Two connected events have caught my attention over the past few weeks. The first one I wanted to talk about is the continuing series of excellent FAAM webinars following the broad theme of the EU’s reduced Occupational Exposure Limit (OEL).
As a reminder, the OEL is the equivalent of our Control Limit. It’s reducing from 0.1 to 0.01 fibres per millilitre of air, and in a few years it’ll reduce further to 0.002. The most recent FAAM webinar addressed respiratory protective equipment (RPE), and asked whether it can cope with the ambitious new target.
That’s a key question if we in the UK are going to adopt the reduced limits – something the Health and Safety Executive (HSE) is actively considering. Garry Burdet, previously of the HSE and now a pivotal member of FAAM, joined Nick Baxter, the HSE technical lead on RPE and the Vice President International Society for Respiratory Protection (ISRP). Together they addressed why RPE performance is based on a complex web of international agreement (or the lack thereof).
It’s worth taking a step back to look at the basics. All masks come with an Assigned Protection Factor (APF), which is the assumed amount of protection that the mask can achieve. This is how APF is supposed to work: contaminants outside the mask will be reduced inside the mask by a factor of the APF. This HSE example (diagram) shows an environment where the exposure is 20, and the APF 10, thus the wearer’s exposure is reduced by a factor of 10, to 2.
In the UK, half-masks are assigned an APF of 20, while full-face powered masks (the ones we use in an asbestos enclosure) are 40. The air-fed masks we typically refer to as RAS masks have a whopping 2,000.
However, how well the mask delivers its APF is based on a number of factors:
Bearing this in mind, a full face mask can achieve an APF of 40, but if you don’t look after it, don’t keep it clean, or it doesn’t fit you perfectly, it won’t be anywhere near that.
Many of us on the crusty end of the industry will remember where we were when the APF for the standard issue full-face powered mask was lowered from around 1,000 to the 40 we accept today. For me it was a night job, where they were blasting sprayed insulation firebreaks.
This horrific wake-up call was prompted by the 1996 Howie research for the HSE, but Howie’s wasn’t the only team looking at this issue in the 1990s. All of the studies were ‘as found’ – essentially workplace observations on actual workers in the field. Around the world, individual teams designed their own approaches, leading to variations in sampling methods, training in mask use, exercises the subjects were asked to do, and different methods of testing the fit.
This led to a huge range of APFs assigned to given mask types around the world. As I mentioned above, in the UK the standard powered full-face mask for enclosure work has an APF of 40. The exact same mask in Scandinavia has an APF of 1,000.
Astonishingly, not every country requires face-fit testing for individuals. Therefore we have a situation where there is no international agreement on how effective RPE is, and some countries don’t even mandate a well-fitting mask.
The Howie research led to the UK’s comparatively pessimistic assessment of full-face APF, but also indirectly to most of the wet-stripping innovations that we now take for granted. In fact, the UK’s cautious approach to APF possibly explains why we have driven innovations on how to minimise exposure at source. It also might explain why European colleagues are less concerned about how the new OEL will impact their removal projects.
In other European countries, everything (including cement window sills and floor tiles) is typically removed inside an enclosure, but dry-stripping is the norm. Essentially, it doesn’t matter what the operative does, he’s protected by equipment which is assumed to have a higher APF than we give it in the UK. This raises important questions about the poor folk outside the enclosure – I’ll come back to that in a minute.
In the UK, what do we see when we test asbestos removal activities inside the enclosure? Assure360, as you may know, is the best mass data resource on this subject, with approaching 20,000 personal monitoring results. In the last year, 95% of results were, when calculated with an APF of 40, below the new EU OEL.
This is clearly very positive news. If the operative follows the method perfectly, and the mask fits, and it’s looked after, UK removal methods are probably adequate to deal with any reduction in the limit. But – and it is quite a big but – all personal monitoring is observed behaviour, and therefore conducted when the operative is working perfectly to the method: slowly and methodically.
If all our assumptions on the efficacy of the mask in the UK were correct, what would we see if the method wasn’t being followed precisely? For example, what if asbestos insulation board (AIB) was being removed dry, as it is in many parts of Europe? Exposure would be much higher, and the existing OEL would be breached – never mind the new one! You would have to have a VERY good mask to deal with that.
There is a second ‘but’: if the mask doesn’t fit well, or if the assumptions made in the EU that the mask in peak condition provides an APF of 1,000 are wrong, or if the mask hasn’t been looked after perfectly, the poor operative is going to be repeatedly exposed. In the EU, that coud be to extremely high levels.
Nick Baxter helped put all this in focus by reminding us that all RPE fails to danger. That’s why regulation and guidance prevent us from using RPE as anything other than the last line of defence, and why it rightly sits at the bottom of the hierarchy of control:
Considering the differing APF figures for the same items, and all the variables regarding how it’s used and maintained, the UK approach has to be the right one: assume that the APF is quite small, and therefore do as much as possible to minimise exposure.
That brings me neatly to what’s going on outside the enclosure, and a heads up that the Asbestos Network (AN) Technical Working Group (TWG) is taking another look at leak monitoring. Around the time that I was getting the RPE-related shock of my life, leak testing was considered part of most or all jobs. But now it’s a rarity: the preserve of nuclear sites and some NHS trusts, it seems. But the regulations haven’t changed: it was mandatory on a virtually daily basis in 1996, and it remains mandatory now.
The next AN appendix to the minutes will be clarifying this: really laying out when you need to do leak testing outside an enclosure. Fundamentally, it’s nearly all jobs, irrespective of duration. That ‘one-day’ domestic job falls under the umbrella, just like the demolition site.
Thankfully the AN approach is now much more practical than it was even a few years ago, as the group increasingly tries to analyse the blockers to a policy and address those. It’s asking questions such as how you do leak testing on a dirty site like a demolition, the practicalities of leaks on a short job, and even where you consider the vicinity of the enclosure to be, given that air can move through risers, ducts and the like.
As we all know, clients can be one of the biggest blockers if they don’t pay for the tests. Again this is recognised by the AN, and there will be extremely clear instructions to those in charge of projects regarding their Construction (Design and Management) duties on the subject.
The new guidance is probably a few months away – I’m predicting early summer – so there’s plenty of time for you to start thinking about it. Of course, Assure360 is already working on the subject, and our solution is taking shape for a release in the spring. As with everything we do, it will be done in the right way. That means keeping things easy for the supervisor and not adding to their day. Instead, everything will be collected as data, so you get the maximum benefit in the office.
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