STANDARD SPECIFICATIONS FOR PRESSURE WATER FILTERS RATES OF FILTRATION Whenever the water is to be used for domestic purposes or to secure full bacterial purification, the capacity shall be based on a rate of filtration not to exceed 2 gallons per minute per square foot of filtering area and a coagulant must be used. Rates of filtration for various uses should conform to the following schedule: 2 gallons per square foot per minute for all supplies used for drinking, or for the preparation of food products. 2 to 4 gallons per square foot per minute when filtering a treated municipal supply of approved bacterial purity. 2 to 4 gallons per square foot per minute for swimming pools, and for all industrial uses. 2 to 5 gallons per square foot per minute as conditions may warrant for double filtration, using sand followed by charcoal where reduction of color, odor, taste or certain forms of iron is desired. This method of filtration not to be applied for bacterial purification. Capacities of filters for rates of 2, 3, and 4 gallons per square foot per minute DIAMETER Minimum joint efficiency Capacities of filters for rates of 2, 3, and 4 gallons per square foot per minute -Continued Length is over-all length of filter, and area of bed is calculated for surface of bed 18 inches above center of shell. Area of segments of the 2 dished heads = 7.42 square feet. = 9.2 square feet. Area in cylinder, 14 by 7.42 = 103.9 square feet. Total effective area = 113.1 square feet. 65 pounds per square inch 100 pounds per square inch 125 pounds per square inch Shell Head Shell Head Minimum joint efficiency Thickness Thickness Standard manholes 11 by 15 inches or 10 by 16 inches. Tensile strength of steel plate 55,000 to 65,000 pounds per square inch. Hydrostatic test 50 per cent in excess of working pressure. Filters to be gray iron castings having a tensile strength of approximately 20,000 pounds per square inch. Hydrostatic test 50 per cent in excess of working pressure to be applied. Heads dished to radius equal to diameter of shell may be modified with rib reinforcement to same thickness as shell. Variations of inch in these thicknesses of shells and heads and flanges to be permissible. SPECIFICATIONS FOR SANITARY DRINKING FOUNTAINS 1. All types of drinking fountains with vertical jets are to be condemned. 2. Most types of drinking fountains with slanting jets are to be condemned. 3. To be sanitary, drinking fountains should conform to the following specifications: a. The jets shall be slanting. b. The orifices of the jets shall be protected in such a manner that they cannot be touched by fingers or lips, or be contaminated by droppings from the mouth, or by splashings from basins beneath the orifices. c. The guards of the orifices shall be so made that infectious material from the mouth cannot be deposited upon them. d. All fountains shall be so designed that their proper use is self-evident. Witnesseth, that the Contractor and the Owner for the considerations hereinafter named agree as follows: Article 1. Scope of the work. The Contractor shall furnish all of the materials and perform all of the work shown on the Drawings and described in the Specifications entitled.... prepared by..... acting as and in these Contract Documents entitled the Engineer; and shall do everything required by this Agreement, the General Conditions of the Contract, the Specifications and the Drawings. Article 2. Time of completion. The work to be performed under this Contract shall be commenced.. and shall be completed... Article 3. The contract sum. The Owner shall pay the Contractor for the performance of the Contract, subject to additions and deductions provided therein, in current funds as follows:.... Where the quantities originally contemplated are so changed that application of the agreed unit price to the quantity of work performed is shown to create a hardship to the Owner or the Contractor, there shall be an equitable adjustment of the Contract to prevent such hardship. Article 4. Progress payments. The Owner shall make payments on account of the Contract as provided therein, as follows: .day of each month.... .per On or about the....... cent of the value, based on the contract prices, of labor and materials incorporated in the work and of materials suitably stored at the site thereof up to * These documents were copyrighted in 1924 by The American Institute of Architects for the Joint Conference on Standard Construction Contracts, composed of delegates of that Institute, American Water Works Association, American Society of Civil Engineers, American Railway Engineering Association, American Association of State Highway Officials, Association of General Contractors of America, Western Society of Engineers and American Engineering Council. These documents call for the arbitration of disputes involving time and money solely, as an expeditious, inexpensive means of settling controversies. If the arbitration feature is not desired, references to it in Articles 12, 18, 23, 31 and 39 and the whole of Article 40 should be stricken out in the Standard General Conditions and Articles 41 and 42 should be made Articles 40 and 41. This will provide a contract form under which all disputes which the parties cannot settle by agreement must go directly to the courts for preliminary trial. These documents must be supplemented by the other forms in local use, such as the Advertisement, Instructions to Bidders, Bond and Specifications. The Joint Conference is not considering Specifications, which are also outside the scope of our Committee's work, and the Conference has not made any recommendations yet as to these other forms. J. Waldo Smith, Chairman, Committee on Standard Form of Contract. |