentially fromthe primary side3. As an example, if demand wereat 8,000 liters per day, the secondary header wouldcontribute 3,600 liters and the primary header 4,400liters. The manifold would also then operate as wewould expect: Primary runs empty, Secondary takesover, Alarm indicates Changeover.

As you can see from the above, a liquid manifold cannotbe operated safely without safeguards additional tothose required for gas cylinders. One safeguard NFPAmandates is the provision of a third header containinggas cylinders enough for 24 hour supply and called theReserve. Adding the reserve, we have the congurationillustrated in Detail 10. This manifold is designed tocascade in this specic order:Primary header in service, no alarms - Primary runsempty, Secondary begins to serve, Changeover alarm -Secondary runs empty, Reserve begins to serve, Reservein Use alarm - Reserve begins to run low, Reserve lowalarm - Reserve runs empty, low pressure alarm(s).

A properly congured liquid manifold with Reserve willoperate more safely than the system shown in Detail9, but still may confuse the operator. The operator

Detail 10A NFPA compliant Liquid x Liquid x Gas Manifold

Primary/Secondary

Primary/Secondary

Reserve

2 This is an ideal picture. In practice, containers are never perfectly balanced and the ratio of useage to vent could vary

greatly between the four containers. However, it may be relied upon that at least 7,200 liters would go somewhere.

3 There is a way in which even this may not be true. Liquid containers come in at least two pressure settings. If thecontainers on the secondary are of a higher pressure type than those on the primary (or are seriously misadjusted),it is entirely possible to have the secondary header drain down faster than the primary despite the manifold settings.


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Primary and are therefore an exception to the generalrule on how manifolds should rotate the stock.

Liquid x gas x gas manifolds require the operatorto replace the secondary cylinders based on apredetermined threshold, and these cylinders willtherefore usually be sent back partially full. This waste

must be accounted for when calculating the potentialsavings from such a system.

Liquid containers are not only subject to being underutilized and venting o their contents because of theNER, but they are also subject to being overdrawn.Overdrawing a liquid container can occur suddenlyand be obvious, but equally the problem can sneakup on you.

Overdraw manifests itself when the demand onthe container is more than the pressure builder cancompensate for. If the pressure builder cannot keep

the headspace pressure up, the internal pressure fallsso low that liquid cannot be pushed out. The surestway to make this happen is to close the pressure builderor, since containers normally arrive on site with thepressure builder closed, never open it in the rst place.

Failure can also occur even though the container isnot being overdrawn, but is actually operating withinspecication. When the pressure builder and internalvaporizer of a container are in continuous use, they willchill the outer vessel of the container and in certainenvironmental conditions ice will form on the outside

of the container. This ice normally appears rst at thebottom of the container and is not an unusual thingto see. With prolonged use, the ice can climb up thesides of the container and begin to act as an insulator,preventing heat from getting to the vaporizer. Whenthis happens, either the pressure builder will fail tomake enough pressure or the vaporizer will begin topass liquid. If the pressure builder fails, the situationis the same as when the pressure builder is closed.However, the recovery time can be much longer as theice must be melted away to restore proper function.

When an internal vaporizer is overdrawn and liquid

begins to pass into the manifold the results can be muchmore dire. Manifolds are commonly not designed totake in cryogenic liquid, and the damage to the primaryregulators can be serious. The pressure may no longerbe controlled and the system may lose pressure or reliefvalves may activate, aggravating the original problem.Replacement of the regulators may be required torestore the manifold to full service.In cases where overdraw is possible or probable, it isbest not to rely on the internal vaporizer but to installan external vaporizer of larger capacity.

The Unexpected

may expect the standard sequence but instead nd theChangeover alarm and the Reserve in Use alarm ring outvirtually simultaneously. This kind of event will occurif the demand is less than or equal to the NER.

Even when demand is greater than the NER, theoperator must remember that when the Changeover

alarm rings, the Secondary is not full, and the timebetween the Changeover alarm and the Reserve in Usealarm may be quite a bit shorter than the time from fullto Changeover. It is entirely possible the operator willgo to the manifold expecting to change the Primarycontainers but nd the Secondary containers also inneed of replacement.

Quality manifolds like the Lifeline Manifold are fullyautomatic and will automatically exchange Primary forSecondary. This is an important feature which preventsthe manifold from swinging back to the original Primaryheader as soon as the empty containers are changed.

By rotating the Primary role between the two liquidheaders, the containers are more completely drainedand can be changed in sequence. Some manifoldsare only semi-automatic and do not perform thisexchange without a manual operation. Semi-automaticmanifolds, if not operated correctly, will inevitably fallto the Reserve on a periodic basis. This complicatesthe operation of the manifold and increases the risk ofthe system running empty.

So far, we have discussed only manifolds which are twocontainers to a side. There are two other variants which

should also be discussed.

First is a manifold with only one liquid container oneach of the Primary and Secondary headers. These maynot be used under the NFPA 99 2002 version, but wouldbe permitted under NFPA 99 2005. Arguably, they werealso permitted under earlier versions. Naturally theycontain less gas, but have the corresponding benetof a lower NER.

Second is a manifold version with one or two liquidcontainers as Primary with a Secondary composedof gas cylinders. A Reserve header of cylinders is

mandated for this conguration as well.

