IR scanning cost effectiveness

[dickerdmann]

Good day. We are in the process of looking into a contract to have IR scanning done at 35 of our US plants. I don't dispute the long term savings if thew porcess finds problems before there is a failure. The vendor stated that there was also an energy savings. They stated that for each degree of heat above the normal under load breaker the there is a loss of $8 per year in energy costs associated with the over heating breaker. Example, if a breaker was 30 degrees hotter than it normally should be, the lost energy related with that breaker would cost the plant $ 240 per year.
My question is, is this an reasonable ball park figure from asny of your experiences?

 

[charlie b]

Re: IR scanning cost effectiveness

I do not speak from experience, but rather from physics. The short answer is ?No.? Here is the longer answer:

Let us presume you are talking about a breaker serving a load at 20 amps and 120 volts. Let us presume the cost of electricity is $0.06 per kilo-watt-hour. You can do the math yourself, if you need to change the cost, amps, or volts to other values.
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• <font size="2" face="Verdana, Helvetica, sans-serif">$240 per year divided by $.06 per KW-Hr = $4000 KW-Hr per year.</font>

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• <font size="2" face="Verdana, Helvetica, sans-serif">4000 KW-HR per year divided by (365 x 24) hours per year = 456 watts</font>

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• <font size="2" face="Verdana, Helvetica, sans-serif">456 watts divided by 20 amps = 22.5 volts. This is the voltage drop across the point on the breaker that is causing the heat problem.</font>

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• <font size="2" face="Verdana, Helvetica, sans-serif">22.8 volts divided by 120 volts is 19 %.</font>

<font size="2" face="Verdana, Helvetica, sans-serif">Under this scenario, the vendor is suggesting that a circuit could drop 19 % of its voltage across the breaker, leaving the rest of the circuit to operate at 81% of normal voltage, and that this situation could go unnoticed for an entire year. I don?t buy it.

(Edited to correct a term in the third bullet above. This edit does not change the answer)

[ August 09, 2004, 04:52 PM: Message edited by: charlie b ]

 

[charlie tuna]

Re: IR scanning cost effectiveness

i have been a certified infrared thermographer since 1989. in my training they have documented a 120 volt-20 amp branch circuit breaker consuming additional energy costs of over two hundred dollars per year. i do not consider these costs as a tool to provide infrared services. sure it's nice to reduce electrical operating costs wherever possible, but planning your next electrical failure is the main issue. if your company has 35 plants---you will probibly learn from the first scans what areas you need to be concerned with. many of these areas might be engineering and/or desgn problems---equipment installed per code and good engineering practices but used beyond design. you will also have an idea what shape your plants are in---will they require yearly scans or every two to three years? your biggest problem is finding an equally efficient infrared operator so that all plants are inspected equally with the same criticality! ideally, it would be best to have the same operator - with the same equipment scan all plants. i do mostly large office buildings and have over the years learnt to look for "big" problems unless it's critical equipment. slightly overloaded branch circuits---hay, what are they gonna damage. i'm looking for internal breaker failures in distribution panels-loose bus duct joints-loose chiller compressor lugs-etc.. i've learnt that many times motor failures are caused by poor connections in disconnect switches or contactors. too many times i have reviewed other thermographer's reports and found they don't know what is supposed to be hot and what is not! one hospital warned me about the chiller overloads always going bad from previous reports. overloads are supposed to be hot!! i have found 4000 amp bus ducts with bad connections that the building noticed a sizable electrical savings--but this savings is a byproduct of the real advantage of repairing equipment before it fails!!

 

[69boss302]

Re: IR scanning cost effectiveness

Exactly Charlie Tuna. You have to know what is the definition of hot. I used to work where we had a lot of cranes and I would get calls when they didn't work and the first comment was the magnatorque was hot to the touch. I had to explain to them that if you could touch it then it wasn't to hot. Those things are supposed to get hot. Anyway, I have always been a strong supporter of thermography and it's a historical record you need to establish, and always look for the big surprises.

