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A better approach to energy-efficient, insulated Pipes

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Microflex Insulated Pipes

Microflex Pipe System

A high performance piping system is essential for energy savings. Microflex® pre-insulated piping system, composed of a thermal insulation around a carrier pipe and covered by a “closed chamber” HDPE outer jacket, is therefore your best choice.

Microflex® piping is suitable for use in both heating and sanitary applications and provides significant advantages.

As the pipes are low-weight and extremely flexible, they can be laid easily and rapidly, even over obstacles and around corners. System accessories can be mounted without any special tools.

Our PEX-a carrier pipe (polyethylene is the raw material and the X refers to the cross -linking of the polyethylene across its molecular chains ) is oxygen diffus ion-proof in accordance with DIN 4726. It can transport a large number of different liquids and is fully corrosion free.

Microflex® is made available as a single (UNO) and twin (DUO) piping system. It is manufactured CFC free. The system is granted approval certificates by various test institutes and monitoring authorities.

NA Standards Approval

The Microflex® line of products delivers complete end-to-end solutions for your insulated piping needs. The system consists of a full set of different diameter pipes with

• NSF/ANSI 14/61 and CSA B 137.5 approved for potable water applications

• Manufactured in accordance with ASTM F 877

• Manufactured in ISO 9001 production facilities

Applications

MicroFlex® Piping Systems are a complete line of flexible piping from 1” to 4” in size with all required accessories for cost effective and permanent installations of:

• District Heating and Cooling running hydronic lines between buildings with minimal energy losses, through unheated spaces, and for extending traditional distribution systems easily and economically

• Underground Piping Systems direct burial of lines up to 328’ in length without joints for chilled water, condenser water, or any sub-terranean system requiring minimal heat gains/losses

• Plumbing Systems for networked cold, hot, and recirculated water lines between buildings, to external or remote facilities such barns, animal sheds, etc.

• Radiant & Snowmelting Systems for feeding remote manifold boxes or adding onto existing systems

• Interior Building Piping to provide the quickest and most guaranteed installation of piping systems with no couplings or joints, already insulated to save time and money at the jobsite, and allow maximum flexibility of carrier pipes through difficult spaces.

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Table of Contents

Microflex Pipe Properties PEX-a Carrier Pipe 4 Insulating material 6 Corrugated HDPE jacket 6 Physical Pipe Properties 7 Table 3: Microflex UNO for Heating Applications 7 Table 4: Microflex DUO for Heating Applications 7 Chemical treatment for Microflex pipes 8 Freeze protection 8 Corrosion protection 8 Table 5: Chemical Resistance 9

System Design Pipe Length 10 Microflex Flexibility 10 System Fill Capacity 14 Fluid Velocity 15 Head/Pressure Loss 15 Influence of Anti-Freeze in the System 16 Fluid Temperature influence 16 Flow Rate Calculation 17 Underground Thermal Loss Compensation 17 Microflex pipe diameter Selection 18 Thermal Expansion 18

Utility Trench and Microflex Pipes 19 Trench Dimensioning charts (inches) 20

Head/Pressure Loss Calculations Table 11: Pressure Loss Table (Medium H2O) 21 - 22 Heat Transfer Calculations Table 12: Heat Transfer through Microflex Pipe - Medium H2O 23 - 24 Heat Loss Calculations Environmental Thermal Loss Microflex UNO Pipes 25 Environmental Thermal Loss Microflex DUO Pipes 25 Table 15: Environmental Thermal loss calculation for low temperatures 26

R-Value Calculations Table 16: Microflex UNO 27 Table 17: Microflex DUO 27

Commercial Specification Texts 28 - 30

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Microflex Insulated Pipes

PEX-a Carrier Pipe

The carrier or medium transport pipe used by Microflex® is a PEX-a pipe, which is manufactured according to DIN standards. Test specimens will be sent on request. PEX-a carrier pipes provide significant benefits.

Outstanding thermal properties

The PEX-a pipe itself has been tested at a temperature of 203°F/87 psi for heating and 203°F/145 psi for sanitary applications (in accordance to DIN 16893). It can also withstand temperature surges up to 230°F. The impact strength is even constant at temperatures below 212°F.Proven long-term strength with a temperature dependent supply temperature (i.e. 194°F winter and 158°F summer) and an operating pressure of 73-87 psi, tests carried out by major testing bodies in a number of countries show that the expected life time can be more than 100 years.

Chemical resistance

Most chemicals have no influence on the pipe, even at elevated temperatures . Chemicals usually causing hair cracks in other materials do not corrode PEX-a.

High abrasion resistance

PEX-a pipes provide an enhanced abrasion resistance and durability. Pipes conveying aggressive sludge at fairly high veloci-ties do not corrode.

Low roughness

The smooth bore offers less resistance to flow than conventional pipes resulting in excellent flow characteristics with minimal flow loss without formation of any sediment deposits.

Environmentally friendly

PEX-a is free from pollutants. The pipe imparts neither taste nor odor and is non toxic, thus ideally suited for differ-ent branches of the food industry.

Physiological behavior

PEX-a pipes comply with international potable water quality requirements.

HDPE Outer Jacket

PEX-a Pipe with O2 diffusion Barrier

Cross-Linked PE Foam Insulation Layer

Microflex insulated pipes consist of three components:

• PEX-a Carrier Pipe w/ O2 Diffusion Barrier

• Cross-Linked PE Foam Insulation Layer

• HDPE Corrugated Jacket

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Microflex Pipe Properties

Oxygen diffusion barrrier

Our PEX-a carrier pipe also features an oxygen diffusion barrier which prevents oxygen to diffuse into the piping system. Such an oxygen barrier layer enhances the life of the components of the system. Water permeability is 0.8x10-6 lbs/gal per day at 104 °F.

Properties Units Typical Value

Density oz/in3 0.53

Modulus of elasticity @ 68F

lbsf/in2 87.022

Tensile stress at yield68F176F

lbsf/in2

2465> 1015

Tensile strength68F176F

lbsf/in2

> 34802610 - 2900

Elongation at yield68F176F

%400400

Impact strength68F-4F

BTU/ft2

no rupturesno ruptures

Thermal Conductivity BTUH/ft 0.22 (tF+459.7)

Linear expansion68F212F

in5.5 x 10-6

7.8 x 10-6

Oxygen Permeability (@ 104F)

lbs/gal 0.8 x 10-6 per day

Surface roughness k in 0.22 x 10-3

Transverse resistivity in >4 x 1017

spec. thermal capacity BTU/lbs 0.6 (tf + 459.7)

Table 1: Mechanical and thermal proper-ties of PEX-a pipe according to DIN 16892/168932

Long-term behavior

Long-term tests prove the strength of PEX-a pipes as a function of time and temperature. PEX-a is cross -linked polyethylene. Through one of several processes, links between polyethylene macromolecules are formed to create bridges between PE molecules (thus the term cross- linked). This resulting molecule is more durable under temperature extremes, chemical attack, and resists creep deformation, making PEX-a an excellent material for hot water applications (up to 203 °F). In contrast to non-cross-linked thermoplastic materials such as PP and PB, the strength curves of PEX-a show a linear course at elevated temperatures. Long-term tests covering more than 30 years prove them safe for a service life of up to 50 years. Admissible pipe stresses can be calculated with the help of the diagram on the next page.

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Insulating material

The insulating material used consists of microcellular, cross -linked polyethylene foam. In addition to the excellent insulating properties, the closed cell structure of the material ensures that there is only minimal water absorption. The material is CFC free.

Corrugated HDPE jacket

The jacket, made of HDPE, protects both the carrier pipe and the insulating material from external influences. The corruga-tion pattern provides flexibility in the longitudinal direction and excellent rigidity against radial forces. The construction is very solid, watertight and resistant to aggressive substances.

Test Method Value

Density ISO 845 1.87 lbs/ft3

Tensile Strength ISO 1926 34.8 psi

Service Temperature -112F to 230F

Water absorption after 28 days

DIN 53428 < 1.04 Vol. %

Thermal Conductivity DIN 52612 50F 0.022 (tf+459.7) BTUH/ft 104F 0.021 (tf+459.7 BTUH/ft

Microflex Properties

Table 2: Insulation Material Properties

Long term resistance to internal pressures of PEX-a pipes as a function of time

Chart 1: Long term stress re-sistance PEX-a Pipes

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Microflex Pipe Properties

Microflex Physical Pipe Properties

Microflex pipes are light and flexible. The standard length of 1 coil is 328 ft. Tailored lengths can be cut. The coils can be conveyed by ordinary means of transport.