This Liquid x Gas x Gas conguration has the advantageof lowering the NER as low as that of one container. Ithas the unusual characteristic that the liquid headeris always the Primary header. When the Primary runsempty, a Secondary in Use Alarm will be activated,and the Secondary will serve the demand. However,when the Liquid container(s) is(are) replaced, theliquid header will immediately revert to being Primary.These manifolds never allow the Secondary to become


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to vent o (i.e. waste) gas for part of the time. It mayseem surprising, but liquid may actually be so muchcheaper than cylinder gas that they can do this andstill save money. However, it is also possible that thiswaste will also evaporate any savings they might haveotherwise enjoyed.

Remember that the NER will vary with the numberof containers. The lowest NER will come with a onecontainer liquid x gas x gas manifold. A liquid x liquidx gas manifold with two containers will have twicethat NER, and a liquid x liquid x gas manifold with fourcontainers will have four times the NER. BeaconMedsnever recommends more than 2 containers per header.(see Other Options below for alternative systemscongurations).With liquid containers it is important to know thepeak demand likely to be experienced. The manifoldwill be limited to the vaporization capacity of thecontainers. If the internal vaporizers cannot serve

the peak demand, an external vaporizer might be asolution. If the containers themselves are inadequate,a mini bulk or bulk tank may raise output high enough.At approximately 2,200 ft3/hr (62,260 liters per hour)in demand, the limitation may become the manifolditself, at which point a Lifeline manifold should not beused and a bulk station with appropriate equipmentshould be considered.

It is entirely possible to have a facility whose lowest usewill be below the NER for a single container but whosepeak use will be above the capacity of those same

container(s). A facility in this situation must decide ifit can live with the waste inherent in two containers inorder to increase the peak output, or if a liquid manifoldis the right choice at all.

It is always best where possible to place liquidmanifolds out of doors (see Annex H). Manifold roomsand any storage enclosures indoors must be ventedadequately. NFPA 99 mandates mechanical ventilation for these rooms or enclosures. If the manifold roomcannot be adequately ventilated, liquid should neverbe considered.

Environmental factors which will increase the NER mustbe considered and dealt with. A typical example isplacing the containers outdoors in the hot sunshine.The heat and solar radiation will drive up the NER.(Placing containers outside in cold climates can havethe opposite eect - reducing the maximum output ofthe container.)

When is Liquid not a Good Idea

Another phenomena associated with liquid containers isvariation in output between the containers themselves.It is not uncommon to have two seemingly identicalcontainers on the same header which have slightlydierent internal pressure settings. In such a case, thecontainer with the higher internal setting will feed thesystem in preference to the container with the lower

setting. A characteristic nding is one container ona header far more full than the other. This is usuallymore annoying than serious, but in extreme cases, lowersystem capacity may result.

Some users interconnect the vent lines of theircontainers to equalize the internal pressures and thus force the containers to feed equally. This practicecan work, but can also have serious consequencesfor operator safety and should only be undertaken bysomeone very knowledgeable about safe practices withcontainers.

When is a liquid manifold not a good idea?

Liquid manifolds can be extremely cost eective, andthe savings from using liquid both in dollars and laborcan be sweet. The facilities which realize these benetswithout the attendant frustrations have one commoncharacteristic: their liquid manifolds are properlyapplied.

There are many, many situations where liquid manifoldscan work well and the user can benet. However, thecloser one gets to the edges, the more likely there will

be issues. For example, there are several makers ofliquid containers, and a given gas supplier may usecontainers from any number of manufacturers, inany number of dierent sizes, pressure ratings, andconditions. Containers which are visually identical willstill have individual characteristics. What workedon paper with a new and up-to-spec container maynot work so well with an old, used container fromanother manufacturer. Therefore, it is best to play itsafe, leaving some margin of error to encompass thevariations in the containers and the experience of theoperators.

With liquid containers there is a oor under whichthey should not be used. In simple terms, this oor isthe NER, and a facility which does not use each day atleast the NER for the number of containers installedshould be considered unsuitable for liquid. Facilitieswhich on an average day use the NER or more shouldremember to consider both the non-average day andthe night. A facility which is close to the NER withaverage usage will probably nd they are below the NERwhen usage is low. For example, a Surgery center whooperates eight to twelve hours a day must be prepared


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Other Options

Other Options

When a liquid manifold does not seem a good option,what other options can be considered?

There are several, depending on the circumstanceswhich makes the liquid manifold undesirable.

If the problem is that the usage is likely to fall belowthe NER from portable liquid containers, clearly it isalways an option to return to gas in cylinders. Thereis no oor on the output of a cylinder manifold, butnaturally there is a ceiling. The ceiling is essentially setby how often one is willing to change the cylinders. Awell sized manifold should not need attention moreoften than once a week, but clearly there is no technicalproblem with changing the cylinders more frequentlyif necessary.

The limitation may be high variation in usage. In such

cases, the system will fall below the NER at times andat other times will challenge the containers output.A typical case where this may prove a problem is anitrogen system used for tools. In some cases, it helpsto simply use a better container. Since permanent tanksare not subject to the abuse inherent in transportingportable containers, the NER can be held lower andis more reliable. A minibulk for instance may have anNER of 0.6% as opposed to 1.5% with a portable. Thislower NER can help solve the problem, but be awarethat these are usually much larger vessels as well,and must be lled from a truck directly, requiring the

cooperation of your gas supplier. They also require anexternal vaporizer. In these cases, consultation withthe container supplier and the facilitys gas supplier isessential.