 

[charlie b]

Re: IR scanning cost effectiveness

Originally posted by charlie tuna:. . . but this savings is a byproduct of the real advantage of repairing equipment before it fails!!

I have always supported the use of themography for this very same reason.

. . . in my training they have documented a 120 volt-20 amp branch circuit breaker consuming additional energy costs of over two hundred dollars per year.

I believe that your training included a statement that that amount of savings has been documented. But did it include a copy of the documentation itself? If so, is there any information related to the documentation that you can share?

I was skeptical of the claim, even before I did the math that I show above. Can you show me any error in the math or the reasoning? Do you have any thoughts about reconciling the math shown above with the ?documented savings??

 

[charlie tuna]

Re: IR scanning cost effectiveness

well, to be truthful, i too was shocked at this statement. the instructor had everyone's attention as he explained the math on the blackboard. first off your only talking about fifty four cents a day, or .0225 cents per hour, or .000375 cents per minute! figures add up fast. its kind of like figuring out how much power an old two light exit fixture consumes! the payback to convert this exit fixture to l.e.d. is shocking! also consider the effects of a breaker in a panelboard that was never tightened. the heat generated in the panels bus may effect the other breakers downstream of the problem. as the heat builds up you get a voltage drop--as voltage drop occurs the circuit current increases, as current flow increases more heat is generated-like a dog chasing his tail! there is a statement that i live by--once an electrical connection is properly made(torqued)using approved materials it will not fail unless overloaded. and over-torquing is just as bad as undertorquing. i have learnt over the years that the manufacturer means little concerning infrared. installation is the number one thing and the design end is another. an example is elevator disconnect switches. if the switch size was calculated close to the upper limitation of that switch--you are subject to problems. how can this be corrected--oversize the switch. and maybe this switch was installed by a real strong guy who was concerned with connections---and as he overtorqued the line side lugs he put too much torque and now the movable blade does not line up vertically with the stationary blade. requires replacement! but if the customer invests in this service and reacts to the infrared reports recommended repair proceedure, eventually his electrical problems are gone! many of these buildings have "down time insurance" and get a reduced insurance rate for having this service on their building. and most of the time the money saved is more than the cost of the scan. it is extreamly important to assure that the people are properly trained. me being an electrician--recommend infrared thermographers with electrical knowledge. this helps out to reduce false issues! if an air handler motor is being fed by a three pole 30 amp breaker and the motor is drawing 23.5 amps constantly, this breaker is gonna look hot! it's loaded! many areas use infrared for finding roof leaks and these same people will send a roof thermographer to scan the electrical system--no way! very sensitive equipment is required which allows the thermographer to look at the full picture of the apperatus being looked at. a direct point instrument is near usless! i have an old unit--but it is very sensitive!

 

[don_resqcapt19]

Re: IR scanning cost effectiveness

Charlie,

first off your only talking about fifty four cents a day, or .0225 cents per hour,

But that amount of money would be 300 to 500 watts of power at the poor connection. I can't imagine the connection that is producing that much heat lasting very long before it completely fails. I would doubt that it could last a week, let alone a year.
Don

 

[charlie b]

Re: IR scanning cost effectiveness

Originally posted by charlie tuna: . . . first off your only talking about fifty four cents a day, or .0225 cents per hour, or .000375 cents per minute!

Make that 54 cents a day, or 2.25 cents per hour, or .0375 cents per minute. But yes, they would add up, and the final sum is just too high to be attempted to be believed.

I wish I could have seen your Instructor?s presentation. It?s a good diagnostic tool, and I agree with you that it should be presented in that light.