Table 3: Microflex UNO

Pipe Jacket diameter

PEX ND Bending Radius

Carrier Pipe

volume

Weight max.Coil

Length

Coil dimensions

inner Da.

outer Da.

width

mm in mm ID (mm) in gal/ft lbs/ft ft in in in

75 3” 1” 7/8” (22.2) 8” 0.031 0.43 328 44 67 16

125 5” 40 1 7/16” (36.4)

15 3/4” 0.083 1.20 328 48 79 30

125 5” 50 1 7/8” (45.4)

19 3/4” 0.130 1.34 328 48 79 30

125 5” 63 2 1/4” (57.2)

19 3/4” 0.208 1.56 328 48 79 30

160 6 1/4” 40 1 7/16” (36.4)

19 3/4” 0.083 1.11 328 48 79 34

160 6 1/4” 50 1 7/8” (45.4)

19 3/4” 0.130 1.28 328 48 79 34

160 6 1/4” 63 2 1/4” (57.2)”

19 3/4” 0.208 1.48 328 48 79 34

160 6 1/4” 75 2 11/16” (68.8)

19 3/4” 0.294 2.08 328 48 79 34

200 8” 90 3 3/16” (81.8)

21 3/4” 0.423 2.55 328 48 95 59

200 8” 110 3 15/16” (100)

23 3/4” 0.632 3.02 328 48 95 59

Table 4: Microflex DUO for Heating Applications

Pipe Jacket diameter

PEX ND Bending Radius

Carrier Pipe

volume

Weight Coil Length

Coil dimensions

inner Da.

outer Da.

width

mm in mm ID in gal/ft lbs/ft ft in in in

125 5” 1”/1” 7/8” (22.2) 11 3/4” 2x 0.031 1.05 328 48 79 30

125 5” 32/32 1 1/8”(29.1) 11 3/4” 2x 0.054 1.19 328 48 79 30

160 6 1/4” 40/40 1 7/16” (36.4)

19 3/4” 2x 0.083 2.34 328 48 79 34

160 6 1/4” 50/50 1 7/8” (45.4)

19 3/4” 2x 0.130 2.39 328 48 79 34

200 8” 63/63 2 1/4” (57.2)

39 1/2” 2x 0.208 3.62 328 48 79 59

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Chemical treatment for Microflex pipe systems

Inhibitors For all systems it is suggested that inhibitors, approved for closed loop hydronic heating systems, be added to the heating fluid for corrosion protection. For calculation of system water content in the particular PEX piping chosen for your project, please inquire at your local ComfortPro Systems supplier.

Freeze protection For systems exposed to freezing temperatures the addition of glycols with built-in inhibitors (that are approved for hydronic heating systems) to the heating fluid is required. A minimum of a 30%-35% (maximum 50%) glycol/water mixture is required for the combined protection against freezing and system corrosion. For calculation of system water content in the particular PEX piping chosen for the project. See table 10 on page 14.

Note: A water analyis should be performed annually (i.e. check corrosion inhibitor and glycol levels) to ensure the warranty for ComfortPro Systems components, and for the longevity of the system.

Corrosion protection For all systems it is suggested that inhibitors, approved for closed loop hydronic heating systems, be added to the heating fluid for corrosion protection. For calculation of system water content in the particular PEX piping chosen for your project, please contact your local ComfortPro Systems supplier for information.

Changes in the properties of plastics in contact with chemicals are primarily the result of physical processes, such as swelling or solution of the polymers. In this respect, PEX pipes (cross-linked polyethylene) behave more favorably than non-cross-linked PE pipes as a result of their chemical linkage pattern.

For assessment of the resistance to different substances, the alteration in tensile and ductile behavior is taken into consid-eration.

The chemical resistance factors shown do not generally apply to the specific behavior of a pipe filled with a specific sub-stance under pressure. In this respect, long-term investigations using test pipes may offer decisive answers.

Chemical resistance of PEX pipes and its tolerance to known chemicals and fluids are shown in table 5.

Pipe Properties - Chemical Treatments

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Substance 68°F 140°FAcetic acid + +

Acetone +

Acrylonitrile + +

Agricultural pesticides + +

Alkyl alcohol + +

Aluminum chloride, anhy-drous

+ +

Aluminum sulphate, aque-ous

+ +

Ammonia, aqueous + +

Ammonium chloride, aque-ous

+ +

Ammonium sulphate, aqueous

+ +

Aniline, pure + +

Aqua regia - -

Beer + +

Benzoic acid, aqueous + +

Benzol o -

Bitumen + +

Bleaching liquor +

Bromine - -

Butanediol + +

Butanol + +

Butter + +

Butyl acetate + o

Butyric acid + o

Carbon tetrachloride o -

Carbonic acid + +

Chlorine gas, wet o -

Chlorine, liquid - -

Chloroform o -

Chromic acid 50% + -

Chromic acid/Sulphuric acid

+ -

Citric acid + +

Cod-liver oil + +

Cresols + o

Cyclohexane + o

Cyclohexanol + +

Cyclohexanone + o

Decahydronaphthalene + -

Detergent + +

Detergents, synthetic + +

Dibutyl phthalate + o

Dichlorobenzene o -

Substance 68°F 140°FDichloroethylene o -

Diesel oil + o

Diethyl ether o

Ester aliphatic + o

aromatic o o

Ethyl acetate + o

Ethyl alcohol + +

Ethylene glycol + +

Fluorine - -

Formaldehyde (40%) + +

Formic acid + +

Freon o -

Fuel Oil + o

Glycerine + +

Glycol + +

Hexane + +

Hydrochloric acid (70%) + o

Hydrochloric acid, conc. + +

Hydrogen sulphide + +

Hydrogen peroxide, 30% + +

Hydrogen peroxide, 100% + -

Lineseed oil + +

Maleic acid + +

Mercury + +

Methanol + +

Methyl ethyl ketone + o

Methylene chloride o -

Milk + +

Motor oils + o

Naphtha + o

Naphthalene + -

Nitric acid, 30% + +

Nitric acid, 50% o -

Nitrobenzene + o

Oils, essential + o

Oils, vegetable + o

Oleum - -

Oxalic acid (50%) + +

Ozone aqueous <0.1% + -

Ozone o -

Paraffin oil + +

Petrol + o

Petroleum ether +

Petroleum + o

Substance 68°F 140°FPhenol + o

Phosphates, aqueous + +

Phosphoric acid, 95% + +

Phtalic acid, 50% + +

Polyglycol + +

Potassium bichromate (40%)

+ +

Potassium chloride, aque-ous

+ +

Potassium permanganate 20% solution

+ +

Propanol + +

Propionic acid, 50% + +

Propyl alcohol + +

Pyridine + o

Salts of magnesium, aque-ous

+ +

Silicone oil + +

Soap solution + +

Sodium hypochlorite + o

Sodium hydroxide + +

Styrene o -

Sulphuric acid, up to 50% + +

Sulphuric acid, up to 98% o -

Sulphuric anhydride - -

Tetrahydrofuran o -

Tetralin + o

Tincture of iodine + o

Toluene o -

Transformer oil + o

Trichloroethylene o -

Turpentine oil + o

Vaseline + o

Water + +

Wine + +

Xylene o -

Table 5 - Chemical Resistance of PEX piping

Pipe Properties - Chemical Resistance

+ = RESISTANTo = LIMITED RESISTANCE- = UNSTABLE

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System Design

Microflex Flexibility

Bending Radius MICROFLEX® DUO MD16040C (PEX-a 2x40mm, HDPE Jacket 160mm (6 1/4”))

When designing a Microflex system for energy transfer applications, several factors have to be considered to optimize the efficiency of all components. In most applications the heat transfer or energy conservation is the most important aspect to be preserved. But all components should work harmonically together in order to achieve the optimal design.

To properly calculate the system the following calculation steps should be taken

1. Determine the total equivalent pipe length2. Determine pressure loss in the system3. Calculate the heat load at the source4. Determine the flow rate based on medium characteristics5. Select the right pipe diameter

Pipe Length

The first parameter to consider is the actual length of the transport system from energy source to the target recipient. Although the goal is to make the system as independant of external influences as possible several key parameters have to be taken into account.

Most important is the handling of the pipes themselves which are determined by the max. length available. If the distance to be connected via Microflex pipes is larger than 328ft, pipes can easily be connected with Microflex PEX adapters and connecting pieces.