The Lifeline manifold can make an excellent control for these systems, but they can also overpower themanifold. The limitations on the use of a manifoldas a control device in these circumstances should bethoroughly understood prior to installation.


14/36


AnnexA

Exam

plesofcontainersand

cylinders.

Type

H

Cylinder

S

mallLP

Liquid

P

ortable

SmallHP

Liquid

Portable

Lar

geLP

Li

quid

Portable

LargeHP

Liquid

Portable

Sam

ple

MinibulkTank

Sam

pleBulk

Tank

Model

Cha

rt160MP

Chart160HP

Chart265MP

Chart265HP

Taylor-

Wharton

EF450HP

Taylor-

Wharton

6000

NormalM

ax.Pressure

2,200psi

15.2mPa

230psi

1

.6mPa

350psi

2.4mPa

23

0psi

1.6mPa

350psi

2.4mPa

350psi

2.4

mPa

250psi

1.7mPa

Diamet

erin/cm

9/22.8

2

0/50.8

20/50.8

26/66

26/66

30/

76.2

96/240

Heightin/cm

51/130

59.6/151

59.6/151

57.8/132

57.8/132

74/188

312/800

Weight(fu

ll)

lbs/kg

O2

153/69.5

6

29/285

640/290

93

5/424

924/420

1,63

7/736

83.9k/38.0k

N2

5

17/234

531/241

758/344

754/343

1,36

4/613

67.7k/30.7k

CO2

667/315

967/439

N2O

640/303

1,008/456

Argon

7

10/322

717/325

1,062/481

1,046/475

1,83

2/824

96.3k/43.6k

Contents(Gas

atSTP)

ft3/liters

O2

244/6,900

4,577/129.5k

4,348/123k

7,183

/203.2k

6,811/192.7k

11,000

/311.3k

676k/19,167k

N2

226/6,400

3,685/104.2k

3,464/98k

5,769

/163.2k

5,438/153.8k

8,750/247k

547k/15,494k

CO2

434/12,300

3,382/95.7k

5,305/150.1k

N2O

558/15,800

3,207/90.7k

5,034/142.4k

Argon

4,448/125.8k

4,226/119.5k

6,982

/197.5k

6,634/187.7k

10,700

/302.8k

661k/18,720k

NER(%/day)

O2/N

2/N2O

NA

1.4/2/NA

1.4/2/0.5

1.4

/2/NA

1.4/2/0.5

O2

=1

O2=0.25

O2Withd

rawalRate

ft3/hr/

liters/hr

Unlimited

35

0/9,905

350/9,905

400/11,320

400/11,320

575/16,272

Unlimited

N2O/CO2

Withdrawal

Rateft3/h

r/liters/hr

VeryHigh

110/3,113

110/3,113

N

S

NA=NotApplicable.Usually,thesecontainersarenotusedwiththis

gas.

NS=non-st

andard.Itmaybepossibletouseacontainerinthismanner,but

thesuppliershouldbeconsulted

.

Unlimitedindicatesthatalthoughthereobviouslyisalimit,itissohighastobeeectivelyirrelevantwithmed

icalgases.

VeryHighin

dicatesthelimitissohighthato

nlyraresituationswillapproachit.

Container and Cylinder Data


15/36


Annex BSafe work practicesCryogenic liquids such as liquid oxygen, nitrogen andargon are liqueed gases that are kept at very lowtemperatures. Contact with these liquids can result inburns, eye irritation and allergic reactions.

Ventilation system

The amount and type of ventilation needed dependson the size and layout of the room. However,continuous mechanical ventilation is requiredwherever cryogenic containers are stored indoors.

Make sure ventilation systems are designed andbuilt so they do not result in an unintended hazard.

Ensure hoods, ducts, air cleaners and fans are madefrom materials compatible with the gas used, andare regularly maintained and cleaned.

Employee training

All employees who handle cryogenic liquids shouldreceive appropriate training. Only trained employeesshould be permitted to handle or work withcryogenic containers. Training must include at least:

Properties of the cryogen both as a liquid and agas.

Specic instructions on the equipment being used,

including safety devices. Approved materials that are compatible with thecryogen.

Selection, use and care of protective equipmentand clothing.

First aid, including self-treatment. Dealing with emergencies such as res, leaks and

spills. Good housekeeping practices. Knowledge of all the hazards of the materials you

work with e.g.. re, explosion, health, chemicalreactivity.

Safety systems including gas specic connectors,

relief valves and burst discs.

Housekeeping

All doors must be labelled. If Nitrogen, NitrousOxide, or Carbon Dioxide is in the room, label perpages 25 and 26. If Oxygen or Air only, label as perpages 27 and 28.

Ensure that proper housekeeping practices in the

Safe Work Practices

workplace are followed at all times. Do not allow smoking or open ames in any area

where liquid oxygen is stored, handled or used. Do not contaminate cryogenic liquids or their

containers. Never allow combustible organic materials near

liquid oxygen.

Prevent the mixing of ammable and oxidizingcryogens.

Never allow any absorbent materials to be exposedto ammable or oxidizing cryogens.

When venting storage containers, properconsideration must be given to all the properties ofthe gas being vented.

Ensure Ventilation is in operation at all times.

Storing and transporting cryogenicliquids

Inspect all incoming containers before storing toensure they are not damaged and are properlylabelled.

