Law Supply, Inc. Web Page - PVC
Pipe Strength Properties VS. Temperatures
% OF 73.4°F PIPE STRENGTH PROPERTY
PVC is a thermoplastic material whose physical
properties change with variations in temperature. Physical properties
are determined at a standard temperature of 73.4° F (23°C).
Temperatures above this level decrease the values of elastic modules (E),
tensile yield strength, and hydrostatic design stress, which is expressed
in terms of pressure rating. Higher temperatures reduce pipe stiffness
and brittleness. Conversely, temperatures lower than 73.4° F
increase the values of elastic modules, tensile yield strength, pressure
rating, and pipe stiffness while increasing brittleness and lowering impact
resistance.
Temperature must be taken into account
for design considerations, most particularly when considering pressure
rating. Provisions must be made for expansion and contraction with
temperature changes in both pressure and non-pressure piping systems.
For a suspended system, the support hangers will have to be increased in
number for a high temperature system.
The maximum recommended operation temperature
for a PVC pressure system is 140° F. Non-pressure systems can
be operated at 150° F provided adequate support and protection is provided.
Operation at temperatures above 150° F for prolonged periods may result
in degradation and early failure of a PVC system.
