I recently visited a factory that was running a CNC machine that was cutting grooves into MDF sheets. I noted that, despite an LEV capture hood being fitted to the head, whenever it changed direction it emitted a substantial cloud of dust for a few seconds. I took this up with the owner who said it was normal and that I would find the same in any woodworking premises. I'm not convinced. Nor am I convinced that the HSE would accept that excuse. No RPE was in use.

He showed me the latest inspection/test cetificate for the LEV which was only a few month's old. I have little experience of woodworking CNC machines and would welcome any thoughts from members.

Please correct me if I am wrong, but isn't an LEV test just to show that the LEV is pulling through the air at the expected rate and without leaks, and has less to do with whether the hazardous substance is being sufficiently controlled at source. Whilst a well desgined LEV system that passed the test should sufficiently control the hazardous substance at source, it is not a given.

Quote from an LEV tester site

"An LEV tester will check the airflows of the ducts, check face velocities of hoods, perform smoke tests to find the maximum capture distance, perform visual inspection of the filters and system in general, and investigate the processes being used to determine if the system is used correctly."

Basically, the owner would need to prove that the LEV was sufficiently controlling the wood dust, and an LEV test certificate is only part of the evidence. 

With Chris on this.

The position and design of the extraction head needs investigating as when it is correctly set there should be no "billowing" at the change of direction.

What you may find is they have set the head to allow quick product changeovers.

As one of my many duties is that of a Statutory Inspector of LEV Systems I am trying to ensure that the dust is being effectivly captured. This is acheived the use of smoke indication and the use of various types of measuring equipment. The only other thing I do that not many other LEV Companies do is a Tyndall Lamp Test to see if the dust is being effectivly captured.

As with everything else it depands upon how the system was initally designed and installed. It is suprising how many systems i come across which have been in use for years passing their statutory inspections that have never been designed correctly in the first instance. The issue is when i fail it and the owner complains it has always been like that.

Most LEV systems will not capture everything. You have to guage if you believe exposure monitoring is required in order to confirm the existance of any exposurer issues and what further PPE may also be needed for that last little bit of dust that escapes the system.

Please be mindful that a poorly designed and performing LEV system is not just a "breach" of COSHH, it breaches PUWER at least Reg 10 & the SMSR, as LEV is specifically listed in Annex 5 as a safety component.

Additionally woodworking LEV has a c-type system standard harmonised to the MD, EN 12779:2015 which was published in the OJEU 13/05/2016.  Before this time the design would have relied upon applicaiton of the a-type & b-type standards.

An LEV system must be CE marked upon completion to the MD.

This is not a new requirement and it has been in place for decades. The issue the LEV industry has is that clients won't pay for this, and there are too many companies who are willing to do the LEV for end users without CE.

So all those of you who have LEV and have hd it installed in the last 20 or 30 years and think that you are compliant with PUWER, unless you have DoC's for the LEV from the manufacturer of the installed system, then think again.

So anything designed or installed since May 2016 and you definitely must have it CE marked, until that is the end of next year when UKCA marking is implemented.