Capacity tests are those which test the design of the meter rather than the workmanship thereof. When a meter of a given make has once been tested for capacity it should not be necessary to again test this type of meter unless a change has been made in its design. The registration tests should be made on each meter, as the results are affected by workmanship and assembly of individual meters. There is no certainty that, because one meter of a given make comes within certain limits of accuracy, another meter of the same make turned out by the factory on the same day will necessarily give similar results. The register furnished with each meter should be used by both the manufacturer and purchaser in making registration tests. Where the purchaser does not have the necessary equipment to test the meters, there should be furnished by the manufacturer a certificate that each meter has been tested for accuracy of registration and complies with the standard specifications in this respect, and that the type of meter furnished has complied with the capacity requirements. The registration tests recommended are as follows: All meters should be tested for accuracy of registration within and as near as practicable to the low and high rates given under "Normal Test Flow Limits." A test at the "Minimum Test Flow" should be made on as many as possible and not less than 5 per cent of the meters. If the results obtained from testing 5 per cent of the meters show that any meter does not comply with the low flow requirement, additional meters should be tested to the extent deemed necessary to make certain that the other meters do comply therewith. The pressure test should be made on each size of meter furnished of a particular type. This pressure is to be 150 pounds per square inch and the pressure may be furnished through the use of a hand pump or such other method as may be available. Before the meter has been tested by static pressure and also after it has been so tested, it should be tested for accuracy to see whether the meter has been so distorted as to affect registration. It is considered unnecessary to make a pressure test of each size of meter of a given type more than once if satisfactory results are obtained. If it be possible to give a working pressure test under 150 pounds per square inch then such a test should be applied rather than a static pressure test. SPECIFICATIONS FOR CHEMICALS USED IN WATER PURIFICATION SAMPLING AND TESTING 1. Sampling and testing a. The composition of the chemicals shall be determined by analyzing samples taken promptly upon the arrival of the material at the point of consumption. b. When chemicals are shipped in bulk, the sample shall be so taken that it will represent an average of all parts of the shipment from top to bottom, and shall not contain a disproportionate share of the top and bottom layers. It shall weigh at least 10 pounds (in the case of lump lime 100 pounds) and shall be crushed if necessary and mixed thoroughly, and "quartered" to provide two 1-pound samples, one of which shall be used for the immediate testing and the other of which shall be kept carefully sealed for use in a possible retest as provided hereinafter. c. When shipped in packages at least 3 per cent of the number of packages shall be sampled. They shall be taken from various parts of the shipment, dumped, mixed and sampled as in the above paragraph. d. When sampling quicklime or hydrated lime, it is essential that the operation be conducted as expeditiously as possible, in order to avoid undue exposure of the material to the air. The sample to be sent to the laboratory shall immediately be placed in an air-tight container in which the unused portion shall be stored until the shipment has been finally accepted or rejected by the purchaser. 2. Retesting a. Notice of dissatisfaction with a shipment based on these specifications must be in the hands of the consignor within ten days after the receipt of the shipment at the point of destination. If the consignor desires a retest, he shall notify the consignee within five days of receipt of the notice of complaint. The duplicate sample shall then be forwarded for a retest to some laboratory agreed upon by both parties. This retest shall be made at the expense of the consignor. The results of the retest shall be accepted as final. SULPHATE OF ALUMINA 1. Chemical requirements a. The material shall be basic, shall contain not less than 17 per cent available water-soluble alumina (Al2O3) and shall not contain more than 0.75 per cent iron (Fe2O3). 2. Insoluble matter a. Sulphate of alumina from which the insoluble material has been removed shall contain not more than 0.5 per cent of material insoluble in distilled water. b. Sulphate of alumina from which the insoluble material has not been removed shall contain not more than 7.5 per cent of material insoluble in distilled water. 3. Size of lumps or grains a. Lump sulphate of alumina shall range in size from 2 to 3 inches. b. Ground sulphate of alumina for use in dry feeding machines shall be of such size that not less than 95 per cent shall pass a woven sieve having 10 meshes per linear inch, and 100 per cent shall pass a sieve having 4 meshes per linear inch. 4. Packing and shipment a. Sulphate of alumina may be shipped in bulk, in bags of uniform weight or in barrels of uniform weight. SODA ASH 1. Chemical requirements con The soda ash shall be that known as 58 per cent light soda ash and shall co tain not less than 98 per cent of sodium carbonate. The material shall be in a dry powdered form, shall contain no large lumps or large crystals, and shall be free from chips and other foreign matter. 2. Packing and shipment Soda ash may be shipped in bulk, in bags containing a uniform weight or in barrels containing a uniform weight. CAUSTIC SODA 1. Chemical requirements The caustic soda shall be that known as 76 per cent actual test sodium oxide and shall contain not less than 98 per cent sodium hydroxide (NaOH). The dry material is manufactured in 3 forms, viz., solid, ground and flaked. 2. Packing and shipment Solid caustic soda is customarily shipped in steel drums containing approximately 700 pounds net weight. The ground and flake material is commonly shipped in steel drums or in wooden barrels containing approximately 400 pounds. LIME 1. Slaking When lumps of quicklime are immersed in water, they shall readily disintegrate into a suspension of finely divided material, 2. Chemical requirements a. For quicklime the standard of composition shall be a content of 85 per cent available calcium oxide (CaO), but quicklime of less CaO content may be accepted where conditions of service permit and the price of the less pure product is such as to give increased economy considering the additional quantity of both lime and sludge to be handled. b. For hydrated lime the standard shall be a content of 90 per cent available calcium hydroxide (Ca(OH)2). 3. Bonus and reduction Where large quantities of lime are to be purchased it is recommended that the contract be drawn to include a bonus or a reduction of 1.5 per cent in payment for each 1 per cent by which the available CaO or Ca(OH)2 exceeds or falls below the standard percentage. In case of small purchases the contract should permit rejection for failure to reach the standard. 4. Packing and shipment Quicklime may be shipped in bulk, in wooden barrels, in metal drums, or in waterproof bags, packages of each kind to be of uniform weight. Hydrated lime is usually shipped in paper bags holding 50 pounds net each. CHLORIDE OF LIME 1. Chemical requirements The material shall contain not less than 33 per cent of available chlorine. 2. Packing and shipment The chloride of lime shall be shipped in sheet iron drums. LIQUID CHLORINE 1. Chemical requirements The liquid chlorine shall be practically chemically pure and anhydrous. 2. Packing and shipment Liquid chlorine shall be shipped in steel containers provided with suitable valve for controlling flow of chlorine. The containers shall be cleaned and dried before filling. SULPHATE OF IRON 1. Chemical requirements a. Sulphate of iron shall be what is commonly known as sugar sulphate of iron, theoretical formula, FeSO4·7H2O. b. It shall contain not less than 98 per cent of pure ferrous sulphate, not more than one fifteenth of one per cent of free acid and shall be clean and free from all dirt and particles of foreign matter. 2. Packing and shipment Sulphate of iron may be shipped in bulk in paper lined tight box cars, in bags, in barrels or in castors, packages of each kind to be of uniform weight. COPPER SULPHATE 1. Chemical requirements Copper sulphate shall be deep blue lumps containing not less than 98 per cent, by weight, of crystalline copper sulphate (CuSO,.5H2O). It shall not contain more than 0.01 per cent of arsenic (As). 2. Packing and shipments Copper sulphate may be shipped in bulk, in bags containing a uniform weight or in wooden barrels containing a uniform weight. |