Plastic Pipe in Buildings

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Plastic Pipe in Buildings

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Ser

NA7110

~ 2 1 h 8

no.

26

c.

2 1973

BLDG

NATIONAL RESEARCH COUNCIL

OF CANADA

DIVISION

OF BUILDING RESEARCH

505-r

o

HOUSING

NOTE NO. 26

(Revised )

by

A. D. KENT

REPRINTED

-

FROM

CANADIAN BUILDING, VOL. XXII, NO.

12 DECEMBER 1972, P. 47-50.

OTTAWA, MAY 1973

This Note may be reprinted without amendment provided acknowledgement is given to Canadian Building

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Plastic pipe in buildings

By A. D. KENT Division of Building Research,

Ottawa

This Housing Note supersedes Housing Note No. 26 of the Division of Building Research: "Plastic Pipe: Its Uses in Building Construction". The Division gratefully acknowledges the assistance of the plastic pipe man- ufacturing industry with the revision. Many building codes recognize the use of plastic pipe and fittings in various forms now that standards to con- trol the quality of pipe are available. For example, the National Building Code of Canada, 1970, calls up the following standards of the Canadian Standards Association (CSA):

B181.1-1967

-

Acrylonitrile

-

Butadiene

-

Styrene Drain, Waste and Vent (ABS DWV) Pipe and Pipe Fit- tings.

B181.2-1967

-

Polyvinyl Chloride

Drain, Waste and Vent (PVC DWV) Pipe and Pipe Fittings.

B182.1-1967 - Plastic Drain and

Sewer Pipe and Pipe Firtings for Use Underground.

B137.1-1970

-

Polyethylene Pipe

for Cold Water Services.

Several additional standards for plastic pipe have been prepared and published by the CSA including:

B137.2.1.-1970 Acrylonitrile

-

Butadiene

-

Styrene (ABS) Pipe for Pressure Applications. IPS Dimen- sions.

B137.3-1970

-

Rigid Polyvinyl

Chloride (PVC) Pipe for Pressure Ap- plications.

B137.4-1971

-

Thermoplastic Pip-

r ing Systems for Gas Service.

B137.6-1971 - Chlorinated Poly-

vinyl Chloride (CPVC) Plastic Piping for Hot and Cold Water Distribution Systems.

Standards currently in preparation include:

B137.0

-

Definitions and General

Requirements for Thermoplastic Pip- ing.

B137.5

-

Polyethylene Pipe for

Brine (Ice Rink) Cooling Systems. The fact that these standards have been prepared will not mean auto- matic acceptance by code authorities or by other regulatory bodies, but it

should facilitate such acceptance.

This article is based upon a

previous article by W. B. Wat-

son published in the 1965, October issue of this publica- tion, and later circulated as Housing Note No. 26 of the Division of Building Research. The present version brings u p to-date the installation practice and the situation with regard to the acceptance of plastic pipe based on current standards.

Kinds of Plastic Pipe

The characteristics of most of the thermoplastic materials used in the manufacture of pipe are shown in Table I. Current interest for building use is confined mainly to ABS, PVC and polyethylene, since these are the materials covered by the current CSA standards. Other plastics listed have properties that make them useful for special piping systems such as industrial process piping and laboratory drainage systems.

In addition to the physical and chemical properties shown in Table I,

there are other characteristics of thermoplastic pipe that should be considered in the design and installation of piping systems.

Fluid Flow

As the bore of plastic pipe is gener- ally smoother than that of ferrous metal pipe, the frictional head loss may be somewhat less for plastic pipe

SUMMARY

Plastic pipe, with its asso- ciated lower cost and relative ease of installation offers po- tential savings as an alternative to metal piping materials, al- though its use has been somewhat restricted in the past owing to lack of established standards. The standards now available should facilitate its recognition by building code authorities and other regulatory bodies and thus encourage great- er use of it in the future.

than for ferrous metal pipe of corre- sponding diameter. Most metal piping, especially that made of ferrous metals, corrodes with age so that the accumulation of rust and scale in- creases the frictional loss and reduces the carrying capacity of the pipe. This will not occur in any appreciable amount in plastic pipe. When pipes are sized from tables, it may be as- sumed that the carrying capacity of plastic pipe is at least equal to that of comparable metal pipe. I n hydraulic computations for the design of water mains and sewers, therefore, some re- duction in size may be appropriate where plastic pipe is used.

