Credibility of Fire Case for the Manifold of an Oilfield Gathering

[e43u8]

Dear All,

Please let's have your opinion if the Fire Case is credible for an Oilfield Manifold receiving the crude oil from several flow lines connecting to Xmas Trees?

 

[Latexman]

The three companies I have worked for did not usually protect pipe from fire. We tried harder to prevent fires.

Good Luck,
Latexman

 

[e43u8]

In general, for piping you are right but what about the manifold in a gathering system receives crude oil plus associated gas through several flow lines...?

 

[Latexman]

Is it more pipe-ular or vessel-ular? Sounds more pipe-ular to me.

We do not protect pipe manifolds from fire either.

Good Luck,
Latexman

 

[e43u8]

It's 12" size means mostly pipe-ular...

Any reference, standard/practice from reputable company,...for oilfield manifold supporting your opinion?

 

[Latexman]

No, I know of no mandatory standard that says piping or pipe manifold shall have a relief device for fire case. Maybe others will add their experience.



Good Luck,
Latexman

 

[RVAmeche]

Has there been a hazop or something that indicated a fire was a high risk, or is someone just asking the question?

 

[e43u8]

One HAZOP chairman, for similar manifold in the same oilfield, mentioned that fire case is credible...

 

[Latexman]

Fire is almost always credible, but how best to use the company resources to prevent or protect against that. There are a few solutions I consider better than a PSV. Anything that will prevent the fire is #1, then foam system, fire water spray system, and fire water sprinklers. Is the manifold within reach of a fire water hose or monitor, or would those be deployed on other assets? Does the site have a fire bragade?

You may have to size and install a PSV, no matter what, just to check this person's box.

Good Luck,
Latexman

 

[e43u8]

Thanks Latexman,

The manifold is located within reach of several Fire Hydrants...Can this facility be adequate to ignore PSV installation?

Actually we prefer to remove the option of PSV installation provided that there would be no risk/consequence due to such decision...

 

[Latexman]

You are welcome Fallah.

Do you have "emergency block valves" between the oilfield sources and the manifold? What about between the manifold and the destination oil/gas tanks/reservoirs? EBV's are fire tested valves that can be closed remotely and can close automatically in a fire that are put to contain/stop flow from/to large inventories of flammables/combustibles. If the inventories of oil can be stopped, spills and fire can be minimized. Then, yes, protecting a manifold with fire hydrants would be viewed as adequate in the 3 internatioal chemical companies I have worked for.

There is no such thing as "no risk". Risk management is a total system approach. One has to manage it down to an "acceptable risk".

Have you checked out

http://www dot

SimpliEngineering dot com?

Good Luck,
Latexman

 

[e43u8]

Thanks again Latexman,

There are ESDVs before connecting the flow lines to manifold and the manifild will be routed to downstream separator through a line with an isolation valve near the separator. Actually there is no concern for overpressure due to all process upsets and the only concern is about the fire case. The ESDVs will be closed following to fire occurrence due to high high pressure signal in the manifold and you well aware that simultaneous fire occurrence and closed downstream isolation valve due to operator mistake can be considered as double jeo-pardy hence the line between the manifold and downstream separator can be considered open during fire case.

There might be the situation in which an instrument valve such as ESDV wouldn't repond to the received signal, i.e. high high pressure, when it's needed to respond in a fire case and then credit may not be taken for ESDV closing.

I think considering the above mentioned conditions for manifold during a fire case the only relieving line to release the inventory is the line between the manifold and separator:
1-Then if ESDVs had been closed there would be no concern as flow is stopped but the manifold might be subject to rupture if fire hydrants cannot cool enough the manifold
2-And if ESDVs stuck opened or not reponded to received signal the flowing crude oil through the manifold made the manifold walls wetted and prevent the manifold from failure

What's your idea?

 

[Latexman]

I was wanting a better understanding of your overall fire prevention/fighting strategy, so I have a better understanding of the risks. Thank you. You have ESDVs. That is very good in my opinion. Besides the hydrants, do you have some fixed fire water protection? Fire water systems on/in tanks? Do you have some fixed fire water monitors dedicated to some high value assets? I just don't want the list of assets those hydrants have to protect to be too long and they can't get to the manifold in a big fire. Thanks for bringing me up to speed on your system.

Good Luck,
Latexman

 

[e43u8]

Dear Latexman,

There are several fixed fire hydrant around the manifold which will cover the manifold and its connected flow lines during a fire case.

 

[Latexman]

IMO, your system would be acceptable risk in my company without a PSV.

Good Luck,
Latexman

 

[e43u8]

Dear Latexman,

Thanks a lot...

 

[georgeverghese]

Firecase relief is not applicable to B31.3 designed piping systems. Overpressure relief due to solar heat gain is.