With the New Year upon us,
many of us will follow the tradition of resolving to change
or better ourselves. With this Tip, we offer suggestions for
making job safety a priority.
The New Year is symbolic for many reasons.
For some, the New Year represents a fresh start or new beginning.
For others, it provides an opportunity to rededicate one’s
self to a set of goals or principles. The New Year provides
a perfect opportunity for thermographers to take stock of
workplace safety practices and procedures. In doing so, be
sure to keep the following in mind:
• Review safety procedures to ensure
that they are complete and current
• Ensure that safety training is
up-to-date for all personnel including First Aid and CPR
• Physically inspect all Personal
Protective Equipment to ensure it is in good condition
• Check calibration and/or replacement
dates for all monitoring or test equipment
Lastly, resolve to make safety your number
one priority each and every day. Safety is not a poster, a
slogan, or a set of actions to be followed only when it is
convenient. Rather, safety is way of life that affects not
only you but those around you.
Thermographer safety is one of the
many topics covered in the Level I Infraspection Institute
Certified Infrared Thermographer® training course. For
information on thermographer training including course locations
and dates, visit us online at www.infraspection.com or call
us at 609-239-4788.
Infrared inspections of building
exteriors often rely on solar loading to create temperature
differentials necessary to detect damage or defects. A common
challenge for thermographers is inspecting building elevations
that do not receive direct sunlight.
Infrared imaging is a proven technique for
testing building sidewalls. Inspecting buildings during evening
hours following a sunny day can reveal the presence of structural
details, missing or damaged insulation, or latent moisture.
These conditions are detectable due to changes in the thermal
capacitance or conductance of the walls.
When using solar energy to drive an infrared
inspection of building sidewalls, it is normal for a building
to heat unevenly. Typically, east elevations receive the least
direct sunlight, while the south and west elevations receive
the most. For many northern latitudes, north elevations do
not receive direct sunlight.
Fortunately, it is not necessary to receive
direct sunlight in order to drive an infrared inspection.
Provided that the building is not in close proximity to other
structures or heavily shaded areas, it will receive indirect
heating from nearby objects such as the ground. For elevations
that are heated indirectly, it is important to note that they
will exhibit weaker thermal patterns when compared to other
exposures that receive direct sunlight.
When using solar loading to drive an infrared inspection,
keep the following in mind:
• Choose an evening when weather
conditions are optimal - sunny day followed by a cool clear
evening with no wind
• Begin infrared inspection on the
North elevation and continue in a clockwise fashion around
the exterior of the building
• Depending upon wall construction,
type of defect, and local weather conditions, it may be
necessary to begin prior to sunset
Lastly, be aware that thermal patterns associated
with defects may only appear for a short period of time on
the North and East elevations. All thermal anomalies should
be investigated for cause and appropriate action taken.
Infrared inspection of building envelopes
is one of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer® training course.
For information on thermographer training including course
locations and dates, visit us online at www.infraspection.com
or call us at 609-239-4788.
With prices ranging to over
$30,000, a thermal imager can represent a considerable investment.
For companies getting started in thermal imaging, renting
an imager can provide a cost effective alternative to purchasing
a system outright.
Whether you are facing an equipment shortage
or looking to evaluate the characteristics of a new imager
prior to purchase, renting a thermal imager may provide a
solution. In some cases, imager manufacturers will credit
short term rental fees toward the purchase price of an imager.
As with purchasing an imager, there are several important
things to consider when arranging for a rental unit.
To help ensure that you select an appropriate
imager for rental, be certain to:
• Identify appropriate spectral response
required for project
• Determine if temperature measurement
is required
• Evaluate the system for objective
specifications
• Ascertain imager compatibility
with reporting software
When arranging for a rental, obtain terms
and conditions from the rental agency. These should include,
but not be limited to: rental period, extension of rental,
shipping costs, and requirements for insurance against loss.
One should also consider the rental agency’s ability
to provide technical support during the rental period.
Lastly, the greatest limiting factor
in any infrared inspection is the thermographer. For accurate
results, infrared inspections should only be performed by
properly trained and certified thermographers. For more information
on thermographer training and certification, please contact
Infraspection
Institute.
“Jack Frost nipping
at your nose.” These lyrics from a popular Christmas
carol evoke romantic visions of winter; however, frostbite
and hypothermia are dangerous medical conditions that can
present serious safety hazards.
For many, the dead of winter is upon us.
Thermographers working outdoors in cold climates can face
serious safety challenges due to frostbite and hypothermia.
Knowing the symptoms of these conditions and proper treatment
is imperative for worker safety.
Frostbite is a severe reaction to cold exposure
that can permanently damage its victims. A loss of feeling
and a white or pale appearance in fingers, toes, or nose and
ear lobes are symptoms of frostbite.
Hypothermia is a condition brought on when
the body temperature drops to less than 90 degrees Fahrenheit.
Symptoms of hypothermia include uncontrollable shivering,
slow speech, memory lapses, frequent stumbling, drowsiness,
and exhaustion.
If frostbite or hypothermia is suspected,
begin warming the person slowly and seek immediate medical
assistance. Warm the person's trunk first. Use your own body
heat to help. Arms and legs should be warmed last because
stimulation of the limbs can drive cold blood toward the heart
and lead to heart failure. If the person is wet, put them
in dry clothing and wrap their entire body in a blanket.
Never give a frostbite or hypothermia victim
beverages containing caffeine or alcohol. Caffeine, a stimulant,
can cause the heart to beat faster and hasten the effects
the cold has on the body. Alcohol, a depressant, can slow
the heart and also hasten the ill effects of cold body temperatures.
Last week’s tip discussed
the dangers of Frostbite and Hypothermia while working in
cold temperatures. This week’s tip covers cold weather
clothing.
Cold weather clothing is a matter of functionality
not fashion. Clothing needs to be worn in layers in order
to trap air which is warmed by the body. When selecting clothing,
start with the innermost layer and work outward. The use of
multiple layers will trap warm air while providing greater
ease of movement. As you add layers, be sure to adjust the
next layer’s size accordingly.
The first layer should be made of a synthetic
material that will wick perspiration away from the body and
maintain its insulating properties when damp. The second layer
is your main insulator and should be a breathable material
that maintains its insulating properties when wet. Synthetic
fleeces or natural wool are good choices. The outermost layer
should be breathable and both wind and water resistant.
Head and neck protection is a must since
nearly 40% of body heat is lost here. Perspiration is the
main enemy of feet. The best footwear will have sturdy outers,
good treads and a removable felt liner. Buy extra liners and
replace them every few hours. Liners can take a full day to
fully dry out so buy enough to get through a typical workday.
Mittens are the warmest but present problems
in grasping tools etc. I have found that a heavy duty welder’s
glove with cotton or wool gloves lining them provide good
warmth and mobility. Buy enough liners to get you through
the day. One final note, the body needs fuel to produce heat.
Your calorie needs increase in cold weather and require regular
replenishment with good wholesome foods.
Infrared thermography is
a proven technology for detecting defects in electrical circuits
that are under load. Thermal imaging can also be used to detect
defective lightning arrestors that are leaking current to
ground.
Lightning arrestors are a common feature
in electrical distribution systems and are used to guard against
voltage surges associated with lightning strikes on power
or communications lines. Installed at strategic locations,
lightning arrestors act like a safety valves to provide a
short circuit path that carries excess voltage to ground during
a lightning strike.
Lightning arrestors are connected between
a conductor and ground. In order to prevent a ground fault,
lightning arrestors are engineered so that normal line voltage
will not pass through the arrestor under normal conditions.
While some lightning arrestors employ a simple spark gap,
others consist of porcelain tubes that are filled with semi-conductive
discs made of silicon carbide or zinc oxide. During a lightning
strike, the resistance of the spark gap or oxide plates is
overcome and excess energy flows to ground.
If a lightning strike is sufficiently strong,
lightning arrestors may be permanently damaged and begin to
conduct electricity to ground full time. When this happens,
the body of the arrestors will heat up allowing them to be
detected with a thermal imager. The images below show two
examples of defective arrestors.
Infrared inspections of lightning arrestors
are primarily qualitative in nature. As such, thermographers
should compare similar arrestors to one another and note any
that are inexplicably warm.
Properly functioning lightning arrestors
should be uniform in temperature and close to ambient air
temperature if they have not undergone recent solar loading.
Individual arrestors should not have any pronounced hot spots
across them. Working early in the morning, on cloudy days
or at night will help to eliminate solar loading which can
hide defective arrestors. When performing your inspection,
don't forget to check grounding connections for hot spots
as well.
Infrared inspection of power distribution
systems is one of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer® training course.
For information on thermographer training including course
locations and dates, visit us online at www.infraspection.com
or call us at 609-239-4788.
Thermal imaging is widely
used to detect evidence of excess energy loss in building
envelopes. Under proper conditions thermal imaging may be
used to detect excess energy loss through spandrel glass panels.
