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Protective Clothing 

Published: 10th Jan 2007

ARTICLE CONTINUES BELOW

The start of the 1990s saw the establishment of a vast structure of committees in Europe tasked with creating test methods and product specifications to enable PPE including protective clothing to be CE marked.

BTTG Fire Technologies (FTS) became closely involved in this process at its start with respect to clothing to protect against heat and flame, work that it continues to do today. The first generation of product specifications are now being updated sometimes jointly by the European Standards body (CEN) and its international equivalent (ISO). This article discusses the development process, sets out the key standards and indicates revised and new standards expected in 2007.

Introduction

The CEN committee responsible for standards for clothing to protect against heat and flame made quite rapid progress in the early years so that it was able to complete most of the key product specification standards by 1995. These standards were all published as ENs as were most of the related test methods developed at that time. However, encouragement to apply the so-called Vienna Agreement made between CEN and ISO now means that some test methods and product specifications are published as EN ISO standards in the interests of assisting world trade, not just European trade. Reaching agreement between European countries is often difficult enough so the route to getting agreement also with major countries outside of Europe can be even more of a challenge!

The first generation of EN standards-rationale and outcome

When the first meetings took place of the CEN working group tasked with developing the necessary test methods and product specifications for the major end-users that needed such standards - industrial workers in oil/gas sectors plus firefighters - we almost all appeared to agree on one important point of principal. This was that our product specification standards would list the test methods and performance to be achieved by these test methods necessary to demonstrate that the performance of the complying protective clothing was at a certain level when the clothing was in its new/never used state. We were not attempting to include within our standards any means of indicating potential, never mind actual lifespan. We only went as far as setting procedures that would prevent the use of non-durable water soluble flame retardants being used on the fabrics from which the garments would be constructed. We achieved this objective by requiring that prior to some of the tests, in particular the flammability test, fabrics shall undergo 5 cycles of a standardised cleansing procedure (with a final dry if washing). Our thinking regarding PPE lifespan was that users should monitor any reduction in protective performance during actual use by means of inspection and testing coupled to effective maintenance/repair procedures. This type of monitoring is undertaken, particularly for firefighter clothing, and is one of the services offered by BTTG FTS.

The reasoning of the CEN committee at this time, the 1990s, was that we did not have any confidence in the ability of laboratory based test procedures to accurately predict by, say accelerated “ageing”, the possible, never mind accurate, lifespan in the diverse end-use situations faced by many industrial workers and firefighters!

During this period of development in CEN, closely related ISO standardisation committees were working slowly on, for example, standards for clothing for firefighters but not with the intention of producing joint EN ISO standards.

In 1995 the first generation product specification standards were published solely by CEN for the types of heat and flame protective clothing mentioned above. The key standards were:

EN 469:1995 - “Protective clothing for firefighters...”

EN 470-1:1995 - “Protective clothing for use in welding and allied processes...”

EN 531:1995 - “Protective clothing for industrial workers exposed to heat...”

The main test methods in these standards had also been developed by this CEN committee but were in some instances very similar to existing ISO ones. They were published as CEN standards, examples being as follows:

EN 532:1994 - the flammability test in the above three specifications

EN 366:1993 - the heat protection test (to radiant heat exposure) in EN 469 and EN 531

EN 367:1992 - the heat protection test (to convective heat) in EN 469 and EN 531

EN 348:1992 - the heat protection test (to welding rod splashes) in EN 470

EN 373:1993 - the heat protection test (to splashes of molten metal) in EN 531

Experience with this first set of specifications/test methods

When test laboratories started to use these tests, apply the results to the related product specifications and then go on to issue EC Type-Examination Certificates enabling manufacturers of clothing to CE mark, some problems came to light. These were essentially in two areas - one being the very poor consistency of test results between different test houses (reproducibility), the other being the level of protection set by product specifications. There is of course a relationship between these two issues - if a test method gives a wide range of results across test houses some will get “pass” results for fabrics and the ultimate clothing product that others cannot achieve thus casting doubt as to whether the performance level is “correct” the effect of which is to confuse the end user and distort the market place.

The most extreme example of a test method reproducibility problem was found to be with EN 366, the test that measures the protection against exposure of the clothing fabric(s) to a radiant heat source provided by electrically heated element rods.

The reasons were soon established as being linked to the very complex nature of the test apparatus design and therefore the specification for its construction. BTTG FTS initiated a re-design to a specification that made it much more likely that test houses would be able to obtain sufficiently identical apparatus to enable them to get much more consistent results.

Interlaboratory trials of this revised test method have proved that it is indeed very much more reproducible, the outcome being that the revised test method was published in 2003 as EN ISO 6942. It is thus an early example of a standard in this particular field of PPE which was accepted by both CEN and ISO.

