Fabric Flammability Investigations Expert Article
The experts at Robson Forensic investigate a variety of product liability claims and incidents to understand how they occurred. This article discusses the standards that apply to fabric flammability and the factors that contribute to the flammability of the textiles used in a product. The raw source material, the gauge of the knit, fabric weight, dyes and chemicals used in treating the fabric, and any treatments applied to the end product all have an impact on flammability and flame intensity.
Fabric Flammability Investigations - Expert Article
The United States has recognized the danger from flammable clothing for some time. In 1953 Congress enacted the Flammable Fabrics Act (FFA) aimed at setting standards for classifying flammability of general use clothing. Its stated aim is to prohibit the use of only the most explosively combustible fabrics, based upon the classification system developed under the Act. In 1967, Congress amended the Act to include interior furnishings and expanded it to cover paper, foam and plastic film used in clothing.
The severity of injuries from fabric burns are the result of a combination of flame intensity and the duration of the flame. If a flame burns with lower intensity over a shorter period of time, it is less dangerous than a flame that burns with greater intensity for a longer period of time. General wearing apparel in the United States is required to be tested using 16 CFR 1610 (Code of Federal Regulations). This standard defines three classes of fabric depending on the rate of flame spread:
- Class 1: Normal Flammability
- Class 2: Intermediate Flammability
- Class 3: Rapid and Intense Burning
Class 1 is considered the safest and Class 3 is prohibited from being sold in the United States.
The test methodology requires a standard flame of ⅝ inches long be applied to a fabric sample that is held at a 45-degree angle. The time the flame takes to spread 5.5 inches across the sample is measured. If it takes less than 3.5 seconds, the fabric is given the Class 3 Rapid and Intense Burning rating and is prohibited for sale in the US. If the flame takes longer than 3.5 seconds to cross the 5.5 inch samples it receives either Class 1 or Class 2 and is acceptable for manufacture and sale in the US.
The FFA was not meant to rid the US. marketplace of all dangerously flammable fabrics. It is true that many fabrics can pass the 16 CFR 1610 standard, receiving a Class 1 or Class 2 rating, but still result in significant injuries including 2nd and 3rd-degree burns. The flammability of clothing is determined by many variables including:
- Fiber Content: Natural cellulosic fibers like untreated cotton ignite easily and burn readily. Wool has a tendency to be difficult to ignite and can self-extinguish.
- Type of Weave or Knit: A loose weave or knit will allow a textile to ignite and burn easier and longer.
- Overall Density: The denser a textile is, the more resistant it is to ignition and burning.
- Surface Finish: Flame retardant finishes can dramatically improve a textile’s ability to resist ignition and burning. Conversely, the application of finishes and decorations can increase flammability.
- High vs. Low Pile: High pile fabrics can cause a flame to flash across the surface of a fabric.
- Fit on Body: A tight fitting garment can deprive the fire of oxygen, limiting the severity of the flame.
The United States has determined that the classification of flammability for children’s sleepwear needs to be more stringent in order to protect those that may not be capable of recognizing the threat of a candle, hot stove or similar ignition source. All children’s sleepwear sizes 0-14 must meet one of the requirements set out by 16 CFR 1615 or 16 CFR 1616.
Because of the elevated requirements, most sleepwear for kids made from cotton or other cellulosic fibers has a difficult or impossible time passing the required tests. Many 100% synthetic fibers, such as polyester, are self-extinguishing and that characteristic helps garments made from those fabrics pass the more stringent standards.
Fabric Burn Investigations
When investigating an incident involving the flammability of textiles it is important to look beyond the raw materials classifications offered by the FFA. For example, fabrics with identical raw material content can undergo vastly different processing on the way to becoming clothing. These processes can include surface texturing, surface finishing with chemicals, laminating and screen printing. Post processing, as well as fuel load, can have a dramatic impact on the flammability of the base fabric. A common example of the impact of fuel load is when a screen print is applied to a cotton t-shirt. The increase of fuel in the plastisol ink interlocking with the cotton fibers of the shirt can create conditions where once ignited, the greater flame intensity caused by the higher fuel load increases the danger.
Robson Forensic employs in-house technical experts with industry experience conducting material flammability tests as well as forensic experience investigating fabric flammability claims. The scope of our investigations will typically include an analysis of how the injury occurred, the condition of the fabric, and the environment in which the incident occurred.
Call us at 800.813.6736 or submit an inquiry to see how we can assist with your case.
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