July 1, 2009
equipment & applications | Pallets

Lots of smoke, not much fire

An arcane technical bulletin on sprinkler systems ignited a firestorm among pallet users before being withdrawn this spring. But the controversy continues to smolder.

By Susan K. Lacefield

It's not every day that an arcane technical bulletin sets off a storm of controversy, rumors, and finger pointing. But when the National Association of State Fire Marshals (NASFM) issued a draft code application bulletin (CAB) in September 2008, it caused just such a flare-up in the pallet community.

The source of the controversy was the humble wood composite pallet—or to be precise, the question of whether it could legitimately be classified as a wood—as opposed to plastic—pallet for purposes of fire code enforcement. That may sound like a semantic distinction, but it has big implications for DCs that use these pallets. A change in classification to plastic (wood composite units contain a plastic resin) would raise the units' fire rating, meaning they'd require higher-capacity (read: costlier) sprinkler systems to protect them.

Fears that they might be forced to retrofit their facilities with expensive new sprinklers sparked an outcry from several large shippers and groups like the National Wooden Pallet and Container Association (NWPCA). At a meeting in May, the NASFM attempted to quell those fears, offering public assurances that it had no intention of pushing for new rules or enforcement practices. Although the hubbub eventually died down, the incident pointed up how much confusion remains when it comes to pallets and fire safety.

The spark
The publication that sparked the incident was not a law or even a fire code, but rather a guide for fire inspectors. Titled "Pallet Fire Loading Impact on Sprinkler Design," the bulletin was written to address issues relating to compliance with section 13 of the National Fire Protection Association (NFPA) standard, which lays out requirements for installing automatic sprinkler systems.

Designing a sprinkler system to the NFPA standard is a complex calculus that involves many variables: floor area, the type of commodity stored, and the type of pallet the product is stored on, to name a few. But that last variable is sometimes overlooked, according to the NASFM. "When automatic fire sprinkler systems are designed pursuant to NFPA 13, the type of pallet intended to be used is a factor that is considered," says Jim Narva, chief project manager for the NASFM. "Changing the type of pallet that is used can have unintended consequences that affect the fire protection and the capability of the system."

What caused all the uproar was a section in the NASFM bulletin that pointed out that the "wood pallets" referred to in the NFPA standard are different from the wood composite units used widely today. The NFPA defines wood pallets as pallets made of pure wood with metal fasteners. Wood composite pallets, by contrast, are formed of sawdust held together with adhesives made out of a plastic resin called formaldehyde urea, the NASFM noted in the bulletin. That comment raised concerns that the NASFM considered composite pallets to be a variety of plastic pallet, and led to worries that wood composite pallets might be regulated as plastic pallets at some point down the road.

Narva insists that the association had no such intentions. "NASFM has been misrepresented as in some way proposing changes to the existing codes and standards or re-interpreting them; that is not what we are doing and that has never been our intent," he says.

In the end, the NASFM withdrew the CAB from its Web site. It also formed a committee to help rewrite the CAB to reflect only what's in the existing fire codes.

What does this mean for pallet users? For practical purposes, nothing. No company is going to have to upgrade its sprinkler systems, nor is anyone suggesting that they might be required to do so in the near future. However, the controversy does highlight the need to understand—at least on a basic level—the implications of the type of pallet you use for the safety of your facilities, your employees, and the surrounding community.

Total meltdown?
As for why fire codes treat plastic pallets differently from wood, it's all in the way the material burns. Although plastic may take longer to ignite than wood, plastic products (if they aren't treated with a flame retardant) burn hotter and faster than wood products do. And when heated, plastic tends to melt and run like lava.

"Plastic commodities typically produce higher-challenge fires and therefore require sprinklers that deliver more water," explains Jim Lake, senior fire protection specialist for the NFPA.

If a plastic pallet is treated with a fire retardant, however, it may be exempt from requirements for higher-capacity sprinklers. To receive that exemption, the pallet manufacturer must have its pallets certified by a testing laboratory, like Underwriters Laboratories (UL) or Factory Mutual (FM) Approvals.

The testing laboratory will subject the pallets to a 30minute burn test in a controlled environment. If the pallets are found to perform as well as or better than wood, they will receive an FM 4996 Approval or a UL 2335 Listing. For example, all of the pallets used by pallet pooling company iGPS have received a UL 2335 Listing, says Bob Moore, the company's CEO. "Our pallet just doesn't burn at all," he says. "It smokes a little bit." (That's not to say that fire-retardant plastic isn't without its own controversies. See sidebar, "another firestorm in the making?")

Name game
So why not simply declare the wood composite pallet to be a variety of plastic pallet, subject to the same requirements as plastic units? For one thing, calling wood composite plastic is stretching things a bit. According to pallet pooler CHEP, there's actually very little plastic in wood composite-block pallets; they are 95 percent wood.

Furthermore, not all plastics are the same. The plastic in the adhesives used in the wood composite blocks is known as a thermoset. "A thermoset doesn't flow like lava; instead, it chars up on the outside," says David Deal, director of product services and industry affairs for CHEP. This means that wood composite blocks react to fire the same way pure blocks of wood do, he says. To confirm this assertion, the NASFM is reviewing the latest evidence as part of the process of revising the CAB.

Then why not just revise the standard to state that wood composite pallets should be considered to be wood pallets? Lake says an NFPA technical committee did review a proposal to change the definition of wood pallets in NFPA 13 during a previous revision cycle but decided it was unwarranted at the time. He adds, however, that the technical committee would be willing to revisit the issue if the NASFM's research shows a compelling reason to do so.

Several pallet suppliers say the confusion surrounding fire performance could be eliminated if all pallets were simply required to undergo a burn test and certification process. "There should be a 'meets and exceeds' standard," says Steve Letnich, vice president of sales and marketing of steel pallet manufacturer Worthington Steelpac. But others disagree, contending that testing would be unnecessary as well as burdensome and expensive.

In the absence of such standards, what should conscientious DC managers do? Since different states have different fire codes and regulations, it's best to work closely with local officials to make sure you stay on the right side of the law.

"Basically, the best thing they can do is go to their local fire marshal and ask questions before they build a building, before they talk about what they're going to put in a building," says Letnich, "so they know exactly what type of sprinkler system they're going to require."

About the Author

Susan K. Lacefield
Editor at Large
Susan Lacefield has been working for supply chain publications since 1999. Before joining DC VELOCITY, she was an associate editor for Supply Chain Management Review and wrote for Logistics Management magazine. She holds a master's degree in English.

More articles by Susan K. Lacefield

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