Managing the risks involved in the working environment is always necessary in order to protect workers and to maintain compliance with health and safety legislation. In terms of thermal protection, a wide range of PPE (Personal Protective Equipment) clothing exists typically produced from inherently heat and flame resistant materials.
Three intended safety standards available to manufacturers producing PPE garments protecting workers against heat and flame hazards cover the following:
• EN ISO 11612:2015 – Protective Clothing against Heat and Flame
• EN ISO 11611:2015 – Protective Clothing for use in welding or allied processes
• EN ISO 14116:2015 – Protective Clothing against Flame, Limited Flame Spread materials, material assemblies and clothing
Note that these dual “EN ISO” standards also hold a “presumption of conformity” within the European Union provided the manufacturer also adheres to the requirements of the European PPE Regulation (EU) 2016/425. Currently each of these standards are under review as part of the 5 yearly standard review process and new versions of these are expected in the coming months.
“often, heat and flame protective clothing can meet more than one standard and additionally comply with other clothing protection standards”
EN ISO 11611 and EN ISO 11612 are specifications for garments providing protection against heat transmission as well as against flame spread. ISO 14116, however, is a specification for resistance to flame spread garments only. Other international standards for clothing protecting against heat and flame are available such as those produced by ASTM for the USA, AS/NZS (for Australia and New Zealand) – these are not considered in this article. Often, heat and flame protective clothing can meet more than one standard and additionally comply with other clothing protection standards such as EN ISO 20471:2013 (High Visibility), IEC 61482 (Thermal hazards of an electric arc) and EN 13034: 2005 (Chemical Protection).
SATRA can both test and certify garments to these international heat & flame standards which have mandatory garment tests for properties such as, limited flame spread, seam strength and design. Other claims can come from tests on the outer fabric.
All three standards share the same flame resistance test (Limited Flame Spread) – ISO 15025, which requires garment testing before and after pre-treatment or cleaning in line with the manufacturer’s instructions. Washed seams are tested along with all outer materials which includes retro reflective tape, hardware (e.g. zips) and badges etc. Single-use/disposable or leather garments are exempt from this pre-treatment.
Cleaning according to care label
In order to be fully compliant with these standards, manufacturers need to have the garments tested after pre-treatment processes based on the care labels and user information the manufacturer intends to apply to the garment. The care label should specify the type of cleaning treatment, the temperature and the maximum number of cleaning cycles the garment may undergo before its protective performance no longer complies with the standard. For example a care label for a protective garment might specify that the garment should be industrially laundered at 75°C and also that the garment should be discarded after 10 cycles because it may no longer be adequately protective. A test house responsible for testing this garment would then carry out testing after 10 cycles of industrial washing according to ISO 15797 at 75°C.
If the manufacturer has not specified a maximum number of cleaning cycles, then these standards specify as a default, 5 wash cycles. However, in such cases, the manufacturer must refer to this number of laundry cycles on the care label and information for use leaflet which should be supplied with each garment. In the case of CE marked garments for the European market it is mandatory that this information for use leaflet accompanies each garment when sold. Should the manufacturer decide that the garment should not be laundered, the care label must display negative symbols only (i.e. symbols with crosses through them) for example do not launder/do not dry clean.
Inherently flame retardant fabrics should not lose their limited flame spread properties provided a build-up of contamination is avoided. Similarly, correctly treated flame retardant fabrics should keep their limited flame spread properties until after the garment has deteriorated through a combination of use, wear and cleaning. Manufacturers may wish to emphasise this in their user instructions.
“inherently flame retardant fabrics should not lose their limited flame spread properties provided a build-up of contamination is avoided”
In terms of specific claims about limited flame spread properties and thermal protection properties, the manufacturer should only make claims which can be backed up by test data. For example, if a manufacturer’s user information leaflet and label states that a garment can be washed 25 times, it is stating that the garment will be adequately compliant with the standard up to this point and that these claims have been tested.
EN ISO 11612:2015
This standard is for protective clothing for use against heat and flame, preferably made from flexible materials, to protect the wearer’s body and optionally, the hands, head or feet with gaiters, hoods and overboots. Typical clothing is a coverall /boiler suit or jacket and trousers. Other clothing for specific parts of the body, e.g. neck curtain, hood, apron, can be tested and certified alongside the suit/coverall that they would be used in conjunction with. Clothing should have limited flame spread properties:
A1 Fabric surface tests and, optionally, A2 Fabric edge.
The ability of a fabric or garment to resist being set alight when it comes into contact with a naked flame is assessed using the limited flame spread test (EN ISO 15025). This test is carried out on samples of seams as well as on the fabric. Clothing must also meet the requirements for Heat Resistance (which has 2 performance levels) and meet at least one performance level requirement in any of the heat transmission tests. ISO 11612 includes five heat transmission tests and assigns a letter of the alphabet to each one. In order for a garment to comply with ISO 11612 it is necessary that it meets the minimum requirements of at least one of the heat transmission tests described below:
• Heat transmission on contact with flame (also called the convective heat test) which is assigned the code letter B
• Heat transmission to radiant heat source which is assigned code letter C
• Heat transmission to contact with molten aluminium which is assigned code letter D
• Heat transmission to contact with molten iron which is assigned code letter E
• Heat transmission to contact with a hot object which is assigned code letter F
The test for heat transmission from a radiant heat source, has four levels but the others have three levels. Heat transmission tests are concerned with measuring how hot the inside surface of a garment gets when a heat source is applied to the outer surface of the garment.
