The American Petroleum Institute Standard 527, Seat Tightness of PRV's, defines the most widely used method for testing seat tightness on PRV's. The rates are defined by pressure category and valve size and range from 20 to 100 bubbles per minute. The tests are conducted at 90% of set pressure. Most PRV's manufactured come in a variety of seat configurations. In normal operation, most valves with metal to metal seats are allowed this certain amount of leakage, past the seat as defined in API 527. Those manufacturers that offer a soft seat design must meet zero leakage to this same 90% of set pressure.

Flow Safe builds High Performance Safety Relief Valves guaranteed to be bubble tight through 98% of the set pressure on most products. This added value allows customers to operate closer to the set pressures, providing value in receiving more performance from the ability to get more out of the mechanical piece of equipment, pressure vessel, or pipeline. With no leakage, the life expectancy on Flow Safe valves may be tenfold to conventional styles, lending value through ownership.

Flow Safe Safety Relief Valves are designed to move to the full lift position at set pressure very quickly. The F80 Series moves to full lift immediately. Pilot operated style valves are wide open no more than 5% above set pressure. This rapid response provides immediate, or near-immediate full capacity and with the modulating and/or adjustable blow down features, Flow Safe valves provide short blowdown, again lending value through the conservation of product and in allowing customers to operate closer to the set pressures. 

In fact, Flow Safe "Guarantees" bubble tight shut-off to 98% on the majority of valves. 

When good safety relief valves are required, Flow Safe is the answer.

There is no equal.