Boiler Set Safety Valve selection Valve Valve Set Pressure Temp Capacity % of Total Location Size Model (PSIG) (F) (Lbs/Hr) Capacity Low Set Drum Safety Valve 2-1/2 K2 6 HE-86 2190 PSIG Sat. Steam 274,145 Lbs/Hr High Set Drum Safety Valve 3 M 6 HE-86 2254 PSIG Sat. Steam 401,428 Lbs/Hr Total Flow thruTotal Flow thru Drum SV's Lbs/Hr SHO

Setting Safety valve to be overhauled and reset at every survey At least 2 pressure gauge required Loosen lock nut, screw down the compression screw few more turns then previous setting.

a safety valve is meant to relieve pressure without operator assistance. a thermal relief valve is used to bleed off pressure in a heat exchanger if the heat exchanger is isolated but the

2) The final setting of boiler safety valves shall be checked and adjusted under steam pressure and, if possible, while the boiler is on 

Set pressure: up to 210 bar. Temperature: up to 593°C. High performance safety valve for the protection of large boilers and superheaters, certified to ASME 

Setting Safety valve to be overhauled and reset at every survey At least 2 pressure gauge required Loosen lock nut, screw down the compression screw few more turns then previous setting. Measure the height make marking With all mounting in place, shut the main steam stop valve. Fire the boiler on auto Once boiler auto cut off, switch to manual.

Take differential pressure in running line and safety valve set pressure (∆P). We already have valve disk area from which we can calculate the force which we have to apply to operate the safety valve. F=∆P/A Where, F = Pulled Force ∆P = Differential pressure A= Valve Disk Area Procedure

Boiler safety valve setting detailed calculation - 10-10- , 15:57 Boiler safety valve is set to lift at any pressure, but not more than 3% above working pressure. Also the safety Valve re-sits at 5% below working pressure. There are 2 safety valves. Both the safety valves are to be set at a pressure not exceeding 3% of the normal working

The safety valve will close once the system pressure reduces to what is called the "reseat pressure." The valve will have to be set in such a way that the reseat pressure is 95% of the set pressure. The percentage of this is called the "percentage blowdown" and is limited to a maximum of 5% to avoid wastage of steam produced.

5. With Safety Valve opening, Boiler pressure must not accumulate to exceed 10% of Working Pressure. Difference Between Safety Valve and Relief Valve: 1. Safety valve fully open at set pressure. Start open at set pressure. But relief valve fully open at 15 – 20% above set pressure. 2. Safety valve close at set pressure. But the relief valve

The simple answer, if using a single valve and no superheater, is that the set pressure of the valve is equal to the design pressure of the boiler, sized to pass 100% of the boiler capacity. If using multiple valves, or a superheater, then the requirements are a little different. khaidz86 (Mechanical) (OP) 16 Dec 08 08:34 Thx to all.