Notes to the Table of Allowable Working Pressures
1. This data is intended to provide a general guide. It must not be relied upon in the absence ofcompetent professional advice.
2. These allowable internal pipe pressures were calculated by the formula given in ASME B31.3-2010 "Process Piping", clause 304.1.2. Other design codes may give different allowablepressures. The original specifications must be consulted for full details.
3. Pipe with Wall Thickness greater than one-sixth of Outside Diameter is not included in thistable; ASME B31.3 states that factors other than those included in the standard formula mustbe considered for such pipe. For pressure design of this heavy wall pipe consult the standard.
4. Calculations are for Grade B seamless pipe to specifications ASTM A53M, ASTM A106M orAPI 5L. A weld join efficiency factor (typically 85%) must be allowed for standard ERW pipe,and allowance made for corrosion or wear loss if appropriate.
5. Conversion of carbides to graphite may occur after prolonged exposure of carbon steel pipe totemperatures above 427°C.
6. Allowable working pressures are given in megapascals (MPa). Conversions to other units are:
