Black metal pipe is no longer the only distribution material for natural gas. Many municipalities allow builders to install alternative gas plumbing pipes, such as lightweight metals and plastics. Each type of natural gas plumbing pipe has its own unique advantages, disadvantages and costs. Once you have an understanding of the common types of natural gas plumbing pipes, you can select a material that matches your budget and your project's design.
Corrugated Stainless Steel Tubing
Corrugated stainless steel tubing (CSST) appears in most homes as the flexible pipe that runs between rigid gas supply lines and individual appliances. Although CSST's use is generally restricted to this type of application, some municipalities allow the use of CSST for entire supply systems. The pipe fittings attached to each end of a length of CSST connect to appliances or rigid pipe fittings. Most commercially available varieties of CSST have a yellow plastic coating or a natural metallic exterior. The primary advantage of CSST is its flexibility; CSST easily contorts to maneuver around obstacles and through walls. The chief drawback of CSST is cost; a 4-foot length of CSST can cost more than $15 as of December 2010.
High-density polyethylene (HDPE), a plastic material, appears outside of plumbing supply shops in large, yellow rolls. Although typically reserved to industrial and commercial applications, some building codes allow the use of HDPE for residential gas piping. The most common type of HDPE gas piping is flexible; plumbers pull lengths of the pipe from its roll and weave it through a building's interior cavities. This flexibility greatly reduces installation time. In contrast to traditional iron gas pipe, which must be threaded at each end, HDPE pipe fittings usually attach to the ends of the pipe by compression. Although these labor-saving characteristics reduce the overall cost of HDPE installation, the base material tends to cost more than traditional iron piping. Also, HPDE's relative rarity might present additional permitting hurdles for the average homeowner. However, as a plastic material, HDPE is nearly immune to deterioration, whereas iron and steel eventually rust.
Black Iron Pipe
The traditional natural gas plumbing pipe, black iron pipe, safely encases a natural gas supply within a thick-walled, metal pipe. Accidental nail strikes don't easily puncture iron gas pipe, and it takes extreme force to bend or break the pipe. Popularity and a large supply make black iron pipe one of the most affordable gas plumbing pipe types. Additionally, it's easy to find do-it-yourself information about iron gas pipe or plumbers who work with iron gas pipe. However, iron gas pipe installation is time-consuming; plumbers must cut the rigid pipe to specific dimensions and manually or automatically thread the pipe's ends. Additionally, black iron pipe exposed to moisture can rust and corrode.