First, you need to understand what PE stands for in HDPE pipe. Normally, we can classify
HDPE pipe based on two standards: Nominal Pressure (PN) and the grade of materials being used to produce the pipe (PE).
While PE100 grade materials are lighter and more durable than other grades of polyethylene materials. They use less polymer and provide larger bore, that will help in encouraging water flow. They also provide long-term strength and creep resistance as compared to PE80, and has significant advantage at low temperature conditions (not easily break at temperature down to -30°C).
The properties of
HDPE PE100 pipe are determined at standard temperatures of 20°C or 23°C. These properties can be significantly affected by temperature, so at higher temperature the properties, including MRS, decrease. At higher temperatures it may be necessary to apply reduction factors to MRS, and consequently MOP.
Some Codes and Standards define the reduction factors that must be applied; AWWA C901 and C906 for example. Otherwise there are standard reduction factors that can be applied in design. ISO13761:1996 defines reduction factors to be applied to MOP at higher temperatures.
MRS (MINIMUM REQUIRED STRENGTH) is a important factor to choose correct Resin grade for a HDPE pipes. Definition of MRS is expressed as the maximum pressure withstanding capacity of the resin for the designed service life. PE-100 gives you 10 Bar internal pressure withstanding capacity with minimum wall thickness.