Do not accept delivery of defective containers. Always use the correct name for all materials, e.g.

never call liquid oxygen liquid air. Do not store containers where they may come

into contact with moisture. Moving parts, such asvalves or pressure relief devices, can malfunctiondue to external ice formation.

Allow only authorized people into storage areas.

Ensure that ignition sources and combustiblematerial are kept far away from liqueed oxygen,and other ammable material storage andhandling areas.

Do not store liquid oxygen containers on wood,asphalt or oil soaked gravel. When saturated withliquid oxygen these materials can explode after animpact as slight as a footstep.

Use concrete or clean gravel under storage areas. Ensure that vessels are insulated from any sources

of heat. Handle cylinders carefully, and avoid dropping,

rolling or tipping them on their sides.

Do not move a container by rolling it on its lowerrim. Always use a hand truck, cart, or other proper

handling device when transporting cryogenicliquid containers. Use a strap to secure thecontainer to the handcart.

Keep the cryogenic liquid containers upright at alltimes except for the minor tilting on the cart duringtransport.


16/36


For the most current and up-to-date information oncryogenics refer to the label on the container and theMaterial Safety Data Sheet (MSDS), available fromdistributors/manufacturers.

Working with cryogenic containers

When containers are not labelled or littleinformation is known of the contents, they shouldbe treated with extreme caution. Never assume anunmarked container contains any specic gas.

For hazardous operations a permit to work systemshould be in place.

Use only the stopper or plug supplied with thecontainer when sealing it.

Prevent all organic substances including oils andgreases from contacting liquid oxygen.

Never wear watches, rings, bracelets or other

jewellery that could freeze to your skin. Thoroughly clean any equipment or container used

with liquid oxygen to the degree required for usewith oxidizing materials.

Ensure warning signs and emergency instructionsare posted wherever cryogenic containers are usedor stored.

Always follow the manufacturers procedures foroperating and maintaining equipment used withcryogens.

Avoid forcing connections, never use cheater hoses,adaptors from one gas specic tting to another, or

hoses and ttings without permanent gas specicends. Never tamper with containers in any way. When doing maintenance work on oxygen handling

systems, cleanliness is essential. Grease or oil mustnot be allowed to contaminate any parts.

Cryogenic liquids should NEVER be transferredfrom one container to another or translled exceptin appropriately equipped facilities by trainedoperators.

Contact with cryogens

If bodily contact occurs with cryogenic liquids, theirvapours and any cooled surfaces, ush the area withlarge quantities of warm (not hot) water. If the skinis blistered or the eyes have been exposed, obtainmedical attention immediately.

Emergency eyewash stations and, if possible, safetyshowers should be provided when working withcryogens.

Remove clothing that is splashed with liquid oxygen

immediately and air it out for at least one hour.

Personal protective equipment (PPE)

The following personal protective equipment should

always be used when working with cryogens.

Loose tting insulated gloves when handlinganything that may have been in contact with acryogen, e.g.. Insulated welding gloves.

Safety glasses. A non-porous, knee length laboratory coat,

without pockets or cus which could catch theliquid.

Boots with tops high enough to be covered bypants without cus.

Safe Work Practices


17/36


Alarms and Alarm Response

Annex CAlarms and Alarm Response

Liquid manifolds require specic alarms, and becauseof the nature of the containers require more actionsbe taken when an alarm sounds. The alarms arevaluable indicators, but they are only indicators,

and determining what must be done in responserequires a person knowledgeable in the operation andpeculiarities of the manifold.

The four required alarms are: Changeover, which indicates the primary header is

empty and the secondary header is in service. Secondary Low (for liquid x gas congurations only,

NFPA 99, 2005) which indicates that the cylindersecondary is low.

Reserve In Use, which indicates the Primary andSecondary headers are empty and that the Reserveheader is now supplying the system.

Reserve Low, which indicates the Reserve Header isbelow one average days supply.

These alarms must appear at both master alarm panels(or at the one master alarm in a level 2 facility). Theymust also have Local Signal analogues at the manifolditself. Local signals are not alarms in that they are notaudible, and may be any kind of device which enablesthe operator to determine the state of the system whenstanding at the manifold. Marked gauges, ippers,lights, ags, etc. all may qualify as local signals.

Two system alarms are also required at both masters: System Pressure High, indicating system pressure is20% or more above normal.

System Pressure Low, indicating system pressure is20% or more below normal.

In normal operation the alarms will cascade asfollows:Changeover, followed by Reserve In Use, followed byReserve Low, followed by System Pressure Low whenthe manifold is entirely exhausted.

If the manifold is liquid x gas, the secondary low will

activate when the supply of gas in the cylinders hasfallen low, and indicates that these cylinders must bechanged.

To lose supply therefore, the facility must ignore threealarms. This usually will be adequate coverage, butonly if with each alarm action is taken.

With a Changeover alarm, the operator should: With a semi automatic manifold, confirm the

switchover by whatever method is provided. (This

step is not needed on a fully automatic manifold.) Examine the containers on the Secondary bank and

determine that both are empty. If so, replace withfull containers. If not, this indicates a problem withthe operation of the containers or the manifold (acommon nding is a pressure builder not opened).

