Water mains supply

Tap water. As city water, mains supply, and the like, tap water is typically under 1,000 to 2,000 ppm TDS. It requires an RO plant operating with an applied pressure of 150 to 300 psig and permeate recovery rates of 80% down to perhaps 50% of the RW supplied... 

Water main supplying foam-making equipment... 

Water. Water mains should be connected to plant fire mains at two or more poiats, so that a sufficient water supply can be deHvered ia case of emergency. The plant loop and its branches should be adequately valved so that a break can be isolated without affecting a principal part of the system. If there is any question of maintaining adequate pressure, suitable booster pumps should be iastaHed. Any connection made to potable water for process water or cooling water must be made ia such a manner that there can be no backflow of possibly contaminated water check valves alone are not sufficient. The municipal supply should faH freely iato a tank from which the water is pumped for process purposes, or commercially available and approved backflow preventers should be used. 

After 1860 in the United States, water mains were only occasionally given coatings of tar. About 18% the activities of Engii.sh undertakings were extended to America, where chiefly bare metal pipelines had previously been laid. Water supply pipes were coated internally with bitumen in America after 1912. Vical (1837) in France and J. Bull (1843) in America introduced the widely known cement mortar as a protective material for water pipes 16]. 

In addition to varying in costs, the chemical composition of the water provided from the mains supply also varies between the water companies, as may that between independent supplies within each company s area. The current criterion on potable water quality requires it to be wholesome i.e. it should not create a health hazard, with relatively wide limits on particular constituents. The cost of removing these constituents (e.g. calcium, magnesium, chlorides, iron and silica) increases with concentration and variability. This imposes a cost burden on, for example, the semiconductor and electronic component industries and on the operation of high-pressure boilers. Therefore both the potential cost of metered water supply and the chemical composition of the supply waters may influence future decisions on the water company s area in which an industry may wish to locate. 

Automatic sprinkler systems have the great advantage that they are comparatively simple in concept and operate automatically, whether or not there are people present on the premises. Water is supplied from the public mains or tanks and pumps into a network of distribution pipes at ceiling level, which covers the whole premises. Water is discharged through nozzles or heads sited at regular intervals in the pipework, which are normally sealed with a he at-sensitive device. 

Raw water. The mains supply or other external source used to prepare make-up. 

Water from towns main supplies is usually suitable for the preparation of water-based cutting fluids. That from factory bore holes is also generally suitable, although occasionally it contains excessive amounts of corrosive salts. Water from rivers, canals and ponds usually contains undesirable contaminants, and should be tested before use. A good first test is to mix a small quantity of emulsion and allow it to stand for 24 hours in this time, no more than a trace of the oil should separate. If serious separation occurs, the water should be analyzed to indicate the sort of remedial treatment required. 

The design is further claimed to fully treat full flows of water in a single pass when installed direct to mains supplies, and water treated magnetically maintains its state for up to five days. Treatment results in hardness ions being attracted to other ions (rather than to pipework), resulting in a larger neutral body that has no ability to adhere to pipe walls or other contact surfaces, so that no incrustations or hard scales form. ... 

Because of the cost of mains water, many companies have utilised on-site boreholes as their water source. Such water, percolating through the soil, will be much more contaminated with micro-organisms than the mains supply and will require treatment before use. River or canal water will contain even more micro-organisms and, although after sand or other filtration may appear clear, it still represents a significant contamination hazard to products in which it is used. 

The water required for general purposes on a site will usually be taken from the local mains supply, unless a cheaper source of suitable quality water is available from a river, lake or well. 

A water main is to be laid to supply water to a subdivision located 2 miles from a water tower. The water in the tower is 150 ft above ground, and the subdivision consumes a maximum of 10,000 gpm of water. What size pipe should be used for the water main Assume Schedule 40 commercial steel pipe. The pressure above the water is 1 atm in the tank and is 30 psig at the subdivision. 

