
Parker Hannifin Corporation
Parflex Division
Ravenna, Ohio
Bulletin No. 4660-PGP2T
Parflex
®
Flexible Gas Piping System
Design and Installation Guide
Section 4.0 Installation Practices
4.9 Underground Installations
I
nstallation Requirements — CSST cannot be buried directly underground or embedded in concrete, When buried
underground the tubing must be routed within a nonmetallic, watertight conduit having an inside diameter 1/2 inch
larger than the outside diameter of the (CSST) tubing. The entry and exit ends of the conduit must be sealed or pro-
tected from the entry of water or contamination. No joints are permitted within the conduit, therefore venting of the
conduit is not required per the manufacturers instructions.
Direct Burial — For permanently mounted grills and gas yard lights, Parflex tubing must be routed and connected in
accordance with manufacturer’s instructions and code regulations. All Parflex tubing installed below grade must be
protected in nonmetallic, weather-tight conduit. Exposed conduit ends must be sealed against the entry of water.
Direct Burial Accessories — Parker also offers Parflex direct burial polyethylene pipe, Permasert
®
couplings, an-
odeless riser assemblies and transition couplings for residential natural gas and propane service. Consult Bulletin
P.L. 4660-PGP-DB or contact factory at 1-888-FASTMATE for component and assembly details. Installation practices
for direct burial polyethylene pipe and couplings are described in local codes and in chapter 3.0 of The National Fuel
Gas Code (NFPA 54/ANSI Z223.1).
4.8.4
Over-Protection Device
•
Gas systems with a pressure exceeding 2 psi must have a regulator with an over-protection device.
This regulator OPD assembly must be assembled and listed by the manufacturer in accordance with
Z21.80, Standard for High Pressure Regulators.