The message to test method developers from this experience with EN 366 is that when designing apparatus for what is often a simple test in concept, keep the apparatus simple!

Although the other examples of test methods listed previously are by no means perfect, collaboration between test laboratories by means of inter-laboratory trials and discussions that are fed back to the CEN and/or ISO standardisation committees is a way forward to improve reproducibility.

There is now increasing pressure from national accreditation bodies in Europe who are responsible for the accreditation of test houses and notified bodies working in the PPE sector to require these bodies to assess the uncertainty of measurement associated with the PPE tests that they offer to clients. This is a very complex and controversial issue which will require considerable time and effort to implement in a way that does not confuse both the clients for testing, usually the PPE manufacturers, and their clients, the users of the PPE. At its simplest the issue is how to deal with the fact that a test result that meets a product specification when the + and – tolerances resulting from application of the uncertainty associated with its measurement are not applied, fails when they are applied! Products such as protective clothing that have been certificated in the past may require modification if they are to be re- certified.

The reasons for revising the exiting standards

Standards are usually reviewed after 5 years, particularly if they are EN or EN ISO designated, the options being either to confirm for a further 5 years or to revise. With respect to the fire protective clothing standards listed above, revision was chosen by voting in the countries concerned to be the preferred action inmost instances.

The reasons that nations had for voting for revision were generally that regarding test methods, an improved test in terms of reproducibility (as examined above for EN 366:1993), and realism of the type and severity of the heat/flame challenge would be the objective.

For the three product standards listed above the reasons were linked to the need to incorporate additional or revised test methods, perhaps broaden the scope and, in particular to look at whether the performance levels were still appropriate to provide sufficient protection for the wearers now that experience in use of the protective clothing was available.

An additional reason for revision, not fully appreciated by most delegates to the CEN standards committee at the time this revision process was initiated, was that product standards must be drafted so as to enable them to verify more of the applicable Basic Health & Safety Requirements (BHSRs) set out in the PPE Directive 89/686 EEC. This outcome, as required by CEN and applied through the CEN Consultant, has become a very contentious and time-consuming task for the delegates to the CEN committee which has taken some years to resolve to the satisfaction of this consultant.

Another complication applicable to two of these three product standard revision is the application of the Vienna Agreement on CEN/ISO collaboration, which when agreed to be applied, requires a decision on whether the work is led by a CEN or an ISO committee.

Compliance of standards with the European PPE Directive

There have been a number of changes proposed for these fire protective clothing standards to make them address more of the requirements of this directive. These cover topics such as the testing of more properties of the clothing that are related to protection, the setting of verifiable “pass/fail” criteria in place of subjective evaluations or recommendations, more and better definitions, and more concentration on determining the protective performance of the final item of clothing rather than the fabric(s) from which it is constructed.

The really difficult issue has been to implement in these three standards and other related ones a means by which they can address the lifespan/ageing/obsolescence requirements of the PPE directive, an aspect which was avoided deliberately in the first generation of these fire protective clothing standards as explained above.

Discussion has centred on whether any cleansing requirements in these standards can or should be applied so that the protective performance is determined after however many cleansing cycles to a specified procedure the manufacturer may choose to claim in user information.

The majority view of test houses/notified bodies and their protective clothing/fabric clients has not changed since the first generation standards were developed - we do not have faith in the relationship between current laboratory procedures and end user workplace reality to be likely to state or endorse a lifespan claim if indeed a manufacturer makes one!

A compromise text dealing with pre-treatment/ageing has been agreed very recently for incorporation into all heat and flame protective clothing product specification standards when they are revised. It will be interesting to see how manufacturers and users react!

Recent guidance from the European Commission on the PPE Directive 89/686 expects manufacturers of PPE to provide users with the information they need so as to be able to determine lifespan. This seems to BTTG FTS to be logical and a correct sharing of responsibilities - users in Europe have to comply with the PPE Directive 89/656 EEC, the so-called “use directive”, which deals with risk assessment, selection of PPE, its use, maintenance etc. Information provided by manufacturers therefore needs to be as comprehensive as possible but may remain cautious with regard to lifespan - time will tell!

Current EN, EN ISO and ISO standards for heat and flame protective clothing

Product performance standards

EN 469:2005 - “Protective clothing for firefighters ...”

This is a direct replacement for the 1995 edition listed above and has been developed solely in Europe by CEN. It incorporates many changes such as two levels of performance for several key properties, The changes introduced mean that re-certification of products is unable to make use of test data used to support EN 469:1995 certification.

It is likely to be revised again, possibly in 2007, to “tidy up” some clauses and introduce the latest text on pre-treatment/ageing as approved by the CEN consultant. ISO 11613:1999 is a closely related standard that also incorporates aspects of NFPA 1971.

EN 470-1:1995 - “Protective clothing for use in welding and allied processes ...”

