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August 17, 2015

Textile Color Theory and its Effect on Arc Flash Ratings

There are color varieties: Red, Blue, Periwinkle, Egg Shell, etc.

And there are dye types: Reactive, Basic, Acidic, Direct, etc.

Then there are also dye methods: Range dyeing, Jet dyeing, Vat Dyeing, etc.

Every day we see materials that are the same in content but come in a variety of colors. Because of this variation, some eyebrows have been raised over the effect of color on arc rating and testing results. Unless the dye types are different, we consider the materials the same… generally speaking.

In terms of the testing involved in ASTM F1506- other than ASTM F1959 Standard Test Method for Determining the Arc Rating of Materials for Clothing– it has been accepted that color varieties have little effect on the results. If the dyes are the same type, they have been considered to have no substantial effect on the material performance in small scale testing focused on material strength and flame resistance.

Consider comparing a blue marker and a green marker drawing, you would expect them to react the same when dipped in water because they are color varieties. Veritably, we typically only test one color variation on small scale tests, which saves manufacturers on material and time.

However, if we are dealing with two different dye types, we will absolutely require testing on two different materials, even if they have the same content. These dyes are chemically reacting with the fibers/yarns/fabrics they are applied or integrated in to. Each type will have a different reaction, and will ultimately affect the performance of the material. It is not uncommon for a manufacturer to change dye types and see a discrepancy in results.

SO, consider a colored pencil to a colored marker drawing. They certainly transfer color differently (dye types) and would not react the same when dipped in water.

Ultimately, we always ask clients to provide the dyeing information so we can help them understand why there may have been a change in performance, even if the material content remained the same. This specific information is not listed in the label but we prefer to retain it in the customer’s file to supplement their future knowledge.

To address the arc test, ASTM F1959 and IEC 61482-1-1, we have studied and found a statistical significance indicating different colored materials receive different arc ratings, despite the fabric content being the same (see Figure 1). ASTM F1506-15 calls out a modification in dyeing as a reason to perform a new design test. A modification in dyeing can be interpreted in three ways: as a change in the dye type itself, as a change in color variety with the same dye type, or in a dyeing method change.

Most clients of ArcWear self-certify their fabrics (though we offer full third-party certification through SEI for ASTM F1506 and with BTTG for CE Mark Certification to IEC 61482-2 through our FlashCert Program).  We recommend due diligence in any case.  Our recommendation is to test the color that would theoretically rate the lowest. This will show the ‘worst case scenario’ and save a client the effort of testing every color among their products or having an embarrassing competitive test.  ArcWear offers scouting testing to determine which color is lowest and then will complete the full rating on the lowest color (and additional colors should a client wish).

Figure 1. ATPV/Weight Ratio vs Weight

Color Theory- Whats your type

From Chapter 20, “Flame resistant textiles for electric arc flash hazards”, Hugh Hoagland, ArcWear, USA in Handbook of Fire Resistant Textiles, 1st Edition, Woodhead Publishing, UK

Edited by F. Selcen Kilinc Ph.D. (NIOSH, USA)

http://store.elsevier.com/Handbook-Of-Fire-Resistant-Textiles/isbn-9780857091239/

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