Document dQvwKmXEXa6drm3O03z0x1a0e

914 CHAPTER 42 1951 Guide vided, and a shower head or its equivalent provided at or very near thepoint where the chemicals are mixed. Chemicals should always be washed from the skin with large volumes of vxUer. For the handling of chlorine and chlorinators, the U. S. Public Health Serine#3 stipulates the following safety requirements: 1. Suitable gas masks and a small bottle of ammonia for testing for leaks should be kept at convenient points immediately outside the room or enclosure in which chlo rine is being stored or is in use. Gas masks should be inspected at regular intervals and kept in serviceable condition. Note:--All-purpose masks offer adequate pro tection only when the concentration of acid gases does not exceed two percent-- see Safe Practises Pamphlet U 64 National Safety Council. 2. Chlorinating equipment and cylinders of chlorine should be housed preferably in separate buildings above the ground level. 3. The room or building housing chlorinators in service should be maintained at a temperature above 60 F, but never in excess of the normal summer temperature. The cylinders of chlorine should be shielded, where necessary, from excessive heat or cold. Direct heat should not be applied to cylinders of chlorine, nor should hot water be poured over them or come in contact with the cylinder valve. 4. Adequate ventilation should be provided for all enclosures in which chlorine is being fed or stored. 5. All joints of tubing connecting chlorine cylinder and chlorinators should be kept absolutely tight and inspected frequently to insure tightness. Tubing should slope upward from the cylinder. LEGAL REGULATIONS In a number of states, the water used for humidification, even, in in dustrial plants, is required to meet , drinking water standards insofar as bacteriological quality is concerned. A ruling of the U. S. Department of Agriculture, Meat Inspection Division, prohibits the use of chromate in water used for air washing when the air later contacts foodstuffs.40 There is an ever growing consciousness on the part of public health officials, of the necessity for regulations to protect potable water supplies. Attesting this, is an ordinance41 now in effect in Detroit, Michigan, which stipulates in part: "No physical connection shall be maintained between lines carrying city water and pipes, pumps, or tanks supplied from any other source. Where dual supplies are necessary or desired, lines carrying city water must be protected against back flow of polluted water by an atmospheric gap. Secondary supplies .and emergency sources shall include: surface waters from rivers, lakes, ponds, lagoons, and reservoirs; well waters both deep and shallow; any supply of water which'has been stored, held, or reserved after being used for industrial purposes; cooling water, or water which has in any way been treated, processed, or has been subjected or exposed to any con tamination of a bacteriological or chemical-nature; and water from any other source than the city supply."- "' The U. S. Public Health Service stipulates: "Salts of barium, hexavalent chromium, heavy metal glucosides, or other sub stances with deleterious physiological effects, shall not be allowed in the water supply system." The same agency recommends that the concentration of the substances listed be held below the values cited in Table 8. . The Board of Directors of the American Water Works Association has accepted these values as standard for all public water supplies in the United States.4* While their action is not binding, prudence dictates that no form of treatment should be used that will result in raising the concentration of the substances listedabove the value cited. Since virtually all of the permissible chemicals used for scale, slime, and corrosion control have deleterious, physiological effects if taken internally Corrosion and Water Formed Deposits, Causes and Prevention 915' Table 8. Recommended Maximum Allowable Content'd! Watbb Supply* Substance -Max Concentration, ppm Substance Max Concentration, . ppm Copper. Iron A Manganese (Total).. Magnesium............................. Enc............ ........................... Lead...................................... Fluorine......... ...................... * U. 8. Public Health 8er*icc. 3.0 0.3 125.0 15.0 0.1 1.0 Arsenic............... . ........... Selenium......... .................... Phenols (Total).................... Poly-phosphate of Sodium.. pH Value @ 25C................ 0.05 0.05 0.001 10.0 10.6 in relatively large doses, they should always be carefully proportioned. To insure this, the Detroit ordinance stipulates that the chemical feeding device must have the following major characteristics: "1. There shall be a visible means of checking the quantity of material being applied by the feeding device. 2. A water metering device, sealed to prevent tampering, shall be installed to measure the flow of water being treated. 3. The device shall be constructed so that in the event of back-flow or vacuums, the maximum amount of material that may be possibly back-siphoned from the device or any of its attachments or parts shall not exceed one fluid ounce. 4. Should there be a failure of the water metering device or the water supply, the feeding device shall automatically cease operating." REFERENCES 1 Annual Report (1947) Committee D-19 (American Society for Testing Materials). * Corrosion Handbook, edited by H. H, Uhlig (John Wiley & Sons, p. 27). * Discussion, Corrosionand Material Protection, May 1945, p. 2. 4 Round-Table Discussion on Organizing the Classification of Industrial Waters, by W. C. Schroeder (Proceedings, American Society for Testing Materials, Vol. 44 1944, p. 1051). * Typical Water Analyses for Classification with Reference to Industrial Use, by W. D. Collins (Proceedings, American Society for Testing Materials, Vol. 44, 1944, p. 1057). 4 A.S.T.M. Standard D-596--41 (American Society for Testing Materials). I Discussion on -Preventing Solution of COi in Condensates, by E. W. Guernsey (A.S.H.V.E. Tbansactions, Vol. 51,1945, p. 69). 4 Studies of the Mechanism of Solution of CO, in Condensates Formed in Steam Heating Systems of Buildings, by L. F. Collins (A.S.H.V.E. Tbansactions,: Vol. 51, .1945, p. 39). * The Analytical Control of Anti-Corrosion Water. Treatment, by W. F. Langelier (Journal, American Water Works Association, Vol. 28,1936, p. 1500). 10 Surface-Active Properties, of Hexametaphosphate, by G. B. Hatch and Owen Rice (Industrial and Engineering Chemistry, Vol. 31,1939, p. 51). II Slime Control in Cooling Equipment with Phenol Derivatives, by J. A. Holmes (Proceedings, Annual Water Conference, Engineers Society of Western Pennsylvania, 1944,p. 61). 14 Tuberculation of Mains as Affected by Bacteria, by H. G. Reddick and S. E. Linderman (Journal, New England Water Works Association, Vol. 46, 1932, No. 42). u Microbiological Anerobic Corrosion of Steel Pipe Lines, by R. F. Hadley (The Oil and Gas Journal, September, 1939). 14 Tests of Corrosion Inhibitors for Water Treatment in Air Conditioning Equip-