Protection from Freezing

Because of its flexibility and impact resistance at low temperatures, polyethylene pipe is less susceptible to failure from freezing of its liquid contents than the more rigid ABS, PVC and RMS (rubber modified styrene) plastics. It is good practice, however, to protect all pipes made of these materials from freezing when they contain water or other liquids.

Fire Safety

The use of plastic piping in buildings requires consideration of fire safety in respect of fire spread and smoke generation. The 1970 edition of the National Building Code requires that ABS and PVC drain waste and vent pipes "not be used in a piping system where such system or part thereof passes through or is enclosed in a required fire separation" and "not be used in buildings required to be of noncombustible construction." Changes in the Code are being pro- p o e d to permit plastic pipe in noncombustible construction where it has a flame spread of 25 or less. Based on experiments conducted by the Fire Research Section of the Division of Building Research a test method has been developed to valuate the effect of penetration of fire separations by plastic piping and the methods that may be employed to permit such practice without adversely affecting the fire separation.

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produces relatively large quantities of these components are toxic and irri- occupants and the operations of fire- smoke containing carbon monoxidc tating to the eyes and throat. Burning fighters, and it is difficult to decide and other components including hy- even relatively small quantities of what restrictions should be imposed drogen chloride from PVC and hy- plastic pipe can be an additional haz- on the use of plastics because of this drogen cyanide from ABS. Some of ard in the safe evacuation of building feature.

TABLE I C h a r a c t e r i s t ~ c s of Therrno3lastic Piping

-

MATERIAL A c r y l o n i t r i l e - butadiene- s t y r e n e (ABS) "

,

Polyvinyl-chloride ( p v c ) COEFFICIENT O F EXPANSION IN. PER IN. PER ' F

Approx. 6 x l o - ' Approx. 3 x L O - ' to T Y P E oF J O L ~ ~ Solvent welding, threading o r t h e r m a l fusion welding. Solvent welding, threading o r t h e r m a l fusion

I

wide range of c h e m i c a l s . C h e m i s t r y l a b o r a t o r y ralnage s y s t e m s . / d Industr,al ' . p r o c " s s MAX. TEMP. FOR PRESSURE LINES 180' 150' PROPERTIES I USES welding. Good i m p a c t r e s i s t a n c e a t low t e m p e r a t u r e s . R e l a - tively high operating t e m p e r a t u r e s . Good c h e m i c a l r e s i s t a n c e . I n s e r t fittings with c l a m p s . E x t e r n a l c o m - p r e s s i o n fittings. T h e r m a l fusion welding f o r d r a i n a g e system.,, Solvent welding o r threading. Welded. Solvent welding, threading o r t h e r m a l fusion welding. T h e r m a l fusion welding. Threaded fittings used a t low t e m p e r a - t u r e . T h e r m a l fusion welding. --Solvent welding.

7

( P E ) low and medium density - - - - c e l l u l o s e - a c e t a t e - butyrate (CAB) Polyvinylidene- chloride Chlorinated 1 Polyvinyl- chloride (CPVC) Polypropylene -- F l u o r o p l a s t i c s Chlorinated Polyether Rubber modified s t y r e n e (RMS) .

