Hot Tapping in Compressed Air Line
Hot Tapping in Compressed Air Line
(OP)
Hello,
Hot Tapping in Compressed Air Line (Carbon Steel line Size 8" –penetration 4")in a HI-TECH plant
1)Is it Common and/or Recommended?
2)Is there any possibility of Damage to Final Filter (0.01 um) due to shaving particles( metal chips)
3)Hot Tapping to be placed close to Air Receiver Inlet in Bottom of Vessel ( Outlet 3 mt above inlet nozzle)
4)If Recommended what is the best way to do ( good Practice Engineering ?)
regards and thanks,
roker
Hot Tapping in Compressed Air Line (Carbon Steel line Size 8" –penetration 4")in a HI-TECH plant
1)Is it Common and/or Recommended?
2)Is there any possibility of Damage to Final Filter (0.01 um) due to shaving particles( metal chips)
3)Hot Tapping to be placed close to Air Receiver Inlet in Bottom of Vessel ( Outlet 3 mt above inlet nozzle)
4)If Recommended what is the best way to do ( good Practice Engineering ?)
regards and thanks,
roker





RE: Hot Tapping in Compressed Air Line
http://www.tdwilliamson.com
and here's the brochure on hot taps,
http://www.tdwilliamson.com/PDF/Catpdf/TDWSbro.pdf
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Hot Tapping in Compressed Air Line
RE: Hot Tapping in Compressed Air Line
RE: Hot Tapping in Compressed Air Line
Also, keep in mind the size, accessibility, and positioning of the tapping machine. If you cannot rig tapping machine for true perpendicular fit-up than you are wasting your time. Remember, the tapping machine will be offset from the 8 inch header by the distance of the 4 inch flanged nozzle and the length of the tapping valve.
RE: Hot Tapping in Compressed Air Line
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Hot Tapping in Compressed Air Line
In terms of reducing pressure, most companies don't require it. In those companies, they have you compute the hoop strength of the line at the hot tap and if it is above a certain percentage of SMYS they don't allow the hot tap.
David
RE: Hot Tapping in Compressed Air Line
On the other hand, if the pipe is long, and cannot be sealed, then a good welding engineer can work some magic to determine whether or not a flow is required and if so, how much. I've done hot taps on 42" flare lines for which establishing adequate flow would have been quite difficult... And if there was a significant flow in the line the hot tappers would probably have evacuated since that flow would have been caused by a major unit upset... I was fortunate to have the support of a good, experienced, practical welding engineer. Easier to conduct the heat away with liquid than with vapors.
jt
RE: Hot Tapping in Compressed Air Line
"Hot Tapping to be placed close to Air Receiver Inlet in Bottom of Vessel..."
RE: Hot Tapping in Compressed Air Line
Ross, the way I read it is the filter is located at the entry to the air receiver vessel, both of which are downstream of the pipe to be tapped.
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Hot Tapping in Compressed Air Line
For what its worth, I've seen several vessles hot tapped and have engineered such taps a few times myself. Not much different from hot tapping a pipe except for the obvious involvement and approval in advance by the AI.
But my interpretation of the OP was that the proposed hot tap was a 4" branch onto a 8" pipe near to, but not a part of, the bottom of the air receiver vessel.
jt
RE: Hot Tapping in Compressed Air Line
I had a vendor perform a mock-up of a hot-tap years ago in our maintenance shop because we were concerned about foreign material entering our system. We wanted to add a 3/4" sockolet connection to a 8" Sch.40 water-filled process pipe. Our results showed a small amount of metallic debris did enter the system - enough that we opted not to perform the hot tap for fear of risking damage to downstream pumps. The debris consisted of fine chips of metal, most of which were no more than 1-2 mm across. We are pretty sensitive about foreign material, so maybe this isn't as big a deal for you.
Regarding foreign material, it's my recollection that smaller drill bits will generate a smaller total volume of debris, but the individual pieces will be larger than you'd get from a larger drill bit (because the larger bit tends to grind up the shavings).
RE: Hot Tapping in Compressed Air Line