Terminology for Flame Resistant, Antistatic and ARC Flash Technical Workwear can be confusing. Here we clarify a few terms that are used in conjunction with the HAZTEC brand.

Flame Resistant is a generic term applied to garments that are resistant to flame (believe it or not!).

There is some discussions on the web that indicate that ‘Resistant’ is indicative of the fact that it offers lifetime flame protection.

We prefer the the following terminology:

  • ‘Inherent’ to indicate that the flame protective properties of the fabric contain yarns that are inherent (e.g. Modacrylic) and for the purpose of not being removed during the washing process which would affect the protective nature of the finished garment.
  • ‘Retardant’ to indicate that the flame protective properties of the fabric have been achieved by the application of a chemical retardant treatment.
  • ‘Resistant’ as a generic term, not implying anything specific regarding the protective properties of the fabric.

According to the dictionary, Inherent means: “existing in something as a permanent, essential, or characteristic attribute”.

In terms of FR fabrics, the word ‘Inherent’ is generally applied to yarn, fabric or a finished garment that is deemed to offer permanent Flame Protection properties not affected by the washing process.

In reality, it is the yarns themselves that are ‘Inherent’ as the finished fabric (and therefore also the garment) always contains other yarns such as Cotton. Generic names for these Inherent yarns would be ‘Modacrylic’ or ‘Aramid’ and brand names would include ‘Nomex’, ‘Protal’, ‘Protex’ to name a few.

The amount of Inherent yarn in a fabric blend will vary according to the specification to which the finished fabric is certified.

For further information, you can discuss with one of our Technical Advisors.

The letter E under the EN ISO 11612 European Norm relates to protection against molten Iron/Steel Splash and the letter D relates to protection against molten Aluminium Splash.

It might be assumed that as the melting point of Aluminium is around half that of Steel, that a E rating on the fabric/garment is ‘better’ than a D rating, but without diving into all the technical detail of this European Norm here are a couple of points to consider:

The test process of D3 and E3 are not comparable with each other in the Laboratory tests:

The D3 rating under EN ISO 11612 relates to 350gms of Aluminium splash and above, and the E3 relates to 200gms and above. The angle at which the molten metal is applied in the label test is also different.

How the molten metal reacts when on the fabric:

Due to the lower melting point of the Aluminium, it is more inclined to stick to the fabric versus the Steel which hotter and typically slides off easier. The result of this is therefore clear that there is a greater risk of the metal burning through to the wearer.


The new version of IEC 61482-1-1 contains a new ‘conservative’ type of arc rating for materials and garments called the Incident Energy Limit Value (ELIM).

Arc Ratings are calculated using at least 20 data points and a logistic regression to determine the incident energy level of a 50% probability that there is enough heat transfer to cross the Stoll Curve (ATPV), or for the material to breakopen and create exposure (EBT). The ELIM value will be even more conservative; it is defined by the anticipated new standard as “the numerical value of incident energy attributed to a product (material or clothing), below which all product responses are below the Stoll Curve and without breakopen”.

ELIM is calculated by averaging the three incident energy levels below the mix zone (all 20 data points are still required).  As a reminder, the “mix zone” is known as the range in testing between the lowest incident energy level that crossed the Stoll Curve, and the highest incident energy level that did not cross the Stoll Curve.

Source: arcwear.com


Occasionally our wording may be our own opinion. Always refer to CE documentation for official clarification.