Potable water supply l i n e s . Residential waste and d r a i n lines. I r r i g a t i o n s y s t e m s . G a s t r a n s m i s s i o n lines. P e t r o l e u m

lines. _-

Very go6d chemical r e s i s t a n c e . Highly flexible. Available in long continuous lengths. Low mechanical strength. D e t e r i o r a t e d by petroleum. Moderate r e s i s t a n c e . c h e m i c a l Available in t r a n s p a r e n t form. Excellent r e s i s t a n c e t o p e t r o l e u m and p a r a f f i n deposition. Low mechanical strength. Low s h o c k r e s i s t a n c e and flexibility a t s u b - f r e e z i n g t e m p e r a t u r e s . Highly r e s i s t a n t t o a c i d s , a l k a l i e s and m o s t o r g a n i c solvents. Affected by s t r o n g a m m o n i a solutions. ketones, e s t e r s and chlorinated hydrocarbons. Excellent c h e m i c a l 1 r e s i s t a n c e . Maintains high s t r e n g t h while c a r r y i n g hot fluids. Very light weight (sp.g. 0.90) Good c h e m i c a l r e s i s t a n c e . High operating t e m p e r a - t u r e s . Exceptionally high c h e m i c a l and heat r e s i s t a n c e , but mechanical s t r e n g t h d i m i n i s h e s with high operating t e m p e r a t u r e s . High chemical and heat r e s i s t a n c e .

-

Wide range of physical and c h e m i c a l proper -' t i e s depending on r e s i n compound used.

----

I Potable water supply l i n e s . I r r i g a t i o n s y s t e m s . Chemical l a b o r a t o r y drainage s y s t e m s .

Oil

i n d u s t r y field piping. p r o c e s s Food

piping, incl. c i t r u s juices, wine, b e e r an! b r i n e solutions.

Chemical i n d u s t r y p r o c e s s piping.

Hot w a t e r l i n e s . Industrial p r o c e s s piping for hot c o r r o s i v e liquids. Oil field piping. C h e m i s t r y l a b o r a - t o r y drainage s y s t e m s . Chemical industry p r o c e s s piping. Hot water l i n e s i n potable w a t e r s y s t e m s .

P l a s t i c lining of m e t a l pipes.

I n d u s t r i a l p r o c e s 5 piping for ho: c o r r o s i v e fluids. Underground d r a i n and s e w e r pipe. Potable w a t e r s y s t e m s . -. --

High t e n s i l e s t r e n g t h and ' Potable w a t e r supply modulus of elasticity. l i n e s . Residential Excellent r e s i s t a n c e to waste and d r a i n lines.

100" -120'

-

-158' 170' 180° 185" 250'+ 250' 150'-170' I Approx. 8 x 10.' to - - Approx.

4

6 x l o - ' to

!

Approx. 10 x 10.' Approx. 4 x - Approx. 4 x Approx. 4 x I I

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Water Piping Inside a Building

Many plastics are technically suitable f o r cold water service in buildings but because of the lack of recog- nized standards and cost they have only recently been widely used. Some. such as CPVC, are capable of with- standing relatively high temperatures

when ~ ~ n d e r pressure (noted in Table

I). and these are being introduced for use in hot water distribution lines.

Water and Gas Supply Lines Outside a Building

P V C pipe conforming to CSA Standard B137.3 is now accepted by some water resources authorities for municipal water distribution systems, including mains and laterals. P V C pipe is currently available in sizes up to 24 in. in diameter and in pressure ratings u p to 200 psi.

Polyethylene pipe conforming to CSA B 137.1 usually costs less than metal pipe of the same size and its physical properties make installation relatively simple and inexpensive. It is available in coils u p t o 400 ft long and in reels of u p to 2.200 f t so that the only joints required in the aver- age service line are a t the main and

at the building. A 400-ft coil of %-in.

pipe can easily be handled by one man and its flexibility allows it to be bent around corners. T h e minimum bending radii for various pipe sizes are shown in Table 11.

Recently P V C and polyethylene pipes have been used extensively in Alberta and Saskatchewan for the rural distribution of natural gas. Pipes have been installed by the "mole- plough" technique whereby pipe is fed continuously from large coils directly into a channel formed under-

ground by dragging a specially

shaped plough through the earth. Polyethylene pipe is usually joined by plastic insert fittings made tight with stainless steel clamps, but it may also be joined by heat fusion welding. Insert adapters are available for join- ing: plastic pipe t o metallic systems. Only water should be used to lubri- cate the fittings, except that a joint compound may be used on the metallic end of a metal-to-plastic adapter. As insert fittings increase the resistance to flow by reducing the effective cross-sectional area of pipe, the use of heat-fusion joints should be considered in systems requiring a large

n ~ ~ m b e r of joints.

