Fire Marshals Clarify Wood Pallet Concerns

Use of plastic composites in some wood pallets leads to fire hazard concerns; fire marshals confirm wood pallets as baseline for warehouse sprinkler standards.
By Chaille Brindley
Date Posted: 4/1/2009

The U.S. supply chain has changed a lot over the last ten years. A significant increase in block pallets and the introduction of composite wood pallets into warehouses has created some new scenarios for existing fire safety standards. An effort to address these changes has caused a major controversy over the last few months as the National Association of State Fire Marshals (NASFM) floated a number of potential options. This included a requirement that all wood pallets would have to be tested and certified similar to what is required for plastic pallets to meet UL2335. Such a move would have significantly reinterpreted decades of precedence as wood pallets have served as the baseline for fire ratings.

As the association that provides technical assistance to the 50 state fire marshals, the NASFM in a recent meeting clarified its position. NASFM indicated that it has no intention to require certification of all wood pallets nor is it particularly concerned about the fire risk posed by various wood species. The only real concern for NASFM is the use of composite wood blocks in some pallet designs. Composite wood blocks contain plastic resins that may raise the fire risk of that pallet to the same as a plastic pallet.

It is not quite clear how much of the controversy was caused by a misunderstanding or whether the strong showing by the pallet industry caused the organization to reconsider earlier proposals.

Unpacking the Block Pallet Controversy

NFPA 13, the standard covering sprinklers, is the primary basis for codes governing pallets used in warehouses. The baseline for NFPA 13 has been wood pallets, which means that wood pallets have not needed to be tested in the past.

NASFM contends it is looking at wood pallets now because the industry has changed as the 9-block, softwood pallet has become more prevalent, thanks primarily to adaptation in the grocery industry. Also, companies like CHEP have recently started to use composite blocks that contain plastic resin. 

CHEP argues that its composite blocks contain trace amounts of plastic resin, yet the current standards seem to indicate that the presence of any plastic at all in a pallet means the entire thing must be treated like a plastic pallet. This oversimplifies a very complex issue. 

CHEP uses urea formaldehyde in its composite block, which chars and breaks down as compared to conventional plastic resins that flow and melt when exposed to heat. This “lava” flowing property of thermoplastics is one of the primary reasons why plastics once they ignite can cause more damage than wood fires. 

Urea formaldehyde as a thermoset actually changes molecularly when exposed to heat. Even NASFM in its recent response has indicated that all plastics do not pose the same fire hazard.

CHEP stated to NASFM, “We are unaware of any information, reported or otherwise, that suggests that wooden pallets containing composite wood blocks pose any new or increased risk.”

How much plastic does a pallet need to have for there to be a significant increase in fire risk? The National Wooden Pallet & Container Association (NWPCA) pointed out that saying a composite block makes a wood pallet a plastic pallet is like saying nails make a wood pallet a metal pallet. Another consideration is the fact that NASFM categorizes composite panels in residential construction as wood materials not plastics. Why would NASFM impose a more stringent standard on warehouses equipped with sprinklers than private residences? 

The controversy erupted thanks to a February memo stating, “As a matter of fairness and because of the varying fire performance of pallets, some comments have suggested that all pallets, regardless of materials, be listed to UL2335…NASFM believes this proposal has merit.”

This language suggested to the wood pallet industry that all wood pallets might soon have to be tested and certified. Trying to understand the motivation for such a drastic change, speculation abounded.

Requiring certification of all wood pallets would be a new revenue stream for NASFM. It could provide a boon to plastic pallets that are treated with a fire retardant. The primary benefactors would be iGPS, the all-plastic pallet rental company, and the bromine industry, which has connections with the NASFM through a common lobbyist. NASFM claimed all along its suggestions are based on fire hazard and not any financial consideration.  

The NWPCA stated in a press release, “Despite the success of existing codes, NASFM is proposing a two-grade increase for fire ratings for wood block pallets and says it will re-examine ratings for all other wood pallets. Compliance would require warehouses to spend enormous amounts for new sprinkler systems.”

Clarification at the Chicago Meeting

The NWPCA organized a large group of pallet companies to attend the recent NASFM meeting in Chicago. The strong turnout clearly showed that fire safety is an important issue to the wood pallet industry. 

Regardless of the politics, the outcome appears to be a win for the wood pallet industry and warehouse operators in general. The only real controversy remaining is how much composite material in a pallet poses a serious fire risk. One outcome of the meeting is that NASFM will convene a small working group to explore this issue and work on a new draft code application bulletin for the future.  

The primary fire code writing organizations in the United States are the National Fire Protection Association (NFPA) and the International Code Council (ICC). The role of the NASFM has traditionally been to interpret codes and provide guidance to the 50 state fire marshals. Code enforcement is carried out by state and local fire marshals. Bruce Scholnick, president of the NWPCA, said local enforcement would likely follow the interpretation established by the NASFM. 

Before the meeting there was widespread concern about new sweeping changes to common interpretations of fire standards covering the use of pallets in warehouses. Some speculated that NASFM may be trying to change existing code standards instead of merely assisting state fire marshals in interpreting them. 

In response, NASFM stated, “NASFM has not proposed changing any language in NFPA 13 and has not attempted to or suggested any reinterpretation of existing model codes and standards.” 

NASFM stated that its interpretation does not prevent the use of any composite wood or a plastic pallet that has been tested and found in accordance with relevant standards. This means that composite and plastic pallets that have been proven to have the same fire risk as wood will not need additional fire protection in order to be used for warehouses. Both CHEP and iGPS, the two largest pallet rental companies in the country, have tested and approved designs that meet these requirements.

