FM Global Design Criteria and local AHJs

[Dormer1975]

We design many automatic fire sprinkler systems under the design criterias of FM Global in our area. Mostly, storage applications. Recently, our local AHJ has raised concerns about accepting FM Global Design Criteria from a legal standpoint. NFPA 13 is an accepted standard by the international building and fire codes, which have been adopted by our state, county, and nearby cities. Granted, there is a provision that allows for "alternative means and methods".

I'm curious if the community here has had experience with their local AHJs and FM Design Criteria approvals and how that was/is handled. Ideally, I would like to placate my local AHJ such that they will accept FM Design Criterias in future. There is enough difference, especially in storage applications, between NFPA and FM Global design criterias. As it is right now, each project is an uphill battle to get the local AHJ to accept the FM Design Criteria.

 

[TravisMack]

There are some jurisdictions where they will not accept FM criteria. For those projects where there is criteria in NFPA 13 for the application, it is often just a matter of submitting different sets of calculations. I will submit calcs with the FM criteria to FM and submit calcs with the NFPA 13 criteria to the AHJ. Doing that has resolved a lot of headache for me in those jurisdictions.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[stookeyfpe]

If you are in a jurisdiction that has adopted the International Fire Code, the jurisdiction can accept Factory Mutual Loss Prevention Data Sheets (LPDSs). Section 102.8 allows the use of other nationally recognized standards, as approved, as prima facie evidence of compliance with this code, this code being the IFC.

The classic example of how to apply Section 102.8 is the case of an industrial dry cleaning plant with vertical conveyors of cleaned clothes. The building is sprinklered. NFPA 13 is silent on how to design an automatic sprinkler system for such storage. Conversely, FM has a LPDS that specifically addresses sprinkler protection for this particular hazard.

 

[TravisMack]

As Stookey states, in cases where NFPA is silent, I have never had an AHJ question the FM criteria. Rolled carpet storage is another area where NFPA has been silent, but FM has some detailed criteria.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[Sdpaddler50]

Other topics where nfpa is silent:
-storage uncartoned expanded plastic.
-carousel racks
-hydraulic fluids under pressure

FM has the largest fire test lab in the world. Much of what is in nfpa, came from fm. sounds like this ahj is not well informed.

 

[LCREP]

Look at NFPA 13, 2013 ED

Chapter 21
21.1* General.
Alternative Sprinkler System Designs for Chapters 12 Through 20

100% from FM Data Sheet 8-9

With heavy influence from Tyco and FM the area density .i.e. .30/2000 is going away in NFPA 13. Based on testing by FM they have determined all area density systems will not control or extinguish a fire! Yep they retested what we all have been using for 30 years and we were/are all wrong!! FM says all you need to know is the height of the building, psi at the head and K factor. They can control a fire with as few of 6 heads vs 20 for area density.

Add non-woven fabrics to the list NFPA does not covered and is often missed and designed as Grp A plastic. Check out the 8 series of the FM data sheets covers many of the storage configurations. Also see 8-1 for commodity classifications FM just updated the document, they now list 160+ commodities. The list in NFPA 13 and is 30 plus years old and will be updated by, guess who..... FM so what you see in 8-1 will be in 13.

Just came back from the annual meeting at NFPA in Las Vegas, this stuff was covered in several seminars I attended by the 13 committee members.

 

[stookeyfpe]

Based on testing by FM they have determined all area density systems will not control or extinguish a fire! Yep they retested what we all have been using for 30 years and we were/are all wrong!! FM says all you need to know is the height of the building, psi at the head and K factor. They can control a fire with as few of 6 heads vs 20 for area density.

The annual report U.S. Experience With Sprinklers published by NFPA doesn't indicate to me that what we've been doing for the past 30 years is wrong. If you look at the performance of sprinklers in multi-family, single-family, assembly and business occupancies, our current design criteria is pretty damn good.

Chapter 21 does provide the code official who is not comfortable with accepting FM LPDS with an alternative for using "the NFPA book" (I've heard this from some AHJs who have very little experience with challenging fire protection designs) and gives design professionals greater flexibility in Storage and Mercantile occupancies with High-Piled Combustible Storage. But I may start calling Chapter 21 the My Listing is Better Than Your Listing chapter.

 

[cdafd]

If a system is designed to a FM data sheet

Can it be written on the plans that the system meets NFPA 13???

 

[LCREP]

Stookey
I agree with you 100%. Working for an insurance company our loss data indicates sprinklers work real well. However, FM has it in their head supported by Tyco that all must change to what they say works. I don't agree with it,I think we are being sold a bill of goods, but if you look at NFPA 13 and where the committee is going it will be following FM criteria. All of the existing NFPA 13 design criteria will be placed in the appendix in future additions and reference.

 

[stookeyfpe]

LCREP:

Does this mean in the future that pipe schedule systems will no longer be allowed by NFPA 13? Which if it is, that's pretty funny because pipe schedule systems are an allowed design option for NFPA 13D systems.

And from time to time, and it's not very often, we'll review a Light Hazard pipe schedule system in our office. I'm not a fan of deleting longstanding provisions that have shown successful performance in the name of advancing technology, which can also mean product dominance in the market place.

 

[LCREP]

Stookey

I believe it is being put in the annex. Once the 2016 Ed of 13 is released for public comment we will know for sure. Good thing I only have a few years left before I retire ...LOL I will not have to deal with the mess!

 

[Sdpaddler50]

LCREP posted "all area density systems will not control or extinguish a fire Yep they retested what we all have been using for 30 years and we were/are all wrong!!"

LCREP: You are over simplifying a comprehensive program of high pile storage testing that spanned several years. Yes, some area/density designs for certain commodities/heights were based on extrapolating from older testing, and found to be deficient, but they never said "everything is bad".

FM no longer has the "ESFR" terminology. Heads are either storage, or, non storage.

A simple explaination: They found by using larger orifice (big K factors), 165F, QR heads, in the pendent position, that suppression could be achieved with lower design pressures, and less operating heads. This was akin to a performance based standpoint. So, contractors can run calcs with less water to squeeze through their pipes (lower frcition loss). The hose demand is often reduced from 500 to 250, to account for the suppression, verses the control mode approach.

When I started in this industry many years ago there were mostly K5.6 and K8 heads. If smart people with PHD after their name stopped fire testing back then, we would still have these heads to protect ever a plastic storage world in higher buildings.

Is this a big change, absolutely. But that is called progress.

If you google it, I am sure you can find a more detailed description of this approach.

 

[LCREP]

Sp50

I got it been doing this since 1979, a lot of things have changed in 35 years. Do you remember the initial and secondary design areas for plastics?

I understand things change for the better and testing is fantastic. BUT what Tyco and FM are doing in the presentations they are doing is painting with a very broad brush. 2 old committee members from 13 are holding back and will let all the old designs go. Tyco and FM are putting a lot of pressure on them to change. I just do not like the way they are doing this. I am on a NFPA committee and believe me I know about politics with in a committee but this is over the top.

 

[Sdpaddler50]

I don't have knowledge of the committee aspects, and who is putting pressure on who, but when reporting technical information, lets stick to the facts, and be accurate in our assertions regarding technical matters.