09-29-2021, 06:51 AM
This chapter presents various types of pipe fittings. Of all the fittings, the elbow is the one most often used. Simply put, the elbow, or ell, is used when a pipe changes direction. Elbows can turn up, down, left, right, or any angle in between. When one finds it necessary to draw a 90° elbow or calculate how much space it will occupy in a routing configuration, knowing its length becomes essential. An elbow's length is commonly referred to as the center-to-end dimension and is measured from the centerpoint of its radius to the end of either opening. Dimensional sizes of fittings are typically provided by the manufacturer of the fitting. Manufacturers issue dimensioning charts containing lengths for a particular fitting. Another elbow that may be used under certain circumstances and with permission from the customer is the 90° short-radius elbow. The 90° short-radius ell makes a much sharper turn than does the long-radius ell.
Emissions from Pipe Fittings and Gaskets
Threaded pipe fittings in the seal flush line can be significant leak sources, with readings above 1,000 ppm.4,17 Similar emission levels may be measured near the gasket region on the seal chamber face. Any leakage from these areas may drift into the emission measurement area for the mechanical seal. The mechanical seal may then be erroneously implicated as a leaker. It should be standard practice to sniff nearby hydraulic fittings and the flange gasket area if excessive VOC concentrations are detected adjacent to the mechanical seal.
8.19.4 Steel pipes
Welded joints shall not be used where a protective lining would be damaged by heat, or where the pipework is employed as a primary circulation to an indirect hot water heating system.
Screwed joints in steel piping shall be made with screwed socket joints using wrought iron, steel, or malleable double crimping fitting. A thread filler shall be used. Exposed threads left after jointing shall be painted or, where installed underground, thickly coated with bituminous or other suitable corrosion preventative agent.
Flange joints shall be made with screwed or welded flanges of steel or cast iron using jointing rings and, if necessary, a suitable jointing paste. The nuts shall be carefully tightened, in opposite pairs, until the jointing ring is sufficiently compressed between the flanges for a watertight joint.
To ensure satisfactory jointing of the materials from which the pipe and transition elbow are made compatibility shall be established. The manufacturer’s instructions shall be carefully followed.
No attempt shall be made to joint polyethylene piping by solvent cement welding.
Emissions from Pipe Fittings and Gaskets
Threaded pipe fittings in the seal flush line can be significant leak sources, with readings above 1,000 ppm.4,17 Similar emission levels may be measured near the gasket region on the seal chamber face. Any leakage from these areas may drift into the emission measurement area for the mechanical seal. The mechanical seal may then be erroneously implicated as a leaker. It should be standard practice to sniff nearby hydraulic fittings and the flange gasket area if excessive VOC concentrations are detected adjacent to the mechanical seal.
8.19.4 Steel pipes
Welded joints shall not be used where a protective lining would be damaged by heat, or where the pipework is employed as a primary circulation to an indirect hot water heating system.
Screwed joints in steel piping shall be made with screwed socket joints using wrought iron, steel, or malleable double crimping fitting. A thread filler shall be used. Exposed threads left after jointing shall be painted or, where installed underground, thickly coated with bituminous or other suitable corrosion preventative agent.
Flange joints shall be made with screwed or welded flanges of steel or cast iron using jointing rings and, if necessary, a suitable jointing paste. The nuts shall be carefully tightened, in opposite pairs, until the jointing ring is sufficiently compressed between the flanges for a watertight joint.
To ensure satisfactory jointing of the materials from which the pipe and transition elbow are made compatibility shall be established. The manufacturer’s instructions shall be carefully followed.
No attempt shall be made to joint polyethylene piping by solvent cement welding.