Page 63 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

PIPING

PIPING 2.13

DESCRIPTION AND CLASSIFICATION

Plastic pipe is as descriptive a phrase as metallic pipe. The properties of various plastic
materials are obtained from the basic chemical composition of the polymer resin, addi-
tives, and the manufacturing process itself. In order to better understand the material called
“plastic,” definitions of the basic terms and ingredients used by the plastic piping industry
are necessary. Please understand that these are simplified definitions.
Plastic is a material whose essential ingredient is an organic substance of large molecular
weight which at some stage in its manufacture can be shaped by flow and becomes solid in
its finished state.
A polymer is a material consisting of molecules with a high molecular weight. A monomer
is a chemical compound capable of reacting to form a polymer. Polymerization is a chemi-
cal reaction in which molecules of a monomer are linked together to form a polymer. When
two or more monomers are used, the process is called copolymerization.
The following are common additives used in the manufacture of plastic piping: flame
retardants, plasticizers to increase flexibility and workability, antioxidants to retard degra-
dation from contact with air, stabilizers to retard degradation at higher temperatures, lubri-
cants to aid in the extrusion process, pigment or dyes to color the final product and protect
against ultraviolet light, fillers to modify strength or lower cost, and modifiers to produce
a special property response.
Another type of plastic is an elastomer. Used mostly for gaskets, an elastomer is a material
that is capable of being repeatedly stretched to at least twice its original length at room
temperature and which will return to its approximate original length upon release.
The following is a partial list of plastic pipe and elastomer materials available from all
sources. The names in parentheses are trade names patented by various manufacturers. Only
those piping materials that are commonly available will be discussed. Elastomers, indicated
as (E), are listed only for reference since they are outside the scope of this chapter:
ABS = acrylonitrile butadiene styrene; also (Buna-N) (E)
BR = butadiene (E)
CA = cellulose acetate
CAB = cellulose acetate butyrate (Celcon)
CAP = cellulose acetate propionate
CIIR = chlorinated isobutene isoprene (E)
CMC = carboxymethyl cellulose
CN = cellulose nitrate
CPE = chlorinated polyethylene (E)
CPVC = chlorinated polyvinyl chloride
CR = chloroprene rubber (Neoprene) (E)
CS = casein (E)
CSP = chlorine sulphonyl polyethylene (Hypalon) (E)
ECTFE = ethylenechlorotrifluoroethylene
EP = epoxide, epoxy
EPDM = ethylene propylene-diene monomer (E)
EPM = ethylene propylene terpolymer (E)
FEP = fluorinated ethylene propylene
FPM = fluorine rubber (Viton) (E)

Downloaded from Digital Engineering Library @ McGraw-Hill (www.accessengineeringlibrary.com)
Copyright © 2009 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.