Buried LPG Tanks

[TLHS]

This is in the intersection of pressure vessels and tanks, but I suspect this is a better place to discuss.

I've got a client asking if they can bury large scale 50,000+ gal LPG Tanks as a fire/explosion mitigation measure and to justify smaller setbacks. I don't like buried tanks generally, and these are not small, but I'm still trying to do my due diligence on the literature. I can't personally find anything of this scale in the major API, NFPA or related LPG system design standards. There are small scale buried tanks referenced in codes, but nothing of this size. However, I'm seeing some (rare) references on the web to projects fabricating things like 60k gallon buried propane tanks, so somebody seems to be doing it. It's also definitely done in some types of LNG installations. That seems to be more for the purposes of helping with refrigeration, though, and there's a fair amount of complexity to those sorts of designs.

There are obviously maintenance and inspection issues relating to burying, and cost implications, but I'm trying to figure out if there are other implications that I should be considering, so I'm trying to track down any literature I can. Anyone seen anything?

 

[TLHS]

And about ten minutes after I posted that I found the clause in API 2510 about buried tanks that sends you to NFPA 58. So I'll chase that thread.

further edit: And now I've realized that if I looked for mounded tanks rather than buried I'd have found a huge amount of information. So I think I've managed to square myself away.

 

[shvet]

Do you mean buried or mounded&backfilled?

 

[LittleInch]

Also pressurised lpg tanks are very often called "bullets"

Searching for mounded lpg bullets will get you a long way.

One I've seen recently is "earth covered tanks"

Nearly all pressurised Large LPG tanks I know are mounded.Mainly for solar gain as well as protection from fire and damage.

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

 

[TLHS]

All the larger LPG tanks I've seen in Canada have been above ground. LNG I've seen mounded. I think it might be an age thing, since the larger LPG stuff I've run into has been fairly legacy.

I've quickly swung from feeling slightly negative about it as a concept to being significantly in favour of mounding.

Thanks for helping point me in some directions.

 

[shvet]

I have seen aboveground and underground liquefied gases storages both ~50/50. There is no a readily available choice. Best choice depends on local conditions: is it urban area, is relief venting tolerable, what is supposed to be exposed to fire or toxic/explosion wave and so on.

50k gal tank is not so large as for me. I recall a LPG terminal 20x200 m3 vessels backfilled in a town outskirts.

 

[LittleInch]

Location, solar gain and fire risk from other equipment is key.

Once you look up BLEVE, you realise why many are mounded once they get to a certain size. Yours is certainly in that size range.

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

 

[georgeverghese]

There is a 34million USgallon (65 000 metric tonnes) underground LPG storage cavern here in Sydney, just a stone's throw away from the main airport. Its carved out of a salt cavern 130metres underground.

 

[ProSafPlant1]

Here's a couple of standards that go into some detail on the engineering. I've seen several aboveground mounded installations at process plants, but only seen one underground cylindrical LPG tank installation (at a pipeline storage terminal).

 

[jt1234]

If you are buying buried LPG bullet, please ask vendor to fully comply with EEMUA 190 as posted above, especially the material requirements. It is a serious matter. Don't take it lightly. We purchased several bullets 3 years ago.