The overal pipe length determines the maximum amount of heat loss intrinsical to the selected pipe, the pressure loss influ-enced by the length of the pipe as well as any connections and branching designs, the average target temperature or any specific localized temperature gradiants.

Microflex’s extreme flexibility minimizes the pipe length and therefore minimizes losses. The bending radius is instrumental in calculating the overall length. Bending radii are listed in the physical property tables 3 and 4 of this book.

The extra length of Microflex pipe for any bend of 90 degree is calculated based on the geometrical formula:

L = p/2 x (RB + dMF/2)

where RB = bending radius based on the measured inside radius as outlined in table 3 and 4, pg. 7 dMF = Microflex HDPE outer jacket Diameter.

Example:

Extra length for one 90 degree bend for a 160mm (6 1/4”) Microflex UNO pipe with a 40mm carrier pipe and a minimum bend-ing radius of 19 3/4” is 6.7 ft.

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System Design

Use of connection fittings, T-pieces, inspection chambers

Please consider the position of your connection pieces in the lay-out with respect to minimizing the sheer stress on the fit-ting.Use the Microflex selection guide to find equivalent length information on T-pieces, inspection chamber, hose and straight pipe connection parts.

Outer Jacket/Pipe Diameter

75mm/1"

125/40mm

125/50mm

125/63mm

160/40mm

160/50mm

160/63mm

160/75mm

200/90mm

200/110mm

Straight Pipe piece [ft] 1 1 1 1 1 1 1 1 1 1

Pipe Bend 90 deg. [ft] 3.0 5.3 5.8 5.8 6.7 6.7 6.7 6.7 8.0 8.3

Pipe Bend 45 deg. [ft] 1.5 2.6 2.9 2.9 3.4 3.4 3.4 3.4 4.0 4.1

Table 6: Microflex physical pipe length -Microflex UNO

Outer Jacket/Pipe Diameter 125mm/1" 125/32mm 160/40mm 160/50mm 200/63mm

Straight Pipe piece [ft] 1 1 1 1 1

Pipe Bend 90 deg. [ft] 3.5 4.8 6.7 6.7 10.3

Pipe Bend 45 deg. [ft] 1.7 2.4 3.4 3.4 5.2

Table 7: Microflex physical pipe length -Microflex DUO

In tables 6 and 7 we summarize the required length of Microflex piping to make 90 degree or 45 degree bends with available Microflex products. The given length data reflects the tightest suitable bends achievable with specific Microflex pipes.

Other bending arc segments can be calculated by substituting p/2 with a/180 * p, where a represents the angle of the bend from its center. One might have to adjust the radius from the minimal bending radius to the desired bending radius.

Microflex DUO pipes

Microflex UNO pipes

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In this example we want to determine the correct length of the microflex pipe shown in sketch 1. We assume to be laying Microflex DUO pipe MD16040C (see bending radius example on the previus page).

1. Draw/map the Microflex piping layout on your project masterplan.

2. Spliting the pipe length into straight and 90 degree angle segments. (in the graphic marked by Segment A through F)

3. Calculating the equivalent length of the angled segments based on formula page 10, paragraph Microflex Flexibility). It is beneficial to lay 90 degree angled bends, although other bends can be implemented based on necessity of the individual project.

4. After the length of all segments have been determined we simply add them all together.

5. To accommodate for the thermal expansion forces and minimize the forces on the fittings, a 5% add-on to the total length is required. This surplus pipe segment should be distributed over the hole length and layed in the trench in serpentine or “zigzag” pattern. In this example we call it “Z add-on”.

EXAMPLE 1: Determining the Physical Length of Microflex Piping

Segment Length [ft] Comment

A 40 straight segment

B 6.7 bended pipe min bending radius

C 6.7 bended pipe min bending radius

D 15 straight segment

E 6.7 bended pipe min bending radius

F 6 straight segment

Z add-on 4.06 5% of total length

Sum 85.16Total length of MF pipe needed to be used to determine pres-sure drop.

Table 8: Example calculation to determine total pipe length of pipe layout (example sketch 1).

Segment A

Segment B

Segment E

Segment D

Segment C

Segment F

Sketch 1: Example Pipe layout

Structure 1

Structure 2

Structure 3

System Design

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System Design

In this example we want to determine the correct equivalent length-length of the microflex pipe shown in sketch 1. We assume to be laying again Microflex DUO pipe MD16040C (see example 1). To calculate the equivalent length for further pressure drop considerations we include supply and return as well as a Tee connection to illustrate the necces-sary steps:

1. Calculate the neccessary physical Microflex DUO pipe length like in example 1, previous page. We calculate the length of all unique physi-cal paths. Segments A through D1 (5ft) up to the Tee connection is Section 1. The branch from Tee to structure 3 (i.e. Segment D2 (10ft) through F) builds section 2.

2. Since we added a connection Tee, we need to add the pipe length on the T-branch. For this calculation we assume 10ft. This branch is called section 3.

3. Brass fittings are being used in this example. Now we need to include the length equivalent of all brass fittings. In this example we use fit-tings of the Microflex product range. Correct length equivalent values can be read from the pressure drop charts or information of the sup-plier. In this example we use Microflex PEX adapters and one Tee branch connector.

4. We assume a 3ft/s flow velocity which gives us a 1ft equivalent length per Microflex PEX adapter and an assumed 1.5ft equivalent length for the T-connector.

5. Adding the fittings’ equivalent length total (table 9) to the total length of Microflex pipes used results in a combined total length of 90.66 for the unique path of section 1 and 2. For the T branch path (section 1 and 3) we calculate 71.82ft pipe length plus fittings (5.5 ft) resulting in 77.32ft total equivalent length.

Note: In this example we have calculated the length for either sup-ply or return pipe. For a full system design we have to take both pipes into account (factor 2x) as well as any pressure drop outside the e Microflex system example like heaters, radiators, storage systems etc.

EXAMPLE 2: Determining the Total Equivalent Length of Microflex Piping

Segment A

Segment B

Segment E

Segment D

Segment C

Segment F

Fittings in Segment

Equivalent Length [ft]

Comment

A 1 1 adapter per supply/return

D1 1 1 adapter per supply/return (main line)

D2 1+1.5 1 PEX adapter and 1 T-connector per supply/return

F 1 1 adapter per supply/return

Sum 5.5Total equivalent length for fittings used in system to determine pres-sure drop.

Sketch 2: Example Pipe layout including MF brass fittings

Table 9: Example summation for fittings along the longest unique path (sect. 1 and 2) to de-termine total equivalent length for fittings in pipe layout example 2.

Segment T

Supply Return

D1

D2

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System Design

Chart 2: Fill volume for various PEX pipes used as carrier pipes in Microflex insulated pipe solutions.

System Fill Capacity

To get an easy approximation of total system fluid capacity for hydronic system fills please see table 10, which gives fill volumes for Microflex PEX pipe systems as a function of pipe length for water as medium. For anti-freeze usage substitute the amount of water with the anti-freeze solution based on the desired dilution ratio and freeze protection. In large systems Specific Gravity information might have to be taken into consideration.

0

50

100

150

200

250

300

350

0 100 200 300 400 500 600

Fill

Volu

me

[US

gallo

n]

L ength of P E X P ipe [ft]

1"

32mm

40mm

50mm

63mm

75mm

90mm

110mm

Pipe Diameter 1” 32mm

11/4”40mm

11/2’50mm

2”63mm

21/2”75mm

3” 90mm

4”110mm

Length [ft] Vol [US Gallon]

1 0.03 0.05 0.08 0.13 0.21 0.30 0.42 0.63

10 0.33 0.54 0.84 1.30 2.07 2.99 4.23 6.32

50 1.64 2.68 4.19 6.52 10.35 14.97 21.16 31.62

100 3.29 5.36 8.38 13.03 20.69 29.93 42.32 63.24

200 6.57 10.71 16.76 26.07 41.38 59.87 84.63 126.48

250 8.22 13.39 20.95 32.59 51.73 74.84 105.79 158.10

300 9.86 16.07 25.14 39.10 62.07 89.80 126.95 189.72

500 16.44 26.78 41.90 65.17 103.46 149.67 211.58 316.20

Table 10: System fill capacity for Microflex PEX pipes by diameter and pipe length.

