Imagine a safety manager auditing their team’s PPE before a rainy shift. They spot a rack of high-visibility rain jackets, check the tags, and see "Tested to ASTM D6413." Satisfied that the gear is flame-resistant (FR) and their workers are protected against a sudden flash fire or arc flash, they sign off.
It’s a common scenario - and it’s a dangerous mistake.
In the safety industry, there is a critical, widespread misconception about what that specific ASTM label actually means. Relying on ASTM D6413 as proof of comprehensive worker protection doesn’t just violate best practices; it puts lives at risk.
Here is the truth behind the label and why your FR rainwear needs to meet much more rigorous, hazard-specific standards.
The core of the misunderstanding lies in confusing a component test with a garment performance standard.
ASTM D6413 is a vertical flame test. It is a small-scale, bench-top laboratory method designed to measure a specific material sample's resistance to ignition.
During this test:
A 3-inch by 12-inch strip of fabric is exposed to a controlled flame for 12 seconds.
Technicians measure the char length (how far the fabric burns) and afterflame time (how long it keeps burning after the flame is removed).
While ASTM D6413 is an excellent tool for quality control and a foundational step in textile manufacturing, it is not a garment pass/fail standard.
The Reality Check: A fabric strip might pass a vertical flame test in a controlled lab, but that does not tell you how an entire rain jacket - complete with seams, zippers, snaps, and coatings—will behave when engulfed in a 1,900°C flash fire or subjected to the massive thermal energy of an arc flash. Rainwear made of melting plastics (like untreated PVC or polyurethane) can pass D6413 if treated with fire retardants, yet still melt into a worker’s skin during a real-world thermal event.
If your workers face flash fire hazards (common in oil and gas or chemical processing), ASTM D6413 is wildly insufficient. You must look for ASTM F2733.
Unlike a simple bench test, ASTM F2733 subjects a fully outfitted thermal mannequin ("instrumented mannequin") to a simulated 3-second flash fire.
The Requirement: To pass, the garment must limit predicted total body burn to less than 40%.
The Scope: It tests the entire garment system, ensuring that closures don't fuse shut, fabric doesn't melt or shrink drastically, and the jacket can actually be removed quickly post-incident.
2. Arc Flash Protection: ASTM F1891
For electrical utilities and live-line workers, an arc flash is a constant threat. Rainwear for these environments must be certified to ASTM F1891.
This standard evaluates the material's Arc Thermal Performance Value (ATPV) or Breakopen Threshold Energy (EBT). It ensures that the rainwear will not melt and contribute to a worker's injuries when exposed to the extreme radiant heat of an electric arc, while establishing a definitive Arc Rating (cal/cm²).
| Standard | What it Does | The Testing Method | The Critical Pass Criterion |
| ASTM D6413 | Fabric Strip Ignition |
12-second vertical flame burner
|
Char length & afterflame time only
|
| ASTM F2733 |
Full Garment Flash Fire Safety
|
3-second thermal mannequin engulfment
|
< 40% total body burn prediction
|
| ASTM F1891 | Full Garment Arc Flash Safety |
Open-air electric arc exposure
|
No melting/dripping; establishes Cal Rating
|
Another point of confusion for safety managers is NFPA 2112, the gold standard for flame-resistant garments protecting against industrial flash fires. It is incredibly common to seek out NFPA 2112 certification for daily workwear like coveralls, jeans, and shirts.
However, rainwear is explicitly excluded from the scope of NFPA 2112.
Because rainwear requires specialized water-resistant coatings (like polyurethane or PVC laminated to a flame-resistant base fabric), it behaves differently under thermal stress than breathable cotton or aramid daily workwear. Recognizing this difference, the National Fire Protection Association left rainwear out of NFPA 2112, leaving ASTM F2733 and ASTM F1891 as the definitive, legally recognized standards for protective outerwear.
It’s time to look closely at your protective outerwear inventory. To ensure your team is genuinely protected, transition from "flame-retardant" assumptions to certified protection:
Audit Your Labels: Check your current rainwear inventory. If a tag only cites ASTM D6413, understand that it is not rated as a protective garment for flash fire or arc flash environments.
Specify the Right Standards in Procurement: Update your safety manuals and purchasing specs. Demand ASTM F2733 for flash fire hazards and ASTM F1891 for electrical arc hazards.
Remember the Hierarchy: Treat ASTM D6413 as a raw material baseline, never the final word on human safety.
When the storm hits and a thermal event occurs, a worker shouldn't have to discover that their rain jacket was only tested on a lab bench. Ensure your gear matches the hazard, not just the buzzword.
For more information on Industrial Rainwear, and to see all of our articles on this topic in one place, CLICK HERE. goSafe offers a wide variety of Industrial Rainwear in both FR and Non-FR versions. We also operate an onsite Customization Department that can customize many PPE items with your company logo. goSafe maintains a constant, ready-to-ship supply of FR Clothing and Safety Footwear, and also partners with Bollé Safety in their Seamless Vision Prescription Safety Eyewear Program. For more information on these products and services or any of our other safety and PPE products, please contact us at sales@gosafe.com.
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