Pipe elbow calculation

Malyl · **Joined:** Tue Oct 03, 2006 7:01 am **Posts:** 58

Dear all,
I cannot find any formula in ASME VIII div.1 to calculate pipe elbow thickness especially in the bend area where we have thinning. Do you have any good solution?

Thanks in advance.
malyl

amol · **Joined:** Mon Sep 01, 2008 2:40 pm **Posts:** 64

EXPERTS COULD THROW LIGHT WHETHER WE COULD USE FORMULA GIVEN IN
TEMA FOR U BEND
FORMULA IS

REQUIRED THICKNESS PRIOR TO BENDING = t1(1+(do/4R))

WHERE,
t1 = MINIMUM THK. CALCULATED AS PER CODE FOR STRAIGHT PIPE FOR SAME PRESSURE & METAL TEMPERATURE

do = OD OF PIPE

R = MEAN RADIUS OF BEND

shmulik · **Joined:** Wed Jun 02, 2010 9:28 pm **Posts:** 31

Malyl / amol,

TEMA rules are not applicable for ASME requirements.
Assuming your elbow is of ASME B16.9, you shall consider it as a straight seamless pipe (wall thickness check acc. to UG-27 ; Joint efficiency acc. to UW-11(a)(5)(b) + UW-12(d) ; available wall thickness is pipe nominal thickness minus manuf. tolerance, namely: nominal thick. X 0.875).

Quote:

UG-44 FLANGES AND PIPE FITTINGS
The following standards covering flanges and pipe fittings are acceptable for use under this Division in accordance with the requirements of UG-11. Pressure–temperature ratings shall be in accordance with the appropriate standard except that the pressure–temperature ratings for ASME B16.9 and ASME B16.11 fittings shall be calculated as for straight seamless pipe in accordance with the rules of this Division including the maximum allowable stress for the material. The thickness tolerance of the ASME standards shall apply.

UG-44(b): ASME B16.9, Factory-Made Wrought Buttwelding Fittings.

akonrad · **Posted:** Wed Nov 10, 2010 8:40 pm

Malyl, get yourself a copy of B31.3.

Javed Nasir · **Posted:** Thu Nov 11, 2010 3:50 am

mayle,

Para. 102.4.5 of ASME B31.1 also discusses the thining alloawance both at intradose and extradose.
You may use it.

Pipe elbow calculation

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