Glass curtain walls are a common feature
found on modern commercial buildings. Opaque glass panels
called spandrels are used to cover materials or prevent construction
elements from being viewed from the exterior of the building.
Examples of such areas include areas between floors, hung
ceiling areas, knee-wall areas below vision lights, and sometimes
even columns or partitions.
Spandrel
panels appear as dark horizontal bands on this high
rise building.
Depending upon building construction, spandrel
glass may be installed as single-thickness panes, as part
of insulating glass units, or as laminated glass. When installed
as single pane units, spandrel panels are often insulated
to prevent excess energy loss; however, construction details
will vary between systems.
When performing an infrared inspection of
spandrel glass panels, keep the following in mind:
• Prior to the infrared inspection,
ascertain building usage and construction. Be aware of HVAC
settings and how they are likely to affect observed imagery.
• Spandrel glass panels can vary
widely. Determine panel construction and characteristics
prior to the inspection.
• When imaging from a building’s
exterior, significant errors can be introduced by hot/cold
reflections from nearby structures or the sky.
• Because spandrel glass often has
a low emittance; detected exceptions are likely to have
low temperature differentials.
Infrared inspections of spandrel glass should
be performed during evening hours with an inside/outside temperature
differential of at least 10ºC. Exceptions associated
with spandrel glass may appear as hot or cold depending upon
building usage, imaging vantage point, and panel construction.
As always, detected exceptions should be investigated for
cause and appropriate corrective measures taken.
Infrared inspection of building envelopes
is one of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer® training course.
For information on thermographer training including course
locations and dates, visit us online at Infraspection
Institute or call us at 609-239-4788.
When documenting an infrared
inspection with no detectable exceptions, thermographers should
be aware that there is a big difference between reporting
“no problems” versus “negative findings”.
Infrared inspections may be performed for
a wide variety of reasons including condition assessment,
quality assurance and predictive maintenance. In its simplest
form, thermography detects, displays and records thermal images
and temperatures across the surface of an object. In many
cases, thermal anomalies are indicative of deficiencies, changes,
or undesirable conditions within the object or system being
inspected. Typically, such conditions are reported with a
thermal image and a description of the anomaly.
Upon completing infrared inspections during
which no anomalies are detected, thermographers will frequently
report that the subject system has “no problems”.
From a liability standpoint, this can increase a thermographer’s
risk since there may exist problems that are simply not detectable
by thermography. Most importantly, a proclamation of “no
problems” may leave an end user with a false sense of
security regarding the condition or integrity of the subject
system.
Since it is not possible for thermography
to detect all potential problems within a given system or
object, it is advisable for a thermographer to report “negative
findings” when no anomalies are detected. This statement
is direct, to the point, and in accordance with terminology
utilized in other types of scientific testing.
Although the difference between “no
problems” and “negative findings” may seem
small, the proper use of terminology can help to prevent costly
and embarrassing misunderstandings.
Infrared inspections
of electrical systems can help to improve the efficiency of
a preventive maintenance program. In this Tip, we focus on
several key considerations for setting up inspection routes.
Electrical infrared inspections
are best performed when carefully designed routes are set
up listing the equipment to be inspected. But how does one
go about designating a route? To answer this, you must first
understand your electrical system layout. Keep in mind that
electrical systems are designed to fit the type of operation
of a facility. In general, in-plant electrical systems begin
with higher voltage classes nearest the incoming source of
electricity and branch down to lower voltage classes via transformers
to meet specific power demands throughout the facility.
As a general guideline, the
following is a list of the types of electrical systems found
at various facilities:
Industrial / Large Manufacturing
23 to 13kV supply voltage on site that
is stepped-down to 4160V and 277/480V for various motor
and lighting loads (substations, load interrupter switches
and large transformers are common with this set-up)
277/480V is stepped-down to 120/208V
via transformers for receptacle, computer, and lighting
loads
Medium to Small Manufacturing / Large
Commercial / Healthcare
277/480V supply voltage is brought into
the facility via outside pad-mount or pole-mounted transformers
to be used for various motor and lighting loads and stepped-down
to 120/208V via transformers for receptacle, computer, and
lighting loads
Small Commercial / Office
120/208V or 110/240V supply voltage brought
into the facility via outside pad-mount or pole-mounted
transformers used for receptacle, computer, and lighting
loads
Infrared inspection routes can set up based
upon various criteria including but not limited to, specific
areas or operations in your facility, by voltage class of
equipment, by individual circuit branches, by criticality
to operation of a facility, or other determining factors deemed
important.
Keep in mind that routes should be limited
to the amount of equipment that can inspected in a single
day or shift. Routes should also start with high-voltage equipment
closest to the incoming power source as failures high in the
electrical hierarchy generally affect larger portions of the
facility than lower voltage equipment.
When performing an infrared
inspection of the interior of a building, you may be able
to visually observe full-size thermal images without your
thermal imager. The cause of this phenomenon is simple dust
and dirt normally found within most buildings.
Many buildings employ cavity wall details
in the construction of interior spaces. When the exterior
of framed walls are exposed to cold temperatures, areas with
diminished R values will cause the interior surfaces of the
wall to cool. Such cold areas may be caused by framing members
or wall cavities with missing or damaged insulation.
If interior humidity levels are high and
outdoor temperatures sufficiently low, moisture will condense
on the wall surfaces within the occupied spaces. Once moisture
condenses on the wall surfaces, dust and smoke particles can
collect in these areas and will remain once the wall surface
has dried.
Thermal patterns caused by dust and condensation
are readily observed for light-colored walls with smooth surfaces
such as drywall coated with smooth latex paint. The intensity
of the resulting dust patterns will be dependent upon humidity
levels, wall temperatures, and the amount of particulates
within the air.
Typically dust patterns are more intense
within areas occupied by smokers, within kitchens, near woodstoves
or fireplaces, or in areas where candles are burned. Over
time, dust patterns can become quite pronounced and will often
clearly show every framing member and insulation deficiency
within the wall.
Infrared inspection of building envelopes
is one of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer® training course.
For information on thermographer training including course
locations and dates, visit us online at www.infraspection.com
or call us at 609-239-4788.
Load break elbows are a common
feature on shielded cables. Thermography may be used to provide
evidence of loose or deteriorated connections associated with
these connectors.
Load break elbows are insulated plug-type
terminals typically used to terminate shielded, underground
cables. Load break elbows act as large power plugs for connecting
cables to transformers, switching cabinets and bushings equipped
with load break receptacle bushings.
Internal to load break elbows are several
mechanical connections each of which is subject to deterioration
over time. A typical elbow contains a crimp connection and
a pin electrode that screws into the elbow. During normal
operation, this pin electrode mates with a receptacle which
also contains mechanical connections. Elbows and receptacles
that have loose or deteriorated connections will operate at
elevated temperatures and are readily detectable with a thermal
imager.
Thermogram shows hot elbow
due to loose internal connection.
~ Images
courtesy Jim Lancaster
Normally, all electrical connections within
an elbow are hidden from view due to the elbow’s molded
rubber insulating body. Due to their high emittance, load
break elbows are excellent candidates for infrared inspections.
In fact, thermal imaging is one of the best ways to inspect
these components for the integrity of their connections.
Since line-of-sight access to the electrical
connections within load break elbows is not possible, temperatures
at the point of origin are likely to be much hotter than observed
temperature values on the exterior surface. Small Delta T’s
observed on the surface of elbows can be indicative of a serious
problem. Because of this, hot load break elbows should be
investigated for cause as soon as possible and appropriate
corrective measures taken.
Infrared inspection of power distribution
systems is one of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer® training course.
For information on thermographer training including course
locations and dates, visit us online at www.infraspection.com
or call us at 609-239-4788.
Many infrared imagers utilize
PC cards to store imagery and data. Due to advances in technology,
storage capacity of flash cards has increased. Unfortunately,
some older thermal imagers will not work with newer, large
capacity flash cards.
PC cards, also known as flash cards, first
appeared as removable storage media on some thermal imagers
beginning in 1995. At that time, the average capacity of PC
cards was 5 MB of data. Over time, the storage capacity of
PC cards has increased dramatically. As of 2008, several thermal
imagers are using PC cards with a capacity of 1 GB or more.
Newer infrared imagers, digital cameras,
pocket pc’s and other devices are likely able to recognize,
read and use smaller capacity PC cards. Older thermal imagers
and electronics may not work with a larger and faster PC card
such as those with 1GB or greater capacity.
With the fast changing digital electronics
market and the demand for larger memory cards, smaller capacity
PC cards are becoming more difficult to find. Most electronic
stores and large retail stores no longer carry PC cards smaller
than 1 GB. Some camera stores still have a limited selection
of the smaller capacity PC cards.
In some instances, it is possible to
use memory card adaptors such as, xD to CF; however, success
is sometimes limited. For example, it may be possible to save
data onto a memory card, but not read or view the data previously
saved on the same device. If you have a thermal imager that
is not compatible with modern PC cards, it may be wise to
obtain compatible PC cards while they are still available.
