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drewkshaw  
#1 Posted : 24 June 2019 13:33:01(UTC)
Rank: New forum user
drewkshaw

Hi everyone. I'd be grateful for some thoughts on a situation I'm faced with concerning LEVs.

My firm has just changed our LEV inspection company and we've just had a round of Statutory Inspections.

As expected, we've got a load of recommendations to work through and in among them, we've got a large number where the inspector has suggested modifictions to the system to bring them in line with HSG258.

The issue I have is that a number of our LEVs are knocking on for 30 years old and though quite old, still seem to operate well enough and haven't had any major issues with past inspections.  The new inspector is now recommending mods to the latest HSG258 which was only introduced (I think) in 2017.  The question I have is - is it reasonable or was it the intention to apply HSG258 retrospectively to older systems ?  Some of the mods will be extensive and will cost a lot !

I've had a look through HSG 258 again and even within the document itself on the first page, it states :-

          This book provides guidance on the design of new local exhaust ventilation (LEV) equipment.

The word "new" here makes me think that the intention isn't to have all existing LEVs brought up to the standard of the current version of HSG 258 but instead is guiding purely on new systems.

Would welcome thoughts / opinions.

Cheers,

Drew Shaw

Ian Bell2  
#2 Posted : 24 June 2019 13:40:26(UTC)
Rank: Super forum user
Ian Bell2

I guess you will have to review what the inspector is asking for compared to what you have now.

Do the suggestions for improvements really improve safety/exposure to hazardous substances by operators or are they just 'nice to have' improvements?

thanks 1 user thanked Ian Bell2 for this useful post.
drewkshaw on 24/06/2019(UTC)
chris.packham  
#3 Posted : 24 June 2019 14:06:08(UTC)
Rank: Super forum user
chris.packham

I would have thought that the fundamental question that needs addressing is whether the 'old' systems are adequately removing the contamination. If they are then what is the purpose of the 'updating'. In the old parlance of engineering: "If it ain't broke don't fix it!"

So a simple smoke/vapour test would show if the systems are moving air such that there is a reasonable chance that the system is working properly and possibly some airborne monitoring to ensure levels are below the WEL.

thanks 2 users thanked chris.packham for this useful post.
stevedm on 25/06/2019(UTC), A Kurdziel on 27/06/2019(UTC)
A Kurdziel  
#4 Posted : 24 June 2019 15:45:52(UTC)
Rank: Super forum user
A Kurdziel

This has been said before but most LEV inspections just test the level of “suck” produced by the LEV based on some standard (but essentially arbitrary) set of criteria. What you need to be looking at is how and if the LEV is providing you with the level of operator protection you require for that particular job. Something like a smoke testing is a good indicator of this. It is perfectly possible that a 30 year old system is giving you exactly what you need and a brand new system could be completely wrong for what you want even though the level of airflow at the face is what some standard says it should be: it’s just the wrong standard for what you need.

stevedm  
#5 Posted : 25 June 2019 07:52:13(UTC)
Rank: Super forum user
stevedm

COSHH R9 compliance...ensure the system remains effective at control.

If it isn't then change it...check competence...

I would have said if you have changed/modified it then you need to bring it up to the existing industry standard if you have only replaced like for like then make sure it complies with R9...

Gerry Knowles  
#6 Posted : 26 June 2019 15:12:34(UTC)
Rank: Forum user
Gerry Knowles

I always worry when a new contractor turns up to do an inspection and suddenly old equipment which is performing well "needs to be replaced or you need to do a lot of work to bring it up to standard to comply with new or updated legislation".  The question I will always ask of them is how do you know and explain to me why and under what legislation.  Especially if they also try provide the replacement/upgrade work.  I have come across a number of companys over the years who will try and gain work following an inspection by bending or omitting parts of legislation.  My message is dig deep into inspection reports and ask questions of the people who have proved it. Then if necessary go out for quotes.

thanks 2 users thanked Gerry Knowles for this useful post.
A Kurdziel on 27/06/2019(UTC), SJP on 27/06/2019(UTC)
chris.packham  
#7 Posted : 26 June 2019 16:32:49(UTC)
Rank: Super forum user
chris.packham

My mentor on LEV - and this is many years ago - was a gentleman called Frank Gill. Those of you who have been in health and safety for long enough will probably know the name, particularly as co-author of that excellent book - Occupational Health (J.W.Harrington, F.S.Gill, T.C.Aw, K.Gardiner). He drilled into me that the key for effective LEV was not how much air was moved but how well the capture system matched what was needed to get the contamination into the duct! One of his comments was: "I don't earn my living designing new LEV systems. I do it by modifying other peoples' systems that could never have worked!' For me nothing much has changed since.

When it comes to standards for LEV my question is "What standard?" Of course, I am interested in airborne skin exposure so I don't have standards to work to, particularly for airborne skin exposure one can develop adverse effects at levels well below the LEV.

thanks 1 user thanked chris.packham for this useful post.
A Kurdziel on 27/06/2019(UTC)
John Elder  
#8 Posted : 01 July 2019 14:59:07(UTC)
Rank: Forum user
John Elder

As a qualified Statutory Inspector off LEV systems I survey Older systems all the time.

Note without knowing what was picked up or recommended it is difficult to make an informed judgement against recommendations in this case so the following is a suggestion for guidance only.

Firstly do you have the original Design Specification for the LEV System and can you produce it for comparison.

If you have and the Flow, Capture, Velocity and Static Pressure readings achieved in the survey are comparative with the  original design specification initial test results or are better and the capture has been deemed sufficient using smoke as a verification then there should not be any main issues.

If no design is available, then the flow rates as mentioned in HSG 258 should at least be met and if so then the system should pass.

Most recommendations raised for older systems are normally around Flow indication not being provided for the system which in the new HSG is a recommendation and the removal of so called (Chinese Hats) from the top of the vent stacks which are for weather protection and are no longer allowed.

These should be replace with something suitable such as a Jet Cowles for Weather protection.  The former type impedes the flow of contaminant from the system and causes back pressure.

Secondly has the process being carried out or substance used changed since the LEV was designed and installed, or has it been modified in any particular way which now prevents or reduces the  capture rate.

Additionally is the method of capture being applied now the most suitable way of controlling the contaminant e.g. is it being drawn away from the face of the operator and not across their face to enter the system. Or would an enclosure, Down Draft or Back Draft bench be better suited to the process as opposed to a canopy over the system. I hope this helps.

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