Hot Tap Floating Roof Tank
Hot Tap Floating Roof Tank
(OP)
Is there any requirements or precautions change on hot-tapping a floating roof tank versus fixed roof tank? I did not see any special notes in API-653 Par. 9.14 for Hot Tap. Please share your experiences. Thank you.





RE: Hot Tap Floating Roof Tank
RE: Hot Tap Floating Roof Tank
RE: Hot Tap Floating Roof Tank
RE: Hot Tap Floating Roof Tank
For my case the hot-tap location will be at the bottom shell course not on the roof. Hot-tapping on the deck of floating roof is a No-No. This is clearly stated in API-RP 2201. In this case will the weight of floating roof raise any concern?
RE: Hot Tap Floating Roof Tank
RE: Hot Tap Floating Roof Tank
Depending on the Specific Gravity of the tank's contents, there will be about 1/3rd to 1/2 psi of pressure per foot of liquid above the weld. A standard floater is made of 3/16" plate, at about 0.85 ounces per square inch. So with 4-ft of liquid and a floater, the pressure at the weld will be less than 5 psi. On piping, I don't start sweating until the internal pressure exceeds 150 psi. Tanks are just really big, really thin pipe.
UT for metal thickness and soundness [no laminations], triple-verify 3-ft of liquid above the top of the weld, and turn the welder loose. And I'm willing to stand beside that welder.