What Are the OSHA Rules for Using PVC Plastic for Air Lines?

Compressed air distribution is basic to every industrial process, so a lot of information on proper design and installation exists. Installation of permanent lines is fairly easy. The tubing used determines the cost (copper tubing, black iron pipe or polyvinyl chloride (PVC)). Most PVC pipe producers advise against PVC use for compressed air service because of possible legal responsibility from failures. The Occupational Health and Safety Administration (OSHA) has taken action to regulate the use of PVC in these applications in many states.

Transport of Compressed Air

• Plastic PVC pipes shall not be a means of transporting compressed air and other compressed gases in above-ground installations. OSHA's position ensues from the warnings of the manufacturers that PVC is inappropriate for compressed air systems. PVC pipes are banned for above-ground transport of compressed air and gases (except where shatter resistant material encases pipelines) because PVC material does not have shatter resistant properties. If employers use PVC pipes and expose employees to hazards, they will be in violation of Section 5(a) (1) of the OSHA Act.

Operation Parameters

• Plastic PVC pipes must comply with American National Standards Institute and American Society of Mechanical Engineers' Standard B 31.8-1986, and manufacturers' specifications. Plastic piping distribution systems operating pressure limit are 100 pounds per square inch (psi). This prohibits installing such systems above ground unless the portion of the plastic service line above ground is put in a sheath or conduit of ample strength, concealed or sufficiently guarded according to a professional consulting engineer approved specifications, to protect the piping from corrosion and external damage.

Potential Hazard of PVC

• Plastic PVC pipes are unsafe when used to convey compressed gas or air since they are designed for the transmission of liquids. There is a risk of explosion when using PVC pipes in compressed air piping systems. PVC can break or shatter with external force unless suitably protected because it is a brittle material. When under stress from compressed gas, a PVC pipe or fitting can fail. It explodes like a bomb, literally. Plastic shrapnel fragments are thrown several feet in all directions when PVC piping explodes.