ASME B31.5:2016 pdf free download

ASME B31.5:2016 pdf free download.Refrigeration Piping and Heat Transfer Components.
501.1 General
Section 501 defines the temperatures, pressures, and various forces applicable to the design of piping systems. It also states considerations that shall be given to ambient and mechanical influences and various loadings.
501.2 Pressure
501.2.2 Internal Design Pressure. The piping component shall be designed for an internal pressure representing the most severe condition of coincident pressure and temperature expected in normal operation or standby (including fluid head). The most severe condition of coincident pressure and temperature shall be that condition that results in the greater required piping component thickness and the highest component rating.
Any piping connected to components other than piping shall have a design pressure no less than the lowest design pressure of any component to which it is connected.
50 1.2.3 External Design Pressure. The piping component shall be designed br an external pressure representing the most severe condition of coincident pressure and temperature expected during shutdown or in normal operation (including fluid head) considering possible loss of internal pressure. Refrigerant piping systems shall be designed to resist collapse when the internal pressure is zero absolute and the external pressure is atmospheric. This is to permit drying the pipe by evacuation. The most severe condition of coincident pressure and temperature shall be that condition that results in the greatest required pipe thickness and the highest component rating.
501.2.4 Minimum Design Pressure. Minimum design gage pressure shall be not less than 15 psi (105 kPa) and, except as noted in para. 501.2.5, shall be not less than the saturation pressure of the refrigerant at the following temperatures:
(a) low sides of all systems: 80°F (27°C)
(b) high side of water or evaporatively cooled systems: 104°F (40°C)
(c) high sides of air cooled systems: 122°F (50°C)
Considerations shall be given to low side systems with hot gas defrost. Such systems impose high side pressure on the low side during the defrost cycle. This may raise the low side design pressure requirements.
501.2.5 Minimum Design Pressure for Specific
Service
(a) Design pressure for either high or low side need not exceed the critical pressure of the refrigerant unless the system is intended to operate at these conditions.
(b) When components of a system are protected by a pressure relief device, the design pressure of the piping need not exceed the setting of the pressure relief device.
(c) In a compound system the piping between stages shall be considered the low side of the next higher stage compressor.
501.3 Temperature
In this Code, metal temperature of piping in service is considered to be the temperature of the fluid conveyed.
501.3.1 BrIttle Fracture. Consideration must be given to a reduction in impact strength occurring in some materials when subjected to low temperatures. Notch effects should be avoided (see para. 523.2).
501.4 Ambient Influences
501.4.1 Ambient Temperature. In the design of refrigeration piping systems, consideration must be given to the influence of ambient temperature.