Posted By holmezy Harvey your paint spray booth will be classed as LEV so I advice you to get hold of a copy of HSG258 Controlling Airbourne Contaminants At Work. Its full of good stuff and things that a HSE Inspector would expect to see. One thing that it recommends is the fitting of flow gauges so you can see if the filters are working at their prime. These could have a pressure scale reading or simply be a red or green zone indicator.I assume that your equipment is currently inspected at 14 monthly intervals and has been commissioned, if not, then you should be doing this also. Holmezy