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Protection for Industrial Workers

Published: 01st May 2009

New International Standards for Fire Protective Clothing

Between 1995 and 1997, three specifications for fire protective clothing for industrial workers were introduced in Europe as EN standards. They covered most industrial activities in which intense heat and/or flame may be hazards to which workers are exposed. Since about 2000 the development of a second generation of these three standards has been progressing by co-operation between European (CEN) and international (ISO) standardisation bodies so that in 2008 the last of them was completed.

BTTG Testing & Certification Limited has contributed significantly to the development of both the original and the revised standards and is very experienced in using them to certify products on behalf of the PPE manufacturing industry. This article draws on this experience to address reasons for the changes now introduced.


In 1995 legislation was introduced in Europe which required personal protective equipment (PPE) to be tested and CE- certified to procedures set out in the European Commission Personal Protective Equipment Directive 89/686/EEC. In order to achieve the free movement of PPE products within the European market and also to encourage better and consistent protection of European workers, the European Commission tasked CEN, the Committee for European Normalisation, to develop so-called harmonised standards for PPE The development of these standards, in effect performance specifications coupled with design requirements, was and still is handled by a structure of Technical Committees (TCs) which supervise Working Groups (WGs) responsible for specific standards.

The work of CEN/TC162/WG2, responsible for standards for “resistance to heat and fire of protective clothing” led to the publication of three major standards for this class of PPE:

  • EN 470-1: 1995 “Protective clothing for use in welding and allied processes - Part 1: General requirements”
  • EN 531: 1995 “ Protective clothing for workers exposed to heat”
  • EN 533: 1997 “ Protective clothing - Protection against heat and flame - Limited flame spread materials and material assemblies”

It is worth noting that when originally published, the title of EN 531 was “Protective clothing for industrial workers exposed to heat (excluding firefighters’and welders’ clothing)”. Somewhat controversially this was changed by the proper voting procedure into the title set out above. This change potentially broadened the scope of use of EN 531 protective clothing into activities such as any kind of firefighting for which specific EN standards such as EN 469:1995 (now 2005 edition) already existed.

When it was agreed that each of these standards should be revised, it was also agreed that the CEN committee should collaborate with the essentially equivalent ISO committee (ISO/TC94/SC13/WG2) so as to produce three joint standards. This task has led to the publication of the following three revised standards for this class of PPE which replace, respectively, the above three standards:

  • EN ISO 11611: 2007 Protective clothing for use in welding and allied processes (ISO 11611: 2007)
  • EN ISO 11612: 2008 Protective clothing - Clothing to protect against heat and flame (ISO 11612:2008)
  • EN ISO 14116: 2008 Protective clothing - Protection against heat and flame - Limited flame spread materials, material assemblies and clothing (ISO 14116: 2008)

Although the title of EN ISO 11612 does not exclude “firefighters’ and welders’ clothing”, its scope says that it is “not applicable to protective clothing that is specified by other international Standards such as for firefighting in structures and for use in welding and allied processes”. Ambiguous overlapping with other standards is reduced if scopes are written in this way.

Background to these standards

The development of EN 470, EN 531 and EN 533 commenced in the early 1990s and was intended to lead to a two-part EN 470 standard , hence the “-1” in the title. This did not occur during the life of EN 470. Neither EN 470-1 or EN 533 were published separately as either technically identical or slightly different ISO standards whereas EN 531 was published as ISO 11612:1998.

When the work in CEN on the three original standards covered by this article commenced it was agreed that the requirements for clothing for welders were sufficiently specialised to justify a stand-alone standard instead of being incorporated into the scope of EN 531, being developed in parallel by the same committee. EN 531 and its successor EN ISO 11612 set requirements for clothing to protect against flame contact and other forms of intense heat contact such as radiant heat and molten metal splash.

This distinction was agreed to be maintained when work started to revise EN 470-1 into EN ISO 11611. The third of these standards, EN 533 and its successor EN ISO 14116, was seen as an entry level standard for flame retardant (FR) fabric (and now flame retardant clothing in 14116) intended to protect the wearer from burn injuries caused by the fabric/clothing igniting. This means that this pair of standards permit FR fabrics/clothing which melt and form a hole but do not ignite when exposed to flame whereas EN 470-1/EN ISO 11611 and EN 531/EN ISO 11612 permit only FR fabrics/clothing that neither ignite or form a hole when exposed to flame.

