Page 201 - Trenchless Technology Piping Installation and Inspection

Pipe and Pipe Installation Considerations 165

Typical ASTM D3350
Material Designation Code Cell Classifications
PE3408 PE345444C a
PE3608 PE345464C
PE4710 PE445474C or PE445574C

a C identifies minimum 2 percent carbon black in the PE compound for UV resis-
tance. For color products, E identifies color with UV resistance. C compounds
are suitable for long surface or above grade service. E compounds are suffi-
ciently stabilized for storage, but must be buried.
TABLE 4.12 Material Designation Code and Cell Classifi cation

crack growth resistance, and long-term hydrostatic strength. Higher
numerical cell classifications represent higher cell property range
values. UV resistance is identified with a letter code at the end of the
cell classification. ASTM D3350 also includes additional minimum
performance requirements for thermal stability, brittleness tempera-
ture, and tensile elongation.
PE pipe materials are generically identified by a material desig-
nation code that identifies the acronym for the type of plastic, ASTM
D3350 cell values for density and slow crack growth (SCG) resistance,
and the hydrostatic design stress (HDS) rating for 73°F water in hun-
dreds of psi with tens and units dropped. For example, PE3408 is a
polyethylene material having density and SCG resistance meeting
ASTM D3350 density cells 3 and 4, and a HDS rating of 800 psi. Typi-
cal material designation codes for PE pressure piping materials∗ are
PE3408, PE3608, and PE4710. Table 4.12 provides material designa-
tion codes and typical ASTM D3350 cell classifications. Figure 4.29
shows the HDPE pipe readied for pullback in a directional bore.

Applicable Standards
Environmental stress cracking may occur where the pipe is subjected
to excessive stress concentrations due to improper embedment or
excessive bending strain due to improper installation. Solid wall
HDPE pipes manufactured to AWWA and ASTM standards are typi-
cally used for trenchless installation applications. OD-controlled
pipes are required for butt-fusion joining that produces a continuous
conduit ideal for pull-in installations such as HDD. Renewal methods
such as pipe bursting also provide a good match for use of HDPE
pipe. Testing has shown that surface scratches sustained during
installation of up to 10 percent of the pipe’s minimum wall thickness

∗ PE materials used for pressure piping are listed in PPI TR-4.