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How Does A Pressure Relief Valve Keep People Safe?


An emergency vacuum relief valve is a vital safety tool fitted to the nozzle opening of a storage tank carrying volatile materials that help to protect it from rupturing and imploding.

As storing flammable liquids and gases can be exceptionally dangerous, the Health and Safety Executive recommend using safety valves as best practice to avoid accidental ignition and explosion.

The internal pressure of a tank can change considerably based on the atmospheric and temperature conditions, which in the case of static tanks could include an unseasonably hot day causing a volatile liquid to evaporate into a gas, or by pumping liquid into the tank itself.

Left to its own devices without a relief valve, the expanding gases cause the tank itself to rupture, often with explosive force, and the opposite can also be the case when liquids are being pumped out.

The way to maintain a nominal pressure is to provide the tank with a way to release excess gas or take in extra air, which is why a relief valve is sometimes known as a breather valve, as it works in much the same way the human respiratory system (especially the nose) works.

They are devices that automatically detect excess pressure and, due to the design of the device, gradually lift to relieve the pressure gradually, relaxing back to return to a tight seal once the excess vapours have passed.

The automated process also ensures that only the minimum amount of vapour required to avoid over-pressuring the system is lost, which saves a business money.

Another type of valve used in these situations when there is an unexpected increase in outside temperature is an emergency vent valve, which is set at a higher pressure point and will quickly open and relieve the pressure quickly, reducing the risk of an emergency.