NPGA — Relief Valve and Cylinder Testing Program
Improving Cylinder Safety and Reliability
Due largely to its reputation as a safe, clean, efficient, and reliable fuel, over 60 million Americans use more than 11 billion gallons of propane for industrial, transportation, agricultural, commercial, and domestic applications every year. While propane does have a remarkable safety record, certain precautions are necessary to assure safe and successful use. As such, the propane industry proactively implements programs, products, and preventions with safety first in mind.
In anticipation of possible regulatory changes, the propane industry proactively sought to gather data on the performance of cylinder inspection methods and pressure relief valve (PRV) performance. Accordingly, the Propane Education & Research Council (PERC) funded a research effort, Relief Valve and Cylinder Testing to gain a clear understanding of propane cylinder and PRV performance issues and concerns. Completed February 2003, the National Propane Gas Association (NPGA) obtained the assistance of Battelle Memorial Institute for developing a technical basis to support the expectation that the service life of propane cylinders and PRVs can safely exceed ten years.
Cylinder Testing
Nearly 400 cylinders were visually inspected according to CGA Standard C-6, Standards for Visual Inspection of Compressed Gas Cylinders procedures. More than 200 cylinders were subjected to hydrostatic expansion and burst testing using a minimum design burst pressure of 960 psi, which is four times the service pressure.
Pressure Relief Valve (PRV) Testing
Over 230 PRVs were subjected to tests adapted from CGA Standard S-1.1, “Pressure Relief Device Standards-Part 1-Cylinders for Compressed Gases,” including measurements of start-todischarge, full-open, and reseat pressures and valve full-open flow rates.
Test results were compiled in a comprehensive database which allows direct and detailed comparison of relief valve and cylinder performance and determines failure safety factors with 95 percent confidence.
For a condensed look at the report, simply download the fact sheet here.