Many electronic devices including
infrared imagers are powered by lithium batteries. Effective
January 1, 2008, US Department of Transportation regulations
prohibit loose lithium batteries in checked baggage onboard
aircraft.
Spare
batteries, also called “loose” batteries, are
batteries which are not installed in equipment. A lithium
ion battery inside your computer is an installed battery.
A battery you carry separately in case that battery runs low
is a spare battery.
Effective January 1, 2008, you may not pack
spare lithium batteries in your checked baggage. You may pack
spare lithium batteries in your carry-on baggage. The following
are tips for packing spare batteries:
o Pack spare batteries in carry-on baggage.
In the passenger compartment, flight crews can better monitor
safety conditions to prevent an incident, and can access
fire extinguishers, if an incident does happen.
o Keep spare batteries in the original
retail packaging, to prevent unintentional activation or
short-circuiting.
o For loose batteries, place tape across
the battery's contacts to isolate terminals. Isolating terminals
prevents short-circuiting.
o If original packaging is not available,
effectively insulate battery terminals by isolating spare
batteries from contact with other batteries and metal. Place
each battery in its own protective case, plastic bag, or
package. Do not permit a loose battery to come in contact
with metal objects, such as coins, keys, or jewelry.
For personal use, there is generally no restriction
on the number of spare batteries allowed in carry-on baggage.
This is the case for cell phone batteries, "hearing aid"
button cells, and AA batteries/AAA batteries available in
retail stores, as well as almost all standard laptop computer
batteries.
For some devices, lithium batteries are permitted
in checked luggage provided they are installed in the device.
If you pack a device containing batteries, secure it against
activation by locking the activation switch in the "off"
position, placing the device in a protective case, or by other
appropriate measures.
Infrared inspections of electrical
systems often include high visibility equipment such as substations,
switchgear and motor controllers. In this Tip we discuss several
critical items that are often overlooked during infrared inspections.
Perhaps one of the most overlooked pieces
of equipment during an infrared inspection of electrical substations
and indoor electrical switchgear is the control cabinets located
beneath breakers in outdoor substations and above or on the
side of rack-in breaker bays on 480V and higher indoor switchgear.
Equipment inside these cabinets is comprised
of both AC and DC current and includes relays, conductor terminal
connections, current transformers, breakers, and fuses. The
primary function of this equipment is to activate the trip
mechanism of a breaker if voltage or current conditions fall
outside the specified trip settings.
Connection failures and other heat related
damage to equipment inside these cabinets can cause a breaker
to trip resulting in widespread power outage throughout a
community and/or a facility. Given the vital importance of
this equipment, it should be on every thermographer’s
inventory list to inspect.
Below are a few examples of thermal
problems that can be detected in these cabinets: 1) Image
1 shows internal heating on a breaker, 2) image
2 shows heating of a impregnated ribbon bus on a
relay circuit board, and 3) image 3 show
heating on a plug-in fuse responsible for the switchgear cabinet
heater.
With onset of warmer weather,
the harshness of winter is but a fading memory for most. Left
undetected, the damage caused by winter’s fury is a
reality that can lead to premature roof failure. Fortunately,
an infrared inspection of your roof can detect evidence of
problems before they can get out of hand.
Performed under the proper conditions with
the right equipment, an infrared inspection can detect evidence
of latent moisture within the roofing system often before
leaks become evident in the building.
The best candidates for infrared inspection
are flat or low slope roofs where the insulation is located
between the roof deck and the membrane and is in direct contact
with the underside of the membrane. Applicable constructions
are roofs with either smooth or gravel-surfaced, built-up
or single-ply membranes. If gravel is present, it should be
less than ½” in diameter and less than 1”
thick.
For smooth-surfaced roofs, a short wave
(2-5.6 µ) imager will provide more accurate results
especially if the roof is painted with a reflective coating.
All infrared data should be verified by a qualified roofing
professional via core sampling or invasive moisture meter
readings.
Infrared inspection of flat roofs and proper
equipment selection are two of the many topics covered in
the Infraspection Institute Level I Certified Infrared Thermographer®
training course. For more information or to register for a
course, visit Infraspection
Institute or call us at 609-239-4788.
A common question among thermographers
who perform infrared inspections of buildings is, “What
emissivity setting should I use?” While this might seem
like a straightforward question, the answer is not that simple.
Recent years have seen a dramatic increase
in the use of thermography as a building diagnostics tool.
While many applications are qualitative, there are occasions
when quantifying temperature can be useful. In order to accurately
perform non-contact temperature measurements, one must input
the correct emittance value into a radiometer’s computer.
While many equate emissivity to values published
in emittance tables, emissivity is a dynamic characteristic
that is influenced by several factors. These include: wavelength,
object temperature, viewing angle, target shape, and surface
condition. Each of these factors can vary between projects
or during a given inspection.
Further compounding the challenge is the
fact that not all imagers are created equal. Imagers lacking
corrective inputs for atmospheric attenuation and/or reflected
temperature often require an exaggerated emittance value be
utilized.
When performing an infrared inspection of
buildings, keep the following in mind:
For qualitative inspections performed
with an imaging radiometer, leave the imager’s E control
set to 1.0. If possible, turn off all temperature measurement
tools.
In general, dielectric materials will
have a relatively high emittance; shiny surfaces and glass
will be quite reflective.
Viewing angle and reflected temperature
can greatly influence the effective emittance of a material.
In particular, smooth-surface roof membranes and building
sidewalls can be quite reflective when imaged at low viewing
angles often associated with ground-based inspections.
Lastly, emittance values obtained from
published tables can introduce significant temperature measurement
errors. Whenever possible, one should calculate emittance
values with the subject imager and cross verify observed temperatures
with contact thermometry.
Infrared Inspections
of Control Panels
Containing Exposed Contacts
~ Tip provided
by Michael Sharlon, Thermasearch of Arkansas
Infrared inspections of relay
panels containing exposed electrical contacts can be hazardous
to your imager’s health! This is especially so when
viewing elevator contact switchboards where momentary arcs
are visible.
Electrical control panels are items that
are frequently included in an infrared inspection of electrical
distribution systems. Even though most of these relays operate
at or around 120 volts AC and 50/60 Hz, the arc that occurs
at break generates high intensity electromagnetic pulses that
your imager’s shielding can rarely handle at distances
of less than four feet.
If many relays are actuating randomly you
may see momentary wavering to all out loss of vertical sync
resulting in a total skewing of the imager’s display
screen. The variation in intensity is directly related to
how close you are to the subject panel.
To minimize the effects of pulsing associated
with operating relays, maintain a distance of at least six
feet when viewing these panels. Doing so will eliminate or
minimize any adverse effect on your imager’s display.
Proper image focus is still
one of the most important aspects of performing an infrared
inspection. A clear image not only allows for optimal problem
diagnosis, but it is also critical to accurate temperature
measurement.
Clear focus is not difficult to achieve if
you follow a few simple steps:
Get as close as safely possible to your
target
Take time to carefully focus for optimum clarity. This
may take some practice if you have a motorized focus mechanism.
Ascertain that your target is stationary.
Only shoot from a stable platform. If
imaging from a motor vehicle, it may be desirable to shut
off the engine to avoid vibration.
Be sure your imager is steady as you
capture the image. Gently push the store button rather than
punching it.
If using a handheld imager, consider
using a tripod or monopod to help stabilize your imager.
Once you’ve stored an image,
recall and check for clarity. If the results are less than
perfect, start over. In addition to greater accuracy, capturing
clear images makes it easier to convey information to the
end user and/or the person who will eventually perform corrective
actions.
Fire Resistant Clothing is
required Personal Protective Equipment for many who work in
high temperature areas or near energized electrical equipment.
If your job requires the use of FRC, there are several important
things of which you should be aware.
Not all garments classified as FRC are created
equal. When choosing FRC you should be aware that:
FRC is not fireproof. It is designed
to protect the wearer from burns by resisting ignition during
brief periods of high temperature exposure such as electrical
arc flashes.
FRC is manufactured with different materials
and different weights. Be certain that the chosen material
is appropriate for the task at hand.
FRC effectiveness can be compromised
by age, wear, contamination with flammable materials and
the attachment of name patches or embroidery. FRC can be
permanently damaged by improper cleaning or laundering.
FRC is only effective when it is worn
properly. It should always be worn as the outer-most garment.
If worn over other layers clothing, the undergarments should
be made of natural fiber and completely covered by the FRC.
Before wearing FRC, be certain to understand
its proper application and limitations and how to use it properly.
As always, remember to work safely!
If you are a thermographer
who performs infrared inspections of electrical distribution
systems, you are not alone and you never should be. Working
alone near exposed, energized electrical equipment is not
only dangerous, it is a violation of federal law!
