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PEX Tubing Ratings
Plastic Pipe Institute (PPI) PEX Tubing Ratings
PPI TR-3 presents the policies and procedures used to develop recommendations of long-
term strength ratings for commercial thermoplastic piping materials or pipe.
The term hydrostatic design basis (HDB) refers to the categorized long-term hydrostatic
strength in the circumferential or hoop direction, for a given set of end use conditions, as
established by ASTM Test Method D 2837, "Standard Test Method for Obtaining Hydrostatic
Design Basis for Thermoplastic Pipe Materials."
The hydrostatic design stress (HDS) is derived from the HDB and is the recommended
maximum hoop stress that can be applied continuously with a high degree of certainty that
failure of the pipe will not occur.
Pressure ratings (PR) are calculated from the dimension ratio of the pipe (DR), the material’s
hydrostatic design basis (HDB), and the overall design factor (DF).
An HDB/HDS recommended rating has been shown, through both scientific procedures
and historical experience, to be a useful indicator of the relative long-term strength of a
thermoplastic material.
HDB and HDS recommended ratings issued by PPI are for conditions equivalent to those
under which the test data were obtained, e.g., constant pressure, temperature and specific
test environment.
Under some conditions, such as pressure cycling, higher temperature, more aggressive
environment, or handling and installation quality, all of which may significantly reduce pipe
durability, a more conservative design factor or design coefficient should be chosen.
PureLink® Plus PEX-a tubing is listed with a standard grade rating in PPI TR-4 as tested in
accordance with PPI TR-3. PureLink Plus tubing carries the temperature and pressure ratings
shown in the table below.
Temperature
PPI - Hydrostatic
Design Basis
PPI - Hydrostatic
Design Stress
Pressure
Rating
73.4°F / 23°C
1,250 psi / 8620 kPa
630 psi / 4340 kPa
160 psi / 1100 kPa
180°F / 82.2°C
800 psi/ 5520 kPa
400 psi / 2760 kPa
100 psi / 690 kPa
200°F / 93.3°C
630 psi / 4340 kPa
315 psi / 2170 kPa
80 psi / 550 kPa
The use of PEX tubing in a potable hot-water plumbing system with an operating temperature
above 140°F (60°C) or system pressure above 80 psig (550 kPaG) or highly aggressive water
quality or any combination thereof can significantly reduce the service life of the tubing.
HeatLink requires following the guidelines described in Plastics Pipe Institute
, Guide
to Chlorine Resistance Ratings of PEX Pipes and Tubing for Potable Water Applications and
HeatLink
, Domestic Hot Water Recirculation Systems.
