We manufacture a plastic covering used by utility companies to cover risers on poles. This item is not affected by the NEC since it is made for utility use, so the covering is not Ul listed. A non-utility customer found us on the internet and is looking to use our covering over electrical heat tape on water pipes. This is the type of tape that is plugged in an there is a heating element that keeps water pipes from being frozen. The customer wants to use the plastic covering to insulate and protect his pipes. My first thought is to say no to this application because of potential fire risk due to the fact that this covering is not flame retardant, but others I work with don't think it is a big deal, since not much heat is generated by the tape, just enough to keep water flowing. Does anyone have any thoughts on this?
Covering over electrical heat tape on water pipes
- Thread starter teejer
- Start date
- Status
hockeyoligist2
Senior Member
- Location
- close to greenville sc
We use something similar, and haven't had any problems. We use fire resistant insulation over the heat tape, then install the plastic covers to keep water out.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
virtually all industrial pipe heat tape installs I have seen are insulated with fiberglass, and then plastic shields over that.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
petersonra said:
Us too. Some of the fiberglass insulation is 2" thick. Have also seen it wrapped in metal for exterior locations.
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
Read the label provided on the cable. I was on a job the other day and the label directed the installer to keep the cable exposed for its entire length. I do not know if this is for all cable. This cable was supplied by cord and plug connection.
weressl
Esteemed Member
Pierre C Belarge said:
That is nonsense.
Heat tracing is designed to keep the mateiral inside the pipe at the desired tempearture. To accomplish this without insulation one would need 50-60 times the wattage per foot of what ordinary heat tracers are designed to do. They are ususally 3-5 W/ft and require 1/2" thinck neoprene or fiberglass insulation. They are "make-up" of the heat loss that occurs accross the insulation thinckness. It is such a low temperature that fire hazard does not exist.
However. Make sure that you are installing a special GFCB - high leakage current 30-40mA - designed for heat tracing and that you have a braided metallic overjacket on the tracer that is properly grounded.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Pierre C Belarge said:
i think this is for the kind of heat tape used to melt ice dams on your roof.
weressl
Esteemed Member
petersonra said:
That is a different kind of animal, however ground fault protection would still be in order.
masterelect1
Senior Member
- Location
- Baltimore
Melting??
Melting??
I have never dealt with heat tape that had the capability to melt frozen materials. When a freeze up occurs due to heat tape failure or power loss, in the applications I have seen, it was necessary to manually defrost the freeze up and then to repair/re-energize the tape.
Melting??
petersonra said:
I have never dealt with heat tape that had the capability to melt frozen materials. When a freeze up occurs due to heat tape failure or power loss, in the applications I have seen, it was necessary to manually defrost the freeze up and then to repair/re-energize the tape.
weressl
Esteemed Member
masterelect1 said:
Both of you are correct.
There are heat tapes designed to prevent ice buildup on roof edges/overhangs although I more often see them forming triangular patches of iceblocks than completely repventing the formation of ice. (You would need to have a continous heat panel for the later.)
Heat tracing is normally applied for the maintenance of process temperature of pipelines or vessels. The tracing heat output is designed to make up for the heat loss occuring through the selected insulating material. However, whenever the heat output of the tracer exceeds the heat loss, the material in the pipe and the pipe will heat up until heat equilibrium is reached, eg. the heat loss through the insulation will equal the output. (Insulating material have different heat losses at different temperatures.) Consequently it is possible to heat up material, but it takes a long, long, long time. If unfreezing the pipes required, extra heat tracing of multiple runs of tracers applied or two tracers of different rating used.
Using heat tracing in Hazardous Areas contains a full set of additional problems and issues that needs to be addressed.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Since the idea is to prevent water infiltration from ice damming, this is usually adequate.weressl said:
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