CHAPTER B12
PLASTIC-LINED PIPING FOR
CORROSION RESISTANCE
Michael B. Ferg
Crane Resistoflex
Marion, NC
John M. Kalnins
Crane Resistoflex
Bay City, MI
INTRODUCTION
Plastic-lined piping and fittings consist of a metal housing lined with chemically
resistant plastic. The combination of a chemical-resistant engineered plastic liner
inside a relatively inexpensive but mechanically strong pipe or fitting housing allows
for the safe and economical conveyance of corrosive and dangerous chemicals. For
this reason, plastic-lined pipe finds widespread use in such industries as the chemical
process, pulp and paper, and metal finishing industries. It is also the desired choice
when product purity is of concern, particularly when metal corrosion by-products
cannot be tolerated in the process fluid. Industries requiring such purity are pharma-
ceuticals, food, power generation, and electronics, to name a few. When service
conditions are within the capabilities of a plastic-lined piping system, it is often an
economical alternative to expensive alloy piping. The methods of lining vary, but
all achieve the same goal: to ensure that the liner and housing expand and contract
as one unit, even though plastic and metal have greatly differing rates of expansion
and contraction.
History
Plastic-lined pipe was first manufactured in the early 1940s and sold commercially
in 1948.1 The first piping system was made by mechanically reducing or swaging a
steel tube housing down onto an extruded polyvinylidene chloride (PVDC) resin
liner. Initially, plastic-lined pipe was not widely accepted by the chemical processing
industries because the PVDC liner could only be used for acids and caustics to a
maximum service temperature of 175F (79C). As new high-performance resins
and different manufacturing techniques were developed, plastic-lined pipe was
taken more seriously as a cost-efficient method of fighting corrosion.
B.533
B.534
GENERIC DESIGN CONSIDERATIONS
Thanks to high standards developed by the various manufacturers in the plastic-
lined