 

[charlie tuna]

Re: IR scanning cost effectiveness

when i first started infrared services i came across a low voltage panelboard where all the branch circuit breakers looked good but the top quarter of the panel was hot? we took the panel cover off and found that about half of the circuit breakers were never tightened onto the bus! the screws were engaged but never tightened! this panel had a copper bus, but the heat had turned it black and the plastic interior was melted and chared! this panel fed about half of the floor and it was a law firm. the infrared image showed a fire ball centered in the bus area about the size of a grapfruit. as we were taking the panel cover off, the lights went out in the kitchen where they were having a birthday party.
of course they knew we were in the electric room and came banging on the door. "what did you guys turn off" they asked! we explained nothing was turned "off" and that they had a problem in their equipment. the lights came back on and they left. i wrote down the necessary information on ordering a new ite panel interior and told the building's chief engineer. i suggested we order next day air, and he agreed. later that afternoon the chief engineer called me and explained that he went to the head attorney and told him we needed to schedual a repair time. the guy blew his top and refused to hear the story, and then went on to tell the chief that "his" electricians had been turning his power "on" and "off" during the last couple of days! and he was "sick and tired" of it!!! told the chief to leave! the chief called me and cancelled the panel interior, of course it was too late. the next day i recieved the panel interior and i just set it alongside my desk. three days later, in the middle of some very important deposition the panel blew up! the chief called me in a panic--we took the panel interior to the building and had it repaired in an hour. charged him extra for aggrevation!!!! but, that panel was really cookin!
consider a 277 volt-20 amp breaker that carries a lighting load of say 12 amps. if you have a loose connection to the bus, it can damage the breakers on either side by the expansion and contraction of the bus in the area of the loose connection. when scanning bus duct---consider where the joints have to be and make sure to scan each one. the ones you can't see are the ones that may have never been torqued. like a horizontal bus duct running through a chase--is there a joint inside the chase? if it's ten foot sections you need to calculate if there is a joint thats not accessible! we had a major 34 story hotel that was split in three sections and bus fed. the top half of the hotel lost power for about five minutes and then come back "on"! their engineers began tracing the busway. knocking holes in chases throughout the hotel. they couldn't find it. they called us and we found it in fifteen minutes. two concrete walls with a two foot space between---the joint was between the walls and never torqued! or maybe where a bus duct joint is covered up by ac ducts. or a square "d" disconnect switch that had a number ten line connection get so hot it caused the plastic axle of the switch to melt in half! when you turned the switch "off" it felt and sounded normal, but two phases were still energized with a 480 volt potential between them. i have seen some strange things and do not question the amount of energy that can be lost by loose connections. remember, the excessive heat generated by the loose connection many times damages the circuit breaker where the trip setpoint no longer functions. we have found circuit breakers that just crumble when you attempt to remove them from the panel! i always consider the damage caused over years of an elevator disconnect switch--sometimes i'll ask the elevator service contractor "oh car 16? we've replaced the motor three times"---loose connections damaged these motors!

 

[tshephard]

Re: IR scanning cost effectiveness

I don't know anything about the usage savings, but I have to absolutely agree with heat and heat damage and service scheduling rather than breakdowns. I worked for the MAJOR tobbacco manufacturer and we had outsiders come in and thermoscan, and found and documented every visit.
Perhaps some else will know better, but I was taught you torque copper twice on installation, and then thermo for faults, not retorque every PM cycle.
I would bet with the improvements in IR costs, you could buy a system of your own now that you could only rent before.

 

[brian john]

Re: IR scanning cost effectiveness

I am not the IR tech at our firm but I have tons of experience with IR and troubling shooting before there was IR unitizing the FOP (fall of potential) test method one can determine the voltage drop across a piece of distribution equipment.

Typically on the high end we see something in the range of 1.5 VAC, the worse I have seen is 3. something VAC. This varies with the type of distribution equipment, load and utilization voltage.

In our area the insurance companies offer savings for firms that complete IR scans.

 

[charlie tuna]

Re: IR scanning cost effectiveness

friday we will scan a 20 story office building we are do yearly---cost about $1500. rebate about $2200...... it will take all day -- two electricians plus about three hours of office work on the report for a secretary. we have been doing this building for about eight years and they have followed up with our recommended repairs. the first scan found problems in the elevator disconnects, cooling tower disconnects,
elevator distribution panel feeder, eight bus duct tap boxes, four air handler feeder breakers, chill water pump contactor, and a line side contact on an ats switch. last scan found only four items. this is typical results when the customer is interested in fixing his problems.

 

[iwire]

Re: IR scanning cost effectiveness

Anything wrong here?