API 650 tank shell growth/rotation

[mech471]

API Standard 650 9th Edition (Addendum 3 December 1996)
We intend to install the upper middle and lower sampling points on Jet A-1 product storage tanks connected to common header at ground level and further to Oily Water sewer.
This requires 03 Nos ¾” nozzles in tanks shell at different elevations (heights). Refer to section 3.7.1.5 openings near the bottom of tank shell will tend to rotate ……… To locate the bottom sampling nozzle out side the rotation area i.e I want to keep value of W (refer to Appendix P, P.3 Nomenclature & P.5.1), unrestrained radial growth of shell in inches =0 so that I can calculate the value of L, vertical distance form the opening centreline to tank bottom, in inches, I referred to Appendix-P and have following queries:

Refer to Appendix P-Allowable loads on tank shell openings P.3 Nomenclature:

1. ∆T= Normal operating temperature minus installation temperature, in degree Fahrenheit
Would you further elaborate the Normal operating temperature and installation temperature?

2. How values of Modulus of Elasticity and Thermal Expansion Coefficient given in Table P-1 cover all the materials as these properties vary from material to material.
3. Any suggestions about small bore pipe (3/4” dia) supports attached to tank shell nozzles

 

[Tankman650]

W=0 exists for an empty tank or at the roof. Don't think that you will want to put sampling at the roof.

DT is usually 70-design temp. 70 degress being the install temp.

Values for carbon steel of Modulus of Elasticity and Thermal Expansion Coeff. do not vary (or vary insignificatly) between grades of steel.

 

[mech471]

Tankman650 thanks for suggestion but I am still not clear with it as in standadard API 650 ∆T is given by
∆T= Normal operating temperature minus installation temperature, in degree Fahrenheit
while you have given it by
DT=70-design temp. 70 degress being the install temp.
You see the difference between the two relations.
Further here is the brief data
Storage tmeperature of JetA-1 =40C
Design metal temperature max/min=85/5 C
If we take Normal operating temperature is 40C(104F) what will be the installation temperature. design temperature? then the answer ∆T will be in negative
Please do suggest.
regards

 

[Tankman650]

opps. my mistake.

should be :
DT= normal operating temp - 70 degrees The answer is positive number for positive radial growth.