A water main is to be laid from a water tower to a subdivision that is 2 mi away. The water level in the tower is 150 ft above the ground. The main must supply a maximum of 1000 gpm with a minimum of 5 psig at the discharge end, at a temperature of 65°F. What size commercial steel sch 40 pipe should be used for the water main If plastic pipe (which is hydraulically smooth) were used instead, would this alter the result If so, what diameter of plastic pipe should be used ... 

The water level in a water tower is 110 ft above ground level. The tower supplies water to a subdivision 3 mi away, through an 8 in. sch 40 steel water main. If the minimum water pressure entering the residential water lines at the houses must be 15 psig, what is the capacity of the water main (in gpm) If there are 100 houses in the subdivision and each consumes water at a peak rate of 20 gpm, how big should the water main be ... 

A new industrial plant requires a supply of water at a rate of 5.7 m3/min. The gauge pressure in the water main, which is located 50 m from the plant, is 800 kPa. The supply line from the main to the plant will require a total length of 65 m of galvanized iron pipe, four standard elbows, and two gate valves. If the water pressure at the plant must be no less than 500 kPa, what size pipe should be used ... 

A water tower supplies water to a small community of 800 houses. The level of the water in the tank is 120 ft above ground level, and the water main from the tower to the housing area is 1 mi of sch 40 commercial steel pipe. The water system is designed to provide a minimum pressure of 15 psig at peak demand, which is estimated to be 2 gpm per house. 

Firewater supply sources can be the city public water main, a dedicated storage tank and pumps, or the most convenient lake, river or if an offshore installation the open sea. Brackish or salt water supplies can be used if suitable corrosion protection measures are applied to the entire firewater system if it is planned to be used for an extended life (i.e., grater than five years). If a short life span of the facility is expected, short corrosion resistant materials may be used (i.e., carbon steel, galvanized steel, etc.), provided periodic testing indicates their integrity is still adequate and scale or corrosion particles do not affect operational efficiency. 

For onshore facilities, water may be supplied from local public water mains, storage tanks, lakes and rivers. In these cases a conventional horizontal pump is used. The preferred design for onshore fire water pumps is a horizontal centrifugal type with a relatively flat performance curve (i.e., pressure versus quantity). The discharge pressure is determined by the minimum residual pressure required at the most remote location of the facility flowing its highest practical demand with allowances added for piping friction losses. 

If a pressure gradient of the entire system is desired, additional pressure cap gages can be placed along several points of the water main from the source of supply to the flow hydrant and these pressure readings taken for each flow measurement. 

Due to the obvious risk of fire, refineries are equipped with sprinkler or spray systems that may draw on the main supply of water, or water held in lagoons, or from reservoirs or neighboring water courses. Such water will be polluting and require containment. 

The catalyst preparation area is protected by an automatic water-spray sprinkler system that is actuated by associated heat detectors. Fixed fire water monitors surround this process area. The water for these fire protection systems is supplied through 8-inch underground water mains by three (two diesel and one electric) horizontal, centrifugal, 2500... 

The water distribution system in the city of Dayton, OH, uses Southdown concrete water mains to deliver water to its citizens. Routine sampling and testing of Dayton s water supply by the city s Department of Water consistently shows that the levels of metals are well below the Ohio EOA Community Drinking Water Standards, and that these levels have remained constant throughout a nine-year testing period from 1982 to 1990. Because metal leaching has not occurred, there is no reason for concern over the safety of Southdown concrete pipes to transport drinking water. 

Looped Water Main A water main arranged in a complete circuit so water will be supplied to a given point from more than one direction. Also called a grid system. 

It must bo remembered that this mode effects the bicarbonate of lime, not the more troublesome earthy salts, each as the sulphates and chlorides, on which the hardness of spring waters mainly depends. The diffi culty of mixing lime and watar, in definite proportions, on the large scale, must he obvious to every one. If toe much be employed, the. companies would supply their customers with litne- icater If too little, the bicarbonate of limo would not be completely destroyed, and the process would be a Failure. Altogether, the difficulties of carrying out the process Will ever prevent its adoption on a large scale. 

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