Fairview Home Inspector owner Jeff Cardile, president of Lookout Capital Inspections answers the question, What is Infrared?  Part 7

Infrared is also known as Thermal Imaging or Thermography.  Infrared is the combination of the physics of light, physics of heat, and the physics of infrared.  The physics of light consists of the Electromagnetic Spectrum, the Frequency, and Color.  The physics of heat consist of (CCR) Conduction, Convection, and Radiation.  The physics of Infrared consists of Delta-T, Emissivity, Reflectivity, Transparency, and Thermal Mass.

Today, we are going to continue our discussion of the physics of Infrared. Specifically,  we are going to talk more about Reflectance.

Metal Roof High Reflectivity

In our previous blog, we discussed the three factors that determine how all objects respond to thermal imaging.  (Transmittance, Emittance, and Reflectance) Lets talk about Reflectance a little more.

Definition: Reflectance, a ratio of incident light striking an object to the amount of light reflected off the object.  Light reflecting off an object may not be accurate of the actual light being emitted by that object.  An object that has a reflectivity of 1 would be a perfect reflector of infrared light.

Reflectance is a measure of how much an object reflects light.  It is almost impossible to perform thermal scans on materials that are highly reflective.  When you scan a highly reflective object your are not reading the thermal energy that is emitted you are reading the thermal energy that is reflected.  Highly reflective objects would be mirrors, shiny metal (screw heads), white siding, and windows.   Materials that are highly reflective do not give accurate in the infrared spectrum.  A thermal scan of a mirror will only give you readings of the heat the mirror is reflecting.

In our next blog, we going to talk about Thermal Mass.

Fairview Home Inspector is owned by Jeff Cardile.  Jeff is a Certified Thermographer.  Lookout Capital Inspections is proud to be a leader in the inspection industry.  Call Jeff at (469) 853-7336 for any of your inspection needs.

Plano Inspection Company owner Jeff Cardile, president of Lookout Capital Inspections answers the question, What is Infrared?  Part 6

Infrared is also known as Thermal Imaging or Thermography.  Infrared is the combination of the physics of light, physics of heat, and the physics of infrared.  The physics of light consists of the Electromagnetic Spectrum, the Frequency, and Color.  The physics of heat consist of (CCR) Conduction, Convection, and Radiation.  The physics of Infrared consists of Delta-T, Emissivity, Reflectivity, Transparency, and Thermal Mass.

Today, we are going to continue our discussion of the physics of Infrared. Specifically,  we are going to talk more about Transmittance.

Light transmitting through glass.

In our previous blog, we discussed the three factors that determine how all objects respond to thermal imaging.  (Transmittance, Emittance, and Reflectance) Lets talk about transmittance a little more.

Definition: Transmittance, a ratio of incident light,  of a specific wavelength, that passed through a material.

The electromagnetic radiation,  can pass through objects as in the image above.  Glass windows allow visual light to pass through them but do not allow infrared light.  The infrared light will not pass through the glass, it is reflected.  Transmittance can also change the frequency of the light.  Ultra-violet light is changed to Infrared light as it goes through glass, but it becomes trapped because glass reflects infrared light rather than transmitting it.  Basically, this is the green house effect.

In our next blog, we will go into more detail about the imaging factors of Emissivity.

Plano Inspection Company is owned by Jeff Cardile.  Jeff is a Certified Thermographer.  Lookout Capital Inspections is proud to be a leader in the inspection industry.  Call Jeff at (469) 853-7336 for any of your inspection needs.

Melissa Inspection Company owner Jeff Cardile, president of Lookout Capital Inspections answers the question, What is Infrared?  Part 5

Today, we are going to continue our discussion of the physics of Infrared. Specifically,  we are going to talk about Transmittance, Emittance, and Reflectivity.

We must first understand Kirchoff’s Law of Thermal Radiation:  The sum of Radiation exiting an object is equal to 1.   Transmission + Absorption + Reflection= 1.   The total sum of energy in an object will either be transmitted, absorbed, or reflected.   Scientist study thermal radiation using a theorem called the black body.  The black body is a perfect emitter of all heat energy the object absorbs therefore it sets the standard by which  all other material is measured (in theory).

The 3 factors that determine how all objects respond to Thermal Imaging:

1. Transmittance, a ratio of incident light,  of a specific wavelength, that passed through a material.
2. Emittance, a ratio of energy radiated from a material to the energy radiated by the black body theorem.  A black body has an emissivity of 1, therefore all other materials/objects have an emissivity of less than 1.
3. Reflectance, a ratio of incident light striking an object to the amount of light reflected off the object.  Light reflecting off an object may not be accurate of the actual light being emitted by that object.  An object that has a reflectivity of 1 would be a perfect reflector of infrared light.

All of these values, Transmittance, Emittance, and Reflectance, are measured in ratios.  Their values are expressed between 0-1.

In our next blog, we will go into more detail about the imaging factors of Transmittance.

Melissa Inspection Company is owned by Jeff Cardile.  Jeff is a Certified Thermographer.  Lookout Capital Inspections is proud to be a leader in the inspection industry.  Call Jeff at (469) 853-7336 for any of your inspection needs.