Document wgOBb2rMENQ35M04BNbkLJeE

20--Industrial Sanitation and Personnel Facilities food areas, personal service rooms, or clothes washing Plumbing Fixtures and faucets should be installed to prevent back-siphonage of contaminated water if the pressure drops in the supply line Faucets and similar outlets should be at least 1 m above the fioodnm of the receptacle be low. To prevent backflow mto the drinking water supply, surge tanks and air gaps may also be required in the drainage lines from process equipment Open joints in underground supply lines mto which ground water or water from leaky sewers can seep are another common source of contamination This condition may arise where pipes are subject to vibration or corro sion and the joints between pipes open me chanically or the pipe sections crack. Codes usually prohibit sewer and drinking water lines to be installed m the same trench, unless the sewer line is placed at a much greater depth and a certain horizontal offset is pro vided Frequently, contamination of the water supply, results when a system is opened for repair or the addition of new pipe and is not disinfected and properly flushed with clean water, before being put back mto service If the supply for sprinklers and fire hydrants is the same as that for drinking water, hy drant drams or "weeps" connected directly to sewer lines may be a source of contamination An open standpipe or reservoir may also per mit contamination Plastic pipe can be considered, but be sure to check local code requirements Unplasti cized PVC (polyvinyl chlonde) is good for cold water lines Hot water up to 165 F and 100 psi can usually be handled in pipe made of chlorinated polyester or unplasticized PVC Private water supplies Industrial establishments in outlying dis tricts commonly supply and treat their own water from private sources Such installa tions should be made and operated under the supervision of a thoroughly trained and ex perienced sanitary engineer The information in the next few paragraphs is not meant to substitute for such supervision. The USPHS Manual of Individual Water Supply Systems Fic 20-1 --Periodic laboratory tests are needed to determine the quality of both source water and treated water Courtesy Olm Industries, Inc should also be consulted for methods of se lecting, developing, and treating private sup plies All underground and surface waters to be used for drinking purposes should be con sidered contaminated until proved otherwise The water supplied from private sources for the personal use of plant personnel should meet the requirements of the USPHS Drink ing Water Standards, and before it can meet these requirements will have to be treated according to the degree of its contamination As a rule, ground water collected from deepdrilled wells will be free of biological con tamination but may be contaminated by vari ous mineral or chemical substances In contrast, surface water usually will be reason ably free of mineral and chemical contamina tion but very likely to have biological con tamination Where there are several sources of water, 530