The selection of material to resist deterioration in service is outside the scope of the B31.3 code. Experience has, however, resulted in the following material considerations extracted from the code with the permission of the publisher, the American Society of Mechanical Engineers, New York.
General Considerations to be evaluated when selecting combining materials are:
- Possible exposure to fire with respect to the loss of strength, degradation temperature, melting point, or combustibility of the pipe or support material;
- Ability of thermal insulation to protect the pipe from fire;
- Susceptibility of the pipe to brittle failure, possibly resulting in fragmentation hazards, or failure from thermal shock when exposed to fire or fire-fighting measures;
- Susceptibility of the piping material to crevice corrosion in stagnant confined areas (screwed joints) or adverse electrolytic effects if the metal is subject to contact with a dissimilar metal;
- The suitability of packing, seals, gaskets, and lubricants or sealants used on threads as well as compatibility with the fluid handled; and
- The refrigerating effect of a sudden loss of pressure on volatile fluids in determining the lowest expected service temperature.