Breather Valves, also known as direct acting Pressure/Vacuum Relief Valves, are special types of Relief Valves which are specifically designed for tank protection.
Without an opening or a controlled opening, a fixed roof atmospheric tank would rupture under increasing pressure caused by pumping liquid into the tank or as a result of vapor pressure changes caused by severe thermal changes. Imploding, or the collapsing of a tank, occurs during the pumping out procedure or thermal changes. As the liquid level lowers, the vapor space pressure is reduced to below atmospheric pressure.
In VALTECT, we are familiar with these very low pressure safety valves and we comply with the API 2000 in our testing procedure.
