Will Membrane Building Melt Before Sprinkler?

12/1/2025

Is it necessary to apply special sprinkler design criteria for a membrane building?

Tension fabric buildings with polyethylene membrane are becoming increasingly common. In this case, the fabric is rated per NFPA 701 and other certs, so it will not propagate fire, but the manufacturer advertises that it will melt/burn under direct flame and release smoke and heat.

Would this not affect the operation of the building's sprinkler system?

FM 1-59 requires quick response sprinklers, which makes a lot of sense, but provides little to no evidence in support.

I can see no similar requirements in NFPA outside special requirements for aircraft hangars; NFPA 102 seems like the main standard and is silent on the subject.

Is there something I'm missing in NFPA? Is there any research out there on sprinkler performance in membrane structures that will melt and release heat?

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12 Comments

Pete H

12/1/2025 07:03:58 am

https://hybridbuildingsolutions.com/fabric-buildings-protect-against-fire-damage/#:~:text=There%20are%20many%20benefits%20to,of%20Brutus%20Salt%20Storage%20Building

Yes, a melting membrane would affect the building's sprinkler system insofar as "Without heat collection, the sprinkler will not operate." However, one would assume the point of melting the fabric membrane to prevent the spread of fire (for most of these fabrics seems to start at 329 F as the lowest) will still be higher than the 125-286 degree (Fahrenheit) temperatures the sprinklers should already have activated at.

Dan Wilder link

12/1/2025 07:58:02 am

Other than area increases for slope, hanging methods for the atypical structural members, seismic considerations for structural load, and restraint methods, the layouts and design approaches are not any different....

And as Pete said for the heat collection. Most membrane MFG's (or their suppliers) have testing reports available when requested.

https://cdn.prod.website-files.com/626d7c3bdc441c114f39f304/65e138028f977434c4f9fcd3_NFPA%20701-2023%20Test%20Results.pdf

https://abastran.com/en/fire-resistance-of-membrane-structures-pvc-ptfe-etfe/

Jesse

12/1/2025 08:10:37 am

Agree with Dan and Pete here. The point at which the membrane deteriorates is above even intermediate temperature sprinklers. Using QR sprinklers I would think would allow the AS system to operate.

Chad

12/1/2025 08:19:14 am

What kind of "evidence" do you need? Section 3.4 of 1-59 applies common sense "evidence" that speaks the inherent, expected conditions as to the why:

3.4 Protection
Fire-exposed fabric structures can impair automatic sprinkler systems or present conditions which are difficult
to protect. Therefore, they are not appropriate for all occupancies.
Fabric materials that are exposed to fire can fail (lose integrity, melt, or burn through) and create holes or
openings in the building envelope or ceiling that allow heat (hot gas) to vent. Automatic sprinklers rely on heat
from fire exposure for proper actuation, and therefore venting can delay sprinkler response and result in
inadequate protection. This is among the fire-related hazards addressed by the recommendations in Section 2.4.

For a two-layered system (e.g., an acoustical interior fabric liner in addition to the exterior fabric), the fabric
liner typically acts as the ceiling when designing or evaluating automatic sprinkler protection. In addition to
overwhelming the sprinkler system, two-layered systems can create a concealed space that may require
additional automatic sprinkler protection.
Fabric structures often have substantial roof slopes or curvature in order to shed rain and snow, or for
architectural or occupational purposes. These large slopes often exceed the maximum recommended slopes
for some automatic sprinkler systems.
Fabric structures can be susceptible to fire damage from exterior sources since the fabric material can burn
or melt away and expose building contents.
It may not be feasible to install automatic sprinkler protection in tensioned fabric structures due to the lack
of adequate support structure, which is needed for the proper hanging, bracing, and restraint of automatic
sprinkler system components.

Nick (OP)

12/1/2025 07:49:20 pm

Thanks! The challenge in this particular case is that the QR sprinkler requirement is in conflict with other requirements, because this is a dry system for an EH1 occupancy (which both FM and NFPA agree should have SR heads). Even if there is no "proper" way to do it according to standard and may be unprotectable, I'm struggling with what the "best effort" solution should be.

Todd E Wyatt

12/1/2025 08:22:12 am

The scoping Code (e.g. IBC-2024) determines WHERE an automatic sprinkler system (ASPS) is required based on the structure’s Occupancy Classification (903.2.1-903.2.10) and Specific Building Areas and Hazards (903.2.11).

Once the Occupancy Classification(s) are determined, then the permitted ASPS standard (NFPA 13, NFPA 13R, or NFPA 13D) is determined. The required ASPS standard determines the sprinkler design criteria.

REFERENCES
IBC-2024
Chapter 9 Fire Protection and Life Safety Systems
Section 903 Automatic Sprinkler Systems
903.2 Where Required
903.2.1 Group A
903.2.2 Group B
903.2.3 Group E
903.2.4 Group F-1
903.2.5 Group H
903.2.6 Group I
903.2.7 Group M
903.2.8 Group R
903.2.9 Group S-1
903.2.10 Group S-2 Parking Garages
903.2.11 Specific Building Areas and Hazards

12/1/2025 08:46:57 am

I agree with Chad. I do not agree with Pete H, Dan Wilder, Jesse and not sure where Todd E Wyatt was going with their response as this is a question about functionality and not design.

Just because a fabric is rated slightly above a sprinkler rating does not mean the sprinkler will operate before the fabric fails. Please refer to the many fire tests where ceiling temperature are measured at much higher temperatures (>500F) than the sprinkler rating before the sprinkler operates.

IMO, there is no protection scheme that will adequately protect fabric structures outside of a deluge system with some type of reliable detection system and usually the size of the structure eliminates this as a practical option.

Franck

12/1/2025 03:54:26 pm

I fully agree with this comment
I see too many possibilities for the sprinkler system not to operate properly, unless you have some kind of reinforced material with a much higher temperature melting point (as outlined by Jack below).

12/1/2025 07:55:58 pm

Thank you for the reply. I am somewhat of the same "no adequate option" opinion, especially since it's going to need a dry system for an EH1 occupancy. The building still needs to be sprinklered per the AHJ so some kind of system will be going in, it's just hard to choose what would be the "least bad" option.

I feel like others must have faced this dilemma too given that these tents are used by auto manufacturers and all sorts of industries these days.

Jack G

12/1/2025 12:12:30 pm

My experiences with fabric structures was with 6 flags Great Adventure and Factory Mutual Engineering. Also Hotel structures , Sheraton for displays, conventions, heated and cooled tents and FM.
The structures there were, both companies were Kevlar. From what I can recall was the fabric was reinforced Kevlar for strength and was rated for over 900 degrees F.
Fm has a guideline for these structures. Also IBC 2021….3103.5..:
The great flag structures were huge ( like Oktoberfest tent ) had triangular pipe trusses about every 30 feet. The tent itself had sag in between.
FM proposed Sidewall sprinklers back to back with baffles in the truss. One sprinkler would hit the “ middle of the sag.
Before contracting, fm did extensive testing for this method.
Fabric ceilings I ve dealt with usually had pendent heads in them ( indoors )

12/1/2025 12:20:58 pm

The pipe was in the trusses to protect the sprinklers. Some runs we bent to the arch, others with angled fittings. Bulk to the “ lines “ was run low along peremeter around 15 or more feet high.
For the Sheraton, the structures were erected and removed seasonally. So we put fabrication tads on all the pipe so it would be like a new install. Pipe would be scrutinized and repared as needed.
Was really interesting.

12/1/2025 07:51:58 pm

Thanks Jack, fascinating projects and insightful! I appreciate the reply.

Will Membrane Building Melt Before Sprinkler?

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