Administered by OSHA, the Occupational Safety
and Health Standards for General Industry, 29 CFR, Part 1910
apply to most thermographers working within the United States
or its territories. Specifically, 1910 Subpart R covers the
operation and maintenance of electric power generation, control,
transformation, transmission and distribution lines or equipment.
Covered facilities include utilities and equivalent industrial
establishments.
According to Subpart R, prior to the commencement
of work, medical and first aid supplies must be provided for,
including persons trained in first aid and CPR when work is
on or near exposed lines or equipment energized at greater
than 50 volts. Since CPR cannot be self-administered, at least
two people trained in first aid and CPR must always be present
when working near most exposed energized equipment.
When performing infrared inspections
in the future, having a second CPR trained person along will
not only satisfy OSHA requirements, it may save your life
should an accident occur!
The onset of seasonably warmer
weather signals that Summer has returned. For many, it also
means the return of mosquitoes and the threat of West Nile
virus.
West Nile Virus (WNV) infection is an illness
transmitted to humans primarily by mosquitoes. Flooded areas,
particularly in warm climates, provide ideal conditions for
mosquitoes to breed in stagnant water. Bites from infected
mosquitoes may result in illnesses which range from mild flu-like
conditions (West Nile fever) to severe and sometimes life-threatening
diseases requiring hospitalization (West Nile encephalitis
or meningitis). If you have symptoms of severe illness, seek
immediate medical assistance.
Signs & Symptoms
of West Nile Fever
(mild illness)
Headache, fever, body aches
Swollen lymph nodes, and/or a skin rash
on the body
Signs & Symptoms
of West Nile Encephalitis or Meningitis
(severe illness)
Headache, high fever, stiff neck
Disorientation (in very severe cases,
coma)
Tremors, convulsions and muscle weakness
(in very severe cases, paralysis
Preventing Mosquito
Exposure
Reduce or eliminate mosquito breeding
grounds (i.e., sources of stagnant or standing water)
Cover as much skin as possible by wearing
long-sleeved shirts, long pants and socks when possible
Avoid use of perfumes and colognes when
working outdoors
Use an insect repellent containing DEET
or Picaridin on skin that is not covered by clothing
Spray insect repellent on the outside
of your clothing (mosquitoes can bite through thin clothing).
Do not spray insect repellent on skin that is under clothing.
Do not spray aerosol or pump products
in enclosed areas or directly on your face. Do not allow
insect repellent to contact your eyes or mouth. Do not use
repellents on cuts, wounds or irritated skin.
After working, use soap and water to
wash skin and clothing that has been treated with insect
repellent
Be extra vigilant from dusk to dawn
when mosquitoes are most active
Thermographer safety is one of the topics
covered in all Infraspection Institute Certified Infrared Thermographer®
training courses. For information on thermographer training
and certification, visit us online at www.infraspection.com
or call us at 609-239-4788. For more complete information on
workplace safety, visit the OSHA
website.
Post processing of thermal
images is a common practice for many thermographers. While
image processing may provide a measure of convenience for
some, it can have significant drawbacks.
For many thermal imagers, infrared images
can be stored in 12 bit format. Saving thermal images in 12
bit format allows thermal images to be recalled at any time
and post processed for level, gain and color palette. For
imaging radiometers, temperature measurement settings such
as emittance may also be changed. Post processing may take
place within the imager or through a separate personal computer
using the manufacturer's proprietary software.
Over time, many thermographers have adopted
a policy of quickly recording imagery in the field and then
returning to the comfort of their office to further process
their imagery. Although post processing affords the thermographer
a variety of options for image analysis, one should be aware
that post processing can be time consuming. Spending as little
as five minutes processing imagery can result in a substantial
increase in report preparation time.
In addition to wasted time, post processing
may invalidate imagery as legal evidence. Not unlike digital
photography, thermal images that have been post processed
are creations and not originals. Should a thermographer’s
report be introduced in a claim, a competent opponent will
likely question if the imagery is original. In such situations,
a thermographer must be able to affirm that his/her report
does not contain processed imagery.
In light of the above, we recommend that
thermographers store images exactly the way they will appear
in their report and endeavor to avoid post processing altogether.
Image recording and reporting are two
of the many topics covered in all Infraspection Institute
Certified Infrared Thermographer® training courses. For
information on thermographer training and certification, visit
us online at www.infraspection.com or call us at 609-239-4788.
A specification commonly
provided for thermal imagers is Instantaneous Field of View
or IFOV. Many people mistakenly believe that IFOV values provide
meaningful information about a thermal imager’s performance.
Unfortunately, this is simply not true.
Originally developed for evaluating the
optical performance of thermal imaging systems, IFOV values
were intended to allow a user to calculate the minimum target
size needed to achieve 50% probability of detection at any
given distance. Using IFOV values to evaluate modern thermal
imagers and radiometers is unreliable for several reasons:
o To date, there is no accepted standard
for determining IFOV. Consequently, imager manufacturers
calculate IFOV values differently, making test results impossible
to compare.
o Because IFOV values are reported for
a single pixel, they cannot be used to accurately calculate
spot measurement size for imaging radiometers since accurate
temperature measurement requires several pixels, not just
one.
o Stated IFOV values are traditionally
reported at 50% radiance or less which is unreliable for
both temperature measurement and accurate thermal imaging.
The Infraspection Institute Standard for
Measuring Distance/Target Size Values for Infrared Imaging
Radiometers provides a simple and effective method for determining
spot measurement size for any quantitative infrared imager.
Proper use of this standard is taught in all Infraspection
Institute Level II training courses.
For more information on thermographer
training and certification or to obtain a copy of the standard,
visit us online at www.infraspection.com
or call us at 609-239-4788.
Video Output –
A Useful Feature on Thermal Imagers
Purchasers of thermal imagers
are often faced with the challenge of which features to look
for on new equipment. For some, a video output jack can be
a particularly useful feature.
Until recently, many thermal imagers featured
a video output jack as standard equipment. Video output jacks
allow imagers to be coupled with compatible video equipment
including external monitors and video recording devices such
as camcorders.
Coupling a thermal imager to a camcorder
offers several advantages when documenting an infrared inspection.
Among these are:
o Ability to quickly and economically record
large amounts of thermal imagery to videotape or digital
media
o Record dynamic events or processes
o Provide a hardcopy record of all items
that a thermographer has imaged
o Camcorders with external monitors provide
an additional viewing screen
Prior to using a video output jack, be certain
that the video signal is compatible with the chosen video
device. For some imagers, video adapters may be necessary
to couple the devices.
A number of engineering considerations including
production costs have caused many manufacturers to remove
the video output feature from several models of thermal imagers.
Because a video output feature cannot be added to an imager,
this feature must be specified at the time of imager purchase.
Prior to purchasing any new thermal imager, be certain to
try the equipment under the same conditions that you will
likely encounter in the future.
Equipment selection and use are two
of the many topics covered in the
Level I Infraspection Institute Certified Infrared Thermographer®
training course. For information on thermographer training
including course locations and dates, visit us online at www.infraspection.com
or call us at 609-239-4788.
Thermal anomalies are not
always as obvious as one might expect. Often, subtle thermal
differences can be indicative of major problems. Because infrared
thermography is a visual inspection technique, its effectiveness
relies on the observation skills of the thermographer. Like
any visual inspection technique, a thermographer must actively
concentrate on the imagery displayed by their thermal imager.
Contrary to popular belief, humans are not
inherently effective observers. Because humans tend to be
casual in their observations, they frequently overlook subtleties.
Whenever imaging, a thermographer’s eyes should always
visually scan the monitor left to right and up and down while
asking him/herself the following three questions:
1. What am I seeing
2. Why am I seeing this
3. Is this normal/reportable
While this approach may sound cumbersome
at first, this practice will soon become instinctive and can
help prevent you from overlooking the subtle thermal patterns
that can be indicative of serious problems.
Experienced thermographers
know that image clarity is one of the most important considerations
in thermal imaging. For thermal imagers, imager frame rate
is an important characteristic that can greatly influence
image quality.
Frame rate or frequency describes the rate
at which an imaging device produces unique consecutive images
or frames per unit of time. Until recently, most NTSC compatible
thermal imagers produced 30 to 60 video frames per second.
This frequency provided imagery that was considered ‘real-time’.
Thermal imagers that have real-time frame
rates permit imaging of either slow moving targets or imaging
of targets while the imager is in motion. Examples include
infrared inspections where the imager is panned across the
face of large targets such as buildings or where the imager
is hand carried such as during walkover inspections of a flat
roof.
For a variety of reasons, many modern imagers
are now manufactured with frame rates of less than 30 frames
per second. When using an imager that produces less than 30
frames per second, a thermographer will notice ‘ghost
trails’ or image smearing should either the imager or
target be in motion. This condition will worsen as lower frame
rates are encountered.
Clear imagery is possible with imagers having
a slow frame rate; however, both the target and imager must
remain motionless in order to eliminate image smearing. For
some imagers, it may take several seconds for the image to
become clear. Because of this, slow frame rate imagers may
not be suitable for inspecting expansive targets or targets
that are constantly in motion.
