Installation Guide

HOME-FLEX Underground 15
can be obtained from: catalog.nfpa.org/NFPA-54-C3324.aspx. Consult Section 4.4 (p.
18) for more information on pressure / leak tests and troubleshooting leaks.
Nut
Main Body
O-Ring
Spacer
Grip Ring
Nut
Nut
Nut
Main Body
O-Ring
Spacer
Grip Ring
Nut
Nut
O-Ring
Spacer
Grip Ring
Nut
Main Body
Figure 4.1 Fitting Re-assembly Diagrams
4.2 Trenching
The minimum required depth for buried pipe will be specified by local code, and may range
from as shallow as 12 inches to as deep as 24 inches. The width of the trench should be
sufficient for the width of the widest fitting. A 12 inch wide trench will allow for sufficient
clearance of the pipe and fittings. The bottom of the trench should be smooth and flat. The
plumbing code requirements at the installation location must be followed.
Keep in mind that trench depth requirements are measured from ground level to the top
of the piping system, including the fittings. For example, if the minimum required depth, or
amount of cover, per code is 18 inches and 1-inch pipe is being installed, the trench depth
will be a minimum of 20.68 inches (18 inches plus the fitting depth of 2.68 inches). Fitting
depth information can be found in Section 2.2 (p. 5). Be sure that trenches comply with
your local code requirements.
Underground Piping Detectability Requirements
In the trench next to the gas pipe, install a 14 gauge or thicker insulated copper tracer wire.
This wire will make the underground routing of the poly gas pipe detectable from above
ground. The ends of the tracer wire should follow the riser above ground and be visible for
future use. Some locations may also require the installation of plastic caution tape to be bur-
ied in the trench several inches above the gas pipe. Consult the local code at the installation
location to ensure compliance with piping detectability requirements.
Backfilling Trenches
If the local code does not include trench specifications, then prepare trenches
and backfill in accordance with ASTM D2774 “Standard Practice for Underground
Installation of Thermoplastic Pressure Piping,” which can be downloaded from:
astm.org/Standard/standards-and-publications.html. Ensure that the fill dirt is free of debris
or rocks that could damage the pipe when the earth is compressed around it. Do not backfill