08/20/2026
Important Pressure Relief Valve Information
This summer’s record heat has had an effect on above ground propane tanks. Regardless of the amount of gas in the tank, as the heat increases outside, the pressure in the tank is also increasing. The safety relief valve performs a vital role in the protection of the propane tank and are generally set at 250 psi.
Relief valves are held in the closed position by the force of a powerful spring. As long as the pressure inside the tank is less than that of the spring, the valve will remain closed. If tank pressure rises to equal of the spring, the valve will partially open resulting in a “hissing” sound outside the tank. If the pressure in the tank rises significantly higher than that of the spring, the valve will fully open. When the valve fully opens, it initially makes a loud pop followed by a blast of released propane gas. Once the pressure is released and the tank pressure falls below that of the spring tension, the valve should close.
Factors that can cause the relief valve to discharge include :
The tank being in direct sunlight.
The tank’s protective coating is dark/dull. (Glossy white tanks reflect heat better.)
The relief valve is older and, thru the years, been ‘stressed’.
Recently having more propane injected into the tank.
If you encounter a relief valve that is "hissing" (opening to relieve pressure) OR if it fully opens, do not ‘tap’, seal or try to adjust the valve. NEVER get directly OVER a relief valve.
Remedies to lower tank pressure:
• Keep tank clean and painted a glossy white finish.
• Find a ‘gunny sack’ or loosely woven blanket, lay it over tank then spray water onto the blanket, thoroughly drenching the cloth-- but not directly on the relief itself! The combination of the cool water and the retention of the water by the blanket may cool the tank down and reduce the expansion of the liquid in the tank.
• Create artificial ‘shade’ by shielding the west side of the tank….but never attached to or OVER the relief !
• Don’t fill tanks during the peak of summer.
Other notes:
• Tanks must be empty before relief valves can be replaced.
• Safety relief valves may need to be replaced if they "pop-off". The spring becomes weaker and may not reseat properly after discharging gas.
• A protective cover should be placed over the relief valve to protect it from debris. Debris may cause the valve to remain open after discharge, resulting in a more excessive loss of propane.
Propane is safe if handled correctly. If you have any questions, give us a call and we will help !
Call us at 405-258-0053