One of HSE's current "hot topics" is Local Exhaust Ventilation (LEV). This seems to coincide with the publication of new LEV guidance, HSG 258, Controlling airborne contaminants at work, a guide to local exhaust ventilation (LEV).

One of our clients in Birmingham has already been picked up on the need for an LEV to control methanol emissions to atmosphere during a routine HSE visit (they have recently received an Environmental Permit, PPC Permit as was).

The Inspector sent our clients a letter pointing out various places where he thought there were fugitive emissions of methanol to air, where an LEV should be used - and totally missed out what we consider to be the point where the most methanol would be released.

This can be a trap for the unwary - if our clients were to make improvements only at the locations which the Inspector has raised in his letter, they would actually find themselves in trouble because they have not assessed the risks as a whole.

The correct course of action is to carry out a full risk assessment of emissions of methanol to atmosphere, resulting in a proposal for the design and build of an improved LEV system which ensures that the risks are adequately controlled, as per the new guidance.

You can't assume the Inspector has covered every possible scenario in any letter or discussion - the liability still rests with you.

LEVs aren't just important for human health, they also affect equipment. LEVs are particularly useful for reducing Zones round point sources, eg a bottle filling point on a packaging line. Although LEVs aren't the most desirable way of reducing DSEAR/ ATEX Zones, good ventilation usually means smaller DSEAR Zones.

The new LEV guidance can be purchased from here http://www.hsebooks.com/Books/product/product.asp?catalog_name=HSEBooks&category_name=&product_id=4998.

There are also some useful LEV calculators - http://www.hse.gov.uk/lev/calculator.htm#airchangerate.

News article Sept/2008/2