EN ISO 11612 outlines the minimum performance requirements for protective clothing designed to protect the wearer against heat and flame exposure. This safety standard is applicable for a variety of situations, ensuring workers are kept safe from hazards such as exposure to molten metal splashes or to radiant, convective. or contact heat.
The EN ISO 11612 standard
EN ISO 11611 is a European standard that specifies the minimum performance requirements for protective clothing made from flexible materials, which are designed to protect the wearer’s body, except hands, from heat and/or flame.
For protection of the wearer’s head and feet, the only items of protective clothing falling within the scope of ISO 11612:2015 are gaiters, hoods, and overboots. However, concerning hoods, requirements for visors and respiratory equipment are not given.
The EN ISO 11612:2015 performance requirements are applicable to protective clothing worn for a variety of situations where there is a need for clothing with limited flame spread properties and where the user may be exposed to molten metal splashes or to radiant, convective. or contact heat.
EN ISO 11612:2015
EN ISO 11612:2015 is the latest update of this safety standard, replacing the previous version of EN ISO 11612:2008. This safety standard was last reviewed in 2020, confirming that this version remains current.
While EN ISO 11612:2015 is currently the most updated version of this safety standard, it is due to be replaced by ISO/DIS 11611 within the coming months. Once the updated ISO/DIS 11611 standard has been developed, EN ISO 11611:2015 will be withdrawn.
EN ISO 11612 minimum performance requirements
EN ISO 11612 outlines the minimum performance requirements for clothing designed for a range of uses where the wearer may need limited flame spread and protection against various thermal hazards including radiant, convective, or contact heat and splashes of molten metal.
The EN ISO 11612 pictogram is the same as the previously withdrawn EN 531 safety standard, featuring a flame inside a badge emblem. Underneath the pictogram, the CE marking for this standard will also feature a series of letter and numerical codes to determine the level of protection offered by the garment.
The code letters on the EN ISO 11612 label indicate the protection offered, as determined by a variety of standardised test methods. Ranging from codes A to F, the test procedures conducted fall into the following categories:
- A: Limited flame spread
- B: Protection against convective heat
- C: Protection against radiant heat
- D: Protection against molten aluminium splash
- E: Protection against molten iron splash:
- F: Protection against contact heat
For protective clothing to be certified to the EN ISO 11612 standard, at least two categories must be tested. Code letter A1 or A1+A2 plus at least one other code letter (B, C, D, E, or F) is mandatory. Where the code letter is followed by a number, the highest number indicates the highest tested level during that test method.
The design of the garment is also tested when certifying EN ISO 11612 certified clothing for protection against heat and flame. Flame resistant garments certified according to EN ISO 11612 B3, C2-C4, D2-D3, E2-E3, and F3 come under PPE Regulation Category III.
Design requirements for garment fabric
EN ISO 11612 garment must be made from fabric that maintains mechanical strength and heat resistance at a temperature of 180°C. The material should not ignite or melt, nor should it shrink by more than 5%.
A: Limited flame spread (EN 15025)
The limited flame spread test method consists of applying a flame to a fabric sample for 10 seconds. To pass the test, the after flame, smoulder times, and hole formation must be within the tolerances of this standard.
There are two parts to this test method, resulting in a class of A1 or A2.
A1: Surface ignition
Procedure A, which leads to class A1, tests surface ignition. During this test, the flame is applied horizontally to the face of the fabric. To pass this test, the following criteria must be met:
- No specimen shall permit any part of the lowest boundary of any flame to reach the upper or either vertical edges
- No specimen shall give hole formation of 5mm or greater in any direction, except for an inter-lining that is used for specific protection other than heat and flame protection.
- No specimen shall give flaming or molten debris
- The mean value of after flame time shall be ≤ 2s
- The mean value of afterglow time shall be ≤ 2s
A2: Edge ignition
Procedure B, which leads to class A2, tests edge ignition. During this test, the flame is applied to the bottom edge of the fabric. To pass this test, the following criteria must be met:
- No specimen shall permit any part of the lowest boundary of any flame to reach the upper or either vertical edges
- No specimen shall give flaming or molten debris
- The mean value of after flame time shall be ≤ 2s
- The mean value of afterglow time shall be ≤ 2s
B: Protection against convective heat (ISO 9151)
The protection against convective heat procedure uses the ISO 9151 test method to determine heat transmission when the garment is exposed to flames. During this test, the fabric sample is held above the flame and the rise in temperature of the topside of the sample is measured using a calorimeter. The length of time the sample can remain exposed before its temperature rises by 24 °C is measured to determine the class level for this test, ranging from 1-3.
- B1: 4-10 seconds
- B2: 10-20 seconds
- B3: 20 seconds or more
C: Protection against radiant heat (ISO 6942)
The protection against radiant heat procedure uses the ISO 6942 test method. During this test, the fabric is exposed to radiant heat (infrared rays). The temperature on the unexposed side of the same is determined using a calorimeter. The length of time the sample can remain exposed to the radiant heat before its temperature rises by 24°C is used to determine the class level, ranging from 1-4.
- C1: 7-20 second
- C2: 20-50 second
- C3: 50-95 second
- C4: 95 second or more
D: Protection against molten aluminium splash (ISO 9185)
The protection against molten aluminium splash procedure uses the ISO 9185 test method. During this test, a membrane with similar properties to human skin is attached to the reverse of the fabric sample sequentially rising quantities of molten aluminium metal are splashed on the sample. The quantity of molten metal which deforms the membrane is measured to determine the class level, ranging from 1-3.
- D1: 100-200 grams
- D2: 200-350 grams
- D3: 350 grams or more
E: Protection against molten iron splash (ISO 9185)
The protection against molten aluminium splash procedure uses the ISO 9185 test method. During this test, a membrane with similar properties to human skin is attached to the reverse of the fabric sample sequentially rising quantities of molten iron metal are splashed on the sample. The quantity of molten metal which deforms the membrane is measured to determine the class level, ranging from 1-3.
- E1: 60-120 grams
- E2: 120-200 grams
- E3: 200 grams or more
F: Protection against contact heat (ISO 12127)
The protection against contact heat procedure uses the ISO 12127 test method. This test was added to EN ISO 11612 during the 2015 update to establish the contact heat protection offered by the clothing.
This test method assesses how long the clothing can block heat generated by direct contact with hot substances and objects. This is done by placing a metallic cylinder heated to 250 ºC on the fabric sample. A calorimeter is placed on the other side of the material, measuring the temperature rise. The time taken for the calorimeter to increase a temperature by 10 ºC is measured to determine the class level, ranging from 1-3:
- F1: 5-10 seconds
- F2: 10-15 seconds
- F3: 15 seconds or more
