With the July 2011 deadline approaching for compliance with NFPA 58, we think it makes a lot of sense to inspect all vital components of your bulk plant. One of the most important safety components of your LP-gas storage vessel is the internal relief valve system. LP-gas relief valves are intended to open only under the excessive pressure conditions indicated below. The container pressure will get high enough to open relief valves under the following conditions:
- Filling containers not purged of air
- Overfilled container exposed to heat, which includes radiant heat (sun).
- Use of an incorrect product such as propane in a container with relief valve set for butane pressures (Low set pressure for service)
- All containers exposed to extreme heat (fire).
- Excessive pressures created during filling
Typically relief valves should be inspected each time the container is filled but no less than once a year. If there is any doubt about the condition of the valve, it must be replaced.
Under normal conditions, the useful safe service life of a pressure relief valve is 10 years from the original date of manufacture. However, the safe useful life of the valve may be shortened and replacement required in less than 10 years depending on the environment in which the valve lives. Inspection and maintenance of pressure relief valves is very important.
As you are upgrading your LP-Gas storage vessels to meet 2011 compliance, please take the time to inspect the status of the relief valves to see when they were last replaced. While your system is offline and the 2011 upgrades are being performed, it is the perfect time to replace your relief valves to maximize your return on the LP-Gas contractor's mobilization costs.
For more questions or assistance with inspecting your LP-Gas Bulk Plant for NFPA 58 or internal relief valve compliance, please contact the propane storage systems specialist at TransTech Energy http://www.transtechenergy.com/ .