Sprinklers with Smoke Venting

[Meerkat]

First post so be gentle...

Large warehouse building under refurbishment - not in the UK.  High bay racking.  Stored goods mostly Class 2.  Proposal to fit ESFR roof-mounted sprinklers and no in-rack sprinklers using NFPA 13 standard.  Local fire code requires significant areas of smoke vents in the roof.  Fire Engineering Consultants are making the detailed specifictions, I am looking at the recommendations on behalf of a client to see if they look sensible and also gathering other views - e.g. of insurers.

Long story short I have two opposing opinions.  One says that smoke vents are a BAD THING in a sprinklered building as they may delay the operation of roof-mounted sprinklers and provide a greater supply of oxygen to the fire.  The other says that this is all tosh and what's more "experiments have shown that venting does not significantly delay the operation of the first sprinklers" but that in fact it actually meant that heads further from the seat of the fire were less likely to operate.

The first opinion says that sprinklers should operate well before vents.  The second says that the operation of vents should not be delayed.   

I have 18 years fire safety management experience in industry and have carried out fire risk assessments for clients under the FSO but I know my limitations!  I'd be interested to hear the learned opinions of those with more experience in this specific field than me.

[Tom Sutton]

I am sure research has been done by Colt or BRE regarding this subject and http://www.sp.se/EN/INDEX/RESEARCH/SPRINKLERSVENTILATION/Sidor/default.aspx would indicate that this subject has been under consideration for some time.

[John Webb]

I can confirm that BRE and Colt did work in a Belgium warehouse some while back (1992/3).

Results were published in BR 213 "Sprinkler operation and the effect of venting: studies using a zone model" by Peter Hinkley (ISBN 0 85125 512 4) and in Fire Science & Technology Vol 13 No.1 and No.2 (19-41) 1993 "Large Scale Experiments with Roof Vents and sprinklers Part 1....."  and in the same journal, pages 43-59, "Part 2: The operation of Sprinklers and the effect of Venting with growing fires"
It is this latter article you will find most useful. 

[CivvyFSO]

There is also BR224, which is possibly the research that the journal article discusses.

I believe Howard Morgan has also done a few papers on the subject.

Or.. Have the vents operate on the sprinkler flow switch. Job done?

[AM]

The Factory Mutual guidance does not like automatic vents with sprinkler systems:

“2.1.1.10 Heat and Smoke Venting

2.1.1.10.1 Factory Mutual Research recommended protection is based on roof vents and draft curtains not being provided. Fire tests have not shown automatic vents to be cost-effective, and they may even increase sprinkler water demand. Hence, permanent heat and smoke vents, if installed, should be arranged for manual operation or equipped with fusible links rated at a minimum 360°F (182°C). Smoke removal during mop-up operations can frequently be achieved through eave-line windows, doors, monitors, nonautomatic exhaust systems (gravity or mechanical) or manually operated heat and smoke vents.”

But, as you say, other guidance does not have a problem with it, and the guidance supporting the Greater Manchester Act states the 'experiments have shown...' qoute in the original post. It does, however state that vents should not be automatic if ESFR system is to be used, and this is also stated in the SVA Guide.

[Meerkat]

Thanks everyone and that's the nub of it really - insurers are anti- but installers are pro- 

NFPA 13 also recommends that vents with ESFR systems should be either manually operated or set to operate on a fusible link rated at 50 degrees F above the sprinkler activation temperature. (Fahrenheit?  Stupid American codes!).

Civvy - sounds easy doesn't it but it's not what the Code says and it's not what the insurers want either!

Anyone point me to where I might get hold of any of the articles suggested?  I knew that British Library reader's ticket would be useful... 

[John Webb]

The BRE Bookshop may still have copies available - try www.bre.co.uk to start with. The Bookshop has its own website but I can't remember its URL but you can get to it from the main BRE site.

[patrickhamblin]

If you let me have your email address I will send some useful information.

[Meerkat]

Thanks Patrick - I've now made my e-mail address visible in my profile.  I will e-mail you later, when I'm back in front of my own PC!