Members Thank you to Brian for his comments on my questions put forward. I am still looking for answers but will address some of Brian,s comments 1) A water mist system works at higher pressure than a normal sprinkler system. Again what pressure is it 200 bar? 2) My point is that there are certain requirements to pipework and fittings to be listed within the standards. For example CPVC has a pressure rating and would not comply with certain sytems.Are you saying that any pipe can be used to link sprinklers? The standards are clear on this issue 3) Residential sprinkler heads are listed and within a standard example NFPA 13D, The NFPA 13D standard can be applied throughout the world even in Barbados. As this is a international standard this can also be used with possible relaxation to local building codes. I must ask the question again is there any mist sprinkler head listed for RESIDENTIAL use. 4) It is a fact that mist systems can be prone to blockages as the aperture is very small. In lab conditions the system is perfect but when filled with standing water for years this then becomes quite the reverse. 5) Leaking diaphram seals are on the pressure cylinders and not on sprinkler heads.Are fire extinguishers checked? 6) Normal sprinkler systems are a different fluid catogory on a water issue than a mist or sprinkler system with additives. A single check valve is required for cat 2 systems. Any other type of system has to gain water approval (United Utilites North west water) if connected to towns main 7) Irrespective of what happens in the USA its what happens here. There are systems that are linked to plumbing and used in USA and conform to NFPA 13D but are cat 1 in water regs and at the moment they no water approval. so the answer is in above at 6 The research you have done is good but you have to know systems and standards to make things work throughout the world. Sprinklers do have a major role in life safety and construction. but they must comply with standards and when I am satisfied that a water mist system complies to a standard that is for residential use then we can install them.This is why I am looking for answers Companies who install systems or products not complying to standards for which they are deemed for leave themselves and clients open for litigation and prosecution for negligence. William ===================================================================== Residential Sprinkler Forum Archives: //www.freelists.org/archives/dd251 WebSite: www.dd251.org.uk To unsubscribe from the list, send an email to dd251-request@xxxxxxxxxxxx with ?unsubscribe? in the Subject line or unsubscribe from the website www.dd251.org.uk