Chapter 15 book one piping materials and connections Flashcards
Steel Piping
Most frequently use material for piping can be cast welded or seamless. Castile is not commonly used for piping, but is extensively used for pipe fittings and valves welded steel pipe is used for low pressure were seamless. Steel pipe is used for higher pressures and temperatures steel has a low resistance to corrosion block. Steel pipe cannot be used for portable, drinking water, but galvanized, steel pipe Ken.
Wrought iron
Wrought iron, is weaker than steel, higher priced and not readily available used in systems where severe corrosion could occur
Ductile cast-iron piping
Normally used for underground pressurized water systems. It is cast iron with a variety of different elements in it that make it ductile and not as brittle as regular cast-iron so it is OK for pressure use where regular cast-iron is not.
Copper and copper alloy’s
Use most often in plumbing systems for hot and cold water supply lines, drainage, and vent piping offer create resistance to corrosion, but it is much more expensive than carbon steel and their use is restricted to low and moderate temperature services since they lose strength at high temperature
Plastic
Lightweight fairly low cost easel assembly and corrosion resistant, but they are restricted to low and moderate pressure and temperature applications
Nominal pipe size
Imperial system uses nominal pipe size which is in inches metric system uses diameter nominal, which is in millimeters remember the pipe up to and including 12 inches is measured using inside diameter as its nominal pipe size and pipe 14 inches and larger uses outside diameter which is equal to nominal pipe size so 5 inch pipe measures 5 inch ID and 15 inch pipe measures 15 inches OD there is no 13 inch pipe
Wall thicknesses of Pipe
The old method used letters for different thicknesses of pipe where S equals standard XS equals extra strong or XXS equals double extra strong now a newer method which she is a scheduale’s is used and has schedules from 10 to 160 with 40 being equal to standard thickness 80 been extra strong and 160 being double extra strong
Three methods to join or connect length of piping
Threaded and screwed connections, flanged, welded joint
Screwed connections
Generally used for pipe sizes 2 inch and smaller for low and moderate pressures. Piping can be easily assembled or disassembled, but threaded connections are subject to leakage, and the strength of the pipe is reduced. When threads are cut in the pipe wall the threads are American standard pipe thread, unless otherwise specified Fittings are designed according to pressure for which they are suited often a separate rating for steam and a rating for cold water oil or gas threaded cast iron fittings cannot be used for gas service piping systems when looking on a fitting if you see S150 psi it probably means steam 150 psi and may be followed by WOG 290 psi which would mean the fitting would be good for 290 pounds with water oil or gas but only 150 pounds with steam
Three types of flange connections
Screwed/threaded flange, welded flange, lapped or loose flange
Flange connections
Suitable for moderate pressure and frequently used on low pressure lines, larger than 6 inches easier to disassemble than welded connections, and usually more convenient to assemble and disassemble than screwed connections. They are also stronger and better suited for high pressure than screwed connections that are subject to leakage, if not properly aligned, or if suitable gaskets are not properly installed.
Screwed/threaded flange
Used because no welding equipment is needed, but leaks may develop along the threaded portion, and the wall thickness is reduced by the threads which weakens the pipe
Welded connections
Well-suited for severe service involving high-pressure extreme temperature or hazardous service. They may be though welded neck flange, the socket, welded flange or the slip on welded flange welded neck flange is the typical flange that welds direct to the pipe. The socket weld has a lip inside the flange, the pipe butts up against, the slip on flange has no lip for the pipe to, but up against and permits Welding on the inside of the flange without damaging the face
Lapped or loose flange
This needs a stub that gets welded to the pipe on either side of the connection, then the stubs, but up to each other with a gasket between them flanges slide on behind the stub and are loose so they can spin and lineup easily which simplifies assembly an alignment for systems, requiring frequent dismantling
Three common flange face arrangements
Raise face, which is most common, and found to be the most suitable for high pressure and easiest to dismantle. Male and female, which is self-explanatory, and the tongue and groove also pretty self-explanatory.