The discussion is not over because the NASFM still must decide how to advise state fire marshals about the presence of composite wood blocks in some pallets. The outcome is likely to impact the future design and materials used by block pallet manufacturers and poolers. This includes the PIMS cooperative pool concept being considered by some industry leaders within the NWPCA.

NASFM explained that the purpose of its code update bulletin is to “remind fire code officials to verify that the automatic sprinkler system has been designed and installed to protect the hazard that currently exists in the area protected.”

Some others worry that whatever motive caused NASFM to issue its revised draft code bulletin in February could resurface. Bruce Scholnick of the NWPCA, said, “We’re not out of the woods yet, but I am cautiously optimistic. One of the most encouraging things is how the wood pallet industry came together on this issue.”

Wood Vs. Plastic

The material the pallet is made of can also affect the severity of the fire. It is certainly easier to light a rough-sawn edge of wood used in a wood pallet than an edge of a plastic pallet. But once a plastic pallet gets going, it will give off more energy than a wood pallet of the same size and weight.

Plastic has 2.5 to 3 times the potential heat energy of wood. As a result, plastic can cause a bigger fire than wood. Typically, plastic pallets require an increased level of fire protection. But there can even be differences in how wood pallets burn depending on the moisture content and the species of the lumber in the pallet. 

Regardless of the material, fire can weaken the pallet to the point of load failure. Although plastic does melt and puddle, both wood and metal can lose strength as well. 

Different materials are given different commodity classifications, which reflect their fire hazard and the amount of protection required. Commodity classifications take into account the item being stored as well as the packaging. As the commodity classification increases, so does the level of protection required to meet the NFPA standard. 

If a pallet manufacturer can furnish fire test data that shows its product does not increase the fire challenge, then no additional sprinkler protection may be required when using that particular pallet.

The two major testing organizations when it comes to pallets are Factory Mutual (FM) and Underwriters Laboratories (UL). FM Approvals is currently revising its pallet standards and UL is reviewing its standards. FM Approvals specializes in loss prevention, testing and industry standards. UL is a major testing organization that provides data for commercial and industrial products used to make insurance and fire hazard determinations. Both FM Approvals and UL have worked extensively to provide real world information for fire hazard assessments.

Internal Industry Fight 

One major dynamic of the fire issue is the budding fight between the two major rental companies – CHEP and iGPS (a new, all-plastic pallet rental company). 

These two companies are extremely competitive since many of the iGPS upper management are former CHEP employees. 

CHEP criticized the all-plastic approach of iGPS when it entered the market. Responding to concern over the fire hazard of its plastic pallet, iGPS retooled its design to include a fire retardant chemical (deca bromine) that is viewed by insurance companies as having the same fire hazard level as a standard wood pallet. This process is called UL 2335 listing and requires the pallet to undergo extensive testing to be certified. 

Now that iGPS has redesigned its new pallets to be UL 2335 compliant, it is aggressively marketing the advantage. Some believe that iGPS and lobbyists for the bromine industry are the ones pushing for new rule interpretations. In a statement to NASFM, iGPS encouraged rapid adoption of new rules citing concerns for public safety. 

Other than anecdotal evidence, iGPS has not provided any specifics to determine to what extent wood/composite pallets are to blame for recent fire incidents. iGPS could not be reached for comment.

How Safe Are Fire Retardants?

The primary chemical used in most conventional fire retardants is deca bromine (DECA). In a CBS News report, the EPA’s senior toxicologist Linda Birbaum expressed concern about DECA’s long-term effects on human health. She said it causes serious health effects in young animals, which raises a major red flag.

Brominated flame retardants have been widely used over the last 30 years to treat upholstery, electronics and children’s products. You may even have trace amounts of these chemicals in your blood thanks to the widespread use of these fire retardants.

Some states are moving to ban the product for consumer goods. In 2007, Maine and Washington established bans on the chemical. Six other states, including California, are considering similar bans.

Environmental groups, such as Friends of the Earth and Greenpeace, have warned about the dangers of brominated fire retardants. Countries in Europe are working to phase out these chemicals as well.

Despite these growing health concerns, the bromine industry is pushing for wider adoption citing the advantage to fire safety. Over recent years, NASFM has become an advocate for the use of fire retardants claiming these products save lives.

As the CBS News article pointed out, NASFM has received money from the bromine industry and shared a lobbyist, Peter Sparber and Associates.

The real benefit of fire retardants is highly debatable for warehouse applications. In severe warehouse fires the fire source is great enough that a retardant has little effect. Remember that these chemicals just make it more difficult to catch fire with a low energy ignition source. Once ignited, a plastic with a fire retardant will not burn significantly different than a plastic without it.

What Lies Ahead?

The future is difficult to predict. It appears that a major revision of fire code interpretations has been avoided for now. The NWPCA is waiting to see what comes out of the NASFM working group on the composite pallet issue before declaring any victory.

CHEP has recently obtained FM Approval for its composite block pallet as meeting the same fire standard as wood pallets. CHEP claimed this new rating means no upgrade in sprinkler protection is required in manufacturing and shipping facilities solely as a result of the use of CHEP’s pallets. 

The plastic pallet and bromide industry could mount a comeback and try to push the issue again. Or opposition to bromide fire retardants could lead to a reduction in the use of these chemicals.

What is clear is that more data needs to be developed before we really understand the full ramifications of various pallets and warehouse fire hazard. Another key point is that toxicity remains a major concern that is not adequately addressed by existing fire codes even though it is a consideration for local firefighters.        

The firestorm over pallets in warehouses may have subsided. But the little debates rage on one conversation at a time.

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