Reduce Hazard Classification Based on Testing?

4/2/2025

We are preparing drawings and hydraulic calculations for the storage of XLPE & XLEVA foam panels in an existing warehouse equipped with an Ordinary Hazard Group 2 (OH2) sprinkler system.

Based on NFPA 13, these products would fall under Group A plastics; however, independent testing indicates they do not exhibit the same ignition characteristics as standard polyethylene.
• XLPE (Cross-Linked Polyethylene) is chemically or physically cross-linked, enhancing its fire resistance.
• XLEVA (Cross-Linked Ethylene Vinyl Acetate) contains EVA, further modifying its properties. Third-party testing found that these materials did not have the same ignition characteristics as Group A Plastics.

Here are notes from the test report:
1. The specimen did not ignite.
2. The specimen ignited but self-extinguished prior to burning into the timing zone.
3. The material stopped burning before it burned for 60 seconds from the start of timing and did not burn more than 51 mm from the point where timing was started.
4. The test was discontinued at 5.0 minutes.

The customer plans to store 4' x 8' panels on wood pallets in a solid pile arrangement exceeding 5 feet in height.

Given that an OH2 system does not support Group A plastic storage above 5 feet, I'm looking for input on whether the test data could justify a reduced design density under NFPA 13 or if this scenario would require a performance-based design approach.

Does NFPA 13 allow adjustments based on fire testing like this?

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10 Comments

Dan Wilder

4/2/2025 07:22:16 am

You can utilize Chapter 1 Section 1.5 but the testing looks to fall short. Yes, there was a 3rd party testing of the materials but was that in the same configuration as the proposed (storage) and per UL/ASTM/NFPA? While the material by itself or in combination with a construction method has shown those characteristics, was the testing completed in storage configurations expected? How about any sprinkler testing or equivalent materials that have had the same testing and density confirmed? Wrap all that up and submit to the AHJ for approval and you are good to go.

You can also find testing methods in the definitions of non-combustible, limited-combustible materials - ASTM E84/E136, NFPA 259, UL 723 to name a few referenced in Chapter 4.

1.5 Equivalency.
Nothing in this standard is intended to prevent the use of systems, methods, or devices of equivalent or superior quality, strength, fire resistance, effectiveness, durability, and safety over those prescribed by this standard.

1.5.1 Technical documentation shall be submitted to the authority having jurisdiction to demonstrate equivalency.

1.5.2 The system, method, or device shall be approved for the intended purpose by the authority having jurisdiction.

Pete H

4/2/2025 07:26:36 am

You can ask the AHJ that will be reviewing the plan and submit your test results that back up your theory to see what happens and if they'll accept you lowering the commodity classification. If you're doing this, I strongly suggest using the definitions of Class IV and Group A found in Chapter 3 of NFPA 13. I also suggest trying to link your test results to the test results NFPA 13 used for PET bottles or jars (empty containers), which in 2016 edition is a Class IV commodity, despite being made of Polyethylene plastic.

As for NFPA 13 themselves, you may need to appeal the committee that writes the updated editions with your test results. But that change wouldn't take effect for years at the earliest.

Joe

4/2/2025 08:10:23 am

So with all fire test report we should ask several questions,

What fire test was used?

Is this the correct fire test?

Was the material tested in a manner that is will be stored vs used?

Was this an approved test lab?

and i am sure others can add additional questions

Jack G

4/2/2025 08:24:04 am

Good Question: was the test used by a UL approved test lab or just 3 rd party.
Remember : Requirements in NFPA are minimal. So is it wise to minimize the standard?
How much would it cost you to replace the facility if you are wrong? Is your insurance company on board with this idea?
What are your qualifications as a design builder contractor, and a lot of insurance companies dot insure design builder contractors .
Nicet is not a PE license.

Jesse

The testing, while done by a third party, was likely not done in the way the UL and others like the old Wassau may have done the test. Meaning in a specified storage array and in conditions that nmay be found in the actual storage arrangement you're protecting. Add packaging, pallets, etc, etc - you get the idea.

Some things, while taking a lot of time and heat energy to pyrolisize and begin the combustion process, burn much more effectively once started and the positive heat feedback loop begins.

I would recommend taking the fire test results to the AHJ, but they may not be receptive. You can also appeal to the 13 technical committee but this is a very long term approach and would take several years

Jon H

4/2/2025 08:25:39 am

The testing that was performed falls short of the requirements from NFPA 13 for determining commodity classifications. From the enhanced content of NFPA 13 (2022), section 20.3: "The likelihood of ignition is not considered in the commodity classifications". It also explains that the chemical heat of combustion and heat release rates are the factors considered for determining commodity classifications.

Jon N

4/2/2025 08:53:09 am

As a former AHJ, I am always skeptical of "3rd party tests" conducted by the product manufacturer. These are often not robust tests that place the product in conditions that mimic how it will be used or stored (similar to what others have mentioned).

This sounds like a glorified "match test" for flaming ignition. I would be looking for more of a full-scale test - like a room corner test - to see how the product behaves when it is exposed to radiant and convective heat from other burning materials. Remember, lots of burning plastics can pass these small-scale tests because the material itself no longer burns because it has melted and is currently a flammable or combustible liquid pool fire.

franck

4/2/2025 09:35:21 am

There is a difference between testing for fire behaviour in construction and classification for commodity class.
If you can demonstrate that the fire behavior is similar to group B or C plastic, then you can protect it as class IV or III. Otherwise it would be group A plastic.
It is not only the product itself that makes the classification but also the way it is stored. Corrugated cardboard is a class III if stored flat on pile, but becomes a class IV when stored as empty formed corrugated carboxes (just because of the quicker fire spread).

Chad

4/2/2025 10:37:38 am

I would like to directly answer the two questions posed.

No.

No.

No AHJ in there right mind is going to allow a loose interpretation or reduction based on those test results.... unless this was a well known organization such as UL. You are going to need to protect as class A or similar.

Most 3rd party "tests" are not performed properly or in alignment with the relevant standard. Oh sure they will reference a standard and follow it, just not the one that needs to be applied.

Jimmy Duke link

4/2/2025 11:34:27 am

Thank you for your feedback. I shared the question because I was also hesitant about relying on third-party testing but wanted to thoroughly evaluate all options before limiting the customer to a 5 ft storage height. I have recommended that the owner conduct a fire modeling study to assess their storage commodities and arrangement.

Thanks again for your input.

Reduce Hazard Classification Based on Testing?

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