The document summarizes research conducted by UL on improving the flammability of residential upholstered furniture. Phase I experiments tested different materials and barrier technologies at the material and mock-up levels. Barriers and FR foams reduced heat release rates. Phase II will examine fire growth with and without barriers in furniture, while Phase III will measure tenability and safe egress times. Preliminary tenability experiments found barriers significantly increased available safe egress time over furniture without barriers.
FB8: 2-layer high-loft barrier. One side is predominantly rayon and the other cotton. Boron detected suggesting boric acid FR treatment.
FB3: monolithic film flat barrier based on glass fiber weave. Coating was a predominantly inorganics (calcium aluminum silicates). Contained about 3% TPP and TBPP FR and antimony oxide.
The fire in the top cannot be mitigated by the home owner whereas there is a possibility of the one depicted on the bottom.
Material-Level Test Results
1. frPU foam usage: Slightly shorter burn duration
2. High-loft barrier usage:
Prolonged time to ignition by 9 to 21 s; extended burn duration by 174 to 355 s
PHRR was modestly reduced but 180 s AHRR was significantly reduced
Total heat releases were 6 to 13 % lower
3. Flat barrier usage:
Prolonged time to ignition up to 2x longer
Para-aramid blends extended burn duration by 106 and 868 s; others were 415 to 433 s shorter
PHRR was reduced up to 34 % and 180 s AHRR was significantly reduced (58 to 91 %)
THR for para-aramid blends was 9 and 42 % lower; others were 80 to 95 % lower
Mock-up Tests Results
1. frPU foam usage: PHRR reduced 24 %, THR reduced 28 %
2. High-loft barrier usage:
Extended survivable ignition exposure durations
PHRR was reduced 36 to 62 %
Total heat releases tended to be greater
3. Flat barrier usage:
Extended survivable ignition exposure durations with 4 of 6 barriers surviving 300 s
Two para-aramid blends that did not survive 300 s exposure still exhibited 59 and 76 % reduction in PHRR
Furniture Test Results
Mitigation Approach 1: TB117 FR foam substitution for PU foam
Exhibited ~20% lower PHRR when cushions were ignited (1.3 vs. 1.1 MW); Comparable PHRR when back was ignited
Fire growth rate was comparable
Mitigation Approach 2: High-loft FR barrier substitution for poly wrap
Reduced PHRR from 1+ MW to 400 kW
Retarded fire growth rate by 3+X when cushions were ignited and 1.5X when back was ignited
Mitigation Approach 3: Approach 2 + FR barrier covered sides
Reduced PHRR from 1+ MW to 200 kW
Retarded fire growth rate by 3+X when cushions were ignited
Ignition of back did not propagate
In the chair fires conducted for the upholstered furniture flammability project we observed peak heat release rates exceeding 1 megawatt, which is flashover conditions, to as low as 200 kilowatts with a fully barrier covered furniture. So if fire growth and the peak heat release rate could be reduced to just 400 kilowatts by simply swapping the polyester wrap with a high-loft FR barrier, would an equivalent living room still flashover, and if so, would it take longer?
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For these experiments we used identically furnished living rooms with the only variation being the materials used in the upholstered couch and chair. Even then, all of the upholstered furniture used the same hard wood frames to further isolate the role of the cover fabric, padding, and cushioning materials. The upper left set of furniture is representative of contemporary furniture you may find in a big box store – polyester wrap covered polyurethane foam cushions and a polyester microsuede cover fabric. The upper right is equivalent furniture pieces representative of legacy furniture, much like what grandma and grandpa had minus the vinyl covers – cotton batting over metal spring cushions and a cotton cover fabric. The bottom two scenarios are the contemporary furniture pieces but with a cotton-based high loft FR barrier substituted for the polyester wrap – same frame, same foam and same cover fabric.
*** Only used FB8 barrier in these experiments (2-layer high-loft barrier. One side is predominantly rayon and the other cotton. Boron detected suggesting boric acid FR treatment.)
*** Cotton batting had boron suggesting boric acid FR treatment (~ ¼ concentration of the barrier though)