Piping pressure class

In order to cover all the lines in the facility, pipe and valve tables are normally included. Each pipe pressure class is assigned a designation. Sometimes it is necessary to assign two classes for a single designation. For ample, in Table 15-1 A, L, and AA are all ANSI 150 cl , but they contain different fluids. 

American Standards Association piping pressure classes are ... 

Figure 2-4A. Forged steel threaded pipe fittings, WOG (water, oil or gas service). Note the working pressures are always well above actual plant operating levels. Pressure classes 3000 psi and 6000 psi, sizes % in. through 4 in. nominal. By permission, Ladish Co., Inc.

Find the tensile load capacity of 5-in., nominal weight 19.5-lb/ft, steel grade E, premium class drill pipe exposed to internal drill pipe pressure = 3,000 psi and rotary torque T = 15,000 ft-lb. 

Some of the standards for components in Table IP-8.1 (e.g., ASME B16.9 and ASME B16.ll) state that pressure-temperature ratings are based on straight seamless pipe. Except as limited in the standard or elsewhere in this Code, such a component, made of a material having the same allowable stress as the pipe, shall be rated using not more than 87.5% of the nominal thickness of seamless pipe corresponding to the schedule, weight, or pressure class of the fitting, less all allowances applied to the pipe (e.g., thread depth and/or corrosion allowance). 

Welding neck flanges are permitted in sizes and pressure classes established in ASME B16.5, MSS SP-44, and ASME B16.47 for large flanges. The bore of the flange should correspond to the inside diameter of the pipe used. For allowable weld end detail, see para. GR-3.4.5. 

Plastic pipes are available in different lengths, diameters and pressure classes with a full complement of standard fittings, valves and couplings. They are compatible with other pipe materials and they can be specified for either new construction or for system upgrades. Plastic pipes can be repaired easily if for any reason they are damaged. On the other hand, traditional metallic and other pipe and tube installations can be sealed and/or repaired, (i.e., by spray coating of epoxy [2]) by use of polymeric materials. 

Valve bodies are also standardized to mate with common piping connections flanged, butt-weld end, socket-weld end, and screwed end. Dimensional information for some of these joints and class pressure-temperature ratings are included in Sec. 10, Process Plant Piping. Control valves have their own standardized face-to-face dimensions that are governed by ISA Standards S75.03, 04, 12, 14, 15, 16, 20, and 22. Butterfly valves are also governed by API 609 and Manufacturers Standardization Society (MSS) SP-67 and 68. 

Differential pressure is included in the pressure instrument class. Good differential readout gauges are still not all that common. Fortunately, in the transducer category, they are more readily available. Figure 8-26 covers some installation details for pressure-oriented instrument piping, supplementing the information presented earlier in Figure 8-8. 

The MAWP of the vessel cannot exceed the MAWP of the no valves, and pipe connected to the vessel. As discussed in Volui Chapter 9, pipe flanges, fittings and valves are manufactured in dan dustry standard pressure rating classes. Table 12-2 is a... 

Maximum allowable working pressure MAWP) Highest pressure to which the system can be subjected during operation. Thus, pressure is established by a relief device set pressure and must be less than or equal to the material strength limitations of equipment. This pressure e.stabli.sh-es piping class for fittings and pipe wall thickness requirements, both of which are discussed in Volume 1. 

Scope, 52 Basis, 52 Compressible Flow Vapors and Gases, 54 Factors of Safety for Design Basis, 56 Pipe, Fittings, and Valves, 56 Pipe, 56 Usual Industry Pipe Sizes and Classes Practice, 59 Total Line Pressure Drop, 64 Background Information, 64 Reynolds Number, R,. (Sometimes used Nr ), 67 Friction Factor, f, 68 Pipe—Relative Roughness, 68 Pressure Drop in Fittings, Valves, Connections Incompressible Fluid, 71 Common Denominator for Use of K Factors in a System of Varying Sizes of Internal Dimensions, 72 Validity of K Values,... 

The torsion, tension, collapse and internal pressure resistance for new, premium class 2 and class 3 drill pipe are specified in Tables 4-80, 4-81, 4-82 and 4-83, respectively. 

Class 2 (Used) Drill Pipe—Torsional, Tensile, Collapse and Internal Pressure Data [30]... 

From Table 4-84, the collapse pressure resistance in uniaxial state of stress, P - 6,010 psi. Reduced wall thickness for class 2 drill pipe = (0.65)(0.337) = 0.219 in. Reduced D for class 2 drill pipe = 3.826 + (2)(0.219) = 4.264 in. Reduced cross-sectional area of class 2 drill pipe equals ... 

Three classes of problems involving orifices (or other obstruction meters) that the engineer might encounter are similar to the types of problems encountered in pipe flows. These are the unknown pressure drop, unknown flow rate, and unknown orifice diameter problems. Each... 

Class 1, Division 2. This Division is a Location Class 1 where the design factor of the pipe is equal to or less than 0.72 and has been tested to 1.1 times the maximum operating pressure. [See Table PL-3.7.1(b)(6)-2 for exceptions to design factor.]... 

Safety Considerations Design and location of storage tanks, vents, piping, and connections are specified by state fire marshals, underwriters codes, and local ordinances. In NFPA 30, Flammable and Combustible Liquids Code, 2003 (published by the National Fire Protection Association, Quincy, Ma.), liquid petroleum fuels are placed in Class I through Class III B based on their flash point, boiling point, and vapor pressure. 

Piping components shall have a pressnre-temperature rating at least equal to the maximum discharge pressure and temperature of the pump casing, bnt in no case less than ISO 7005 PN50 (300 pound ANSI Class) flange at ambient temperature (2.2.2)... 

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