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Fluid Velocity Calculation

The flow velocity through the pipe is an important factor in determining the head loss within the system, therefore we want to first determine the velocity parameter before getting into the pressure loss calculation.The flow volume of the medium through the pipe is dependent of the density of the medium against its standard density at 68oF, In order to calculate the flow velocity, we determine the volume of 1ft of the PEX carrier pipe out of tables 3 or 4 on pg 7.

We convert US Gallon into cubic inches of the medium and multiply with the density of the fluid used in the system.

VolMedium = VolPipe [USGal/ft of pipe] x ρ (density of medium at target system Temp) = VolMedium [ Gal/ft]

Now we determine the flow rate q as the amount of gallon which get pumped through the system pipe per time element. Typically this is calculated as Gallon per minute or GPM. The velocity is then defined as follows:

v = q [GPM] / VolMedium [Gal/ft] = v [ft/min] / 60 = v [ft/s]

The velocity is alternatively calculated as

v = 0.4085 q / d2 (Engeneeringtoolbox.com)

where v = velocity (ft/s), q = volume flow rate (US gal. /min), d = pipe inside diameter (inches)

Head/Pressure Loss

For practical reasons we included easy-to-read friction based head/pressure loss table (table 11) for all Microflex pipes with water as medium. The exact pressure loss for pipes in specific applications is dependent on the density of the transport medium (i.e. water vs. glycol, etc.), temperature influence of viscosity and thus density. Qualitatively the following assumptions can be made:

Pressure loss per foot decreases with

• Decrease in density through a mixture in the medium (i.e. percentage of glycol or other chemicals in the medium)• Decrease in flow rates or medium velocity• Increase in temperature (density is temperature dependent)

The pressure loss in a pipe or tube can be expressed with the D’Arcy-Weisbach equation

Δp = λ (L / dh) (ρ v2 / 2)

whereΔp = pressure loss λ = friction coefficient (Microflex PEX-a carrier pipe surface roughness = 0.27 x 10-3 inch)L = length of duct or pipedh = hydraulic diameter (i.e. pipe ID)ρ = fluid density of the mediumv = velocity of medium through the carrier pipe

System Design

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Influence of Anti-Freeze within the System

Depending on the environmental conditions for your system design, a anti-freeze solution might be needed to avoid damage to the system in extreme temperature conditions. Most real application uses some kind of anti-freeze solution in the system propylene and ethylene glycol based. Propylene glycol is the preferred anti-freeze solution these days because of its lower environmental impact and ready made solutions for the market place.

Anti-freeze solutions can typically be applied right out of the box. The use of anti-freeze solutions depends on the degree of freeze protection your design needs within the environment and region of your project. For underground pipe projects the annual soil temperature variance as well as the laying depth of the pipe system determines the amount of anti-freeze needed. But even above ground installation of Microflex pipes might require anti-freeze protection depending on location.

For system designs the influence of anti-freeze solutions used in the system changes the calculations for heat transfer and flow rate and have to be planned in order to obtain accurate design parameters for pump sizing and heat storage tank di-mensions. Thereby the dilution ratio of anti-freeze solutions is the main variable in determining the exact design parameters. Typically freeze protection products vary by manufacturers and thus we highly emphasize to read the product’s technical and safety information. For propylene glycol the following general changes should be applied to the system parameters:

Flow rate: To achieve the same heat transfer up to a 10% - 15% higher flow rate should be considered depending on system temperature and anti-freeze dilution. Rough estimate is 1.5% flow rate increase per every 10% of glycol in the mixture.

Heat transfer: To maintain the same heat transfer as with regular water the flow rate should be adjusted by up to 15%.Or by maintaining the same flow rate a wider pipe diameter should be chosen to deliver the same heat capacity.

Another factor to consider is the systems temperature. Since for all materials density and specific heat (see “flow rate calculation” paragraph, pg. 17) are temperature dependent, they have also be considered.

Medium/ Fluid Temperature Influence

Density and specific heat parameters are required for the calculation of flow rate and heat transfer capacity. In the following tables we summarize some generic data:

System Design

Solution base Temperature Density

(oF) [lbs/gal.]Water (H2O) 110 8.27Water (H2O) 140 8.21Water (H2O) 180 8.10

Propylene Glycol (avg.) 60-65 8.73

Solution base Temperature Specific Heat cH

(oF) [Btu/lb.oF]Water (H2O) 110 0.998Water (H2O) 140 0.999Water (H2O) 180 1.003

Propylene Glycol (avg.) 140 0.810

Note: This generic data does not replace manufacturers information for accuracy

In general the heat capacity transfered decreases with increasing temperature. It also decreases the capacity with increasing glycol substitution.

The heat transfer capacity for water as a medium for common applications (like snowmelt, hydronic heating, etc.) varies by around 2-3% and might have to be considered in certain projects.

17

Systems


Underground Thermal loss compensation

One of the most important consideration when planning an insulated pipe system project is the total heat or energy needed at the recipient side of the system. Therefore the key question arises how much energy/heat capacity needs to be inserted in the system at the source side for compensation of heat transfer losses due to environmental/soil conditions.

An easy approximation is to assume a 1 BTU/H*ft heat loss when using Microflex pipes in non-freezing soil conditions. For low temperature approximation consult table 15. The total heat capacity at the source side of the system is then calculated as

Qtotal = QRecipient + 1 BTUH/ft x L

where

Qtotal = Total heat capacity at source side of the system needed to get a guaranteed heat transfer capacity at recipientQRecipient = Target heat capacity at recipient sideL = Overall length of the Microflex system in feet

The largest impact on thermal loss is based on the temperature differential between the surrounding soil temperature and the medium temperature in the carrier pipe. The strong dependency on the soil temperature is based on the thermal conductivity of the soil. While a coarse ground allows for good drainage of water - which guarantees a low conductivity of almost 1 BTU*in/h*ft2*F, wet soil with clay like features can easily push the thermal conductivity up to 15 BTU*in/h*ft2*F. For planning purposes in general wet conditions a 8 BTU*in/h*ft2*F can be safely assumed.

In summary the thermal loss compensation can contribute substantially to the heat loss in a project. There are two potential thermal loss sources:

1. Regular thermal loss through the insulation with temperature difference based on medium and surrounding environmental temperature as residual thermal loss through the insulation, typically expressed by the R-value (see tables 13&14, 16&17).

2. Thermal conductivity of energy based on underground soil or ground conditions like drainage and insulating air pockets based on a gravel fill.

Flow Rate Calculation

Table 12 in Appendix “Heat transfer table” lets easily read out low rate vs. total heat capacity for available Microflex carrier pipes with water at various supply and return temperature differentials DT. For exact project heat capacity calculations with insulated pipes thermal loss into the surrounding environment has to be taken into consideration, too. Please see paragraph “Underground Thermal Loss Compensation” below for details.

To calculate flow rates for other hydronic fluids a designer has to know the total heat capacity at the source, density r, and specific heat cH of the system. When this is known the flow rate can be calculated as:

FR = Qtot/(r x cH x DT x 60) [US GPM}

WhereQtot = total heat capacity within the systemr = density of the systems fluid (H2O/anti-freeze mix)cH = specific heat of system fluid (H2O/anti-freeze mix)DT = temperature differential between supply and return temperature60 = Unit conversion factor sec/min

The flow rate based on a simple entry in this equation will give the unit of US gallon per hour. To calculate in GPM the result has to be devided by 60.

System Design

18

Systems


Microflex pipe diameter Selection

For selection of the right Microflex pipe, heat transfer (capacity) and flow rate should have been calculated and compared based on TABLES 12 and 11. It is further necessary to check the pressure loss in order to optimize pump capacity at the source of the system. Selecting the right Microflex Pipe is a re-iterative process based on the heat loss along the pipe length. We show the main steps to determine the pipe size:

1. In Table 12 we select heat transfer capacities for specific Microflex pipes by choosing flow rate and specific supply/return temperature differences based on the target heat energy transfer needed for the system design.

2. Now we have to compensate for the energy losses through the pipe which depends on the length of the pipe the thermal losses occuring along the designed pipe path (use of anti-freeze solutions, underground thermal loss, low temperature non linear losses). This increases the heat capacity needed at the source side of the system to deliver enough heat energy to the recipients within the system.

3. We look up the new calculated heat transfer capacity in table 12 and select the new flow rate.4. With this flow rate we check whether the selected pipe size is suitable for the application based on friction pressure loss table

11 (within an acceptable rate between 10 - 20 ft of hd/100ft).