Examine the container(s) on the Primary Bank. A

decision will be required based on how full thesecontainers are. They may be left in service orreplaced. If nearly empty, it is often better to replacethem to save labor, but this means not fully using thecontainer contents. The decision to be made willvary between facilities and on the usage at the time.

Examine the contents of the reserve header. If thecontents are low, these must be replaced as well.

With a Secondary Low alarm, the operator should: Examine the cylinders on the Secondary bank and

determine that all are empty. If so, replace with fullcylinders.

With a Reserve in Use Alarm, the operator should: Examine the containers on the Primary and Secondary

banks and determine that all are empty. If so, replacewith full containers. If not, this indicates a problemwith the operation of the containers or the manifold(a common nding is a pressure builder not opened).

Examine the contents of the reserve header. If thecontents are low, these must be replaced as well.

With a Reserve Low Alarm, the operator should: Examine the containers on the Primary and Secondary

banks and determine that there is gas in each. If not,replace with full containers. It is not uncommon tohave a Reserve Low alarm occur despite the Primaryand Secondary headers being in service. Reserveheaders can weep either into the system becauseno regulator is entirely leak tight or through leaksat the cylinder connections. If this occurs, the LowContents alarm will eventually sound.

Examine the contents of the reserve header. If thecontents are low, these must be replaced. Note thatwith a new system it is possible to have the headersized for a 24 hour supply, which means the alarmmust sound if the header loses any gas at all. This

is a sizing problem which can only be solved byenlarging the header and adjusting the switch.Remember that the Reserve will still have considerablegas in it when the alarm rings. Inexperiencedoperators can be fooled when they look at the gaugeand see the cylinders are still mostly full. They maydecide to not change the cylinders and ignore thealarm. There is no better way to guarantee thesystem will run empty sooner or later.

It is entirely possible that all three of the operating


18/36


alarms can ring virtually simultaneously. This is mostlikely when the facility operates at low usage, and isinevitable if they operate below the NER. Such an eventindicates that all three headers are essentially out of gas,and requires the most rapid response to avoid systemfailure. All containers and cylinders will normally needto be replaced. If this happens often, the facility has

an oversized system, and they should consider makingchanges which will reduce the NER and cause themanifold to return to operating in a proper cascade.Continued operation in this mode is very high risk.

If the manifold is operating and has full supplies, butthe Low Pressure Alarm sounds, (with or withoutother alarms) this is a possible indicator of overdraw.Typically, the alarm will be intermittent and in somecases can even be traced to the operation of a specicpiece of equipment, like a nitrogen tool in the O.R.When this occurs, it is necessary rst to determine thatoverdraw at the manifold is indeed the cause. This

will best be done simply by observation. Symptomsto look for include: Liquid containers running at low pressures. Every

container has a normal pressure range for which thepressure builder is set, and the container should beoperating close to that range. There are two commoncauses for low container pressures (other than thatthe container is empty): a closed pressure builder anda buildup of ice. If the pressure is low, check rst toensure the pressure builder is open. If heavy ice hasaccumulated, you may need to melt it o to restorethe containers function.

The wrong type of containers. This is particularly aproblem with high pressure systems like nitrogen.Such systems need a high pressure container in orderto perform correctly, and if a low pressure container isused the output of the manifold may be inadequate.

Seeking at the manifold. If the manifold is swingingback and forth between Primary and Secondaryheaders (which may also be causing the Changeoveralarm to sound), this may be occurring because themanifold is looking to satisfy the demand by drawingo both headers.

Alarms and Alarm Response


19/36


CylindersIn

Storage C

ylindersOnSecondar

y

Cylinders On Reserve

Liquid Containers

Secure Door with lock

One Hour (or greater)Fire resistive construction

Cable or chainrestraints

ExtractionBlower

(intake at floor)

Air inlet(at ceiling)

Detail D.1An Example of a Liquid Manifold Installation

Minimumof 155

(393 cm)

Minimum of 90 (239 cm)

Annex DA Manifold Room Layout(also see Annex H for outdoor locations)

The following is a typical layout for a manifold room.This is by no means the only way to lay out a manifoldnor necessarily the

best. Every situationmust be evaluatedon its own. However,this is included to helpdefine some of theimportant criteria foran eective manifoldlayout.

Figure D-1 illustratesa L i q u i d by G a smanifold with thenecessary gas cylinder

reserve.

T h e d i a g r a millustrates requiredfeatures including: All elements of themanifold system arein the same enclosure. T h e e n c l o s u r e(in this case insidethe building) is of1 hour fire resistive

construction.Al l cyl inders andc o n t a i n e r s a r erestrained. A singlecable is illustrated, butindividual restraints for each cylinderand container arerequired under the2002 standard (arequirement whicha p p e a r s o n l y i nthat one edition).

Note that the loosecyl inders ( ful l or e m p t y ) a r e a l s orestrained. The room is providedwith a mechanicalventilation systemas required by NFPA99. In addition, theventilation system hasan intake for make

up air. The extraction is at oor level, the make up airat ceiling level. The reserve is placed at an angle to the main manifold.This is entirely optional, but can save considerablespace. The Secondary and Reserve are the same number

Manifold Layout


20/36


Manifold Layout

of cylinders. This is not mandatory, but is commonpractice. Sucient room has been allowed for manipulation ofthe liquid containers. However, no provision has beenmade for cylinder or container handling equipment(handtrucks, etc.) which are commonly stored in theserooms.

