Polymer Case Studies
HMMWV Cab Liner Program
Armoring the military HMMWV (Humvee) for combat missions
In the process of up-armoring the military HMMWV (Humvee) for combat missions in Iraq and Afghanistan, enough heavy armor plating was added to the base vehicle that each crew door now weighed in excess of 400 lbs. This helped protect the troops from rocket-propelled grenades but when the vehicle was upended by an IED (Improvised Explosive Device) planted in the road, it became difficult for soldiers to quickly extricate themselves from the vehicle, given the weight of the doors, now overhead.
In some cases, the blast would result in a fire that involved the acoustical/thermal cab liner insulation. While these common automotive products met the normal flammability criteria for passenger cars and trucks (FMVSS 302), that standard assumes that most vehicle operators and passengers have ample time to exit the vehicle. As such, it allows for the dripping of molten foam residue, as the material slowly burns, prior to self-extinguishing.
Army hospitals in Germany were reporting a higher than normal incidence of soldiers suffering from burns on the face, neck, head and arms as a result of contact with the dripping molten foams.
TACOM (U.S. Army Tank Automotive Command) challenged is prime HMMWV manufacturer to develop an
acoustical/thermal cab liner that would pass a much more stringent flammability standard; one that does not allow for the dripping of molten foam when the material is involved in a fire. The standard chosen was UL 94-V0. This is a burn test whereby the sample burned is in a vertical orientation.
- PTI, along with seven other materials companies, was invited to participate in this developmental challenge to help protect U.S. combat troops. Contending composites would need to not only pass UL 94-V0, but would have to be very durable and watertight, as the HMMWV is capable of fording deep streams. Anti-fungal capabilities were also a must.
- PTI engineering and applications specialists considered all parameters that might prove important in a military vehicle setting, calling on its past experience in providing cab liners for such military stalwarts as FMTV, MRAP, HIMARS and LSAC.
- PTI developed a rugged closed-cell foam base and introduced a tough aerospace-oriented woven facing for added long-term endurance in a military setting. Its unique through-foam perforating technique allows air to escape from behind the closed cell foam during installation. This, in addition to a very aggressive adhesive system, provides for a most secure and lasting bond.
- PTI’s superior cab liner composite was chosen over the other contenders and is now in production on the HMMWV. Other military vehicle OEMs as well as commercial vehicle manufacturers have shown a keen interest in this new Non-Burning cab liner composite.
AM General 2 Door Hood Configuration
AM General 4 Door Hood Configuration
Specifications subject to change without notice. Check with factory for latest revisions. The Federal Trade Commission considers no existing test methods or standards regarding flammability as accurate
indictors of the performance of cellular plastic materials under actual fire conditions. Results of existing test methods, such as UL-94, MVSS-302, SAE J-369, and FAR 25.853 are intended only as
measurements of the performance of such materials under specific controlled test conditions. Any flammability ratings shown are not intended to reflect hazards presented by these materials under actual
fire conditions. The information contained herein is based on laboratory test data developed for PTI and is believed to be reliable, but its accuracy or completeness is not guaranteed. The buyer must test
any product to determine the suitability for h is specific application before use. PTI DISCLAIMS ANY RESPONSIBILITY FOR: 1) WARRANTIES OF FITNESS AND PURPOSE, 2) VERBAL
RECOMMENDATIONS, 3) CONSEQUENTIAL DAMAGES FROM USE AND 4) VIOLATION OF ANY PATENTS OF TRADEMARKS HELD BY OTHERS.
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