We want to install block valves on subheaders of pilot line in a big terrace wall reformer heater (8 block valves for 8 subheaders) for maintenance. According to safety rules, is this action is safe? Is there any standard or design note for this action?
Answers
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23/11/2007
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A:
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KengYong Chan, Air Products & Chemicals, Inc, chanky@apci.com
Without looking at the P&ID, it's difficult to know what's the impact of valve being closed in error. On the main FG supply header, there must be some control valves or automatic shutoff valves or block valves. So, the impact may be very similar as upstream supply valves closed. One needs to understand the impact on the heater (flame off for that burner etc) when that particular pilot FG is isolated off by error.
The best approach is to convene a team to perform a hazard review to get the team's input.
If there is a safety hazard, one way is to lock open these valves or implement captive key lock system for higher reliability.
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