An optional, whole garment, test procedure is also included for prediction of burns, using a thermal manikin such as the SATRA Instrumented Manikin (SID). The manikin testing should be carried out according to EN ISO 13506 at a heat flux over the manikin surface of 84 kW/sqm. When required, garments intended to protect against the thermal hazards of an electric arc should be assessed according to IEC 61482-2 which includes specific design requirements plus performance requirements and test procedures for the assessment of fabrics and garments against an electric arc.
Physical tests common to the standards EN ISO 11611 and 11612 include dimensional stability to washing, tensile strength, tear strength, seam strength and burst strength of knitted fabrics.
Any claim for molten metal splash or higher levels of heat transmission, will mean that the garment falls under Category III of the European PPE Regulation and therefore requires monitoring of manufactured production by a European Notified body (see box 1) this can be via annual check testing or auditing of the factory production control system.
Garments certified to EN ISO 11612:2015 shall bare labels which include the “Heat and Flame” pictogram with the performance levels beneath; (x) denotes the performance obtained:
A1 or A1+A2, B(x), C(x), D(x), E(x). F(x)
(where no performance is declared, the letter is omitted)
EN ISO 11611:2015
This standard covers the requirements for protective clothing for use in the welding and allied processes and includes hoods, aprons, sleeves and gaiters. This standard does not cover requirements for the feet, hand, face or eye protection. This standard is intended to protect the wearer against:
• Welding spatter
• Short contact time with flame
• Radiant heat from an electric arc used in welding etc.
Clothing will also minimize the possibility of electrical shock by short term, accidental contact with live conductors at voltages up to approximately 100V dc.
This standard has 2 classes:
ISO 11611 includes two heat transmission tests both of which should be carried out on material from the test garment i.e. i) impact of molten metal droplets and ii) resistance to the transfer of radiant heat. The test results are classified according to the performance achieved into either class 1 (providing the minimum requirements for class 1 are achieved) or class 2 (providing the minimum requirements for class 2 are achieved). The introduction of this classification allows some flexibility in designing and specifying welders’ garments. It allows manufacturers to produce lighter weight garments for situations where heat loads are relatively low and heavier duty garments with greater protection against thermal hazards for use in areas exposed to higher levels of spatter or higher heat loads. The standard includes an informative annex in which appropriate welding operations are suggested as suitable for each class of garment.
a. Limited flame spread with requirements:
A1 Fabric surface and optionally
A2 Fabric edge
b. Impact of spatter (small splashes of molten metal) where
Class 1 needs >15 drops
Class 2 needs >25drops
c. Heat transfer where radiant heat protection again has 2 classes
d. Electrical resistance when tested to EN 1149-2
e. For leather garments, a fat content of <15%
Garments certified to EN ISO 11611:2015 shall bear labels which include the “welding hazard” pictogram and the appropriate class
EN ISO 14116:2015
This standard is for protection against flame for materials, material assemblies and protective clothing when in occasional and brief contact with small flames. Should protection against heat hazards be needed, EN ISO 11612 is relevant.
Clothing outer surface should have limited flame spread index of 1, 2 or 3 when tested in accordance with ISO 15025. A garment is tested before and after pre-treatment with the seams, hardware and all outer materials tested. The limited flame index shall be the lower value determined before or after pre-treatment. No specimen shall give off flaming or molten debris.
Index 3 is the better class with no hole >5mm and an after flame <2 seconds.
Index 2 allows a hole <5mm.
Index 1 fabric must be worn over Index 2 or 3 material to avoid skin contact and its presence and position indicated.
The only other test requirements are physical tests – tensile, tear, burst and seam strength along with dimensional stability. Garment labels and information supplied will include the limited flame spread index and the presence of any index 1 material indicated. A claim to EN ISO 14116 does NOT permit the use of the Heat & Flame pictogram and no pictogram is used.
Both EN ISO 11611 and 11612 require that the coverage provided by protective suits, either one piece or two piece, covers the upper and lower torso from the neck to the wrists and to the ankles. Other standards cover PPE for the hands, feet and face. Additional protective items such as aprons, sleeves etc. can be tested and certified to these standards but should only be used as additional protection on top of a compliant coverall or two piece suit.
For welders clothing according to EN ISO 11611 and for EN ISO 11612 clothing designed to protect against splashes from molten metal, specific design features are required, for example: i) cover pockets with flaps except for vertical side pockets below the waist and behind the side seam, ii) ensure no upward facing seams are present.
The coverage and design requirements in EN ISO 14116 are somewhat less onerous. Perhaps the most important requirement is that index 1 materials (basically those materials which sustain holing in the flame ignition test) must be positioned so that they cannot come into contact with the bare skin of the wearer or a non-compliant under garment. If a garment consists completely of index 1 material then it must be worn on top of index 2 or index 3 material. Similarly, a multilayer garment may consist of an outer shell of index 1 material but the innermost lining which would be in contact with the wearer must be in index 2 or 3 material.