This important distinction means also that EN 533/EN 14116 do not provide for measuring any heat transmission protective properties of fabrics/clothing (because hole formation obviously prevents any protection against heat transmission to the wearer’s body) The other two pairs of standards provide for various levels of protection from potential burn injury depending on how much heat transmission from the choices of intense heat challenge the fabrics/clothing are able to prevent. For example EN 531/EN ISO 11612 have various levels of heat transmission protection, the highest requiring multilayer clothing similar to that needed by firefighters (see EN 469:2005 and ISO 11613:1999).

An arguably unfortunate consequence of the sensible decision to revise these three EN standards into EN ISO standards, expected to be used widely around the world rather than essentially in Europe, is that ISO rules take precedence over those of “regional standards bodies” such as CEN. This has two major effects - the standard number is changed to a completely unrelated ISO five digit sequence and the test methods called up in the standards have ISO references and numbers rather than EN ones except when there is no suitable ISO test method. At least the move to ISO numbers has given us three consecutive numbers for closely related standards, the third one being ISO 11613:1999 for firefighting clothing.

As mentioned earlier the primary purpose of EN standards for PPE, such as these three in their original form, was to provide the most straightforward means for manufacturers to meet the requirements of the European PPE Directive 89/686/EEC. The principle requirement of all PPE to be placed on the market in Europe since 1995 has been to demonstrate that the so-called Essential Requirements (in effect a list of properties of the PPE considered necessary to protect the wearer adequately) set out for most types of PPE in Annex II of this directive are covered by EN standards.

Therefore these three EN standards were developed so that at that time they were considered to have included all tests and related minimum performance levels plus design requirements necessary to meet the Essential Requirements for protective clothing covered by their scopes. For example Annex B of EN 470-1 set out these Essential Requirements and clauses of the standard that deal with them.

These three EN standards became very widely used to CE-certify protective clothing for sale/use mainly in Europe by certification bodies such as BTTG Fire Technology Services.

When it was agreed to start work on revising these EN standards into EN ISO standards, it was recognised that significant changes were necessary to “improve” the standards in terms of their compliance with the Essential Requirements of the PPE Directive if they were to continue as the widely accepted route to CE- certification for products to be used in Europe. At the same time it was also going to be necessary to convince ISO member nations outside of Europe that this approach would not lead to unacceptably complex standards with levels of performance difficult to achieve by current flame retardant textile fabrics.

Because EN 533 was really only an FR fabric specification as opposed to an FR fabric and PPE clothing specification such as EN 470-1 and EN 531, EN 533 could not be used on its own as a CE-certification standard for fire protective clothing in Europe. It was decided, rightly, to address this deficiency when revising EN 533 so as to make it into a stand-alone specification addressing the Essential Requirements necessary for what is still an entry level standard for fire protection but now dealing adequately with clothing aspects such as design.

The voting system for EN ISO standards requires, logically, that they meet the (different) approval criteria applied by CEN for its European member nations and by ISO for its mix of worldwide nations (which of course includes many European nations). If this joint approval is not achieved the outcome can be either the publication of an ISO or EN standard. Fortunately this confusing outcome did not occur with these revisions, both CEN and ISO votes on the final drafts being positive.

After completion of voting on what are ISO texts, additional text to include the European Directive Essential Requirements, an EN ISO cover page and finally a national standards body front cover page and national forward are added, for example to create BS EN ISO 11612:2008. None of these “regional” additions alter the basic ISO content of test methods, performance requirements and design requirements in any way - they just make these joint EN and ISO standards look a little confusing compared to their EN predecessors.

Content of EN ISO 11611 compared to EN 470-1

Both standards set performance requirements based on tests for resistance to ignition from flame contact and resistance to heat transmission to the wearer’s body. The latter is measured by impacting the fabric from which the clothing is made with small molten metal drops produced by a laboratory scale apparatus complying with an EN and ISO test method. This is an example of an EN ISO specification citing an ISO test method (ISO 9150) which is identical to the EN method cited in the original EN specification (EN 348).

Each specification contains similar clothing design requirements and also requirements for fabric strength.

Content of EN ISO 11612 compared to EN 531

Both standards set out performance requirements based on tests for resistance to ignition from flame contact and resistance to heat transfer to the wearer’s body. The latter is measured by exposing the fabric from which the clothing is made to radiant heat or convective heat or large splashes of molten metal. As when comparing EN ISO 11611 with EN 470-1, ISO test methods, often the same as the EN test methods in the old standard, are cited in the new standard. The revised standard is much more comprehensive than its predecessor in that it includes several more tests and requirements. It is therefore much more adequately aligned with the Essential Requirements of the European PPE Directive.

