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1. Are calibrated leak testers available to confirm monitor is calibrated correctly?
YELLOW JACKET does not sell calibrated leak testers, but gases for testing leak monitor installations are available through MSA Mine Safety Appliances, 121 Gamma Drive, Pittsburgh, PA 15238-2919.1-800-672-2222
2. What refrigerants will the leak monitors detect?
Leak monitors will detect most CFC, HFC, and HCFCs such as R-11, R-12, R-13, R-22, R-113, R-123, R-134a, R-404A, R-407C, R-410A, R-500, R-502, and R-507. YELLOW JACKET also has leak monitors available for ammonia and hydrocarbon-based refrigerants.
3. Can the leak monitor be calibrated for specific applications?
Yes, the YELLOW JACKET leak monitor can be calibrated for specific applications. Contact customer service for your specific need.
4. If the unit goes into alarm, can it switch on the fan? Can it turn off the system at the same time?
The leak monitor has a pair of dry, normally open/normally closed contacts that can handle 10 amps at 115 volts. When the sensor indicates a gas presence higher than the set point, it opens the closed contacts and closes the open contacts, which will turn equipment on or off.
5. After a unit goes into alarm and the contacts close, what can it be connected to?
The open contacts can shut the system down, call a phone number, turn on a fan or emergency light, etc.
6. How does the sensor work?
When the sintered metal oxide surface within the sensor absorbs gas molecules, electrical resistance is reduced in the surface allowing electrons to flow more easily. The system controller reads this increase in conductivity and signals an alarm. Metal oxide technology is proven for stability and performance.
7. What is the detection sensitivity level of YELLOW JACKET fixed monitors?
The dual sensitivity system has a low alarm level of about 100 ppm and a high level of about 1000 ppm for most CFC, HFC and HCFC products. The high level for R-123 is an exception at about 300 ppm. Ammonia detection levels are about 100 ppm low and about 150 ppm high. The alarm level of all YELLOW JACKET single level systems is about 100 ppm. Detection levels are preset at the factory to cover most situations. If necessary, however, you can order a custom level, or adjust the set point on site.
8. What concentration must be detected?
Depends on the refrigerant. For a more thorough answer, terms established by U.S. agencies must first be understood:
• IDLH – Immediately Dangerous to Life and Health
• TWA – Time Weighted Average concentration value over an 8-hour workday or a 40-hour work week (OSHA or NIOSH levels)
• STEL – Short Term Exposure Level measured over 15 minutes (NIOSH)
• Ceiling Concentration (c) that should not be exceeded in a working day (OSHA)
Obviously, the first consideration is IDLH. For most refrigerants, the IDLH is relatively high (e.g. R-12 is 15,000 ppm), and such a concentration would be unusual in a typical refrigerant leak situation. Leak detection, however, is still an immediate condition, so the STEL should be the next consideration, followed then by the 8-hour TWA or Ceiling Concentration. R-22, for example, has a STEL of 1250 ppm and a TWA of 1000 ppm. (The TWA for most refrigerants is 1000 ppm).
The draft UL standard for leak monitors requires gas detection at 50 percent of the IDLH. In other words, R-12 with an IDLH value of 15,000 ppm must be detected at 7500 ppm. As with most refrigerants, the TWA is 1000 ppm.
All of the foregoing suggests that for most CFC, HFC and HCFCs, detection at 1000 ppm provides a necessary safety margin for repair personnel. Ammonia with a significantly lower IDLH of 300 ppm and a TWA of 25 ppm requires detection at 150 ppm to comply with 50 percent IDLH requirements. R-123 has a TWA of 50ppm and an IDLH of 1000 ppm; therefore detection at 100 ppm provides a good margin of safety.
A monitor with a detection threshold of about 100 ppm for any gas provides an early warning so that repairs can be made quickly. This can save refrigerant, money and the environment.
9. Will the system need recalibration?
Factory calibration should be adequate for 5-8 years. Routine calibration is unnecessary when used with intended refrigerants. YELLOW JACKET sensors cannot be poisoned, show negligible drift, and are stable long term. However, you should routinely check performance.
10. Can there be a false alarm?
For monitoring mixtures, the semiconductor must be able to respond to molecularly similar gases. With such sensitivity, false alarms can be possible. Engineered features in YELLOW JACKET monitors help minimize false alarms:
• The two level system waits about 30 seconds until "certain" that gas is present before signaling.
• At about 100-1000 ppm calibration levels, false alarms are unlikely.
To prevent an unnecessary alarm, turn off the unit or disable the siren during maintenance involving refrigerants or solvents. Temperature, humidity or transient gases may occasionally cause an alarm. If in doubt, check with us.
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