Rainwear Alert: How ASTM F2733 and ASTM D6413 Apply to FR Rainwear

We’ve all experienced it – waking up to rain or seeing a storm cloud in the forecast. Normally, wet weather prompts you to grab an umbrella or rain jacket but for anyone required to wear flame resistant clothing (FRC) on the job, there are other considerations. You must ensure your clothing protects from the elements and the hazards you face. FR rainwear is protection that is commonly overlooked but is critical to comfort, safety, and compliance in wet work conditions.

The standard that governs FR Rainwear for workers who face hazards associated with short-duration thermal exposures from fire is ASTM F2733, the Standard Specification for Flame Resistant Rainwear for Protection Against Flame Hazards. The intent of this standard is ensure that rainwear sold as FR for flash fire is truly and fully flame resistant and insulates well using the appropriate test methods, as opposed to an outdated method that’s ineffective at measuring flame resistance of rainwear fabrics.

If your workers face an arc flash hazard and are not exposed to flash fire, read our post on ASTM 1891, Standard Specification for Arc and Flame Resistant Rainwear for more information about arc protective rainwear.

Flame resistance of rainwear was originally tested by ASTM D6413, the Standard Test Method for Flame Resistance of Textiles (vertical test). However, this standard alone was deficient in ensuring rainwear  products performed as intended, as explained by Scott Margolin, Tyndale’s Vice President of Technical in the video below. Therefore, ASTM F2733 was created for flash fire hazards to correct the issues by adding critical additional testing. ASTM F2733 still includes a performance requirement that the rainwear material shall be flame resistant and shall not melt or drip when tested in accordance with ASTM D6413 and shall exhibit no more than a 2-second afterflame time and less than a 4” char length. So, if your FR rainwear complies with ASTM F2733, it still complies with ASTM D6413.

You might already be familiar with ASTM D6413 from the performance requirements of NFPA 2112. In fact, you can think of NFPA 2112 as the parallel, or complementary, standard to ASTM F2733. Both set forth minimum requirements to maximize protection for workers facing short-duration thermal exposures from fire. The main difference is NFPA 2112 is for traditional woven and knit fabrics used in daily wear and outerwear while ASTM F2733 is specific to rainwear.

Additional key performance requirements of ASTM F2733 include:

  • Thermal Protection: Rainwear material shall be tested in accordance with ASTM F1930, a design test, after one washing and one drying.
  • Flash Fire Protection: Total body burn must be less than 40%.
  • Leak Resistance: Material must withstand water pressure of 30 psig without leaking. The seams of the rainwear must not exhibit any evidence of leakage when exposed to water at 3 psig for 2 minutes.
  • Tear Resistance: Material shall have a trapezoidal tear resistance of 6 pounds in the warp direction and 6 pounds in the fill direction.
  • Moisture Vapor Transmission: If the rainwear is marketed as being breathable, it must be tested.
  • Markings and Reflective Materials: These materials attached to the rainwear shall be permanent and shall not degrade the performance of the rainwear.
  • Rainwear Construction: Utilize materials, stitchings, tapes, coatings, fasteners, and closure materials that minimize heat conduction for the construction of compliant FR rainwear. Fasteners and closures used, for example, zippers, snaps and buttons that are made from metal shall be covered with a layer of rainwear material on the inside of the garment such that these items of construction will not contact undergarments or skin.

Interested in adding rainwear to your Tyndale program?

Tyndale makes it easy to outfit your workforce with proven, cost-effective rainwear – complete with the direct-to-user spend enforcement, OSHA audit tracking, reporting, and customer service you know and trust from your FR clothing program.

Contact us today to discuss your requirements and choose one of our flexible program extensions to outfit your workers for safety, compliance, and comfort.

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