Distance between compressor building 1

[gazepdapi]

Is there a guideline (maybe from AGA) that provides requirements for the minimum distance between two compressor buildings so that they can still utilize the same ESD system? For example if there are 3 compressor buildings in the same facility, what is the minimum distance they can be from each other so that when one building ESD's, the other two can still be running?

 

[BigInch]

B31.8 requires a complete station block out and "station gas piping" blowdown. Operation of the ESD system shall also cause the shutdown of all gas compressing equipment and all gas fired equipment. Operation of the system shall cause all electrical facilities located in the vicinity of gas headers and in the compressor rooms, except emergency lighting, to shut down. See paragraph 843.3.3

IMO that means all station gas piping.

 

[gazepdapi]

Yes I am aware of that but we have determined that "station gas piping" is limited to the compressor building and the headers associated with that building, excluding yard piping. We have several sites where we implement this logic and the state public service commission understands this. My questions is what is the minimum distance the building have to be to prevent blowing down multiple building. I have seen a few insurance policies stating 350 ft but cannot seem to locate where that originates from.

 

[BigInch]

Some ideas

Saudi Aramco's unit spacing guide,

Major Oil Company,

 

[gazepdapi]

Can you tell me what book this is from? From what I can see here, the major oil company and Aramco states 3m for compressors? That is way too close...just 10 ft. The size of the building alone will be much larger. I was thinking around 100ft would work but I really have no basis for it.

 

[Gator]

"...what is the minimum distance the building have to be to prevent blowing down multiple building?"

Are you asking about how far apart you should space buildings so that blast pressure from one possible explosion will not collapse an adjacent building?

I'm still not sure what the ESD has to do with anything if this is what the question is.

Piping Design Central

 

[gazepdapi]

In effect yes that's what I'm asking. Well an ESD vents all the gas from inside the building during a possible gas leak inside the building or a fire. The question is how far would an adjacent compressor building need to be for it to be considered safe to run. Now I understand depending on the pressure inside the building at the time the blast pressure could wipe out buildings next to it but the question is what would be considered safe.

 

[Gator]

Ah, OK. When I read "ESD" I was thinking of an "Emergency Shutdown Skid" on the plant inlet.

The last time I recall being somewhat involved in something related we had a consultant's report that provided LB/FT^2 values for increasing distances from the theoretical point of ignition. Do you have the buildings' structural/construction details?



Piping Design Central

 

[gazepdapi]

I do but this is more of a question for a new facility being built. Is the one way to do this by calculating blast pressure? I realize this would be an accurate method...I guess I was just thinking there was some recommended practices when it came to this similar to what BigInch posted.

 

[BigInch]

No. 3m is compressor, machine to machine minimum edge distance.
Building to building would be like G1 to A1, or B1, which is 30m, or 15.
I'd use 15m if the buildings are unoccupied (no continuous personnel duty station within), as a control building always is assumed to have people within 24-7. If you mean this to be more of a blast resistant structure, rather than just fire safe for a few hours, use 30m, or more.

You could check with your company's risk control department. Perhaps they have you insurance company's requirements on hand.

 

[gazepdapi]

I see...thanks for your help that will work.

 

[EmmanuelTop]

Upon an ESD event, you don't want to run any of your equipment. That is why it is called ESD. No hydrocarbon operations should be permitted under emergency conditions, for all facilities within the same fence (= units being parts of the same process).

Imagine a scenario in which one of the 3 compressors in parallel catches fire. I think it would be quite reckless to keep the other two running.

Dejan IVANOVIC
Process Engineer, MSChE

 

[LittleInch]

I don't understand why you want to have this same ESD system. I think what you mean is unit ESD trips. There is no reason why an individual compressor trip should necessarily cause an adjacent unit trip. If the reason for the ESD is a gas leak inside the compressor building that shouldn't affect the next one.

The issue over distance is really one of fire and explosion. If this is your concern then yes, 100m or so will take most adjacent buildings out of the way of jet fires or explosion, however you don't really want to be operating in those conditions, but might want to separate them to avoid damage. This however is highly unlikely and in most locations you don't have the space and it costs more to connect them all back to a single control room and the operators will get very fit walking between them cursing all the time about why these are so far away.

I would go for somewhere between 10 to 20m.

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

 

[gazepdapi]

That's correct ESD compressor building trips...there would be 1-3 compressors in one building and 1-3 in another. I completely agree but I think we might stick to 30m just to be on the safe side and we have the room to do so.