Thermal Expansion

Microflex pipes should be laid in a serpentine pattern in trenches to avoid exessive force on connection fittings. While the ther-mal pipe expansion is typically absorbed within the Microflex pipe certain forces due to temperature dependency are working on the connections and it is recommended to clamp down both ends of the Microflex pipe or enough strength needs to be placed on the connection fittings. See Microflex Installation Guide for details.

System Design

Regular (environmental) Tem-perature PEX carrier pipe is laying without force.

High Temperature

PEX pipe expansion creates stress on connection fittings. 100% force on end fittings. Ex-pansion gets absorbed largely by deformation and pushing against soft insulation walls.

Expansion Force FExpansion

FResultFResult

FZ

FExpansion

FExpansion

Serpentine ground laying

Laying pipes in “zigzag” or ser-pentine pattern reduces forces FResult on end fittings.

19

Systems


Up to a trench depth of 4 feet, we recommend digging a vertical trench; deeper than 4 feet, we recommend a V-shaped trench.

Excavation work must be carried out in the approved manner, according to local codes and regulations.

The depth of the trench must be in accordance with the guidelines of the following pages. These guidelines relate to laying of Microflex pipes.A land register plan might be useful to eliminate possible conflicts with existing or future utilities and structures.

After completion of the pipe-laying process, the route can be marked with a warning tape. Entry in the land register plan is recommended.

Note:

Utility Trench and Microflex Pipes

Minimum laying temperature for Microflex pipes is 23°F.

Particular attention must be paid to ground frost depth when laying sanitary pipes. Check with local codes for compliance.

Layout Considerations

Effect of Sheer stress at T-pieces and connection elbows

Thermal expansion of Microflex PEX carrier pipe causes sub-stantial sheer stress on pipe connections and fittings like T-pieces, or elbows if not allowed to move with the expansion.

By using a Microflex or appropriate ComfortPro Systems flex-ible PEX pipe to connect to rigid piping, sheer forces can be avoided. We further recommend the use of Microflex T-pieces, hose, and straight connectors to hold the outer HDPE jacket in place.

20

Systems


Trench Dimensioning charts (inches)

Note: The trench dimensions given in this chart are for references only. Please consult all aplicable codes before laying down Microflex pipes in trenches.If trenches are crossing underneath areas with a high surface load (driveways, streets, etc.), depth and width of the trench needs to be adjusted. Use values in brackets as minimum values.

Jacket OD A B C D b d Excavation Sandfill

mm in. in. in. in. in. in. in. ft3/ft ft3/ft

125 5 6 4 6 10 (26)

17 25 (41)

2.9 1.8

160 6 1/4 7 4 6 10 (26)

20 27 (42)

3.7 2.4

200 8 7 4 6 10 (26)

22 28 (44)

4.2 2.7

Trench profile for Microflex twin pipe (DUO)



75 3 6 4 6 10 (26)

22 23 (39)

3.4 2.2

90 3 1/2 6 4 6 10 (26)

24 25 (39)

3.7 2.4

125 5 6 4 6 10 (26)

26 25 (41)

4.4 2.8

160 6 1/4 7 4 6 10 (26)

31 26 (42)

5.5 3.4

200 8 7 4 6 10 (26)

34 28 (44)

6.5 4.1

Trench profile for 2x Microflex single pipe (UNO) without underground connection



300 12 6 4 6 10 (26)

36 32 (48)

7.8 4.8

Trench profile for 2x Microflex single pipe (UNO) with underground connection

1 Backfill2 Route Warning tape3 Sand Fill4 Sandbed5 Microflex pipe

1 Backfill2 Route Warning tape3 Sand Fill4 Sandbed5 Microflex pipe

dd

d

12

3

4

5

1

2

3

4

5

1

2

3

4

5

Trench Planning

21

Systems


flow rate Pressure Loss for Microflex PEX Carrier Pipes [ft of head/100ft]

[GPM] 1” 32 mm11/4’

40 mm11/2”

50 mm2”

63 mm21/2”

75 mm3”

90 mm4”

110 mm

0.5 0.05 0.02 0.01

1 0.19 0.06 0.02 0.01

1.5 0.40 0.12 0.04 0.01 0.00

2 0.68 0.21 0.07 0.02 0.01

3 1.45 0.44 0.15 0.05 0.02 0.01

4 2.46 0.75 0.25 0.09 0.03 0.01 0.00

5 3.72 1.14 0.38 0.13 0.04 0.02 0.01

6 5.22 1.59 0.54 0.18 0.06 0.02 0.01 0.00

7 6.94 2.12 0.71 0.24 0.08 0.03 0.01 0.01

8 8.89 2.71 0.91 0.31 0.10 0.04 0.02 0.01

9 11.05 3.37 1.14 0.39 0.13 0.05 0.02 0.01

10 13.44 4.10 1.38 0.47 0.15 0.06 0.03 0.01

11 16.03 4.89 1.65 0.56 0.18 0.07 0.03 0.01

12 18.83 5.75 1.93 0.66 0.21 0.09 0.04 0.01

13 21.84 6.66 2.24 0.77 0.25 0.10 0.04 0.02

14 25.05 7.64 2.57 0.88 0.29 0.12 0.05 0.02

15 28.47 8.69 2.92 1.00 0.32 0.13 0.06 0.02

16 9.79 3.29 1.12 0.37 0.15 0.06 0.02

17 10.95 3.69 1.26 0.41 0.17 0.07 0.03

18 12.18 4.10 1.40 0.45 0.19 0.08 0.03

19 13.46 4.53 1.55 0.50 0.20 0.09 0.03

20 14.80 4.98 1.70 0.55 0.22 0.10 0.04

22 17.66 5.94 2.03 0.66 0.27 0.12 0.04

24 20.74 6.98 2.38 0.77 0.32 0.14 0.05

26 24.06 8.10 2.76 0.90 0.37 0.16 0.06

28 27.60 9.29 3.17 1.03 0.42 0.18 0.07

30 31.36 10.55 3.60 1.17 0.48 0.21 0.08

32 11.89 4.06 1.32 0.54 0.23 0.09

34 13.31 4.54 1.48 0.60 0.26 0.10

36 14.79 5.05 1.64 0.67 0.29 0.11

38 16.35 5.58 1.81 0.74 0.32 0.12

40 17.98 6.14 1.99 0.81 0.35 0.13

42 19.68 6.72 2.18 0.89 0.38 0.14

44 21.45 7.32 2.38 0.97 0.42 0.16

46 23.29 7.95 2.58 1.05 0.45 0.17

48 25.20 8.60 2.79 1.14 0.49 0.18

50 9.28 3.01 1.23 0.53 0.20

Friction Pressure Loss Table

Tabl

e 11

: Fric

tion

indu

ced

Pres

sure

dro

p ta

ble

for M

icro

flex

Carr

ier P

ipes

.(H

azen

-Will

iam

s Fo

rmul

a, c

PEX=1

40)

22

Systems


flow rate Pressure Loss for Microflex PEX Carrier Pipes [ft of head/100ft]

[GPM] 1” 32 mm11/4’

40 mm11/2”

50 mm2”

63 mm21/2”

75 mm3”

90 mm4”

110 mm

52 9.97 3.24 1.32 0.57 0.21

54 10.70 3.48 1.42 0.61 0.23

56 11.44 3.72 1.51 0.65 0.25

58 12.21 3.97 1.62 0.70 0.26

60 13.00 4.22 1.72 0.74 0.28

62 13.82 4.49 1.83 0.79 0.30

64 14.65 4.76 1.94 0.84 0.31

66 15.51 5.04 2.05 0.88 0.33

68 16.39 5.33 2.17 0.93 0.35

70 17.30 5.62 2.29 0.99 0.37

72 18.22 5.92 2.41 1.04 0.39

74 19.17 6.23 2.54 1.09 0.41

76 20.14 6.55 2.67 1.15 0.43

78 21.14 6.87 2.80 1.20 0.45

80 22.15 7.20 2.93 1.26 0.48

85 24.78 8.05 3.28 1.41 0.53

90 27.55 8.95 3.65 1.57 0.59

95 30.45 9.89 4.03 1.74 0.65

100 10.88 4.43 1.91 0.72

105 11.91 4.85 2.09 0.79

110 12.98 5.29 2.28 0.86

120 15.25 6.21 2.68 1.01

130 17.69 7.20 3.10 1.17

140 20.29 8.26 3.56 1.34

150 23.06 9.39 4.04 1.52

160 10.58 4.56 1.72

170 11.84 5.10 1.92

180 13.16 5.67 2.13

190 14.55 6.27 2.36

200 16.00 6.89 2.59

225 19.89 8.57 3.22

250 10.42 3.92

275 12.43 4.68

300 14.60 5.49

325 6.37

350 7.31

375 8.31

Friction Pressure Loss Table

Tabl

e 11

: Fric

tion

indu

ced

Pres

sure

dro

p ta

ble

for M

icro

flex

Carr

ier P

ipes

.(H

azen

-Will

iam

s Fo

rmul

a, c

PEX=1

40)

