In the event of a large-scale conflagration, the ERGIL Storagetech™ Model 420 Spring-loaded Emergency Pressure Relief Vent is designed to operate in the last resort in the event that the conventional pressure-vacuum relief valve has failed to operate.

The closure lid is retained in position by a calibrated coil spring. A build up of pressure in the tank will overcome the resistance of the spring and the weight of the closure cause it to open sufficiently to allow the internal pressure to dissipate, thereby preventing the risk of tank rupture or explosion. It will close automatically when the internal pressure is reduced.

There is a choice of pressure release settings to enable a selection close to the maximum working pressure of the vessel.

The spring-loaded emergency pressure relief vent is installed in the horizontal plane on a flange at the top of the tank. A secondary use of the unit is to access the tank for product sampling or depth gauging.

The integrity of the seal is tested for leakage in accordance with API Standard 2521 – Use of Pressure-Vacuum Vent Valves for Atmospheric Loss.

The size of the vent should be calculated in accordance with API Standard 2000 (ISO 28300) – Venting Atmospheric and Low-Pressure Storage Tanks or other international standards.