Hi all, so I'm trying to improve my knowledge with regards COSHH and one of the things I've realised, whilst I understand the RA process for COSHH items, what I don't know how to evaluate is the WEL. It's all well and good knowing what those limits are by referring back to EH40, but I need to know a) how to measure them in our workplace with regards the specific task or activity and b) how to interpret the results so I can check these against the WELs.

Please can anyone recommend a course that can help me do this?

Thanks.

Appreciate you are looking for a course but this is one of those areas I have always defered to the specialist knowledge of an occupational hygienist.

They will have the training and appropriate kit for the substances to be monitored, provide an "expert" report and recommendations based upon their observation across other clients.

As Roundtuit correctly points out, what you’re really asking for is a course to become an Occupational Hygienist.

However, as a COSHH assessor, your COSHH Risk Assessment training should already cover how to determine when an exposure assessment is needed. In other words, it should teach you how to identify situations where the risk of exposure from the process being assessed might approach or exceed any assigned Workplace Exposure Limit (WEL). It should also help you recognise when the risk is high enough that you may want to carry out an exposure level assessment to confirm that existing controls are effective.

That said, you’re unlikely to find a COSHH course focused exclusively on this specific aspect of the risk assessment process.

If you were cutting hard wood (dust is a carcinogen) day in / day out your COSHH assessment would likely have recommended the use of LEV as an engineering control. Having installed the LEV you then need to demonstrate it is doing what was intended i.e. getting exposure as low as reasonably practicable (not forgetting the filter changes and maintenance activities that have been introduced over an above cutting) - this is where you would arrange for an on-going assessment by an occupational hygienist.

If you are merely a hard wood stockist then there is still a potential hazard from dust (from the mill) on the material however you are not conducting your own work so LEV would not be an appropriate control measure. You could employ a hygienist to determine the actual level OR you can document conclusion that because it is an open yard and you are not creating additional dust the hazard does not warrant monitoring.

Same material - same WEL 3mg/m3 - different decision based upon local conditions.

Remember the WEL is not the target - zero exposure is always the aim (those values in EH40 whilst not changing all that often do occassionlay change).

Originally Posted by: Roundtuit

If you were cutting hard wood (dust is a carcinogen) day in / day out your COSHH assessment would likely have recommended the use of LEV as an engineering control. Having installed the LEV you then need to demonstrate it is doing what was intended i.e. getting exposure as low as reasonably practicable (not forgetting the filter changes and maintenance activities that have been introduced over an above cutting) - this is where you would arrange for an on-going assessment by an occupational hygienist.

If you are merely a hard wood stockist then there is still a potential hazard from dust (from the mill) on the material however you are not conducting your own work so LEV would not be an appropriate control measure. You could employ a hygienist to determine the actual level OR you can document conclusion that because it is an open yard and you are not creating additional dust the hazard does not warrant monitoring.

Same material - same WEL 3mg/m3 - different decision based upon local conditions.

Remember the WEL is not the target - zero exposure is always the aim (those values in EH40 whilst not changing all that often do occassionlay change).

So essentially, it's an interpretation based on the likelihood of exposure based on current control measures?

Reported

Hi Svick

The first thing you need to do is to consider why you might need to be doing monitoring of one or MORE contaminants.

At the start of the COSHH (or other) assessment process, there are typically three scenarios (this is marginally over simplistic).

1. You should be able to work out that you DO have a problem and, perhaps, should do something about it without bothering with monitorin (yet).

2. You should be able to work out that you SHOULDN'T have a problem.

3. You really don't know.

For many processes there is plenty of authoritative guidance that will help you to determine whether you are in category 1 or 2, except when you might rightly question the validity of that guidance in your circumstances, usually when the guidance tells you to do things that you may think are unnecessary due to the work being of short duration and intermittent.

As example take Roundtuit's scenario with one change - cutting softwood rather than hardwood.

Hardwood dust is a designated carcinogen, whereas the jury is out on whether exposure to softwood dust causes cancer and hence different COSHH rules apply.

So, for the soft wood dust COSHH tells you to reduce the exposure, so far as reasonably practicable and to keep within the WEL. If worker is expousre is say half the WEL, the chances are that you are also doing all that is reasonably practicable.

However, recent HSE from HSE tends to implicitly assume that the process is going on for long periods and thus advocates LEV and RPE. 

Perhaps though you are only cutting the soft wood very infrequencly and whilst LEV probably is reasonably practicable, adding RPE (and all the procedures that you need to apply to ensure that the RPE is used, maintained, etc etc) may be over the top. So, may be you need to do some sampling to enable you to challenge the validity of HSE's guidance.

So, if we than take the category 1 and 2 cases where circumstances mean that you are not so sure and add the category 3 activities, next you need to work out what you want to sample and a strategy - which location or locations to put the sampling equipment, when and for how long + whether to look for one or more than one contaminant.

AND if you have more than one contaminant to consider whether to treat the risks as being separate, additive or even "synergistic".

Your training to date might have explained most of this, might not.