Page 299 - Trenchless Technology Piping Installation and Inspection

Pr oject Considerations for Pipe Replacement Methods 263

FIGURE 6.18 Grooves on the outside surface of the HDPE pipes after bursting.
(Source: Handbook of Polyethylene Pipe, 2008.)

conducted at Louisiana Tech University and Bowling Green State
University, Ohio, indicates any possible grooves are very shallow and
narrow when bursting clay, asbestos, and concrete pipes. The widest
groove was 0.07 in. across and the deepest groove was 0.03 in., as shown
in Fig. 6.18. Cast iron, clay, concrete, and asbestos pipes generally
shatter without producing sharp shards that may potentially produce
significant damage to HDPE pipe (Atalah, 1998, 2004). An exception
to this rule occurs when attempting to significantly upsize ductile iron
(DI) pipe. It is therefore recommended to limit PE replacement pipe to
size-on-size bursting, or a single upsize, when bursting DI pipe. If
larger upsize of DI pipe is required, HDPE pipes with a protective
outside surface, similar to that shown in Fig. 6.19, may be used.

FIGURE 6.19 Protecting the HDPE pipe from shards. (Source: Handbook of
Polyethylene Pipe, 2008.)