tsenthil
Mechanical
- Mar 13, 2003
- 41
Please furnish details about Fire safe design in Ball valves.
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Ball valve -Fire safe design 1
- Thread starter tsenthil
- Start date
- Status
jsummerfield
Electrical
Among USA fire safe design standards check API 6FA Fire safe valves including API 6A and 6D valves and API 607 Fire safe quarter turn valves applicable to ANSI B16.34 valves. For the WWS2 - Worldwide Standards II Combined Index consider the SABS - South African Bureau of Standards 1056-1. Ball valves Part 1: Fire-safe valves.
John
John
Adding to John's excellent post
We used a lot of "fire safe" ball valves from different companies. All our valves were metal seated with the stem captured by the packing gland. We had a fire that exposed 5 of the valves, 3" and 4" flanged valves, to very intense heat with only one that showed any signs of leaking around the stem. There were 4 different manufactures valves represented.
One thing we did find that it required varying torque to operate the different valves.
We also had stem failures in some of the larger valves, 6" and above, due to stem failure. We had no blowouts but a lot stem twisting that required refurbishing the valves with a redesigned stem.
We used a lot of "fire safe" ball valves from different companies. All our valves were metal seated with the stem captured by the packing gland. We had a fire that exposed 5 of the valves, 3" and 4" flanged valves, to very intense heat with only one that showed any signs of leaking around the stem. There were 4 different manufactures valves represented.
One thing we did find that it required varying torque to operate the different valves.
We also had stem failures in some of the larger valves, 6" and above, due to stem failure. We had no blowouts but a lot stem twisting that required refurbishing the valves with a redesigned stem.
jsummerfield
Electrical
I do not know what new technology you address. However, many fire-safe valves have a soft seats. Metal seats become an issue when the process design temperature exceeds the limits of commonly used elastomers.
My previous post excluded some standards that you may want to see. One is API STD 589 for valve stem packing leak testing. API 598 includes the maximum allowable seat leak rates for acceptance testing. Also obtain copies of API 6FB and 6FC.
John
My previous post excluded some standards that you may want to see. One is API STD 589 for valve stem packing leak testing. API 598 includes the maximum allowable seat leak rates for acceptance testing. Also obtain copies of API 6FB and 6FC.
John
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1ton,
The epoxy fiberglass valve from AVT has been qualified by fire test. see their site .
Now, has a fiberglass piping system been qualified by any fire test? It seems FPSO designs are driving requirements.
The epoxy fiberglass valve from AVT has been qualified by fire test. see their site .
Now, has a fiberglass piping system been qualified by any fire test? It seems FPSO designs are driving requirements.
Tsenthil was querying about a Ball Valve fire safe design (not the test).
Fire safe design applies to both soft and metal seated ball valves but the way it is achieved is practically the same:
a)A Soft seated valves: at Seats/Ball interface the seat is designed with a lip which secure the M/M seating once the soft seal insert is melting down.
b) For M/M seated this contact M/M is continuous;
1)Consider for both cases above, valves are trunion mounted and as such at LP the contact Seat/Ball is helped by springs whilst at HP is the pressure itself keeping the upstream seat in contact with the ball.
2)for external leaks all sealing areas (Body/adapters or Body/cover flage and Body/stem) a secondary sealing system,mostly graphite must be provided for this purpose.
Design, is sure, must be validated by Fire Safe tests as already mentioned.
Fire safe design applies to both soft and metal seated ball valves but the way it is achieved is practically the same:
a)A Soft seated valves: at Seats/Ball interface the seat is designed with a lip which secure the M/M seating once the soft seal insert is melting down.
b) For M/M seated this contact M/M is continuous;
1)Consider for both cases above, valves are trunion mounted and as such at LP the contact Seat/Ball is helped by springs whilst at HP is the pressure itself keeping the upstream seat in contact with the ball.
2)for external leaks all sealing areas (Body/adapters or Body/cover flage and Body/stem) a secondary sealing system,mostly graphite must be provided for this purpose.
Design, is sure, must be validated by Fire Safe tests as already mentioned.
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