I have just started in a new position in H&S and found out that we have a spraybooth waterwash or curtain system in place. Due to a downturn in that aspect of the business, the system is only used a few times per year, nevertheless it is still in use. Has anyone got any experience of these systems? I'm thinking checks for legionnaire bacterium and LEV test and inspections should be carried out? It would appear the system has not be subject to checks / maintenance of this type for sometime! I'm slightly concerned? Any views?

Yes possibly, but i think i will call the manufacturer for some guidance. Not sure if equipment of this type requires LEV testing...

You don't say what you are capturing in the water curtain. From my experience (thermal spray) there are three aspects to consider: 1. Legionella in the water itself - already mentioned by the above 2. The accompanying air extraction (assuming there is one). If the air velocity is too high (I have seen a recommended maximum figure of 9 m/s, but do not recall where it came from) there is a danger of water droplets being entrained in the air. You would then need to consider where the outlet is sited and whether people can inhale any droplets that emerge there. 3. What is being captured in the water. If it is something like titanium, aluminium or zinc over-spray you have metals that can react with water to produce hydrogen. This could build up if the booth is not used very often.

Hi Garfield Esq, I dont have expeirence of waterwash or water curtain systems but do have experience of vehicle spray booth/ovens. If your employees are breathing air via a compressor (not self containted), you will need to carry out test on your breathing air to relevant air quality standards (possibly BS4275 or EN12021). If you havent already done so, you need to establish the clearance time for each booth and display this on the door(s) to each booth. From an environmental point of view - if you have a PPC Permit and emissions stacks you will need to carry out emissions stack monitoring as per the conditons of your permit (usually annually) to demonstrate your environmental controls are effective. And dont forgot Biological monitoring for isocyanates for all your spray painters to check the effectiveness of your engineering and RPE controls. Usually a urine test - we use HSL for this, reasonably cheap and effective. Even though you are using this only a few times a year, I would still advise it given the risk of sensitisation and occupational asthma. Hope this helps a little. Regards, Barry

Chris Exposure can arise in two ways. If the air extraction is switched off before the water flow, then there is a possibility of exposure to droplets (and the converse at start-up). If the air flow is too brisk, there is a possibility of water droplets being pulled out via the air extraction system. In my experience the water in these systems can sit around for months on end, at room temperature or above, and they get full of all kinds of useful nutrients. Note from this topic that they are used in two major industrial processes - paint spray and thermal spray (where the materials being sprayed are likely to be metals and/or ceramics).

Thanks for the replies which have been extremely helpful. I have decided to recommend the water curtain system and indeed any paint spraying required is put on hold until a full test / maintenance check of the system is carried out. As the unit is not required regularly then I feel this is not a 'knee jerk' reaction. As 2-pack systems are being used in conjunction with water that appears stagnant I think 'erring on the side of safety' is the right and legal thing to do. Empirical records suggest the last formal checks were carried out in 2006! Quite shocked really...Considered to be ignorance rather than budgetary!