ARS | Publication request: Cone calorimeter evaluation of two flame retardant cotton fabrics

Submitted to: Fire and Materials: Flammability and Flame Retardant Textiles
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 2011
Publication Date: N/A

Interpretive Summary: The manuscript describes tests of two flame retardant treatments for grey cotton nonwoven fabric which can be used as barrier fabric in residential mattresses using cone calorimeter. The manuscript discusses resistance to small open-flame ignition of residential mattresses and thereby compliance of California AB 603 and the Federal regulation, CFR 1633 (the regulation is in force since July 1, 2007) with the use of a fire blocking, barrier interliner in the manufacture of mattresses. A cost-effective fire barrier flame resistant (FR) cotton nonwoven is incorporated in the manufacture of mattresses, and is designed to protect and prevent ignition of the major cushioning component materials of a mattress. Limiting the fire involvement of the major cushioning component will significantly restrict the fire and thereby produce residential mattresses resistant to open flame ignition that burn at a much slower rate, and the flash point may not occur in 30 minutes. This will permit occupants to escape fire and save lives. The residential mattresses of the earlier type (without FR barrier) ignited and produced flames capable of engulfing an entire bedroom within 2-5 minutes. In a 2003 Consumer Products Safety Commission (CPSC) study, it was found that in 1999 there were 18,000 mattress and bedding fires that led to 330 deaths and $300 million in property damage.

Technical Abstract: Unbleached (grey) cotton needle punched nonwoven (NW) fabrics with 12.5% polypropylene scrim were treated with two phosphate-nitrogen based fire-retardant (FR) formulations, SRRC-1 and SRRC-2. The SRRC-1 formulation contains diammonium phosphate as the flame retardant chemical along with urea and dimethyloldihydroxyethyleneurea (DMDHEU). Because a trace amount of formaldehyde was still expected to be released from SRRC-1 treated FR cotton under high heat, it was preferable to eliminate the DMDHEU leading to the revised formulation SRRC-2. It has a higher content of diammonium phosphate and did not use the polyethylene emulsion that was in SRRC-1. Both formulations were of low cost as they were developed at SRRC using industrial grade chemicals. The fabrics were evaluated with a cone calorimeter using three heat flux levels, 20, 30, and 50 kW/m2. Based on the overall cone calorimeter results for heat released and ignition times, FR NW fabrics that were treated with SRRC-2 were found to be slightly superior in flammability properties to those treated with the earlier SRRC-1 formulation but the differences were statistically insignificant. Both preparations were much less flammable than the untreated control cotton NW fabrics. Compared to the untreated NW fabrics, the FR fabrics had higher visible smoke production.