Pipe Economy

Pipe economy depends primarily on the length of lines arranged in the yard. Fittings, valves and instruments are relatively few compared to pipe length. 

with good layout practices, the same number and size of equipment can be arranged on a shorter yard length, yard piping cost can be reduced 

The elevation difference between the main yard bank and laterally connecting pipe lines is about 2 to 2-1/2 feet. This gives an elevation difference of 4 to 5 feet between two main yard banks. 

If a building (control house, pump house) is located under the main yard piping, elevations will be higher than without a building. Clearances in the building, pitching of the roof, steel structures and pipe line clearances will affect the yard height. 

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Two header combinations are thus possible. The one with 18 inches for 1 and 6 inches for 2 is preferred for pipe economy. 

Figure 6-14. Sizing of headers. Two combinations (a) and (b) are possible but (b) is preferred for pipe economy.

Chemical-Process Vessels. Explosion-bonded products are used in the manufacture of process equipment for the chemical, petrochemical, and petroleum industries where the corrosion resistance of an expensive metal is combined with the strength and economy of another metal. AppHcations include explosion cladding of titanium tubesheet to Monel, hot fabrication of an explosion clad to form an elbow for pipes in nuclear power plants, and explosion cladding titanium and steel for use in a vessel intended for terephthaHc acid manufacture. 

Saline Water for Municipal Distribution. Only a very small amount of potable water is actually taken by people or animals internally, and it is quite uneconomical to desalinate all municipally piped water, although all distributed water must be clear and free of harmful bacteria. Most of the water piped to cities and industry is used for Htfle more than to carry off small amounts of waste materials or waste heat. In many locations, seawater can be used for most of this service. If chlorination is requited, it can be accompHshed by direct electrolysis of the dissolved salt (21). Arrayed against the obvious advantage of economy, there are several disadvantages use of seawater requites different detergents sewage treatment plants must be modified the usual metal pipes, pumps, condensers, coolers, meters, and other equipment corrode more readily chlorination could cause environmental poUution and dual water systems must be built and maintained. 

Support spacing must be much closer than for carbon steel. As temperature increases, the allowable stress for many plastic pipes decreases very rapidly, and heat from sunhght or adjacent hot uninsulated equipment nas a marked effec t. Successful economical underground use of plastic pipe does not necessarily indicate similar economies outdoors aboveground. 

The second largest market is that of profiles, particularly for the building industry. UPVC has become well established for guttering, waste piping and conduits, where economies arise not just in basic product costs but also in transportation and installation costs. Unlike with cast iron products, corrosion and maintenance is less of a problem, although UPVC products are more liable... 

Refrigeration system pipes are sized to offer a lowresistance to flow, since this reflects directly on compression ratio, commensurate with economy of pipe cost and minimum flow velocities to ensure oil return with the halocarbons. 

Pipe racks normally divide a facility into major areas. For economy and process efficiencies the piping arrangement is typically a central corridor in any facility. On either side of this pipe corridor or rack the process units are provided buy its nature divides the facility into units or process areas. 

Electrical and pipe penetrations may be brought into the building underground. Based on economy and design, this type of entry may be preferred. 

Metallic pipe systems comprise the majority of applications. Metallic pipe, tubing, and pipe fittings are divided into two main categories seamless and welded. Both have advantages and disadvantages in terms of economy and function. Specifications governing the production of these products dictate the permissible mechanical and dimensional variations, and code design calculations account for these variations. 

During the past several years such stills have been largely replaced by tube or pipe stills because of their lower initial cost, greater throughput, and economy of operation. A common type of operation utilizes a two-stage atmospheric and vacuum distillation unit (13). This type of operation has an important advantage—the asphaltic residue remains at the extreme temperature for only a fraction of a minute in the pipe stills as contrasted to several hours in shell-type stills. 

CANDLE.—Read, in connection with the processes described at pages 430,431 —The operations of saponification of the fat, and decomposition of the lime-soap by sulphuric acid, have been hitherto effected in open vessels, under the ordinary pressure of the atmosphere. An improvement on this plan has been recently proposed by M, Delapchiek, of Besangoo, who substitutes dose vessels in Order to saponify the fat. Wash and decompose the lime-soap under a pressure of about twenty-two pounds to the square inch, by which the operations are considerably facilitated, and their duration shortened. The products by this process are said to be superior to those obtained in open vessels, and a considerable economy of flaid is effected. The apparatus consists essentially of a horizontal boiler, with a man-hole and two safety valves at the top, The heat is furnished by a large steam-pipe, running in a depression along the bottom of the boiler. The... 

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