PE gas pipeline instruction manual

1PE material properties and advantages and disadvantages
① performance
a. Polyethylene is a polymer with high crystallinity, which can be divided into three states with the change of temperature: crystalline state (hard solid), high elastic state (rubber-like elastomer), viscous flow state (viscous fluid).
b. Standard Size Ratio (SDR): Refers to the ratio of the nominal outer diameter to the nominal wall thickness. There are two series of SDR11 and SDR17.6.
c. Small required strength pMRS: The pMRS of PE80 (medium density) is 8.0MPa, and the pMRS of PE100 (high density) is 10.0MPa.
d. The maximum working pressure pMRS≤0.7MPa, and the working temperature range is -20～40℃. The pMRS values of natural gas are shown in Table 1.

②Advantages and disadvantages
PE pipes for gas pipelines have the following advantages:
Light weight; good corrosion resistance (no need for corrosion protection);
With good flexibility, it can be bent and laid according to the terrain during construction, and has strong anti-seismic and anti-subsidence capabilities; it has good welding performance, and the connection is convenient and fast; the gas cut-off tool can be used to clamp the gas to reduce the gas stop range and facilitate quick repair; Long service life, can be used for at least 50 years.
But it also has the following limitations: Due to the fear of ultraviolet radiation, oil corrosion, bumps and other reasons, the storage period of PE pipes is generally relatively short; the material strength is much lower than that of steel pipes, and it is easily damaged by external forces; it can only be buried or blocked from ultraviolet rays. It is strictly forbidden to be used for laying on the ground; the performance index is obviously affected by temperature. Table 1 PMOP value of natural gas
SDR11PE1000.7SDR11PE800.5SDR17.6PE1000.4SDR17.6PE800.32 Quality Management 2.1 Relevant standards and specifications PE gas pipelines shall comply with current national standards: GB50028—2006 {Code for Design of Urban Gas”, CJJ33—2005 “Construction and Construction of Urban Gas Transmission and Distribution Projects” Acceptance Code", CJJ63-2008 "Technical Regulations for Polyethylene Gas Pipeline Engineering", GB15558.1-2003 "Buried Polyethylene (PE) Pipeline System for Gas Use Part 1: Pipe Materials", GB15558.2-2005 "Buried Gas Pipeline System" Polyethylene (PE) Piping System Part 2: Fittings" regulations.