23

Systems


Heat Transfer for Microflex Carrier Pipes (100% Water @ 140°F)

Density = 8.206 lbs/gal Specific Heat cp = 0.999 BTU/ lb°F

flow rate DT=5F DT=10F DT=15F DT=20F DT=25F DT=30F DT=35F DT=40F DT=45F DT=50F

[GPM] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h]

0.5 1,231 2,462 3,693 4,923 6,154 7,385 8,616 9,847 11,078 12,309

0.75 1,846 3,693 5,539 7,385 9,231 11,078 12,924 14,770 16,617 18,463

1 2,462 4,923 7,385 9,847 12,309 14,770 17,232 19,694 22,156 24,617

1.5 3,693 7,385 11,078 14,770 18,463 22,156 25,848 29,541 33,233 36,926

2 4,923 9,847 14,770 19,694 24,617 29,541 34,464 39,388 44,311 49,235

2.5 6,154 12,309 18,463 24,617 30,772 36,926 43,080 49,235 55,389 61,543

3 7,385 14,770 22,156 29,541 36,926 44,311 51,696 59,081 66,467 73,852

3.5 8,616 17,232 25,848 34,464 43,080 51,696 60,312 68,928 77,544 86,160

4 9,847 19,694 29,541 39,388 49,235 59,081 68,928 78,775 88,622 98,469

4.5 11,078 22,156 33,233 44,311 55,389 66,467 77,544 88,622 99,700 110,778

5 12,309 24,617 36,926 49,235 61,543 73,852 86,160 98,469 110,778 123,086

6 14,770 29,541 44,311 59,081 73,852 88,622 103,393 118,163 132,933 147,704

7 17,232 34,464 51,696 68,928 86,160 103,393 120,625 137,857 155,089 172,321

8 19,694 39,388 59,081 78,775 98,469 118,163 137,857 157,550 177,244 196,938

9 22,156 44,311 66,467 88,622 110,778 132,933 155,089 177,244 199,400 221,555

10 24,617 49,235 73,852 98,469 123,086 147,704 172,321 196,938 221,555 246,173

11 27,079 54,158 81,237 108,316 135,395 162,474 189,553 216,632 243,711 270,790

12 29,541 59,081 88,622 118,163 147,704 177,244 206,785 236,326 265,866 295,407

13 32,002 64,005 96,007 128,010 160,012 192,015 224,017 256,020 288,022 320,024

14 34,464 68,928 103,393 137,857 172,321 206,785 241,249 275,713 310,178 344,642

15 36,926 73,852 110,778 147,704 184,629 221,555 258,481 295,407 332,333 369,259

17 41,849 83,699 125,548 167,397 209,247 251,096 292,945 334,795 376,644 418,493

20 49,235 98,469 147,704 196,938 246,173 295,407 344,642 393,876 443,111 492,345

25 61,543 123,086 184,629 246,173 307,716 369,259 430,802 492,345 553,888 615,432

30 73,852 147,704 221,555 295,407 369,259 443,111 516,963 590,814 664,666 738,518

Heat Transfer Tables

Heat transfer in hydronic systems follows the equation of DQ=c*Flow rate *DT. The heat transfer and thus the heat capacity of the system is therefore in any recipient within the system a function of the flow rate and the desired temperature between supply and return temperature.

Below we tabularize heat transfer for various flow rates and temperature differentials (table 12)

24

Systems


flow rate DT=5F DT=10F DT=15F DT=20F DT=25F DT=30F DT=35F DT=40F DT=45F DT=50F

[GPM] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h] [BTU/h]

35 86,160 172,321 258,481 344,642 430,802 516,963 603,123 689,283 775,444 861,604

40 98,469 196,938 295,407 393,876 492,345 590,814 689,283 787,752 886,222 984,691

45 110,778 221,555 332,333 443,111 553,888 664,666 775,444 886,222 996,999 1,107,777

50 123,086 246,173 369,259 492,345 615,432 738,518 861,604 984,691 1,107,777 1,230,863

75 184,629 369,259 553,888 738,518 923,147 1,107,777 1,292,406 1,477,036 1,661,665 1,846,295

100 246,173 492,345 738,518 984,691 1,230,863 1,477,036 1,723,209 1,969,381 2,215,554 2,461,726

110 270,790 541,580 812,370 1,083,160 1,353,950 1,624,739 1,895,529 2,166,319 2,437,109 2,707,899

120 295,407 590,814 886,222 1,181,629 1,477,036 1,772,443 2,067,850 2,363,257 2,658,665 2,954,072

130 320,024 640,049 960,073 1,280,098 1,600,122 1,920,147 2,240,171 2,560,195 2,880,220 3,200,244

140 344,642 689,283 1,033,925 1,378,567 1,723,209 2,067,850 2,412,492 2,757,134 3,101,775 3,446,417

150 369,259 738,518 1,107,777 1,477,036 1,846,295 2,215,554 2,584,813 2,954,072 3,323,331 3,692,590

160 393,876 787,752 1,181,629 1,575,505 1,969,381 2,363,257 2,757,134 3,151,010 3,544,886 3,938,762

170 418,493 836,987 1,255,480 1,673,974 2,092,467 2,510,961 2,929,454 3,347,948 3,766,441 4,184,935

180 443,111 886,222 1,329,332 1,772,443 2,215,554 2,658,665 3,101,775 3,544,886 3,987,997 4,431,108

190 467,728 935,456 1,403,184 1,870,912 2,338,640 2,806,368 3,274,096 3,741,824 4,209,552 4,677,280

200 492,345 984,691 1,477,036 1,969,381 2,461,726 2,954,072 3,446,417 3,938,762 4,431,108 4,923,453

210 516,963 1,033,925 1,550,888 2,067,850 2,584,813 3,101,775 3,618,738 4,135,700 4,652,663 5,169,626

220 541,580 1,083,160 1,624,739 2,166,319 2,707,899 3,249,479 3,791,059 4,332,639 4,874,218 5,415,798

230 566,197 1,132,394 1,698,591 2,264,788 2,830,985 3,397,182 3,963,380 4,529,577 5,095,774 5,661,971

240 590,814 1,181,629 1,772,443 2,363,257 2,954,072 3,544,886 4,135,700 4,726,515 5,317,329 5,908,143

250 615,432 1,230,863 1,846,295 2,461,726 3,077,158 3,692,590 4,308,021 4,923,453 5,538,884 6,154,316

275 676,975 1,353,950 2,030,924 2,707,899 3,384,874 4,061,849 4,738,823 5,415,798 6,092,773 6,769,748

300 738,518 1,477,036 2,215,554 2,954,072 3,692,590 4,431,108 5,169,626 5,908,143 6,646,661 7,385,179

Heat Transfer Tables

Heat transfer table continued (Medium 100% water, temp @ 140°F)

Table 12: heat trnasfer capacity for various flow rates and temperature varia-tion between supply and return pipes.