It is intended that, as with EN 470-1/EN 531, a clothing item will be able to be CE or otherwise certified to both EN ISO 11611 and 11612 because some types of fabric can comply with both standards.

Scope Hoods made from flexible material and also gaiters added. Other items remain as protective garments such as coat, trousers, overall, apron
Classes of performance Now two levels instead of one for several properties. Lower level for heat transmission resistance from welding spatter droplets unchanged
Heat protection Measure of heat transmission resistance when exposed to radiant heat added (choice of two performance levels)
Electrical resistance Test method and one level of performance requirement added
Knitted fabrics Test methods and one level of performance requirement added
Seams Test for seam strength and for seam flammability added – one performance level
Tensile strength and tear strength Performance requirements increased but only one level of performance specified. Tear strength level is controversial as is ≥ twice the level in EN 470-1 and is being re-considered
Pre-treatment Most tests now have to be performed after pre-treatment (washing or dry-cleaning) “in line with the manufacturer’s instructions” instead of only prior to flammability and welding spatter tests - controversial. Flammability behaviour is still only measured after the pre-treatment (see EN ISO 11612)
Ageing The flammability test (Flame Spread) now has to performed also “after the maximum number of cleaning procedures indicated by the manufacturer” - again controversial and intended to be linked to claims of clothing lifespan!

Scope Overboots added to 11612 (coats, trousers, overalls, hoods, gaiters included as previously)
Classes of performance Now three levels of performance instead of five for protection against convective heat exposure and boundaries between levels changed. For protection against radiant heat exposure, four levels retained but boundaries adjusted. (no real changes to molten metal splash levels – three for aluminium and three for iron)
Heat protection Test for protection against exposure to contact heat added (that is contact with a solid metal block heated to 250oC). Three choices of performance level to choose from
Clothing design Requirements now included for all clothing, not just for molten metal splash protection as previously
Strength Test methods and performance requirements (usually one level only) introduced for tensile, tear and burst strength. As in EN ISO 11611, the tear strength is higher than necessary and may need to be amended
Seams Test for seam strength and seam flammability added
Water penetration and water vapour Optional tests and performance requirements introduced for water penetration resistance and for water vapour transmission resistance ( a measure of perspiration removal)
Manikin fire testing Optional test introduced to provide predictions of burn injury using an instrumented heat sensing manikin complying with ISO 13506 method of test
Pre-treatment Introduces the same requirements “in line with the manufacturer’s instructions” as does EN ISO 11611. Most tests have to be undertaken after these washing or dry-cleaning procedures whereas in EN 531 only the flammability test was undertaken after a washing or drying pre-treatment. In addition the flammability test has to be also undertaken before the pre-treatment
Ageing As in EN ISO 11611, the flammability test (Flame Spread) has also to be undertaken “after the maximum number of cleaning procedures indicated by the manufacturer”!!

Content of EN ISO 14116 compared to EN 533

Both standards set out performance requirements based on tests for resistance to ignition by flame contact and the durability to cleaning (cleansing) of flammability behaviour. This was essentially all the old standard measured as it was developed from a British Standard test for the durability of FR fabric flammability behaviour. The new standard is much more comprehensive for the reasons set out earlier in this article.

Final remarks

It is to be hoped that these three new standards, being truly international and also more comprehensive in their requirements for the type of protection they offer than their European predecessors, will become widely adopted. This will depend on safety managers in the many industries to which these standards are applicable being aware of them and asking the PPE industry to make available protective clothing meeting one or more of these standards dependent on the end-user’s risk assessment. Each of these new standards can be expected to have a life of at least five years and perhaps more than ten years as did their predecessors.

Scope There is no precise definition of the protective clothing covered by this standard but it can certainly consist of several separate garments each with one or more layers of material and can be a coat, trouser, overall etc
Classes of protection Both standards set three levels of performance for flammability behaviour which differ only in that the new standard sets a more stringent requirement for “afterflame” duration in its Index 3 (highest category) requirements
Strength Tests and performance requirements for tensile, tear and seam strength introduced at lower levels (one for each property) than in EN ISO 11611 and 11612
Design A few requirements introduced mostly linked to restrictions of use of Index 1 items (lowest index permitting hole formation in the flammability test)
Pre-treatment As for EN ISO 11611/11612 in principle and requiring flammability behaviour to be measured before and after the pre-treatment and the strength properties to be measured only after the pre-treatment
Ageing As for EN ISO 11611/11612 in principle and requiring the flammability behaviour and strength properties to be measured

Published: 01st May 2009 in Health and Safety Middle East

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