A final draft is about to go out for parallel vote by European nations who are in CEN and by nations who have voting powers in ISO. The latter include a number of non-European nations. If the vote is positive in both organisations, the resulting standard will be published in 2007 as EN ISO 11611:2007. It will be again be unable to make much use of test data used to support EN 470-1 certification. Please note that an EN 470-2 was envisaged some years ago but is not being progressed.

EN 531:1995 - “Protective clothing for industrial workers exposed to Heat ...”

An intermediate stage parallel vote By CEN and ISO member nations is about to take place. If the vote is positive in both organisations, the next stage will be the preparation of the final draft for parallel voting as above for EN ISO 11611. If this final vote is positive in both organisations, the resulting standard will be published as EN ISO 11612 perhaps in 2007. It will have the same consequences as EN ISO 11611- better fit to the directive, unable to make use of much EN 531 test data.

The current ISO 11612:1998 is essentially equivalent to EN 531:1995.

Since 1995 several more product performance standards for heat and flame protective clothing have been published. The main examples are as follows:

EN 533:1997 - “Protective clothing ... Limited flame spread Materials and material assemblies”

This standard is also being revised, the reasons being also that it needs to be able to assess garments rather than the materials from which they are made. To achieve this aim it needs considerable changes. The revised text is about to undergo a final vote as for EN ISO 11612 etc, the resulting standard to be EN ISO 14116:2007.

EN 1486:1996 - “Protective clothing for firefighters ... reflective clothing for specialised firefighting”

This is being revised solely by CEN and is expected to undergo a final vote in 2007. If the vote is positive it will retain its number but with the changed year. The purpose of this standard is to provide clothing to fight fires in close proximity where the major hazard is radiant heat which can be very effectively reflected by aluminised clothing.

A very similar ISO standard exists as ISO 15538.

ISO 15384: 2003 - “Protective clothing for firefighters ... wildland firefighting clothing”

This standard was intended to be an EN ISO with this number but the final draft was unacceptable to the CEN consultant so was not subjected to a vote by CEN member nations.

A final draft of a proposed EN is about to undergo voting but any resulting standard will have a different number from the ISO standard and slightly different content/requirements!

EN ISO 14460: 1999 - “Protective clothing for automobile racing drivers - Protection against heat and flame ... ”

This was the first EN ISO in this heat and flame sector and its development was lead by ISO. It was confirmed in 2004 for a further anticipated five years.

Of the above list of product standards and expected revisions only ISO 15384, existing without CEN involvement and endorsement, is not eligible for European Commission “presumption of conformity” status. The consequence for standards without this status is that manufacturers may seek CE certification based on meeting the standard but that notified bodies such as BTTG FTS have to be satisfied that the applicable BHSRs of the PPE Directive 89/686 EEC can be met by this means which is known as the “technical file route”.

Test methods

The five first generation examples listed in this article have the following current status:

EN 532: 1994 - now EN ISO 15025:2002 with procedures amended to to include “bottom edge” application of the test flame.

EN 366: 1993 - now EN ISO 6942:2002

EN 367: 1992 - confirmed in 2002 because, unlike EN 366, the apparatus is of simple design easily constructed to give acceptable reproducibility!

EN 348: 1992 - current and now likely to lead to its retention alongside a completely different method intended to become EN ISO 9150 perhaps in 2007. This situation will have consequences for EN ISO 11611.

EN 373: 1993 - current but being revised slightly, in part to improve its reproducibility. Intended to become EN ISO 9185 in 2007.

Other test methods for heat and flame protective clothing

EN 702: 1994 - the third major heat transmission test, complimenting

EN ISO 6942 and EN 367 and featuring exposure to a heated metal block by contact (conductive heat). Used mainly to test heat and flame protective gloves.

prEN ISO 13506 - this draft method of test for predicting the burn injury resulting from exposing complete items of protective clothing on a heat sensing manikin to engulfment in flames from a gas burner array is expected to undergo final voting in 2007.

BTTG’s latest generation “RALPH manikin meets this draft standard which is called up as an optional test in EN 469 and is intended to be introduced in other related standards.

Conclusions

The standards that have been developed for heat and flame protective clothing, firstly as ENs, have been hugely effective in encouraging the trade and use of adequate PPE of this type, not only in Europe but increasingly worldwide.

The development of joint EN and ISO standards, incorporating the thinking of users, manufacturers, test houses and product certifying bodies internationally can only help to encourage this trend which is also seen in many other PPE sectors.

The link that EN and EN ISO standards must have with European PPE Directives has also encouraged worldwide recognition of the benefits of third party certification processes for PPE, a route to certification which is mandatory for items such as heat and flame protective clothing.

For more information on Protective Clothing http://www.osedirectory.com/product.php?type=health&product_id=17

Published: 10th Jan 2007 in Health and Safety International

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