Piping and fittings

The factors fp and fj have not been applied to installation costs because installation costs are not a simple function of purchase cost. Although process piping and fittings made for the same unusual conditions are proportionally more expensive, labor, foundations, insulation, etc. are not. Furthermore, only about 70 percent of piping is directly exposed to process fluid. The balance is auxiliary or utility piping made of conventional materials. 

Pipe and fittings remain a significant market for ABS, particularly in North America. ABS foam core technology allows ABS resin to compete effectively with PVC in the primary drain-waste and vent (DWV) pipe market. 

Ammonia is corrosive to akoys of copper and zinc and these materials must not be used in ammonia service. Iron or steel should usuaky be the only metal in ammonia storage tanks, piping, and fittings. It is recommended that ammonia should contain at least 0.2% water to prevent steel stress corrosion. Mercury thermometers should be avoided. 

Because carbon is difficult to machine, very tittle impervious carbon equipment is made. However, impervious graphite has been accepted as a standard material of constmction by the chemical process industry for the fabrication of process equipment, such as heat exchangers, pumps, valves, towers, pipe, and fittings (9,10). 

Impervious graphite centrifugal pumps, pipe fittings, and valves were developed because most chemical processes require the movement of Hquids. Graphite pipe and fittings in sizes ranging from 25 to 635 mm ID are used to convey corrosive fluids. 

Impact polystyrenes have found use in the manufacture of refrigerator door liners and in packaging. They are also commonly used for appHance housings, radio and television cabinets, sporting goods, toys, cameras, furniture, luggage, pipe and fittings, automotive parts, and women s shoe heels (96). 

Friction Head This is the pressure required to overcome the resistance to flow in pipe and fittings. It is dealt with in detail in Sec. 5. 

These alloys are available in the cast form only. Pipe and fittings are cast with the upset ends being joined by split flanges. IntegraUy cast flanged pipe is also available. Allowable working pressures cannot be... 

CViemical Ware Acidproof chemical-stoneware pipe and fittings withstand most acid, alkah, or other corrosives, the main exception being hydrofluoric acid. The range of sizes made with the bell-and-spigot joint and with plain butt ends is shown in Table 10-40. 

Polypropylene Polypropylene (PP) pipe and fittings have excellent resistance to most common organic and mineral acids and their salts, strong and weak alkahes, and many organic chemicals. They are available in sizes V2 through 6 in, in Schedules 40 and 80, but are not covered as such by ASTM specifications. 

FIG. 10-163 Operating pressure-temperature ratings for Haveg 41NA and 61NA pipe and fittings. (°F — 32)% = °C to convert poiinds-force per square inch to Idlopascals, multiply by 6.895 to convert inches to millimeters, multiply by 25.4. 

Nominal thicknesses and outside diameters of pipe and fittings shall be used in flexibihty calculations. 

The treatment of vent flow calculations in most typical relief wstem configurations involves two classes of computation models flow in low-fric tion geometries such as nozzles and frictional flow in pipes and fittings. 

In some service stations, stainless steel or aluminum materials are used for all the filters, pipes and fittings to maintain the purity of the fuel. The rest potentials of these materials are different from that of plain carbon steel (see Table 2-4). 

The largest single use area for UPVC is for pipes and fittings. One particular area here is in chemical plant. It is of course necessary to check that all of the components of the PVC compound will be resistant to any of the chemicals with which the plant is liable to come into contact (at the appropriate temperatures) and also that additives will not be leached out by these chemicals. Particular uses are in acid recovery plant and in plant for handling hydrocarbons. 

Over the years there has been some difference in the balance of use between UPVC and ABS in the United States compared with Western Europe. This was due largely to the earlier development in Western Europe of UPVC and in the United States of ABS. Thus, for example, whilst ABS consolidated its use for pipes and fittings in the United States, UPVC was finding similar uses in Europe. Whilst some of these traditional differences remain, ABS is now well established in both Europe and the United States. 

F = Ratio of cost of fittings plus installation cost of pipe and fittings to cost of pipe only... 

USCG Tank, including all piping and fittings Propane or specific gas 3 Atmospheric Yes... 

Figure 2-5A. Lined-steel pipe and fittings for corrosive service. By permission. Performance Plastics Products.

For a system of multiple components of valves, pipe, and fittings. Equation 2-25 can be used to establish a component size to which each separate resistance can be expressed as a common denominator, or common pipe size. Under these conditions, the corrected Rvalues are additive and can be used as one number in Equation 2-27. These types of corrections should be made to improve and more accurately represent the pressure drop calculations. 

An example procedure connecting 3-in. and 6-in. pipe and fittings, using (>in. as the final reference, is as follows ... 

Copper may be used above ground and for buried pipework at pressures up to 75 mbar and outside diameters of 67 mm. If utilized for buried pipework it must be factory sheathed and should not be attached to buried steel pipe and fittings. 

This may be used for buried pipework, in ducts and above ground at pressures up to 2 bar. Not to be used for plant pipework. Ductile iron pipe and fittings shall be to BS 4772, Specifications for ductile iron pipes and fittings. 

Brazed Silver-brazed connectors are commonly used for joining non-ferrous piping in the pressure and temperature range where their use is practical. Use of this type of connector is limited to installations in which the piping temperature will not exceed 425°F and the pressure in cold lines will not exceed 3000 psi. Heating the joint with an oxyacetylene torch melts the alloy. This causes the alloy insert to melt and fill the few thousandths of an inch annular space between the pipe and fitting. 

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