No provision has been made for storage of liquidcontainers. These generally should be stored outside,where any gas they will discharge is not conned. Ifthis enclosure were open and out of doors, there wouldneed to be room provided for these standby and emptycontainers.


21/36


Gas Manifold Dimensions

Annex EDimensions

Liquid manifolds present unique challenges as to spaceand arrangement. The following sections give basicdimensional information and some examples of Liquidmanifold layouts for the guidance of the designer.

45 (111.8 cm)

61155 cm

84213 cm

96244 cm

WALL

Recommended minimum access clearance

20 (50.8 cm) Recommended cylinder space11 (27.9 cm) manifold enclosure front

Cylinder Header

System Connection (Typ.)

Ceiling (Typ.)

Note1

Note 1 : Overall Manifold Minimum Space Allocation(Outermost cylinder to outermost cylinder, staggered cylinders)

# Cylinders per header (total cylinders is 2x this number)2 3 4 5 6 7 8 9 10 11 12 13 14

21 36 47 57 67 77 87 97 107 117 127 137 14753 cm 91 cm 119 cm 145 cm 170 cm 196 cm 221 cm 246 cm 272 cm 297 cm 323 cm 348 cm 373 cm

Minimum permitted number of cylinders is two x two (ref. NFPA 99 5.1.3.4.10.4 (2))Other cylinder header configurations are possible. Consult your BeaconMeds representative for exceptionalsituations.

TM

Lifeline Gas x Gas ManifoldMinimum Clearance Dimensions

11/2004

MWA

Detail E.1 Gas Manifolds


22/36


Detail E.2 Liquid x Liquid Manifolds

TM

Lifeline Liquid x Liquid ManifoldMinimum Clearance Dimensions

11/2004

MWA

45 (111.8 cm)

56 (143 cm)

61155 cm

84213 cm

96244 cm

WALL

20 (50.8 cm) Recommended cylinder space11 (27.9 cm) manifoldenclosure front


Ceiling (Typ.)

26 (66 cm)Recommendedcontainer space

(will vary withcontainers used) Recommended minimum cylinder access clearance

Recommended minimumcontainer access clearance

26"(66 cm)1

52(132 cm)1

1

Recommended minimum design dimension is shown. Actual containers vary in diameter.2 Dimension is variable and Reserve may be located wherever convenient so long as it does not interfere with othercylinders or containers.

Note2 Note3

Note 3 : Reserve Cylinder Header Minimum Space Allocation(Point of connection to outermost cylinder, staggered cylinders)

# Cylinders3 4 5 6 7 8 9 10 11 12 13 14

30 35 40 45 50 55 60 65 70 75 80 8576 cm 89 cm 101 cm 114 cm 127 cm 139 cm 152 cm 164 cm 178 cm 190 cm 203 cm 216 cmMinimum permitted number of cylinders is three (ref. NFPA 99 5.1.3.4.10.4 (2))Other cylinder header configurations are possible. Consult your BeaconMeds representative for exceptionalsituations.

Liquid Manifold Dimensions


23/36


45 (111.8 cm)

61155 cm

84213 cm

96244 cm

WALLWALL

20 (50.8 cm) Recommended cylinder space

11 (27.9 cm) manifold enclosure front

Reserve CylinderHeader

Secondary CylinderHeader


Ceiling (Typ.)

26 (66 cm)Recommendedcontainer space(will vary withcontainers used) Recommended minimum cylinder access clearance

56 (143 cm)

Recommended minimumcontainer access clearance

26"(66 cm)1

52(132 cm)1

Note4

Note2

Note3

1 Recommended minimum design dimension is shown. Actual containers vary in diameter.2 Dimension is variable and Reserve may be located wherever convenient so long as it does not interfere with other

cylinders or containers.

Note 3 : Manifold Cylinder Minimum Space Allocation(Cabinet centerline to outermost cylinder, staggered cylinders)

# Cylinders2 3 4 5 6 7 8 9 10 11 12 13 14

10.5 18 23.5 28.5 33.5 38.5 43.5 48.5 53.5 58.5 63.5 68.5 73.527 cm 46 cm 60 cm 72 cm 85 cm 98 cm 110 cm 123 cm 136 cm 149 cm 161 cm 174 cm 187 cmMinimum permitted number of cylinders is two (ref. NFPA 99 5.1.3.4.10.4 (1))Other cylinder header configurations are possible. Consult your BeaconMeds representative for exceptional situations.

Note 4 : Reserve Cylinder Header Minimum Space Allocation(Connection point to outermost cylinder, staggered cylinders)

# Cylinders

3 4 5 6 7 8 9 10 11 12 13 1430 35 40 45 50 55 60 65 70 75 80 8576 cm 89 cm 101 cm 114 cm 127 cm 139 cm 152 cm 164 cm 178 cm 190 cm 203 cm 216 cmMinimum permitted number of cylinders is three (ref. NFPA 99 5.1.3.4.10.4 (2))Other cylinder header configurations are possible. Consult your BeaconMeds representative for exceptional situa-tions.

TM

Lifeline Liquid x Gas ManifoldMinimum Clearance Dimensions

11/2004

MWA

Detail E.3 Liquid x Gas Manifolds

Liquid x Gas Manifold Dimensions


24/36


CAU

TION

M

EDICAL

GASESI

NSIDE

NoSmoking~NoOpenFlame

s

Annex F

Signage

Page 24:English, for manifold rooms containingonly oxygen or air.Page 25: Spanish, for manifold roomscontaining only oxygen or air.

