A Blog

A Blog

What is Fever Screening and what does it have to do with thermal infrared (IR) imaging?

For the purpose of this discussion, normal core body temperature in the human body varies, but the average is 37°C or 98.6°F. Among other reasons, infections cause the body's temperature to rise. When a human's body temperature rises, it's called a fever. A fever is considered anything above 38°C or 100.4°F.


In its purist form, Fever Screening is the act of checking the internal temperature of a human being by placing an analog or digital thermometer in the mouth, armpit or rectum. This is accomplished by a qualified person with a thermometer at a check point -for instance, at an airport, factory or office building, before entry is granted. Tympanic thermometers (infrared ear thermometers) have gained popularity because they are fairly accurate, more non-contact and faster than other types. But this process takes a considerable amount of time.


Since there is a closely locked relationship between the internal and external body temperatures of humans, it has been determined that; a) to reduce screening times, and b) to reduce the risk of cross-infection between the incoming person and the screener, that thermal infrared imaging does have an acceptable level of accuracy and repeatability to be used confidently as a primary screening method.


In the primary screening process, when people with a skin surface temperature higher than that of a given set point are found, this apparent elevated body temperature warrants that person should be directed to secondary fever screening, using thermometers.


So, it can be said that thermal infrared imaging is a valid method of detecting Elevated Body Temperature in humans by using Skin Temperature Measurement -which speeds the process of entry screening for Human Febrile Temperature Screening.

Home Maintenance Tips for Spring

  • Loose or leaky gutters can lead to drainage issues that can allow water into your basement or crawl space.  Downspouts should be clear of debris and drain away from the foundation.
  • The grade around your home should be sloped away from the foundation to prevent water from pooling up and entering the home.  Use compact soil to increase the grade so that water flows away from the foundation. 
  • Check any wood trim surrounding windows, doors, railings, or decks for rot.  This can easily be done by using a screwdriver to probe the material.  You'll want to repair any trouble areas before the spring rains begin.
  • Examine the roof's shingles and flashing around skylights, vents, and chimney's from the ground.  Missing or damaged shingles should be replaced.
  • The exterior of the chimney should be examined for signs of damage. Have the flue cleaned of debris from any winter fires you may have had in your fireplace.
  • Concrete slabs should be inspected for signs of movement or cracks. All exterior concrete should drain away from the home's foundation. Fill cracks with a concrete crack filler. When weather permits, power-wash and then seal the concrete to increase longevity.
  • Check outside hose faucets for freeze damage. Turn the water on and place your thumb or finger over the opening. If you can stop the flow of water, it is likely the pipe inside the home is damaged and will need to be replaced. While you're at it, check the garden hose for dry rot.
  • Have a qualified heating and cooling contractor clean and service the outside unit of the air conditioning system. Clean coils operate more efficiently, and an annual service call will keep the system working at peak performance levels. Change interior filters on a regular basis. 

Using Tmax Corrected to Prioritize Electrical Exceptions

Thermographers have long used temperature differentials or Delta T measurements as a means of prioritizing electrical and mechanical exceptions. Typically, Delta T values are calculated by comparing the temperature of an exception to similar components under similar load or to ambient air temperature. Although they work well in many circumstances, Delta T readings are not applicable for components that do not qualitatively manifest themselves as an exception.


An alternative to Delta T calculations is a formula known as Tmax Corrected. This formula is based upon an IEEE formula and calculates pass/fail criteria based upon several factors including equipment type, ambient air temperature, and circuit load.


Although requiring a little more time to apply than Delta T calculations, Tmax Corrected allows one to determine if a component of interest is running within specification for any load or ambient temperature. Tmax Corrected is especially useful for equipment that is not manifesting itself as an exception. Tmax Corrected can be an invaluable tool for those who perform infrared inspections as part of commissioning studies or use thermography for acceptance testing of new installations, repairs, or retrofits.

COVID-19 Air Testing

We have received a number of inquiries in regards to air testing for the virus that causes COVID-19. As far as we are aware there is no test for the virus in the air. The current test kits in use now only test for the presence of the disease in a person.


The testing kits for COVID-19 are in short supply and are being strategically distributed to areas in need. Due to the shortage of test kits for health care facilities themselves.


We will inform you of any changes to air quality testing options as soon as anything is available. Be safe, use common infectious disease control procedures, and stay up to date.

Do Infrared Thermometers Detect Accurate Temperatures on Humans?

It has been said that desperate times call for drastic measures. However, when faced with a crisis, it is imperative to ensure that measures taken are appropriate and effective for the challenge at hand.