25

Systems


Environmental Thermal Loss

ΔT [°F] 18 36 54 72 90 108 126 144 162 180 BTUH/ft.°F

MD1251C 3.33 6.55 9.88 13.52 17.16 20.49 23.92 27.25 30.47 34.03 0.171

MD12532C 3.43 7.28 11.13 15.08 18.72 22.88 26.42 29.85 33.80 37.43 0.189

MD16040C 3.12 6.86 10.19 13.52 16.64 20.07 23.92 27.56 30.68 34.15 0.172

MD16050C 5.10 9.67 15.08 19.76 24.86 29.43 34.84 39.52 44.30 49.14 0.245

MD20063C 4.16 8.84 14.35 19.03 24.65 29.12 34.32 39.55 44.62 49.68 0.253

ΔT [°F] 18 36 54 72 90 108 126 144 162 180 BTUH/ft.°F

M751C 2.43 4.6 6.8 9 11.8 14.2 17.1 19.2 22 24.2 0.121

M12540C 2.1 4.3 6.6 8.7 11.8 14.0 16.8 19.0 21.2 23.8 0.121

M12550C 2.5 5.3 8.2 11.4 14.2 17.8 20.5 23.5 26.1 29.4 0.149

M12563C 3.7 7.5 11.8 16.1 20.2 24.1 27.8 31.7 35.6 39.9 0.201

M16040C 2.2 3.8 5.5 7.5 9.5 11.8 14 15.8 17.8 19.7 0.097

M16050C 2.4 4.5 6.7 8.7 11.2 13.5 16.1 18.3 20.8 23.0 0.115

M16063C 2.7 5.7 8.4 11.7 15 17.8 20.6 23 25.5 29.0 0.146

M16075C 3.0 6.7 10.4 14.2 18.2 21.9 25.7 29.0 32.2 36.4 0.186

M20090C 3.2 6.8 9.9 13.7 17.2 20.4 24.1 27.3 30.3 34.1 0.172

M200110C 4.3 8.9 13.8 18.6 23 27.70 32.4 37 41.8 46.47 0.234

ΔT = (TF + TR)/2 - TS TF = Flow medium temperatureTR = Return medium temperatureTS = Soil temperatureΔT = TF - TSUNO

DUO

Table 13: Microflex UNO heat loss data as a function of the soil and the medium temperature

Table 14: Microflex DUO underground thermal loss data

Note: The temperature difference is calculated based on the following approximation

Environmental thermal loss in Microflex Insulated PEX carrier pipes is occurring when there is a difference between the aver-age medium temperature and the surrounding environmental temperature. In the tables below DT denominates the differ-ence between these two temperatures. Environmental thermal loss can thereby be expressed as BTU/h per ft of pipe or per degree Fahrenheit.

For Microflex UNO pipes

For Microflex DUO pipes

26

Systems


Environmental Thermal Loss Calculation - Low Temperature

Pipe classification (HDPE Jacket /

PEX)75/1” 125/1” 125/32 90/40 125/40 160/40 125/50 160/50 160/63 160/75 200/90

Carrier pipe ID 3/4” 3/4” 1” 1 1/4” 1 1/4” 1 1/4” 1 1/2” 1 1/2” 2” 2 1/2” 3”

outer jacket OD 3” 5” 5” 3 1/4” 5” 6 1/4” 5” 6 1/4” 6 1/4” 6 1/4” 8”

Insulation thick-ness 3/4” 1 1/2” 1 1/2” 3/4” 1 1/4” 2” 1” 1 3/4” 1 1/2” 1 1/4” 1 3/4”

30 1 1 1 1 1 1 1 1 1 1 1

Soil Tem-perature

(° F)

28 1 1 1 1 1 1 1 1 1 2 1

27 1 1 1 2 1 1 2 1 1 2 2

25 2 1 1 2 2 1 2 1 2 2 2

23 2 1 1 2 2 1 2 2 2 3 3

21 2 1 2 3 2 2 3 2 2 3 3

20 2 2 2 3 2 2 3 2 2 3 3

18 3 2 2 4 3 2 3 2 3 4 4

16 3 2 2 4 3 2 4 3 3 4 4

14 3 2 3 4 3 2 4 3 4 5 4

12 4 2 3 5 3 3 4 3 4 5 5

10 4 3 3 5 4 3 5 3 4 5 5

9 4 3 3 5 4 3 5 4 4 6 5

7 4 3 3 6 4 3 5 4 5 6 6

5 5 3 4 6 4 3 6 4 5 6 6

3 5 3 4 6 5 4 6 4 5 7 6

1 5 3 4 7 5 4 6 5 6 7 7

0 5 4 4 7 5 4 6 5 6 8 7

- 2 6 4 4 8 5 4 7 5 6 8 7

- 4 6 4 5 8 6 4 7 5 7 8 8

- 6 6 4 5 8 6 5 7 6 7 9 8

- 8 6 4 5 9 6 5 8 6 7 9 8

- 9 7 4 5 9 6 5 8 6 7 9 9

- 10 7 5 6 9 7 5 8 6 8 10 9

- 13 7 5 6 10 7 5 9 6 8 10 9

- 15 7 5 6 10 7 6 9 7 8 10 10

- 17 8 5 6 10 7 6 9 7 8 11 10

-18 8 5 6 11 7 6 10 7 9 11 10

-20 8 5 7 11 8 6 10 7 9 12 11

- 22 8 6 7 11 8 6 10 8 9 12 11

- 24 9 6 7 12 8 6 10 8 10 13 11

- 26 9 6 7 12 8 7 11 8 10 13 12

- 27 9 6 7 13 9 7 11 8 10 14 12

- 29 9 6 8 13 9 7 11 8 10 14 13

Heat loss calculation (in BTUH/ft) for Microflex pipes based on soil temperature (sub-freezing temperature)

Note: This table features thermal losses in the event of a negative ambient temperature around the pipe jacket. If the heat loss exceeds 9 BUTH/ft pipes might freeze.

Tabl

e 15

: The

rmal

loss

cal

cula

tion

in lo

w s

oil/u

nder

grou

nd te

mpe

ratu

res

[BTU

H/f

t]

27

Systems


R-Value Calculations

UNO BTUH/ft d(in) k=L/d R-Value W/m d(mm) k=L/d U-Value

M751” 17.80 0.68 0.41 2.44 17.16 17.5 2.280 0.44

M12540 15.80 1.30 0.21 4.76 15.20 33.0 1.210 0.83

M12550 19.20 1.10 0.25 4.00 18.48 28.0 1.430 0.70

M12563 25.40 0.84 0.33 3.00 24.42 21.5 1.860 0.54

M16040 12.40 1.93 0.14 7.14 11.88 49.0 0.810 1.23

M16050 15.10 1.73 0.16 6.25 14.52 44.0 0.910 1.10

M16063 19.20 1.47 0.19 5.26 18.48 37.5 1.070 0.93

M16075 23.30 1.24 0.22 4.55 22.44 31.5 1.270 0.79

M20075 18.50 1.90 0.15 6.67 17.82 48.5 0.825 1.21

M20090 22.65 1.61 0.17 5.88 21.78 41.0 0.970 1.03

M200110 30.20 1.22 0.23 4.35 29.04 31.0 1.290 0.77

Microflex DUO

Average fluid temperature 170°F ΔT=120°F (76°C, ΔT=66°C)Soil temperature 50°F

Thermal conductivity of ground 8.307 BTU.in/ft2.h.°F 1.2W/m*°KThermal conductivity of PEX foam 0.277 BTU.in/ft2.h.°F 0.04W/m*°KThermal conductivity of PEX Pipe 2.631 BTU.in/ft2.h.°F 0.38W/m*°KHeatloss BTU/h*ft 1W/mK=6.923 BTU*in/h*ft2*F

d = insulation thickness

Microflex UNOAverage fluid temperature 170°F ΔT=120°F (76°C, ΔT=66°C)Soil temperature 50°F (10°C)

Table 16: Microflex UNO Thermal Resistivity Values

Table 17: Microflex DUO Thermal Resistivity Values

Metric System

Metric System

DUO BTUH/ft d(in) k=L/d R-Value W/m d(mm) k=L/d U-Value

MD1251” 24.80 1.06 0.26 3.80 21.0 27.0 1.50 0.67

MD12532 24.80 1.06 0.26 3.80 23.8 27.0 1.50 0.67

MD16040 20.60 1.42 0.20 5.08 19.8 36.0 1.10 1.02

MD16050 28.00 1.14 0.25 4.06 27.0 29.0 1.38 0.72

MD20063 28.80 1.30 0.22 4.65 27.7 33.0 1.21 0.83

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Commercial Specification Texts

Typical Commercial Specification for MicroFlex Pre-insulated PEX Carrier Piping For Radiant, Snowmelt, or Domestic Water Systems

A. Pre-insulated Transmission Mains

1. Provide a complete hydronic system for transmission of the (Designers note: select one of the following) radiant/snowmelt/domestic water as shown on the plans and as specified. System shall be complete with all materials and controls from one single manufacturer source. Submittals must include manufacturer complete specification sheets for all components and accessories being supplied as part of the system for engineer’s approval.

2. The installation shall be in strict accordance with all manufacturers instructions in accordance with their warranty policy. All materials shall come complete with a manufacturers standard 10-year warranty.

B. PEX Carrier Tubing

1. Carrier piping shall be MicroFlex polyethylene (PEX-A) cross-linked piping with Oxygen Diffusion Barrier or engineer approved equal. All tubing shall be protected with a manufacturer applied oxygen diffusion barrier. Oxygen barrier shall perform in accordance with DIN Standard 4726 or better.

