Looking for some input on typical corrosion allowances for D100 welded steel water tanks. Working on a spec and I want to be reasonable compared to an industry standard. The D100 standard doesn't provide any specifics that I can find. Any experience on this forum?
Eng-Tips is the largest forum for Engineering Professionals on the Internet.
Members share and learn making Eng-Tips Forums the best source of engineering information on the Internet!
-
Congratulations JStephen on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
AWWA D100 Tank Corrosion Allowance
- Thread starter Rabbit12
- Start date
I don't have D100 in front of me...but going from my memory, that seems right that there isn't any specific guidance. Maybe there is something in the commentary? I can look tomorrow when I get in the office.
I've analyzed what seems like 100's of tanks for wireless carriers and 95% of the time the tanks are at a DCR of 99% in the original condition (before any telecom loads put on top)...especially the tanks from the 50s/60s. I usually think I messed the calcs up if I don't calculate this DCR.
My guess is they get around accounting for any corrosion issues by specifying regular maintenance. They also have a pretty low allowable stresses. For example, A36 has an allowable stress of only 18ksi. They do still allow the 1/3rd increase on flexure...even in the newest standard that came out in 21.
I've analyzed what seems like 100's of tanks for wireless carriers and 95% of the time the tanks are at a DCR of 99% in the original condition (before any telecom loads put on top)...especially the tanks from the 50s/60s. I usually think I messed the calcs up if I don't calculate this DCR.
My guess is they get around accounting for any corrosion issues by specifying regular maintenance. They also have a pretty low allowable stresses. For example, A36 has an allowable stress of only 18ksi. They do still allow the 1/3rd increase on flexure...even in the newest standard that came out in 21.
HTURKAK
Structural
- Jul 22, 2017
- 3,405
Corrosion allowance is not a mandatory requirement for AWWA D100 standard. However copy and paste of the relevant clause at Appendix A
Corrosion Allowance and Protection
A.3.9.1 General. Careful consideration shall be given to the proper allowance for corrosion. This allowance will depend on the corrosive nature of the stored
water, the proximity of the tank to salt water or other causes of atmospheric corrosion, and the care with which the paint or other protection will be maintained.
Apparently this allowance shall be considered depending on the corrosive nature of the stored water, environment ..
Pls consider other requirements such as painting, CP, galvanic corrosion and isolation of dissimilar metal contact.
Corrosion Allowance and Protection
A.3.9.1 General. Careful consideration shall be given to the proper allowance for corrosion. This allowance will depend on the corrosive nature of the stored
water, the proximity of the tank to salt water or other causes of atmospheric corrosion, and the care with which the paint or other protection will be maintained.
Apparently this allowance shall be considered depending on the corrosive nature of the stored water, environment ..
Pls consider other requirements such as painting, CP, galvanic corrosion and isolation of dissimilar metal contact.
- Status
Similar threads
- Locked
- Question