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Is double block and bleed mandatory by any standards (API or OSHA...etc.) in High pressure systems ?

Is double block and bleed mandatory by any standards (API or OSHA...etc.) in High pressure systems ?

Is double block and bleed mandatory by any standards (API or OSHA...etc.) in High pressure systems ?

(OP)
Hey guys,
Can anyone tell me whether the DBB valves is a must or mandatory in high pressure systems as per certified entity codes ?

RE: Is double block and bleed mandatory by any standards (API or OSHA...etc.) in High pressure systems ?

Not as far as I am aware. This is why individual companies all write isolation philosophies to cater for the range of fluids, pressures, locations and potential consequences of a leak following isolation.

There are guidance notes e.g. HSG 253 from the UK HSE, but there are too many combinations to state at this pressure (and not that pressure) you require DBB.

See also https://www.eng-tips.com/viewthread.cfm?qid=440025 for a discussion I started last year which might help.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Is double block and bleed mandatory by any standards (API or OSHA...etc.) in High pressure systems ?

Block and bleed valve configurations are required for boiler blowdown in ASME B31.1

MJCronin
Sr. Process Engineer

RE: Is double block and bleed mandatory by any standards (API or OSHA...etc.) in High pressure systems ?

Subject to your definitions, I note the following:

Standards Australia, AS3892 Pressure equipment—Installation (AS 3892) Standards Australia, Australia Cl 2.2.8 recognises double block and bleed [et al isolations] to isolate a new system from an existing system.

Standards Australia, AS3873 Pressure equipment—Operation and maintenance (AS 3873) Standards Australia, Australia, Cl 3.4.3 recognises double block and bleed [et al] isolations.

Standards Australia, AS 1210-2010 Pressure Vessels (AS 1210 - 2010), Standards Australia, Australia, Cl 8.15 recognises double block and bleed [et al] isolations.

RE: Is double block and bleed mandatory by any standards (API or OSHA...etc.) in High pressure systems ?

Isolation philosophies for piping and pressure vessels / equipment are Company specific good practice and not mandated by external statutes. In the company I used to work for, DBB is required for all services 600lb and above for non toxic service. DBB (with bleed routed to remote safe disposal)is required for all pressure classes in toxic service. For all pressure classes where personnel entry is required, positive isolation is enabled by augmenting DBB with a blind or dropout piping spool. Globe/check/butterfly valves cannot be used in DBB.

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