In an effort to help stem the spread of coronavirus, many people have been using non-contact infrared thermometers to determine human body temperature.  Often, the chosen instruments are industrial grade devices which are unreliable for human body temperature measurement.


Unlike infrared thermometers that are designed for medical use, industrial grade instruments can vary as much as 7.2 Fahrenheit (4 Celsius) degrees from a target's actual temperature.  In other words, using an industrial grade instrument on a person with a normal body temperature could yield temperature values ranging from 91.4°F (33°C) to 105.8°F (41°C).  Inaccuracy aside, the greatest risk in using industrial grade instruments is missing feverish persons who could infect others.


When using infrared thermometers on humans, one should only use medical grade instruments that have been certified for such use.  These instruments are far more accurate and will provide temperature values that are acceptably close to body core temperature.  For those electing to use infrared thermometers, we strongly encourage them to be trained in the proper use of their chosen equipment.


Thank you to all involved in treating the sick and helping to control the spread of COVID-19.  For those who are ill, we wish you a full and speedy recovery.

How to Clean Your Home After a Flood

By Haniya Rae

Last year, tens of millions of Americans experienced just how devastating floods can be. From January to October 2019, the estimated overall losses for damage caused by severe thunderstorms and flooding in the U.S. was more than $180 billion, according to the National Oceanic and Atmospheric Administration.

If your house has flooded, once your local police or fire department says you can return, you’re in a race against mold growth to clear out debris from your home. If you have flood insurance, the very first thing to do is file a claim—you have only 60 days to send in a proof of loss form documenting the contents of your home.....

Read more.

How to Avoid Drain Clogs and Sewer Backups

One extreme truth about drain clogs and sewer backups: They only happen on weekends and holidays when it is either expensive or impossible to get a plumber.

Here are three main ways to avoid sewer backups and clogged drains. They may seem simple, but people often don't take them seriously.

  1. Don't flush anything but toilet paper. Seriously, don't flush feminine products of any kind. Don't flush paper towels, facial napkins, and certainly not diapers.
  2. Don't dump a bunch of stuff down your garbage disposal at one time. This might become clear if, for example, you try to stuff all your potato peelings down the garbage disposal at once. After you do that, you can take the disposal trap apart and fish them out that way. This experience usually cements this rule in the mind of most cooks. Most find this out in preparation for a holiday dinner. Worse, if the large lump of stuff makes it through the trap, it is going to lodge in the sewer line. Very bad look for Thanksgiving.
  3. Don't pour grease down your drain. Some people actually think grease is the only thing you can put down the drain. And, that is wrong. All fats can be melted by running hot water down the drain with them, but the fats won't stay that way. They will ultimately harden and block the sewer line.

If you have slow drains or a block, solve the problem and call a plumber. Liquid drain openers can hurt pipes and that will cause many expensive future problems. At least a plumber can discover the cause of clogs and backups.


Your Monthly Maintenance Minute


Utility workers caution that ...Wipes in the pipes are clogging sewers

Sewers everywhere are stopped up and there is plenty of blame to go around from personal carelessness to faulty products.

For one thing, people think that any thin cleaning wipe or baby wipe can be flushed down the toilet. How wrong they are.

Non-flushable cleanup wipes, baby wipes, and sanitary products must not be flushed down the toilet.

The reason is simply that, unlike toilet paper, these other materials do not dissolve. Instead they clog up the sewers, damage equipment, and cost cities and taxpayers a lot of time and money.

In one city, they had to hire a contractor to vacuum out a lift station and remove a truckload of cloth material. It's happening all over the country.

The Association of the Nonwoven Fabrics Industry says researchers collected and analyzed materials from wastewater pumps and found that most items clogging equipment are not labeled flushable.

These items, experts suggest, should be more clearly labeled Do Not Flush.

Kimberly-Clark's flushable Cottonelle cloths undergo extensive testing to ensure they are compatible with home and city sewer systems. However, some flushables do not comply.

Some companies have heavily promoted bathroom wipes, while some cleaning product manufacturers have also advertised sponges they say can be disposed of in a toilet.

A Consumer Reports test showed that toilet paper disintegrated after about eight seconds, but some wipes still hadn't broken down after 30 minutes. They should never have been classified as flushable.

