2 replies to this topic

[jayesh nair]

hai..

it will be really appreciable if you could let me have a manual calculation of piping stress analysis ?

Edited by jayesh nair, 03 June 2010 - 01:25 PM.

[fallah]

hai..

it will be really appreciable if you could let me have a manual calculation of piping stress analysis ?

Hand calculation of piping stress is a time consuming effort and has been introduced in all piping handbook.

Try to do by Cesar II software.

[kkala]

it will be really appreciable if you could let me have a manual calculation of piping stress analysis ?

A simplified view can be found in Perry's "Chemical Engineers' handbook", Section "Transport and storage of fluids", subsection "Process Plant Piping" -"Piping system design" (p.10-102 to 10-126 in 7th edition). Nowadays stress analysis is done by software (Cesar II already mentioned). However its first step seems similar to Pressure vessel thickness calculation.
E.g. a fluid of 400 oC design temperature and 40 kgf/cm2 g design pressure (=39.2 Barg) has to be transported by 8" seamless pipe of A106 Grade B carbon steel (corrosion allowance=CA=1.5 mm).
Allowable tension stress at design temperature=13000 psi (p. 10-114 of Perry). Required pipe thickness, excluding CA, (40*14.223)*8.625/2/(13000+0.7*40*14.223)= 0.183 in (p. 10-103), so thickness with CA t=0.183+1.5/25.4=0.242 in.
8" Sch 80 pipe is selected, 0.5 in thick (p. 10-73). Thickness excluding CA is 0.441 in and stress calculations are based on this.
So max stress due to pressure (p. 10-103)is (40*14.223)*8.625/2/0.441-0.7*40*14.223 = 5165 psi.
To this value several additional stresses have to be considered, e.g. due to thermal expansion or contraction of pipe, weight of (full) pipe and resulting bending moments between two supports, fitting reactions (e.g. tees), earthquake loads, forces created from acceptable displacement (or settlement) of supports, etc.
I have not met Chemical Engineers responsible for this survey, it is specialized Mechanical (or Piping) Engineers that do it. A software reprint could be useful in having a general idea.

Edited by kkala, 07 June 2010 - 01:29 AM.