Page 26:English, for manifold rooms containingany gas other than oxygen or air.Page 27: Spanish, for manifold roomscontaining any gas other than oxygen or air.

Signage


25/36


PR

ECA

UCI

N

GASES

MDICO

SADENT

RO

NoFum

ar

ApagueCualq

uierLlam

a

Signage


26/36


CAU

TION

M

EDICAL

GASESI

NSIDE

NoSmoking~NoOpenFlame

s

ASPHYXIA

TIONHA

ZARD

Room

mayhave

insufficientoxygen!

OpenDoora

ndallow

roomto

ventilatebeforeen

tering

Signage


27/36


PR

ECA

UCI

N

GASES

MDICO

SADENT

RO

N

oFumar~

ApagueCualquier

Llama

PELIGRODE

ASFIXIA

Lahabitacinnopuedet

ener

suficienteo

xgeno!

Abrala

puertayp

ermitaque

la

h

abitacin

seventileantesdein

gresar

Signage


28/36


Annex GOxygen Monitors and Conned Space Regulations

The hazard of axphyxiation is always a concernwhen dealing with medical gases. We routinelyconfine large volumes of gases in small rooms, andthese gases (with the obvious exceptions of oxygen

and medical air) are largely considered primaryasphyxiants. If they get loose they will quicklydilute the oxygen in the air below the normal20.9%.

Under NFPA 99, several things must be done tominimize this hazard:

1. Every manifold room must be ventilated. Oneopening at floor level and one at ceiling level arethe minimum requirement, and once the totalamount of gas in the room gets beyond 3,000ft3,(1) there is a requirement for mechanicalventilation adequate for 10 air changes perhour(2).

2. All the relief valves need to be piped to outside,so if a relief valve operates, the gas does notsvent into the room. Obviously, one also needsto consider where its going to vent .

3. Signage must be provided on the doors warningworkers not to enter without taking care to

ventilate the room first. (See Annex F)

Ventilation helps prevent accumulations fromoccurring due to ordinary leaks, and signage is usedto attempt to compensate for more catastrophic failures. The problem is that gases are odorless,colorless and therefore undetectable withoutspecial instruments. A worker entering a manifoldroom does not have these, and of course is used tojust going in there and getting the job done.

Manifold rooms and cylinder storage spaces meetthe OSHA definition for confined spaces :

A confined space has limited or restrictedmeans for entry or exit, and it is not designed forcontinuous employee occupancy. Confined spacesinclude, but are not limited to undergroundvaults, tanks, storage bins, manholes, pits, silos,process vessels, and pipelines. OSHA uses the termpermit-required confined space (permit space)to describe a confined space that has one ormore of the following characteristics: ... containsor has the potential to contain a hazardousatmosphere...(3)

The OSHA regulations for Confined Space entry arequite detailed. They are probably more elaboratethan required in the average health facility setting.Many labs have found a satisfactory middle groundby requiring a monitor for the manifold room airwhich allows the worker to know if the room is safebefore entering. Called Oxygen Depletion monitors,they are a very useful and inexpensive way to ensurethe hazard is recognized and mitigated.

Typically these work by installing a simple sensorwith an annunciator in the room and a remote

annunciator or alarm outside the room (ideally nearthe door handle). They give a visual indication ofthe atmosphere in the room (usually a green light)if all is OK, and a red indicator and alarm horn ifthe room oxygen is low. A simple glance will allowthe worker to know if entering the room is safe. Inthe event an accident occurs while the worker isphysically in the room, they will also give warningand should allow the worker time to exit the room.

They can be obtained with remote contacts for

19.5%

15%

12%

10%

8%

6%

4%

0%

Minimum permissible oxygen level

Decreased ability to work strenuously.May impair coordination and may induceearly symptoms in persons with coronary,pulmonary, or circulatory problems

Respiration increases in exertion, pulseup, impaired coordination, perception,judgement.

Respiration further increases in rate anddepth, poor judgement, lips blue.

Mental failure, fainting, unconsciousness,ashen face, blueness of lips, nausea, andvomiting.

In 8 minutes, 100% fatal.In 6 minutes, 50% fatal.In 4-5 minutes, recovery with treatment.

Coma in 40 seconds, convulsions,respiration ceases, death.

Detail G.1Health Eects of Oxygen Depletion


29/36


connection to the master alarm as well.

BeaconMedaes is recommending the installationof Oxygen Depletion monitors for any manifoldenclosure which is not open air (they would beunnecessary if your manifolds were outdoors and theenclosure was a chain link fence) and which contains

asphyxiant or toxic gases. This would include anyenclosure, whether provided with ventilation or not.Exceptions would be enclosures which contain onlyair, oxygen and/or mixtures with oxygen contentequal to or greater than 20% (e.g. Helium-oxygenmixtures, O2>20%).

Depending on the gases in the room, differentmonitors may be required. Carbon Dioxide willproduce a false oxygen level with many monitors,and a separate CO2 detection sensor is required forrooms which contain CO2 or mixtures containingCO2. It is very important to use the correct monitor

type.