Infrared Inspections of Arc Fault Circuit Interrupters

Tip written by: Infraspection Institute Excess heating is often a sure sign of defective electrical equipment; however, the absence of heat can also be a sign of component failure. In this Tip, we demonstrate how thermal imaging may be used to detect defective Arc Fault Circuit Interrupters. An Arc Fault Circuit Interrupter (AFCI) is an advanced type of electrical circuit breaker that automatically opens a circuit when it detects a dangerous electrical arc on the circuit it protects. Designed to help prevent electrical fires, an AFCI can sense between electrical arcs caused by defective equipment versus those associated with the normal operation of devices such as light switches. In order to monitor for dangerous electrical arcing on a circuit, AFCI devices have electronic circuitry built into them. This circuitry can cause the body of the AFCI to run several degrees warmer than ambient temperature. Depending upon the settings of your thermal imager, these devices may show a marked contrast to their surroundings. Thermogram shows three out of four AFCI devices operating at ambient temperature. These devices had failed and were no longer protecting against arc faults. Images courtesy Houston Thermal Inspections and Infrared Imaging. When thermographically inspecting AFCI devices, be sure to inspect the line and load side connections at the AFCI device as well as the neutral bus bar connection for the subject breaker. Should you find an AFCI device that is operating close to ambient temperature, it is likely that the internal circuitry has failed making the device incapable of protecting against arc faults. Such devices be further tested and replaced should they be found defective.  

Infrared Inspection of Capacitors


Capacitors are devices commonly found in AC electrical distribution systems where power factor correction is required. Like any electrical component, capacitors need to be regularly checked for proper operation. Infrared thermography can be used to rapidly inspect capacitors from a safe, remote distance.

Capacitors are wound devices that are electrically connected between potential and ground. Capacitors used for power factor correction are generally encased in painted, rectangular steel canisters and often have two equal sized bushings for electrical connections. In a three phase circuit, there may be several capacitors connected to each phase.

The most common failures of capacitors are loose/deteriorated bushing connections, open circuits due to internal winding failure, and open supply circuits. When inspecting capacitors, be sure to:

  • Visually inspect capacitor bodies. Capacitors should not be misshapen/swollen.
  • Thermographically inspect capacitor bodies. Capacitors should be warmer than ambient air temperature and exhibit equal temperatures across all phases.
  • Check bushing and wiring connections for hotspots.

Any thermal anomalies detected should be investigated and corrected as soon as possible. Capacitors operating at ambient temperature should be corrected immediately as imbalanced capacitance can be more detrimental than having no capacitors at all.

Using an Auto Image Function

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Auto Image is a feature found on many modern thermal imagers. While this feature may be helpful in certain imaging situations, its usage can cause thermographers to overlook significant thermal anomalies.

Humans have come to rely on technology to make our lives easier. We frequently take for granted how many mundane chores of the past have been automated. Each day we rely upon automatic transmissions in our cars, auto correction in word processors, and auto flush in lavatories. As infrared imaging has matured, automatic image adjustment has become a common feature on thermal imagers.

Auto Image, also known as auto adjust, is a feature commonly found on today’s thermal imagers. When engaged, the thermal imager will automatically adjust Level and Gain values so that the coldest and hottest objects within the imaged scene will be set as the lowest and highest temperature limits respectively. Auto Image may be for a single frame or it may allow for constant adjustments to automatically take place in real time.

While single-frame auto image may provide a good starting point for level and gain settings, full time usage of auto image will cause level and gain values to constantly change as the imager is panned across a given target. With values constantly changing, it is nearly impossible to make comparisons between imaged objects since there is no fixed, baseline value. In addition to making thermal imaging confusing, the use of fulltime auto image will cause many thermal anomalies to go undetected.

Thermographers who own thermal imaging equipment should familiarize themselves with their equipment to determine if their imager features automatic image mode(s). For imagers featuring single frame auto, a thermographer may use this feature to allow the imager to ‘suggest’ initial level and gain settings. For scenes that do not have a wide variation in temperature such as building envelopes or roofs, auto image may provide optimal imagery. If not, the thermographer should then manually adjust the imager’s level and gain settings in order to optimize the displayed image.

For thermal imagers that do not have onboard level and gain controls or for those that feature full-time auto image, the technique for optimizing the displayed image is as follows:

  • Set imager to Auto Image mode
  • Aim and focus imager on item of interest
  • Pan imager slightly to obtain optimal contrast within scene
  • Immediately switch to Manual mode to lock range/level settings
  • If possible, adjust range and level controls to further optimize displayed image

ith the above steps completed, the thermographer may continue imaging similar objects under similar conditions. Should scene conditions change, the above steps may be repeated as necessary.

Properly adjusting level and gain is an extremely important part of thermal imaging. For best results, a thermographer should never rely on full time auto image to provide optimal imagery.