Because frame rate cannot be changed for
any imager, this feature must be considered at the time of
imager selection and/or purchase. Prior to purchasing any
new thermal imager, be certain to try the equipment under
the same conditions that you will likely encounter in the
future to ensure that the frame rate is adequate.
Equipment selection and use are two
of the many topics covered in the
Level I Infraspection Institute Certified Infrared Thermographer®
training course. For information on thermographer training
including course locations and dates, visit us online at www.infraspection.com
or call us at 609-239-4788.
For many, the peak of Summer
brings high temperatures to the workplace. For others, high
temperatures in the workplace are an everyday occurrence.
Understanding heat stress and its attendant safety challenges
is crucial for those working in hot environments.
What is heat stress?
Heat stress is a physical hazard. It is caused
by environmental conditions and results in the breakdown of
the human thermal regulating system.
What are the symptoms of heat stress?
There are various degrees of heat stress.
Each has its own unique symptoms. The most common form of
heat stress is heat exhaustion. Symptoms of heat exhaustion
include dizziness, confusion, headaches, upset stomach, weakness,
decreased urine output, dark-colored urine, fainting, and
pale clammy skin.
What do I do If I think I am experiencing
some form of heat stress?
Act immediately –
Advise a co-worker that you do not feel
well
Move to an area away from the hot environment
Seek shade and cooler temperatures
Drink water (1 – 8 oz. cup every
15 minutes) unless sick to the stomach
Have someone stay with you until you
feel better
What should I think about before
working in a hot environment?
Before working in a hot environment,
consider the type of work to be performed, duration of time
to be spent in hot areas, level of physical activity, and
other nearby hazards. Always use appropriate PPE and work
together as a team.
An ounce of prevention is
worth a pound of cure. In last week’s Tip, we covered
the topic of heat stress, its symptoms, and treatment. This
Tip focuses on the importance of hydration as a preventive
measure.
What is heat stress?
Heat stress is a physical hazard. It is
caused by environmental conditions and results in the breakdown
of the human thermal regulating system. If you work or play
in hot environments, your body needs a lot more water than
you might think.
What is hydration?
Hydration is the process of adding water.
Our bodies need water to do many things. In hot environments
we need large quantities of water to help keep our bodies
cooled to a temperature that allows them to function properly.
Heat stress becomes a health and safety concern when the volume
of water we need to function drops below the level necessary
to maintain homeostasis. We call this low water condition
dehydration or under-hydration. The average person is 7% under-hydrated.
How can I avoid being under-hydrated?
Developing the habit of drinking water at
routine intervals. One 8 oz. cup every hour on hot days will
assure proper hydration.
How will I know if I am properly
hydrated?
Check the color of your urine. You are properly
hydrated if your urine is clear, copious in volume, and light
yellow in color.
What are the benefits of proper
hydration?
Staying properly hydrated will help
to avoid heat stress and may increase your energy level. For
every 1% under-hydration, you lose 5% of your energy potential.
Determining exceptions in
single phase power panels is often challenging due to the
absence of appropriate reference components. In this Tip,
we offer suggestions for properly inspecting these panels.
Infrared inspections of single phase circuits
are often challenging due to the absence of similar components
under similar load. Unlike polyphase panels, single phase
power panels typically contain circuits of different sizes.
Oftentimes, these circuits are under widely varying loads.
Depending upon power usage, many circuits may be under zero
load causing other circuits to appear quite ‘hot’
by comparison.
Typical single phase power panel showing warm breakers.
Overloads confirmed with ammeter.
Prior to performing an infrared inspection
of single phase panels, make certain that the panel is under
adequate load. When inspecting, keep the following in mind:
Inspect panels in an orderly fashion
working from line to load side for all circuits. When possible,
compare similar components under similar load to each other.
Inspect each overcurrent device for uneven
heating between the line and load side connections. Check
all connections within the panel to ensure that hot spots
do not exist.
Check warm conductors for load using
a true RMS sensing ammeter. Don’t forget to include
neutral conductors.
Document all exceptions with a thermogram,
control photo and all pertinent data including time, date,
and load conditions.
Be aware that some devices such as GFCI
breakers may normally appear warm due to their construction
and/or operation.
Lastly, be certain to observe all necessary
safety practices when working on or near energized electrical
equipment.
Infrared inspection of power distribution
systems is one of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer® training course.
For information on thermographer training or to obtain a copy
of the Standard for Infrared Inspection of Electrical Systems
& Rotating Equipment, visit us online at www.infraspection.com
or call us at 609-239-4788.
Whether you are
considering instituting an IR inspection program or already
have one in place, obtaining competent manpower can be a challenge.
One potential solution is to outsource services for additional
manpower and expertise.
There are many factors that will determine
if a person is capable of effectively supporting your infrared
program. Your success in qualifying your thermographers can
be increased if you keep the following in items in mind when
qualifying individual thermographers.
Proof of formal infrared training and
certification level
Amount of experience with the type(s)
of inspections planned
Experience with the selected test equipment
Knowledge of the system(s) being inspected
Documentation of requisite safety training
If you choose to outsource your thermographers
through an infrared consulting firm, you may also wish to
check the following.
Number of years in business
Type of infrared equipment to be utilized
and calibration dates
Insurance coverage
Safety records and experience modification
rating
Professional references
Depending upon your company requirements,
be sure the chosen vendor is capable of complying with security,
background screening, and substance abuse policy requirements.
Lightning is
one of the most spectacular natural phenomena. For thermographers
who work outdoors, it can present a serious safety hazard.
This week’s Tip discusses how you can protect yourself
from this serious safety hazard.
Each year, lightning kills an average of
67 people in the United States; hundreds more are injured.
Few people really understand the dangers of lightning. Many
fail to act promptly to protect their lives and property don't
understand the dangers associated with thunderstorms and lightning.
Thunderstorms are most likely to develop
on warm summer days and go through various stages of growth,
development and dissipation. On a sunny day, as the sun heats
the air, pockets of warmer air start to rise in the atmosphere.
When this air reaches a certain level in the atmosphere, cumulus
clouds start to form. Continued heating can cause these clouds
to grow vertically upward in the atmosphere into "towering
cumulus" clouds. These towering cumulus may be one of
the first indications of a developing thunderstorm.
During a thunderstorm, each flash of cloud-to-ground
lightning is a potential killer. The determining factor on
whether a particular flash could be deadly depends on whether
a person is in the path of the lightning discharge. In addition
to the visible flash that travels through the air, the current
associated with the lightning discharge travels along the
ground. Although some victims are struck directly by the main
lightning stroke, many victims are struck as the current moves
in and along the ground.
Lightning can strike as far as 10 miles away
from the rain area in a thunderstorm. That's about the distance
you can hear thunder. When a storm is 10 miles away, it may
even be difficult to tell a storm is coming.
IF YOU CAN HEAR THUNDER, YOU ARE
WITHIN STRIKING DISTANCE. SEEK SAFE SHELTER IMMEDIATELY!
The first stroke of lightning is just as
deadly as the last. If the sky looks threatening, take shelter
before hearing thunder. Once indoors, stay away from windows
and doors and avoid contact with anything that conducts electricity.
Wait at least 30 minutes after the last clap of thunder before
leaving shelter.
Loose connections,
overloading and imbalanced loads cause overheating of components
within an electrical system. Depending upon construction and
operation of the electrical system, a perplexing and possibly
serious condition called inductive heating can cause non-current
carrying components to overheat.
As current flows through an electrical circuit,
a magnetic field forms around the conductor. When current
flow is high, a strong magnetic field can develop and extend
for several inches around the subject conductor(s). If ferrous
materials such as steel are positioned within this magnetic
field, they can heat up even though they are not part of the
circuit.
Inductive heating can occur on bus supports,
cable tray fasteners, bushing skirts and switchgear enclosures.
Affected components can become hot enough to cause significant
heat damage or even skin burns. The temperature of the affected
component will depend upon the strength of the magnetic field,
and the composition and location of the affected component.
Because inductive heating can cause
components to reach temperatures of over 200ºF, thermographers
should pay particular attention whenever combustible materials
or dielectric insulation are located near, or in contact with,
an inductively heated item.
Having the right
tool for the job is often essential for success. When performing
infrared inspections of smooth-surfaced roofs, a short wave
thermal imager can significantly outperform a long wave imager.
Smooth-surfaced roofs, both single-ply and
built-up, can present significant challenges during an infrared
inspection due to reflectivity of the roof membrane. Should
reflectance be sufficiently high, areas of latent moisture
may be undetectable to a thermal imager.
Most infrared inspections of flat or low
slope roofing systems are conducted at night by walking across
the roof surface using a handheld thermal imager. This technique
often results in a relatively shallow viewing angle thereby
lowering the emittance of the subject roof membrane.