Table II Bending Radii for Polyethylene Pipe

Pipe Size Minimum Bending (inches1 Radii (inches I

% . . . 7 'h 3h . . . 10 1 . . . 10 1 % . . . 12 . . . 1'12 16 2 . . . 20

Polyethylene pipe is frequently

used for jet action or other pumping systems such as deep well turbine o r submersible pump installations. T h e depths listed in Table I11 should not be exceeded, and it is recommended that the weight of the pump be sup- ported by a polyethylene or polypropylene rope.

Drain, Waste and Vent Piping Inside a Building

T w o kinds of plastic pipe and fittings a r e available f o r this applica-

tion: ABS a n d PVC. T h e physical

properties of the two materials are

somewhat similar (Table I), but the

solvent cements may be quite differ-

e n t a n d they must not be intermixed

in individual installations unless they a r e specially designed f o r this purpose. T h e pipe, fittings a n d solvent cement f o r each job must b e compatible.

The thermal expansion coefficients of P V C and ABS are much larger than those of copper, steel o r cast iron. and this property must be considered in the design and installation of a piping system where they are used. T h e coefficient of expansion of P V C and ABS is such that. when un- restrained. P V C will expand as much as 3/x in. per 1 0 0 ft for each 1 0 F deg rise in temperature, and ABS will

expand -5'H in. under the same condi-

tions. Commercial expansion joints are currently available.

Joints in ABS o r PVC may be

Table Ill

Allowable Depths for Plastic Pipes in Wells

Shut-off Pressure Allowable Depth

I psi 1 (feet1

( 7 5 psi pipe) (I00 psi pipe)

. . . . . . 40 77 132 . . . . . . 50 55 110 . . . . . . . 60 . d o not u s e . . 8 8

made by solvent welding, threading, or thermal fusion welding, but solvent

welding is the most satisfactory

method for plumbing systems. F o r niunicipal piping, rubber ring joints are available in sizes from 2 to 24 in. Solvent cements are made by dis- rolving the respective plastic material in a solvent ( P V C in tetrahydrofuran. ABS in methyl ethyl ketone). In mak- ing a joint, the cement is brushed on the pieces to be joined and these are

pushed together. Threaded joints

weaken the pipe and should not be used where the depth of the thread may leave a wall thickness not able to withstand the design working pressure. Stress concentrations in the thread notch may accelerate failure. Further recommendations for the installation of drain. waste, and vent pipe and pipe fittings may be found

in CSA Special Publications B 181

.

1 1 -

1967 and B181.12- 1967 for ABS and P V C pipes, respectively.

The use of plastic pipe for drain pipes in buildings has met with some opposition on the grounds that it is noisy. Water flow in the pipes, especially when a toilet is flushed, is morz audible than with heavier pipe material such as cast iron. Where the sound is objectionable it may be nec- essary t o surround the pipe with high- density sound insulating material.

Underground Drainage Piping

Plastic pipe and fittings are suitable for use underground in applications such as building sewers, storm sewers. housing connections to septic tanks. septic tank effluent disposal beds and foundation and subsoil drainage systems. Pipe conforming t o CSA Stand- ard B 182.1. "Plastic Drain and Sewer Pipe Fittings for Use Underground" is available in ABS o r P V C with either standard fitting o r bell and spigot ends.

Plastic pipe can support large earth

loads without excessive deflection it'

the fill is carefully selected and placed. This can be accomplished by

using selected backfill material of % -

in. maximum particle size or sand. hand tamped beside the pipe, fol- lowed by normal backfilling. Com- plete information o n installation and

backfilling is included in the CSA

Special Publication B182.11

-

1967.

"Recommended Practice for the In- stallation of Plastic Drain and Sewer Pipe and Pipe Fittings."