2. Tubing shall be DIN and ASTM approved and stamped with the appropriate code references. The PEX pipe shall have an operating temperature of 203F at an operating pressure of 87 psig.

3. Tubing shall be sized as indicated and scheduled on the plans, without restriction or reduction of cross-section within the insulated jacket.

C. Internal Pipe Insulation

1. Insulation of all carrier piping shall consist of a microcellular, cross-linked polyethylene foam in multi-layer arrangements. The insulation closed cell structure shall insure minimal water absorption at all times to preserve insulating effect against thermal loss.

2. Insulation shall have a thermal conductivity performance equal to DIN Standard 56212 or higher for underground thermal loss.

3. All material shall be CFC free and completely flexible to the radius required to meet the layout of the piping as shown on the plans.

D. Corrugated HDPE Outer Jacket

1. The exterior jacket shall be made of high-density polyethylene (HDPE) to protect the carrier pipe and insulating materials from external influences.

2. The jacket shall be cast with a corrugated pattern along its entire length. The corrugation pattern shall provide flexibility in the longitudinal direction and rigidity against radial forces.

3. The corrugation outer edges shall employ a closed cell construction to provide a double layer of protection from piercing of the outer jacket. Single wall exterior jackets shall be deemed not equal for the long-term protection of the Owner.

E. Installation – Handling, Trenching, and Backfill

1. Pipe should be stored and transported in such a way to avoid sharp objects, stones, or other damaging external influences. Pipe coils should not be dragged along the ground, but rolled or lifted into place.

2. All PEX carrier piping ends shall be protected with tape over the ends during the installation process. Tape shall not be re-moved until carrier tubing is connected to system piping.

3. Only nylon or textile straps should be used for fastening or hoisting. Chains should not be used under any circumstances.4. All trenches up to 4 feet deep shall be vertical trenches with straight sidewalls. Excavation should be carrier out in an ap-

proved manner, within the rules and regulations of all local and OSHA requirements. 5. A minimum laying temperature of 23F outdoors is recommended.6. A minimum layer of 4” sand shall be placed and compacted along the entire bottom of the trench, or as specified in the site

trench details.

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7. Tubing can be laid out directly from coil by puling on the carrier pipe. Pulling connections should never be made onto the outer jacket, but on the carrier pipe end.

8. An adequate excess of material for connection should be left and secured at the beginning of the trench as the remaining coil is rolled out into place.

9. As the tubing is uncoiled, sand shall be placed on to the outer jacket every 10 feet or as required to keep the tubing in place.

10. Once the tubing has been installed and pressure tested in the trench as needed, backfill can be made over the entire tub-ing length. Backfill in direct contact with the tubing outer jacket shall be layered sand in 8” depth without rocks or sharp objects. Sand shall be compacted by hand only. Care should be taken to remove any stone or sharp objects from backfill to avoid damaging the outer jacket layer. When backfill has been brought to a minimum of 20” above tubing outer jacket, a vibrating tamper may be used to compact the remainder of the soil.

F. Connections and Underground Protection

1. All connections from the carrier pipe as sized to equipment and internal connections shall be a cast bronze clamp-on style connection to convert to a male NPT threaded end similar to a Jentro connector. The connectors shall have a clap on type closure around the entire perimeter of the carrier tubing. Compression ring type connectors will not be considered equal.

2. All underground joints will be composed of the appropriate number for PEX x NPT adapters and the required fitting (tee, coupling, etc.). Manufacturer shall provide preformed plastic insulation casings to be clamped over the pipe connections after assembly and pressure testing. Casing shall completely encased connections and all edges of connecting outer jacket HDPE corrugations for a watertight fit. Casings shall be supplied complete with internal dry insulation and watertight sealant for edges of casing.

3. Where a set of supply and return or hot and cold water lines are being taken off a set of parallel mains, an inspection chamber with removable top cover shall be provided with re-enterable top inspection port. All outer jackets of entering pipe shall be secured to inspection chamber with water tight fit.

4. Manufacturer shall supply the appropriate number of dry or shrink-wrap end sleeves as required by the project. Contractor shall install end caps after installation of the tubing but before installation of end connectors.

5. If the exterior HDPE jacket is damaged in any way during the installation process, contractor shall install heat-shrinkable heat tape from the system manufacturer to seal outer jacket. Tape shall be wrapped completely around the exterior jacket with an overlap of at least 3” from each side of the damaged portion. Tape shall be heated with a heat gun or low heat torch to conform to the corrugations of the exterior jacket.

G. Hydrostatic Pressure Testing

1. Pressure testing shall be required for any run of piping that has underground piping connections.2. Any runs that do not contain any connections can be back filled directly after laying the pipe in the trench without further

testing. 3. After installation of pre-insulated tubing and before backfilling of the trench, all MicroFlex piping required shall be pressure

tested to a minimum of 60 psig for a 24-hour period. Contractor shall notify factory and general contractor representatives for verification both before and after testing period.

4. All piping shall be bled of air pockets and minimum 4 inch test gauges shall be installed temporarily for testing. If test pres-sure drops more than 2 psig over the 24 hour period, system shall be re-checked and re-tested. Any tubing showing signs of damage at the jobsite before pour shall be replaced without any concealed joints whatsoever.

H. Building Penetrations, Attachments, Sleeves

1. All penetrations below grade into and out of building sections shall be installed in a manner that protects the exterior jacket of piping and provides a watertight seal to prevent any water entering building.

2. For all sub-grade penetrations, an appropriate size plastic or metal sleeve shall be set into the wall or core drilled to guide and protect the piping entry.

3. Wall sleeves shall be sized and planned to allow the installation of a mechanical link seal type filler between sleeve interior and exterior HDPE casing of MicroFlex piping. Link type seal device shall be field supplied.


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4. Where piping system penetrates building walls, a fixed-point bracket shall be installed to secure piping and allow minor expansion and contraction of the PEX carrier tube. A bracket shall be used to secure the line attaching to the carrier tubing after the point of conversion to hard piping. Do not clamp onto the PEX carrier tubing at any point.

5. Where exterior jacket and insulation end inside, a heat shrinkable cap shall be provided by the manufacturer to prevent water or other liquids from entering the insulation space. Installers shall use a heat gun or low heat torch to completely surround exterior jacket and interior PEX carrier piping after all connections are made and pressure tested.

6. For entry above grade, a non-watertight entry may be made. A heat-shrinkable sleeve shall be installed over exterior of HDPE exterior jacket for protection. Sleeve shall be placed on jacket so that sleeve is inside wall penetration when in the final installed position. Any air gaps or spaces shall be filled with foam type insulation to complete penetration.

Chemical treatment

Inhibitors For all systems it is suggested that inhibitors, approved for closed loop hydronic heating systems, be added to the heating fluid for corrosion protection. For calculation of system water content in the particular PEX piping chosen for your project, please in-quire at your local ComfortPro Systems .

Freeze protection For systems exposed to freezing temperatures the addition of glycols with built-in inhibitors (that are approved for hydronic heating systems) to the heating fluid is required. A minimum of a 30%-35% (maximum 50%) glycol/water mixture for combination system corrosion plus freeze protection is required. For calculation of system water con-tent in the particular PEX piping chosen for the project.

Note: A water analyis should be performed annually (i.e. check corrosion inhibitor and glycol levels) to ensure the 18 month warranty for ComfortPro Systems components, and for the longevity of the system.

Corrosion protection For all systems it is suggested that inhibitors, approved for closed loop hydronic heating systems, be added to the heating fluid for corrosion protection. For calculation of system water content in the particular PEX piping chosen for your project, please contact your local ComfortPro Systems Supplier for information.

Warranty:

Insulated Pex Tubing: All Uno (Single) and Duo (Double) tubing, outer jacket, insulation and carrier pipes have a ten (10) yearfactory limited warranty.

Accessories and Fittings: All wall sleeves, shrink and dust caps, casing tees, elbows, trousers, inspection chamber and Jentrohave a ten (10) year factory limited warranty. For complete installation details refer to installation guide book MIC002


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NOTES

AquaHeatSystems


ComfortPro Systems LLC9645 Willow Lane, Mokena, IL 60448 Phone: 1-800-968-8905www.comfortprosystems.com Insulated pipe and fitting products

CPSMIC007-070108

Mf design guidelines

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