Depending upon site conditions and roof materials,
roof membranes can appear to be as reflective as polished
metal surfaces. Membrane reflectivity will be especially noticeable
on cool, clear nights that permit the cold night sky to be
reflected from the roof surface. It will also be significant
on roofs that have been coated with aluminum paint.
Thermal image shows warm
area caused by subsurface moisture beneath smooth single-ply
membrane. SW imager reduces reflections from roof membrane.
To this day, the most practical way to deal
with the reflectivity of smooth roof membranes is to utilize
a thermal imager with short wave (2 to 5.6 micron) spectral
response. This will help to eliminate reflections from the
roof and can significantly increase inspection accuracy. Although
long wave imagers can be used for smooth membranes, they can
significantly understate the size of moisture-damaged areas
or miss them entirely.
Infrared inspections of low slope roofs
is of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer® training course.
For information on thermographer training and certification,
visit us online at www.infraspection.com or call us at 609-239-4788.
It is often necessary
to heat a surface to check its emissivity. Various methods
are used in the field, some of which have possible problems.
One method is to use a radiant heating source such as a high
intensity light to heat the surface and the adjacent or contained
reference which is typically a patch of electrical tape. This
will cause uneven heating of the unknown (to be measured)
surface in comparison with the reference surface such as electrical
tape. The pickup of energy by the unknown and the reference
will be impacted by their relative emissivities.
Another method uses a heat gun or hair dryer to blow hot air
on the surface. This should not have the pickup issues of
the first method, but may be adversely affected by uneven
air flow or manipulation of the dryer. A secondary issue,
which may also affect the accuracy of this method, is that
the unknown and the reference are rejecting heat to the surroundings
by radiation at different rates due to their differing emissivities.
The higher emissivity surface may actually be cooler than
the unknown. This is probably a small effect and under typical
usage will not impact the measurement at a noticeable level.
Calculations of this effect could be performed to estimate
the size of the error. I have not done the calculations.
An alternate method is to heat the surface by contact. For
many surfaces this can be accomplished with a hot water bottle.
Carry one in your tool kit, fill it with warm or hot tap water,
hold it on the surface for a sufficient time, remove and grab
the image. As long as good contact is maintained, the surfaces
should reach the same temperature and provide an accurate
measurement.
Cautions for this approach are: if the surfaces
have sharp corners they may puncture the hot water bottle,
if the surfaces are extremely rough the contact may not be
uniform, and if the underlying materials vary considerably
then the heat transfer from the surface into the underlying
material will not be uniform and may impact the temperature
achieved by the surface.
Of course, if the surfaces are already
hot, then it may not be possible to use a hot water bottle,
either because it will not provide enough temperature or may
fail, so be careful. Also, this method assumes that you can
safely contact the surface for the required time to heat it.
Tip Provided by:
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
4011 Hillman Ave.
Bronx, NY 10463
phone: 718-884-6644
Affiliate Marketing –
How to Turn Your Website into a Profit Center
As the worldwide web has
matured, websites have become a business necessity filling
a key role in the marketing, promotion, and sales of many
companies. In addition to direct sales, websites can generate
additional revenue through a concept known as affiliate marketing.
Affiliate marketing represents one of the
newest opportunities for websites to generate revenue. With
the right content, affiliate marketing can generate sufficient
revenue to turn an existing website into a profit center.
Affiliate marketing is a system of revenue
sharing between websites. The primary participants are an
Affiliate Partner and an Advertiser. With affiliate marketing,
the Affiliate Partner features ads and content on his/her
website that refer traffic or sales to an Advertiser’s
website. The Affiliate Partner receives a fee based upon amount
of traffic or sales generated for the Advertiser’s site.
Simply defined, Affiliate Marketing is risk-free advertising
that rewards performance.
Examples of highly successful affiliate marketing
programs include Amazon.com and Google. Under the affiliate
marketing concept, everybody wins. Advertisers gain exposure,
Affiliates enjoy commissions and increased website relevance
and traffic, and customers find new products and services
via familiar websites. With the right ads, Affiliates can
actually generate a positive cash flow for their website.
The Infraspection Institute Affiliate Partner
program allows thermographers to turn their website into a
profit center. The Infraspection AP program utilizes state-of-the-art
software to automatically feed non-competitive ad content
to your website. When customers place an order for any Infraspection
product or service, Affiliate Partners earn a 5% commission.
Best of all, the Infraspection AP program requires no capital
investment and can actually help to increase your website’s
prominence and traffic! For more information, call us at 609-239-4788
or visit the Affiliate Partner area of our website at
Heating
Up a Surface
Part 2: Non-Destructive Testing
In Part 1 I discussed
using a hot water bottle for heating a surface to do emissivity
testing. Part 2 extends the approach to another significant
application, NDT.
One method of using IR for NDT depends on
heating or cooling the surface to generate a thermal signature
for sub-surface features or defects. Using a hot water bottle
as a method to apply uniform heating to a small surface is
an alternative to some of the other methods used for heating.
It also offers the possibility of being used for cooling the
subject surface. The rate of heat transfer and uniformity
can be increased by agitating the hot water bottle during
application.
For larger surfaces, larger flexible liquid
containers can be used. If the surface is horizontal, an open
container can be used.
As before, the surface has to be suitable
for direct contact of any sort. It also has to be such that
it will not cut or break the hot water bottle or liquid container.
In other words, be careful.
Tip Provided by:
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
4011 Hillman Ave.
Bronx, NY 10463
phone: 718-884-6644
HVAC systems play an important
role in building performance and tenant comfort. Under the
right circumstances, an infrared imager can be used to help
document and analyze airflow patterns within conditioned spaces.
Infrared imagers are capable of detecting
and displaying thermal patterns across the surface of an object.
Using an infrared imager to diagnose HVAC airflow problems
is a challenge since air does not have a surface. While infrared
imagers cannot image air currents directly, they can detect
the effect of air currents on building surfaces.
Before attempting to diagnose airflow patterns,
one should ensure that the building’s insulation is
sound and the HVAC system has been checked for appropriate
delta T, clean filters, etc. An infrared imager may then be
used within occupied spaces to document thermal patterns associated
with airflow.
Due to its graphic nature, thermal imaging
can be particularly useful when documenting results for clients.
The thermal images below show an air-conditioned church interior.
The left image shows the building as found. The right image
shows the resulting thermal pattern after blocked air returns
were corrected.
When using an infrared imager to troubleshoot
airflow or distribution issues, the following steps can serve
as a guide:
o Make the HVAC system call for cooling or
heating in a given area
o Image supply diffusers and surfaces that
are in the path of diffusers such as windows and walls
o Check for air patterns that indicate the
throw of the conditioned air
Unexpected thermal patterns should
be investigated for cause and adjustments or corrections made
as required. Most air diffusers can be adjusted for both volume
and direction. In many cases, conditioned air does not wash
the walls or windows properly. Sometimes, conditioned air
may be found to be blowing on the HVAC controls causing improper
cycling of the system.
Infrared imaging is a proven
technology for detecting hot spots caused by loose or deteriorated
electrical connections. It is also capable of detecting hot
components associated with open neutral conductors.
Basic principles state that electricity travels
in a loop and needs a return path. Whether the electrical
system is residential, commercial, or utility, this same principle
applies. Therefore, one should see “outgoing”
current flow on the main feed conductor and “return”
current flow on the neutral conductor when measured with an
ammeter. If the neutral conductor becomes open as a result
of a failed connection or broken conductor, the return current
is rerouted from the neutral pathway to a grounded object.
Common problems experienced with an open
neutral are lights that burn dimmer on some circuits and others
that burn brighter on other circuits. Also common are lights
that flicker or turn brighter when heavy loads are applied,
such as an air conditioning unit turning on.
Infrared imaging is an excellent tool
for locating open neutral problems, especially for utility
clients. The images below were captured during a periodic
infrared scan of a overhead distribution feeder. The image
shows an eyebolt anchor on a neutral line with a temperature
rise of over 65 Fahrenheit (36 C) degrees. Not only did the
discovery of this problem save unknown amounts of time to
locate, it also prevented possible serious injury to an unsuspecting
utility worker.
Having an open neutral is a dangerous situation
that should be corrected as soon as possible. With an open
neutral, the grounding conductor becomes energized and can
cause injury to someone coming in contact with any bare metal
that is intended to be at ground potential.
In most cases, open neutral problems
experienced in residential and commercial buildings can be
traced backed to the utility’s side of the power system.
This makes sense since utility connections are far more exposed
to outdoor elements that can cause breaks and failures to
conductor connections.
Tip Provided by:
Brady Infrared
Inspections
935 Pine Castle Court
Stuart, FL 34996
When it comes to spending
year end budget monies, the phrase “Use it or Lose it”
often applies. Training can be a wise choice for those looking
to reduce a budget surplus.
Staying within budget is a constant challenge
for maintenance managers. For many, it seems that there is
never enough money in the budget. On occasion, however, it
is possible to experience a surplus in one’s budget
when nearing year end.
When faced with a budget surplus, it is
imperative to fully utilize allocated financial resources.