(1) NFPA 99 2005 5.1.3.3.3, 5.2.3.3 and 5.3.3.6

(2) ASHRAE 170 Ventilation Requirements for Health

care Facilities - 2008 and AIA Guidelines for Design and

Construction of Health care Facilities 2006

(3) http://osha.gov/SLTC/confinedspaces/index.html

(4) European Industrial Gas Association IGC Document

44/09/E

Sample Specication for Oxygen Depletion Monitors

Manifold Room Monitors

1. Furnish each manifold room with an oxygendepletion monitor mounted in the manifoldroom at 1.5 meters (5 feet) AFF in a positionwhere cylinders will not contact the sensoror meter. Monitors indicate oxygen low levelat 19.5% or less and a second indication at18% or less. Audible and visual indication isprovided.

2. Provide audible and visual indicator outsidedoor at 1.5 meters (5 feet) AFF to alertoperator prior to entry. Label AtmosphericOxygen Content Low Do Not Enter.

3. Monitors are provided with volt free contactfor connection to master alarm.

See also specification sheet SSB 830-10

Oxygen Depletion Monitor

The oxygen depletion monitor is an easilyinstalled, mains powered monitoring device. Itis constructed in two parts: the main monitoringunit, which is mounted in the manifold room, anda repeater alarm which is mounted outside the

room to provide warning prior to entering.

The oxygen depletion monitor provides an alarmat 19.6% oxygen and a second alarm at 18%. Acontinuous flashing indicator assures the user themonitor is active and normal.

The monitor provides facility for connection ofmultiple repeaters if the enclosure has multipleentrances.

Calibration should be performed annually but canbe performed by simple pushbutton.

Order number 4107 2107 26 (110 vac)

Carbon Dioxide and Oxygen Depletion Monitor

(Because Carbon Dioxide has specific respiratoryeffects in addition to oxygen depletion, a carbondioxide accumulation monitor is required by OSHAwhen carbon dioxide is present and may be thecause of or contribute to oxygen depletion.)

The Combination monitor is an easily installed,

mains powered monitoring device. It isconstructed in two parts: the main monitoringunit, which is mounted in the manifold room, anda repeater alarm which is mounted outside theroom to provide warning prior to entering.

The Combination monitor provides an alarm at19.6% oxygen and a CO2 alarm at 0.5 and 1.5%.A continuous flashing indicator assures the userthe monitor is active and normal.

The monitor provides facility for connection ofmultiple repeaters if the enclosure has multiple

entrances.Calibration should be performed annually but canbe performed by simple pushbutton.

Order number 4107 2107 27 (110 vac)


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Bulk and MiniBulk Implementations

Annex HUsing Bulk and MiniBulk Sources with the LifelineManifold

The Lifeline manifold can act as controller for a bulkor minibulk installation and such an installation maybe the very best way to serve a medium sized facility.

There are a number of important considerations whichmust be accounted for in order to have a satisfactorysystem. They include: Siting. The location of a system which contains

more than 20,000 ft3 is subject to additional rulesabove those applicable to manifolds. BeaconMedsrecommends these rules should be considered asapplying to any installation involving stationaryliquid containers.

Please refer to the drawing in Annex H for sitingrequirements.

BeaconMeds recommends that stationarycontainer installations always be out of doors.Although it is possible under NFPA 99 to place someminibulk systems indoors (eg. those with contentsunder 20,000 ft3), the practice is fraught withproblems which are better avoided. Although theNFPA 99 has dened a 20,000 ft3 limit for systemsplaced indoors, there is no magic to this number.The real concern begins when liquid containerscome indoors and simply worsens as the containersget larger. While there are compelling reasons tobring portable containers indoors in some cases,

those arguments grow less and less acceptable asthe volume increases and are largely invalid once thecontainer is made stationary. However, it is entirelypossible to place the stationary container outdoorsand the manifold, secondary and reserve indoors(see Detail G.1).

Conguration of the system. Please see Detail G.1for a general conguration diagram.

Pressure output. A bulk or minibulk can outputat higher pressures than is typical of portablecontainers and the output pressure is important to

overall function.

As with any manifold, the Lifeline manifold willimprove in ow capacity with higher inlet pressures.Therefore, with a stationary container, the pressuresshould be as high as is consistent with the containercapabilities, and low pressure containers should notbe used.

Sample Manifold throughputsat varying input pressures

Inlet pressurepsi/kPa

Flowft3h / liters per hr.

150 / 1,035 2,220 / 62k

300 / 2,070 3,660 / 103k

450 / 3,105 6,420 / 181k

Vaporization. BeaconMeds recommends externalvaporizers always be used with these installations.


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ReserveCylinder

Header

SecondaryCylinder

Header

BulkorMiniBulkSystem

(includin

ga

llnecessarycontrols,

ie.pressurebuilder,

regulatorsifre

quired)

DetailG.1

ImplementingaLifelineManifoldasaControllerfo

raStationaryContainer

DuplexExternal

VaporizerSet

withcontrols

LocatingtheStationarycontaineroutdoors

isrecommendedbutmaynotbere

quired.

Fillconnectionandterminationofallrelief

valve

ventsoutdoorsisabsolutelymandatory.

Locatingthemanifold,secondaryheaderandreserveheaderindoorsisnot

requiredbutmaybedesirableinsomeclimates.

Manifoldsandcylinders

locatedoutdoo

rsmustbeprotectedfromdirects

un,rainetc.andcylinders

mustbemainta

inedat>32Fand

Cryogenic Liquid Manifold- Application Guide

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