Presentation

INFRARED SPECTRUM & THE SCIENCE BEHIND THERMAL IMAGING:

What is infrared? Well the best way to develop this concept would be to list out a few technical ideas, thoughts, and constants:
Infrared energy is part of the electromagnetic spectrum.
Visible light down to wavelength 0.7 mm
Infrared wavelength 2 mm to 100 mm.
Infrared behaves similarly to visible light.
Infrared travels at the speed of light (2.988 x 1010 cm/s).
Infrared can be reflected, refracted, absorbed and emitted.
Infrared is emitted by all objects as a function of their temperature.
Infrared is generated by the vibration and rotation of atoms and molecules.
Absolute zero = -273 Degree C.

Stefan – Boltzmann Law: Infrared power given off by an object is proportional to the 4th power of the objects absolute temperature. Power output would increase very rapidly with object temperature.
Plank’s Law: Emissive radiated power is distributed by wavelength for a specific temperature of an ideal radiating surface. This theorem is represented as a family of curves that look like arches. As the temperature of a surface increases, each arch is higher and broader, meaning more infrared power and covers more wavelengths.
Heat Transfer:
Conduction – Heat travels from the warm end toward the cool end
Convection – Heat from a burner is transferred to circulating water in a tank
Radiation – Heat travels through space in the form of infrared radiation


The Electromagnetic Spectrum


The choice of an infrared band depends on the type of performance required for your specific application. There are two (2) bands to consider. The first band is the mid wavelength band (MWIR) in the range of 3 mm to 5 mm, while the long wavelength band (LWIR) is in the range of 8 mm to 14 mm. Note the high interference zone between the two (2) bands. The MWIR is appropriate for hotter objects, or if sensitivity is less important than contrast. Additionally, smaller optics are required in this range. The LWIR is preferred for high performance thermal imaging due to its sensitivity to ambient temperature of objects and better transmission through mist and smoke.
Summarizing the differences between MWIR & LWIR and their specialized applications. The two bands differ in background flux, temperature contrasts, and atmospheric transmission:

MWIR
High resolution due to smaller optical diffraction.
High contrast.
Clear weather performance.
Transmission through high humidity conditions.

LWIR
Good performance in fog, haze and mist.
Atmospheric condition has little effect on transmission.
Reduces solar glint and fire flare sensitivity.

APPLICATION CHART

THERMAL IMAGES

View more information and examples on thermal imaging!

SAMPLE GENERAL FIELD OBSERVATIONS

Please note that the field observations below are not intended for use as an in depth engineering field survey, but as a general observation for the enhancement of the facility. We offer the following observations and recommendations for your consideration:

1. Three-phase system protection is often accomplished through the use of fuses. Fuses are used to interrupt fault currents and certain types limit fault current levels to downstream equipment. The recommended practice is to have fuses of the same manufacturer in each phase of any given circuit. Fuses from different manufacturers that are rated the same may in fact have slightly dissimilar operating characteristics. These differences in operating characteristics may be caused by the use of unlike materials. Furthermore, the labels from different manufacturers may lead to maintenance personnel misreading the labels and installing the wrong fuses. Fuses of the same size may have different time delay characteristics. Mismatched fusing may reduce the overall system protection. Improperly sized fuses may create a safety hazard. The following locations have fuses of different manufacturers utilized at the same time.
   • Equipment Identification


2. The 2002 National Electrical Code (NEC) Article 110-26 specifies that: "Sufficient access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment." For equipment with a nominal voltage to ground between 0 and 600 volts, the minimum clear working distance is three (3) feet. We suggest implementing an awareness program to inform your employees. This program should include the code requirements and the potential hazards of not maintaining this working clearance. The following areas did not have the minimum working distance:
   • Equipment Identification


3. The 2002 National Electrical Code (NEC) Article 210-20 states that where a branch circuit supplies continuous loads or any combination of continuous and non continuous loads, the rating of the over current device shall not be less than the non continuous load plus 125% of the continuous load. Example, the maximum continuous load on a 20 Amp Circuit Rating is 16 Amps. We recommend reviewing the loads at the following locations:
   • Equipment Identification


4. We recommend a review of egress from the facility and/or the need for exit signs in the following areas according to the Code of Federal Regulations, Labor 29, Parts 1910.36 & 1910.37:
   • Equipment Identification


5. We recommend completing a facility wide labeling system of all Electrical Equipment, Electrical Rooms, Power Panels, Lighting Panels, Disconnect Switches, MCC's, Starters & Breakers. The 2002 National Electric Code (NEC), Sections 110 & 408 are a good starting point in the facility labeling process.


6. Consider cleaning, general and preventive maintenance of all electrical equipment such as Power & Lighting Panels, Disconnect Switches, MCC's, Starters & Breakers, etc.


7. Consider performing a Ground Grid Analysis & Lightning Protection Survey to determine the capability and reliability of the existing protective systems.


8. Consider performing the following facility wide studies: Short Circuit, Load Flow, Flash Hazard and System (Relay) Coordination. Please feel free to contact us for further details on Industry Standards, NEC Requirements, Economics and general information on Power System Studies.


9. The following locations require cover plates, breaker blanks (space covers) or dead front covers. These items are an integral safety design feature of the equipment, and should not be excluded.
   • Equipment Identification


10. Note that numerous locations throughout the facility were found to have different sized cables fed from the same breaker, reference the 2002 NEC for Safe Practice.


11. The following locations have loose, non-terminated wires & cables:
    • Equipment Identification


12. We would recommend implementing a Maintenance Program that includes Oil Quality and Dissolved Gas Analysis Tests on all oil field transformers. These tests are to insure the oil maintains good electrical properties by monitoring its dielectric strength.


13. Review use and/or maintenance of locks. Implement a locking system with a master key for maintenance personnel to prevent future complications. The following locations had locks removed:


14. The following abnormalities were found on these transformers:
    • T34-0406, check fluid level and/or gauge.
    • T20-0402, check fluid level.
    • T20-0400, front right cooling fan has fallen off, motor running. Back left cooling fan has fallen off, motor running.
    • T12-0401, check fluid level and/or gauge.
    • T13-0415, need to add dry nitrogen. Transformer is under a vacuum (-1.0 psi).

REFERENCE MATERIALS