Protection criteria for obstructions under ESFR system?

[UFT12]

The application is industrial located in the US. Typically we go by EH G1 and we are installing process protection and for obstructions (including platforms) much lower below the roof. We need to provide data for the building sprinkler contractor for some tie in points and flow requirements. This time however the building is protected by ESFR sprinklers (12 heads K16.3, 52 psi).

What should we follow here for just obstruction protection? Abide by the roof criteria (ESFR) or standard criteria like EH G1? To me the flow of ESFR is absurd for just one dimensional platform or duct as it seems not rational to expect fire travel like that. We are not talking for flammable liquid installation. Mostly is metallic with ordinary combustibles, pumps, cable trays and lot of ducts and piping.

Has anyone encountered that and what criteria were applied for obstructions?

 

[TravisMack]

On some projects, we have protected for the occupancy / hazard class under a solid platform. For duct, we always put the ESFR under the duct and size the pipe supplying those sprinklers the same as the overhead so that you do not have to include 2 additional sprinklers in your ESFR calculation.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

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[UFT12]

Can you please provide the reference in NFPA 13 of what you said about the ducts and the two additional sprinklers?

 

[LCREP]

Is this a warehouse occupancy if not ESFR is not advised.

 

[cdafd]

Follow NFPA 13 obstruction rules for esfr?

https://sprinklerage.com/esfr-sprinklers-obstructions/

 

[UFT12]

LCREP,

This is not a warehouse and I already expressed my concerns about the ESFR sprinklers. That wasn't something I could influence. I believe there is a misunderstanding of building contractors about ESFRs in non storage occupancies. I would attributed mainly to two reasons, a) "throw a bunch of ESFRS and we can protect pretty much any occupancy that may come in the future", b) a rule in IBC which allows the omittion of smoke exhaust systems when the building is protected with ESFRs. This seems quite tempting for building contractors or owners. But I believe they fail to understand that such a decision will bring other implications. For example in our applications, meeting all obstruction rules can be sometimes impossible, especially between machinery/equipment and platforms. We most likely end up with more heads but that doesn't seem the right approach to me especially when you clearly don't need a waterfall (e.g. water mixed with liquids that may require containment etc).

cdafd,
we will have to meet all obstructions rules but the initial question is all about how one would have to do the hyd. calculation.

 

[LCREP]

UFT12

Have you reached out to the insurance carrier loss prevention engineer for guidance? As someone who worked in this area I would strongly advise the client not to use ESFR in a non storage application. The water damage potential alone is a concern. When I was involved in these types of discussions and the client would not change the sprinkler design our underwriter would hit them with either a $500K water/ sprinkler damage deductible and or withdraw the sprinkler damage coverage all together. That usually got them to reconsider. [pre][/pre]The saving on not having to install a water supply i.e. fire pump etc was usually enough to convince them when they really started to look at $$.

 

[TravisMack]

Can you please provide the reference in NFPA 13 of what you said about the ducts and the two additional sprinklers?

I'm sorry, but I can't spend the time doing a keyword search of NFPA 13. Please review all of the calculation criteria for ESFR in NFPA 13. You will find the criteria.

However, as others have said, in a non-storage application, ESFR is likely not the best choice.

Best of luck and Merry Christmas!

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692

 

[UFT12]

No problem, I just though you had it handy in mind.

 

[TravisMack]

Sadly, as I get older, those little details seem to fall away. I can tell you basically what the page looks like and where you may find it on the page, but I lose the citations. Oh, the joys of getting older.

Merry Christmas!!

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692

 

[LCREP]

Sadly, as I get older, those little details seem to fall away. I can tell you basically what the page looks like and where you may find it on the page, but I lose the citations. Oh, the joys of getting older.


Travis

Do not retire.....lol been out of action for little over 2 years and stuff I knew off the top of my head is gone! After 36 years the last 5 years being the to go to guy for 65 folks with a 100 questions a day.....stuff is gone.

Now I have important stuff to worry about....where to travel to next....lol

Merry Christmas

 

[UFT12]

Well, this huge standard was always a brain stress test every time you need to dig up something, no matter how old you are.

Merry Christmas

 

[UFT12]

So I managed to short things out with the customer and it seems we are going with standard spray sprinklers below obstructions. It seems these will need to be of quick response which, the way I see it, it violates NFPA 13 for EH occupancies unless I am wrong and something in NFPA 13 eludes me.

But there is an other concern now. I m trying to understand par. 8.12.5.3.1 (4) which says:

"Additional sprinklers shall not be required where the obstruction is 2 ft (600 mm) or less in width and located a minimum of 2 ft (600 mm) horizontally from the sprinkler."

If we consider two statements that both need to be true

"the obstruction is 2 ft (600 mm) or less in width"
and
"located a minimum of 2 ft (600 mm) horizontally from the sprinkler".

would that mean that if the first is not correct, obstructions in any elevation below the sprinkler wider than 2 ft and in any horizontal distance from the head will require additional sprinklers? My obstruction is 20 ft below the deflector.

I appreciate any help on this. Thank you.