PVC and CPVC pipe are primarily designed to withstand
internal pressure under continuous or steady state loading.
Short-term higher pressure surges can be accommodated to
varying degrees, but it is the long-term strength of the
material that determines its performance.
In North America, PVC and CPVC pipe designed for pressure
applications must have a defined minimum hydrostatic
design basis (HDB) of 4000 psi (27.58 MPa) as per ASTM D
2837. To ensure useful long-term service (minimum of 50
years) a design or safety factor is applied to provide an
adequate safety margin. A design factor of 2 is usually applied.