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On average,
approximately one third of all property losses are electrically related. Fully
one fourth of those losses are caused by faulty electrical connections. In such
cases, loose, dirty, damaged, corroded or oxidized connections and contacts
inevitably lead to increased electrical resistance - generating heat and
infrared energy as a result. Such problems, given sufficient time, inevitably
result in fire or explosion.
Identifying
electrical threats before they reach combustion or component failure
temperatures is becoming increasingly more difficult due to the complexity of
today’s building operation systems and control equipment. In addition, the
sheer number of contactors, breakers, fuses, and other electrical service
hardware make it virtually impossible to physically inspect, shut down, and
tighten every electrical connection on any regular
basis.
With occupant safety, energy
conservation, minimal downtime and the protection of capitol equipment all
being synonymous with proper maintenance, more and more building operators are
turning away from occasional physical electrical checks in favor of the latest
preventative maintenance technologies.
Infrared
Thermography (IR) operates by measuring the infrared energy of any
object’s surface and producing a detailed visual image showing its
temperature profile. Since IR operates without physical contact, it offers
building operators a safe, on-line, and cost-effective means to evaluate the
electrical operation of any property. While many borderline problem areas
typically remain undetected during an off-line physical inspection, they can be
easily pinpointed using IR.
Infrared
Thermography is ideally suited for detecting faults in electrical panels,
breakers, switchgear, splices, insulators, starters, contactors, wiring,
distribution systems, disconnects, and transformers, etc. With a lesser degree
of reliability, IR can locate water leakage in roofs, steam trap malfunctions,
ineffective HVAC air distribution patterns, motor and bearing defects, building
energy loss, pipe blockages and underground pipe leakage - providing a visual
representation of the heat generated or lost in almost any physical
application.
The below series
of photographs help show the potential of infrared technology, and why it is
considered one of the most valuable nondestructive tools available. The control
or standard photograph on the left helps to identify the source of the problem;
the infrared image the problem.
In many
cases, the highest temperature value and most defined point within an infrared
photograph will identify the actual source of the problem - such as a single
bolt, electrical component, or contact surface.
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Knife Switch - Knife switch
contacts present a constant maintenance problem to most older properties.
Annual IR inspections of such properties typically find multiple contact
problems which can only be repaired by shutting down the equipment, disassembly
and cleaning of the contacts, reassembly, and re-tensioning. Upgrading with new
disconnect equipment is recommended as the obvious long term
solution.
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Transmission Lines - This 460
volt tower between buildings showed a problem at an old splice. Temperatures
were measured at near 300 degrees F., and had charred the nearby wire to bare
metal. A combination of weathering, old age, and a less than acceptable wire
splice ultimately produced this electrical problem.
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Knife Switch - Knife switches
and most types of sliding electrical contact always present the potential for
hot spot problems. Add to them the moisture present in an outdoor environment
and serious faults can result. In this example, the A phase of this disconnect
switch was found exceeding 350 degrees F. |
For most infrared
inspections, a client's primary interest is to identify the hot spot locations
presenting the most serious and immediate threat. However, other electrical and
mechanical problems may exist which may also present a potential threat to
reliable building and plant operations.
A
typical IR inspection may identify panel doors damaged, mismatched or over
rated fuses in place, indicator lights out, inoperative safety mechanisms, as
well as various other forms of potential electrical or mechanical threats and
liabilities. Unlabeled panels, while not in themselves an operating problem,
would likely slow an emergency response to one.
Emergency automatic transfer switch (ATS)
equipment, tested only in normal mode, would not guarantee proper operation
during emergency power. Similarly, testing switchgear and starter panels under
little or no load, such as often exists for momentary or standby equipment,
would not likely show a problem. Identifying such equipment for special
attention during future inspections, therefore, will greatly benefit any
building or plant operation.
For further
information on infrared electrical testing and other nondestructive testing
services, please contact East Coast Industries,
Inc.
©
Copyright
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