Failure to do so can cause a reduction in future budgeting
if management perceives that your department is over funded.
When searching for wise choices for year-end spending, training
is always a good option.
Thermographic training is a sound investment
for initiating a PdM program or expanding an existing one.
Whenever considering infrared training be certain to:
Examine course curriculum to ensure that
it meets your needs
Ensure that course will be germane to
all infrared imagers
Determine course locations or availability
of Distance Learning courses
Ascertain if certification is included
with course, its expiration date, and renewal fees
Insist that instructors be practicing
thermographers with documented field experience in their
area of instruction
Infraspection Institute
has been providing infrared training and certification for
infrared thermographers since 1980. Our Level I, II, and III
Certified Infrared Thermographer® training courses meet
the training requirements for NDT personnel in accordance
with the ASNT document, SNT-TC-1A. Certification and applications
courses are offered as open enrollment or on-site classes
or through our Distance Learning program. All courses are
taught by expert Level III thermographers whose field experience
is unsurpassed anywhere in the world. For more information
call 609-239-4788 or visit us online at www.infraspection.com.
Infraspection
Institute Certified Infrared Thermographer, Level III
PIET Infrared, Naples, FL
FM
Global Data Sheets –
A New Powerful Tool for
Thermographers
Thermographers and facility
managers now have a powerful new tool available to them. Property
loss prevention guidelines are now available online from FM
Global at no cost.
FM Global, one of the world’s largest
commercial and industrial property insurers, has recently
released thousands of pages of its previously exclusive property
loss prevention engineering guidelines at no cost through
its web site.
FM Global's Property Loss Prevention Data
Sheets provide large-scale businesses, facility and risk managers,
consultants, contractors and thermographers a valuable tool
to help prevent property damage and maintain business continuity
due to threats posed by fire, weather conditions, and failure
of electrical or mechanical equipment.
These engineering data sheets contain a wealth
of risk prevention information on hundreds of topics, ranging
from building construction, fire prevention and to industrial
equipment preventive maintenance, maintenance and natural
disaster preparedness.
The goal of FM Global has been to remove
the current barriers such as cost and licensing fees to obtaining
critical property loss prevention information including access
to their technical data sheets. By making this information
readily available to those who need it, particularly in developing
countries and emerging markets, FM Global is able to further
promote risk improvements worldwide by providing engineering
and research-based information on property loss prevention
and control practices.
To learn more about this free service or
to register, visit FM Global online at: www.fmglobaldatasheets.com.
Tip Provided by:
Jack R. Weaver
Infraspection Institute Certified Infrared Thermographer,
Level III
PIET Infrared
Naples, FL
HVAC systems play an important
role in building performance and tenant comfort. Under the
right circumstances, an infrared imager can be used to help
locate ductwork hidden behind walls or ceilings.
Heating, ventilating and air conditioning
(HVAC) systems often employ ductwork to move air throughout
a structure. Identifying the pathway of ducts within finished
buildings is often a challenge since ductwork is often hidden
within walls or located above finished ceilings. Under the
right conditions, it is often possible to detect the presence
of heated or cooled ductwork by imaging the finished surfaces
of a building’s interior.
HVAC ducts that move heated or cooled air
typically operate at temperatures significantly different
than the rooms they supply. Depending upon circumstances,
duct temperature may differ by 20 or more Fahrenheit degrees.
An infrared imager may be used to locate ductwork whenever
duct temperature is sufficient to cause a detectable temperature
differential on building surfaces.
Thermal image indicates
pathway of air conditioning duct
(medium blue area) above drywall ceiling. Ceiling register
appears as dark blue area. Inspection performed from building
interior.
When using an infrared imager to help locate
hidden ductwork, the following steps can serve as a guide:
o Operate the HVAC system in a given area
long enough to ensure sufficient Delta T. Use A/C in warmer
months; use heat in cooler months.
o Inspect areas of interest looking for
the regular, geometric patterns usually associated with
ductwork
o Mark detected thermal patterns on subject
surfaces and/or scaled drawings
The ability to detect hidden ductwork
via thermal imaging can be significantly affected by wall
construction and interior finish. In general, this application
is best suited for walls or ceilings constructed of drywall
and having a high emittance finish.
While any picture is worth
a thousand words, a thermal image needs an interpreter. When
thermal imagery is used as evidence, thermographers can expect
to be called upon to testify.
Robert
J. Incollingo
An infrared picture is more like an x-ray
than a photograph in this respect, in that its admissibility
at trial will depend on an expert thermographer to explain
its meaning, since without that expert testimony the judge
or jury may be misled rather than helped by the evidence.
An expert thermographer may be hired to give an opinion in
court regarding the meaning of a thermal image which he did
not make. If so, it is likely that the author of the image
must also be called to testify in order to “lay the
foundation” for the introduction of the image into evidence.
When a thermal image is used as proof of
some fact relevant to the outcome of a case, it must be “authenticated”
or identified for the court, which requires other evidence
such as the maker’s testimony that the image is what
it claims to be.
Although an ordinary photograph may be authenticated
by anyone with first hand knowledge of the scene depicted,
a thermal image is a bit more complicated - more like an x-ray,
cat scan or sonogram whose introduction into evidence may
require the technician to testify that the image was taken
of a particular patient on a particular day.
In the same way, if a thermal image
is proposed for introduction into evidence, to be used as
the basis for an expert opinion at trial, the thermographer
who made the image will be called as a fact witness to lay
the necessary evidentiary foundation.
Tip Provided by:
Robert J. Incollingo 416 Black Horse Pike
Glendora, New Jersey 08029
(856) 234-3800 RJI@RJILAW.com
Using
IRINFO.ORG Resources
to Make Your Job Easier
Information that is relevant
to your job in the thermography and NDT world can come to
you on a regular basis as a member of the IRINFO Group. Just
about every week since 2002, the IRINFO Group listserve sends
out an invitation by email to a select group inviting recipients
to visit the current Tip of the Week online.
And, for just about as long, an email invitation
is sent when the Article of the Month becomes available at
www.irinfo.org.
Both the Tip of the Week and Article of
the Month offer information that you can use. If you would
like to see what some of the previous tips have been, you
may do so by visiting this link: Tip
Archive.
You can also take a look at the titles of
some of the Articles of the Month by going here: Article
Archive.
But, the listserve is not a one-way street!
If you have a thermography-related question, you can ask a
large number of individuals for input to help you solve it
by sending an e-mail with your question to the IRINFO Group.
If you have an observation that you think would be beneficial
for others to know about, you can share it by sending an e-mail
message to the IRINFO Group.
To sign up for the IRINFO Group, complete
the form on this webpage: IRINFO
Group Signup. Please note that information for use of
the IRINFO Group is here: IRINFO
Group FAQ.
But wait! If you’re reading THIS e-email,
you are already a member of the Group. Please forward this
e-mail to a colleague who may be interested in joining.
Should you ever wish to leave the IRINFO
Group, you can do so easily by sending an e-mail message to
irinfogroup@irinfo.org and putting the word Unsubscribe in
the Subject Line. Do NOT click reply to an e-mail message
to do this, send a new message.
Remember, when you click Reply to any message
you receive from the IRINFO Group, your reply goes to EVERY
member. To know if a message is from the Group, look for [IRINFO
Group] in the Subject Line just before the actual subject
of the message.
If you read a message
that interests you and you wish to contact that person directly
do NOT click reply to the e-mail sent by the IRINFO Group.
You need to create a new message and send it to that person
directly.
With the onset
of seasonably cooler weather, autumn is the time to prepare
your steam system for the upcoming heating season. Testing
your steam traps before the season begins can help to pinpoint
costly leaks before the heating season begins.
Traditionally, two different non-destructive
technologies have been employed to test steam systems –
contact ultrasonics and temperature measurement. Used individually,
each of these techniques has limitations that can lead to
false positive and/or false negative results. Combining temperature
measurement with ultrasound can result in a highly accurate
test method by following a few simple steps:
Measure trap inlet to ensure that
temperature is above 212º F
If trap inlet is below 212º
F, ascertain why steam is not reaching trap
Listen to the trap outlet with
contact probe of ultrasonic unit
Continuous hissing or rushing sounds
usually indicate a failed trap
Ascertain that trap is cycling
periodically
Frequent cycling may be caused by
an undersized or worn trap
Tag defective traps and document in written
report
Re-test defective traps after repair
to ensure effectiveness of repair.
Always be sure to follow appropriate safety
precautions especially when working with high pressure steam
or when using ladders or lift equipment.
Infrared inspection of steam traps is one
of the many topics covered in the Level I Infraspection Institute
Certified Infrared Thermographer® training course. For
information on thermographer training including course locations
and dates, visit us online at www.infraspection.com or call
us at 609-239-4788.
It’s that time of year
when brightly colored trees remind us that Autumn is upon
us. Taking a few precautions can help to make driving safer
by addressing challenges unique to the fall season.
