Busway hot spots, the rest of the story - what would you do? Now is your chance!

[MPdesign]

If this were YOUR building that you just inherited from your cousin, what would you do?
Situation:

• I-Line II busway feeding from the MDP up 8 floors to mechanical gear on the upper floor
• The busway has no drop-offs to other floors (only feeds the mechanical gear and nothing else)
• Circa 1970s installation
• The busway has 3 hot spots radiating around three busway splices
• The hot spots have been present since the late 1980's with no appreciable increase in temperature
  • from last year to this year, temps have decreased, likely for energy upgrades.
• The busway is designed by the manufacturer to operate at a constant temperature of up to 203 degrees F
• The busway is now measured twice a day with temps typically 120 & up to 146 degrees F
• Infrared reports over the past years show temps of up to 147 degrees F
• Historic temps recorded sample: 1999 -140 degrees F; 1997 - 125 degrees F; 1994 - 119 degrees F;
• 4 years ago, ALL bolts were torqued to manufacturers spec which caused no change in the readings. One of the hot spots was also re-torqued in the 80's with no change in the temps.
• 3,000 Amp busway. The busway is not overloaded. Most of the busway reads normal temps.
• The reason for the overheating is likely blasting next door in the 80s.
• Additional considerations
  • I originally wanted to maybe just replace on of the splices and see if the temp goes down
    • The splice is obsolete and I would have to buy aftermarket or used
    • The duct could be pitted from the heat making installing new improper or impossible
      • leaving the whole office building with no HVAC - until I get a whole new busway... could be weeks or longer...
    • Used or reconditioned busway could have been sitting in a dirty warehouse, flooded, or anything else. who knows...
  • Replace the hot spot ducts areas only with new, non-obsolete, busway
    • I cannot just replace the current busway with new busway because the new has different dimensions. This would require the manufacturer to be onsite custom forming parts as needed during the installation as well as moving existing panels on different floors because of the new busway dimensions. Not cheap.
  • This is not a class "A" fully occupied building with lots of money. Many floors are empty and they do not have lots of choices in this economy.
  • The busway has never been disconnected and megged to ensure that the insulation integrity has not diminished over time from transient high temps that may have occurred between testing causing insulation degradation

What would you do - & why?
You have all been so helpful - thank you for your insights here as well.
Joe

 

[eHunter]

If this were YOUR building that you just inherited from your cousin, what would you do?
Situation:

• I-Line II busway feeding from the MDP up 8 floors to mechanical gear on the upper floor
• The busway has no drop-offs to other floors (only feeds the mechanical gear and nothing else)
• Circa 1970s installation
• The busway has 3 hot spots radiating around three busway splices
• The hot spots have been present since the late 1980's with no appreciable increase in temperature
  • from last year to this year, temps have decreased, likely for energy upgrades.
• The busway is designed by the manufacturer to operate at a constant temperature of up to 203 degrees F
• The busway is now measured twice a day with temps typically 120 & up to 146 degrees F
• Infrared reports over the past years show temps of up to 147 degrees F
• Historic temps recorded sample: 1999 -140 degrees F; 1997 - 125 degrees F; 1994 - 119 degrees F;
• 4 years ago, ALL bolts were torqued to manufacturers spec which caused no change in the readings. One of the hot spots was also re-torqued in the 80's with no change in the temps.
• 3,000 Amp busway. The busway is not overloaded. Most of the busway reads normal temps.
• The reason for the overheating is likely blasting next door in the 80s.
• Additional considerations
  • I originally wanted to maybe just replace on of the splices and see if the temp goes down
    • The splice is obsolete and I would have to buy aftermarket or used
    • The duct could be pitted from the heat making installing new improper or impossible
      • leaving the whole office building with no HVAC - until I get a whole new busway... could be weeks or longer...
    • Used or reconditioned busway could have been sitting in a dirty warehouse, flooded, or anything else. who knows...
  • Replace the hot spot ducts areas only with new, non-obsolete, busway
    • I cannot just replace the current busway with new busway because the new has different dimensions. This would require the manufacturer to be onsite custom forming parts as needed during the installation as well as moving existing panels on different floors because of the new busway dimensions. Not cheap.
  • This is not a class "A" fully occupied building with lots of money. Many floors are empty and they do not have lots of choices in this economy.
  • The busway has never been disconnected and megged to ensure that the insulation integrity has not diminished over time from transient high temps that may have occurred between testing causing insulation degradation

What would you do - & why?
You have all been so helpful - thank you for your insights here as well.
Joe

While I can empathize with your sitiuation and with all due respect, you asked the question in http://forums.mikeholt.com/showthread.php?t=154703 and was answered.

If after cleaning, inspecting and testing, including a ductor test, the results indicate that the bus condition is servicable and you still have concerns, disassemble the hotspot joints and physically inspect. Enlist the manufacturer for help, the proper procedures and guidance concerning servicability and replacement parts if needed.
Or hire a professional to inspect the bus and respect their findings.

In order to afford the repairs you would need to increase the occupancy and I assume that would increase the load on the bus, only exacerbating the hotspot issue.
If you are this concerned with a low occupancy and load on the bus and express that you cannot afford to make repairs you are between the proverbial rock and a hard place.
Run the numbers, put your engineering skills to use.

 

[MPdesign]

Thank you eHunter, many people seemed angry at me for not describing the whole situation so that they could state their concerns!
I posted this only because I gave those people my word that I would further describe it.
I look forward to their wisdom and I appreciate yours.

 

[iwire]

Am I following this correctly?

• It is running well below recommended temps and has been for years
• These hot spots have been there for 30 years without an issue
• The hot spots are cooler now than they have been.

I would not do a thing even if the place had tons of money.

 

[broadgage]

Agree, if it is below the suppliers stated operating temperature I would not worry, especialy if it has been like that for 30 years.

I might add temperature recording labels, that permanently change colour to indicate the maximum temperature reached.

 

[mgookin]

Am I following this correctly?

• It is running well below recommended temps and has been for years
• These hot spots have been there for 30 years without an issue
• The hot spots are cooler now than they have been.

I would not do a thing even if the place had tons of money.

+1

 

[MPdesign]

As I thought, you guys are complete...

great guys.

You have run the gamut of solutions that I brainstormed for a long time - and included a few more: Ductor and PI Index.

FYI - whenever there is a hot spot between 2 points of the same equipment of this magnitude, it HAS to be labeled by the National Electrical Testing Association as "Priority 1: Major discrepancy; repair immediately". There is no higher rating. If you couple this with a mgmt company who just dealt with the fallout of a bus duct failure in major building in another city, then it gets a LOT of attention.

Thank you for your insight.

 

[petersonra]

I just do not see a problem here.

 

[zbang]

If you couple this with a mgmt company who just dealt with the fallout of a bus duct failure in major building in another city, then it gets a LOT of attention.

I just do not see a problem here.

Sounds like the problem is more political than mechanical.

 

[MPdesign]

Kudos for the temperature recording label idea as well.
This will save much labor, a few infrared scans, and be more accurate. I did not know such a thing existed. I was thinking a data-logger but this is considerably cheaper and yields great information.

 

[gadfly56]

Kudos for the temperature recording label idea as well.
This will save much labor, a few infrared scans, and be more accurate. I did not know such a thing existed. I was thinking a data-logger but this is considerably cheaper and yields great information.

Temp labels have been around for decades. See here for products from Omega Engineering. On the TL-8 series you can go from 40 to 260C. Accuracy is about 1.5C on the low end series and 1% at the higher end. They also offer crayons and lacquers.