Posted By CJP A search of the HSE site gave this: http://www.hse.gov.uk/co...sragcwh/hazards/haz2.htm in paragraph 2.6.2, albeit for COMAH sites searching for wind sock rather than windsock.

Posted By Mike Brettle This question raises some interesting issues. I'm a professional meteorologist with an interest in wind measurement at COMAH and similar sites. There is a real problem in that although the HSE may require sites to have wind instruments (a wind sock is a very simple, and reliable, wind instrument) it does not say anything about quality assurance regarding the instrument. In practice an incorrectly installed or badly exposed wind vane or wind sock can be worse than useless. Possible errors are not small. Small wind vanes mounted on the edges of buildings could give errors of 180 degrees! As to the initial problem posed of where to mount a wind-sock: - there is a lot of material available on the location of wind instruments but this tends to focus on measurements intended for climate studies or weather forecasting and may be unrealistic in an urban or industrial environment. Probably the best advice is to locate it so that it experiences wind representative of that which is going to spread the hazardous material over shorter distances. As regards wind sensors intended to support of site plans and potentially to be used by the emergency services or in plotting dispersion of toxic plumes, this is a real quagmire with little guidance available that I can see. This issue is attracting some interest in the Royal Meteorological Society Special Interest Group on Observing Systems and I would be very interested in the views of IOSH members or anyone who is involved in installing wind instruments at COMAH sites or in assessing the fitness for purpose of the installation.