Document Qgbz1noxJQDMgmvzmwppqgJd8

992 CHAPTER 43 Virtually all the chemicals used in water conditioning are injurious ,ifr taken internally in large doses. Many also cause severe skin irritationf^: Thus, they should be handled with caution. Caustic soda, lime, and concentrated sulphuric acid will bum the flesh;s In addition, if mixed with small amounts of water, sufficient heat may be-generated so that spattering occurs or the container becomes too hot to handle. The chlorophenol compounds, even in the low concentrations used in water conditioning, have been reported41 to produce dermatitis. Chrom- ` itch is not uncommon among workers handling chromates. The amines are said to be absorbed through the skin.42 Morpholine is said to cause kidney and lung trouble when so absorbed. Chlorine gas irritates the skin, eyes, and mucous membranes. Concen trations as low as 0.004 percent by volume in air cause dangerous illness in 0.5 to 1 hour. When relatively large amounts of the non-gaseous chemicals are to be handled, protective clothing, including goggles, should always be pro vided, and a shower head or its equivalent provided at or very near the point where the chemicals are mixed. Chemicals should always be washed from, the skin with large volumes of water. For the handling of chlorine and chlorinators, the U. S. Public Health Service42 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 chlorine is being stored or is in use. Gas masks should be inspected at regular inter vals and kept in serviceable condition. Note:--All-purpose masks offer adequate protection only when the concentration of acid gases does not exceed two percentsee Safe Practices Pamphlet #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 ana 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 industrial plants, is required to meet drinking water standards insofar as bacteriological quality is concerned. A ruling of the V. S. Department o; Agriculture, Meat Inspection Division, prohibits the use of chromate water used for air washing when the air later contacts foodstuffs.44 There is an ever growing consciousness on the part of public health officials, of the necessity for regulations to protect potable water suppH^' Attesting this is an ordinance46 now in effect in Detroit, Michigan, which stipulates in part: { > Corrosion and Water Formed Deposits, Causes and Prevention 993 i "No physical connection shall be maintained between lines carrying city water !' pipes, pumps, or tanks supplied from any other source. Where'dual supplies are necessary or desired, lines carrying city water muBt be protected against back \ gow 0f polluted water by an atmospheric gap. Secondary supplies and emergency sources shall include: surface waters from rivers, lakes, ponds, lagoons, and reser voirs; 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 contamination 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 Table 8. Recommended Maximum Allowable Content in Water Supply* Substance Max. Concen tration, ppm Substance Max. Concen tration, ppm Iron & Manganese (Total). Magnesium.......................... Lead................ Fluorine 3.0 0.3 125.0 15.0 0.1 1.0 Poly-phosphate of Sodium. 0.05 0.05 0.001 10.0 10.6 * U. S. Public Health Service, of the American Water Works Association has accepted these values as standard for all public water supplies in the United States.46 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 listed above the value cited. bince virtually all of the permissible chemicals used for scale, slime, and corrosion control have deleterious, physiological effects if taken internally in relatively large1doses, they should always be carefully proportioned. To insure this, the Detroit ordinance stipulates that the chemical feeding device must have the following major characteristics: ,,,, There shall be a visible means of checking the quantity of material being applied by the feeding device. ~^ water metering device, sealed to prevent tampering, shall be installed to measure the flow of water being treated. the ^U: device shall be constructed so that in the event of back-flow or vacuums, devi'naximum amount of material that may be possibly back-siphoned from the ce or any of its attachments or parts shall not exceed one fluid ounce, the there be a failure of the water metering device or the water supply, eaing device shall automatically cease operating." REFERENCES _ Report (1947) Committee D-19 (American Society far Testing Materials). ' Corrosion Handbook, edited by H. H. Uhlig (John Wiley & Sons, p. 27). ^ i-cuasion, Corrosion and Material Protection, May 1945, p. 2. (Proc^tu^d'abie Discussion on Organising the Classification of Industrial Waters, by W. C. Sebroeder Amsriam Society for Testing Materials, Vol. 44, 1944, p. 1057). lnM. Amjw* Analyses for Classification with Reference to Industrial Use, by W, D. Collins (Proceed- "*er'can Society for Testing Materials, Vol. 44, 1944, p. 1057).