• Patches of fallen leaves can be
just as treacherous as patches of ice. Fallen leaves retain
large amounts of water and can create a slippery surface.
Drive slowly through them and avoid hard or panic braking.
• Fall brings the first frost. Be
aware of slippery conditions that occur with frost. At freezing
or near freezing temperatures, the moisture on bridges and
overpasses will become ice much more quickly than the approach
roadway. The roadways hold heat and the bridges do not;
you can go from wet roadway to ice in just a fraction of
a second.
• Fall weather such as rain, fog,
sleet and wet snow require full driver attention. Remember
the "two-second rule" when following other drivers,
and in severe weather increase your following distance.
If you are being tailgated, let the other driver pass.
• Later sunrises and earlier sunsets
can create sun glare. Be sure your windows are clean, inside
and out, and have sunglasses handy. If you're driving away
from a low sun, glare will not be a problem for you, but
it can be for the drivers approaching from the other direction.
It may help to use your low beam headlights, allowing you
to be seen more readily.
• In most areas, animal collisions
are at their peak in the fall. Be on guard when traveling
through areas where wildlife is likely to cross the road.
Common sense along with the basics
of safe driving - always wearing a safety belt, driving alert
and sober, and driving at safe and legal speeds - can help
you travel safely in the fall.
~ Tip provided by Michael
Sharlon Thermasearch of Arkansas
Batteries are the lifeblood
of portable thermal imagers. Without them, nothing happens.
This Tip provides a possible solution for solving one type
of problem with Lithium Ion batteries.
Two common problems with late model Flir
imagers are aging of the Lithium Ion battery and the inability
to charge one of these batteries because you get a blinking
red failure light on the charger.
In the first instance, the battery does not
seem to last as long. Try to recharge in the external charger
then use the battery until the first low battery indication
on your imager. Do not wait for the imager to shut down! This
is one of the most common reasons for the battery chargers
blinking red “battery failure” light. With the
first low battery indication, charge the battery as soon as
possible while still in the imager. Do not use the external
charger. Do this a couple of times. The charger in the imager
is better equipped in most instances to (re)condition the
battery.
In the second instance, the blinking red
battery charger light may be caused by the battery being used
until completely discharged and faulting the battery’s
embedded PC chip. If this indication occurs, try putting the
battery back into the imager (unless shorted, the battery
charge will partially bounce back when removed from the imager)
and turning the imager back on. Once cycled on immediately
turn it off (this resets the battery’s embedded chip)
and try putting it into the external charger for recharge.
If the battery now starts to charge you can breathe a little
easier. If not, replacement of the battery pack may be necessary.
FLIR reps and techs provided the above
suggestions and I have found them to be good tips.
~ Tip provided by Michael Sharlon Thermasearch of Arkansas
When it comes to heat transfer
and safety, thermographers traditionally think of the workplace.
With the Thanksgiving holiday upon us, neither of these topics
should be overlooked when it comes to preparing the holiday
feast.
According to estimates from the Centers for
Disease Control, approximately 76 million Americans become
ill each year as a result of foodborne pathogens. Of these,
approximately 5,000 die. Proper hygiene practices before,
during, and after food preparation can reduce the risk of
food poisoning.
As part of their nationwide Be Food Safe
public education campaign, the US Department of Agriculture
offers four simple tips for safe food preparation:
Clean –Wash hands, surfaces and utensils
often to avoid spreading bacteria when preparing food.
Separate –
Use different cutting boards for raw meat, poultry, seafood
and vegetables. Keep raw turkey away from vegetables and
side dishes that won’t be cooked.
Cook– You can’t
tell it’s done by how it looks! Use a food thermometer.
Every part of the turkey should reach a minimum internal
temperature of 165ºF.
Chill – Keep
the refrigerator at 40ºF or below to keep bacteria
from growing. Pumpkin pie should always be refrigerated
and all food should be refrigerated within two hours.
If deep fried turkey is your preference,
be sure to observe all safety precautions and never leave
your fryer unattended. For more information on food safety,
visit the US
Department of Agriculture website.
From all of us at Infraspection Institute,
Happy Thanksgiving to all of our readers and friends! May
you enjoy a safe and happy holiday in the company of those
you love.
Calculating
savings and/or avoided costs is one of the most difficult
tasks associated with an infrared inspection program; however,
doing so is required in order to gauge how effective a program
is.
In short, there
is no way to calculate the exact value of the findings of
an infrared inspection other than allowing the component run
to failure and adding up the subsequent losses. Unfortunately,
this is not a practical approach to maintenance.
As an alternative,
there are several methods that professionals use to estimate
program savings. A brief description of each of the most common
methods is listed below:
1. Summary
of Findings - A report comprised of the deficient items
found during a given time period. Reports may be by the day,
month, year, etc. This type of report does not provide any
financial data.
2. Performance
Effectiveness Ratios - Use accounting data to trend how
an infrared inspection program impacts an overall maintenance
program. Typically calculated for a single facility over an
extended period of time. Improvements in efficiency can be
compared to similar facilities or to the performance history
subject facility.
3. Avoided
Costs Method - A summary of the estimated cost of repairs
for breakdown versus proactive repair efforts. Typically,
proactive repairs are always cheaper since the outage can
be planned and the cost of the actual repair is usually less
since the subject equipment often suffers far less damage
when not allowed to run to catastrophic failure.
4. Permanent
Improvement Method - This is a summary of the financial
impact on a given facility due to the implementation of an
infrared inspection program. For example, infrared can be
used to supplement a maintenance program by directing repair
efforts to only those areas in need of attention rather than
periodic application of labor-intensive manual work. In such
cases, the cost difference between the two methods results
in a savings every time the manual maintenance procedure is
avoided in the future.
5. Statistics
Based Method - This method is based upon insurance industry
statistics associated with loss claims that have been paid
to clients over a several year period. This method takes into
account the value of the overall facility along with the severity
of the problem. While this method is not as accurate as the
Avoided Cost Method, it can be applied quickly and easily
with a minimum of effort. Infraspection Institute's Exception
2000™ software utilizes this method for calculating savings
as one of its standard features.
Each of the above
methods varies in the information provided as well as the
ease of use and accuracy. We cover each method in depth in
our Level III Certified Infrared Thermographer Course.
When calculating savings, we recommend that
thermographers consult with their end user and choose one
of the above methods that will best suit his/her needs and
consistently apply the chosen method over time. While you
will not be able to calculate savings exactly, you should
obtain a good indication of the value of your program.
Many infrared consultants
go about their daily tasks assuming that their insurance providers
are taking care of their interests so that they do not have
to worry about potential liabilities. Depending upon one’s
business, a Designated Premises endorsement can create a significant
gap in coverage.
There is an endorsement that some insurance
carriers “quietly” slip onto property and liability
policies. The “Designated Premises” endorsement
is a form that severely limits your liability coverage. The
wording of this form does exactly what it implies. This endorsement
limits your coverage for liability situations to the premises
listed on the declarations page of your insurance policy.
This can create several complications with respect to protecting
your hard-earned assets.
The first is that you very simply do not
have any coverage for lawsuits or issues arising from situations
that take place anywhere other than your primary office location.
This means that you only have liability coverage for things
that happen at your office. If you are at a client location
and you injure someone or damage their property, you would
not have any coverage to defend you in a lawsuit or to pay
for any damages that are levied against you.
This is the primary danger of the “Designated
Premises” endorsement. If your work requires that you
travel to client locations you should make certain that it
is NEVER included on your liability policies. In addition
to a general liability gap in coverage, your professional
liability insurance could also be affected.
In order to best
determine insurance needs, a Thermographer should consult
with an insurance professional who can provide the best guidance
on insurance options.
Among thermographers,
few things can cause an acute stomach ache like damaged equipment.
Damaged equipment is not only costly to repair, but may also
interrupt an inspection program while the equipment is being
repaired.
With infrared equipment, an ounce of prevention
is worth several pounds of cure. Fortunately, preventing
equipment damage is easy and inexpensive. Some of the best
ways to prevent damage are as follows:
Store IR equipment in hard sided shipping
cases that have die cut foam to fit the subject equipment
and its accessories
Keep lens caps on camera and extra
lenses while in the storage case
When not in use, store IR equipment
and accessories in a cool, dry place
When transporting or shipping equipment,
utilize extra padding to prevent components from shifting
in the carrying case
When traveling on an aircraft, hand-carry
your imager. Be sure to allow extra time when going through
airport security and encourage inspectors to be extra
careful with your equipment
Lastly, maintain your equipment
carrying cases in good working order. Repair or replace
defective or worn hardware. If your case should become
worn, replace it with a new original or an after-market
case suitable to the task. Some shipping cases are guaranteed
for life and replacement parts may be available at no
charge.
Spare
batteries, also called “loose” batteries, are
batteries which are not installed in equipment. A lithium
ion battery inside your computer is an installed battery.
A battery you carry separately in case that battery runs low
is a spare battery.
