AwAir gas detection system for Refuge Alternatives uses gas extraction and includes automatic calibration.
Rel-Tek Paper for Refuge Alternative Session at SME 2019 Annual Conference, Denver, CO
Authors: Albert E. Ketler P.E., Lauren E. Sargent, Craig D. Mattock,
Thayananthan Narayanan, and Bryan A. Dale.
Abstract: “The AwAirTM gas detection system manufactured by Rel-Tek Corporation monitors five gases (CH4, CO2, CO, O2 and H2) inside and outside of a Refuge Alternative (RA) using gas extraction means via five ¼” OD Teflon tubes. A data viewing window displays sensor values, alarm and automatic calibration status. An Intrinsically Safe external alarm and two manual switches are provided for occupant controls. Enclosed in two XP boxes, are one housing the five gas sensors and computer electronics, and another holding a 96-hour battery and AC charger. The MSHA approval (18-A150009-0) covers the complete AwAir system, including the fully automatic sensor calibration utility which maintains sensor accuracy for up to five years on standby. Redundant air pumps are capable of drawing gas sample from as far as 100 ft (30.4m) so can accommodate “Built-in-Place” RAs as well. Recent innovations have replaced the PLC with an embedded PC, now providing HMI color graphics, as well as data logging, diagnostics, networking and other PC capabilities.”
Introduction -- This Part 18 approved system (#18-A150009-0) is available for use in your Refuge Alternatives (emergency underground shelters.) This electrical approval also covers use as a stand-alone system for monitoring gob areas and other hazardous mine locations. For nearly a decade Rel-Tek has worked to develop and perfect this unique gas monitoring system to satisfy the demanding RA monitoring requirements, per 30 CFR, Parts 7 and 75. Conferring with MSHA and NIOSH for assessment of safety issues along the way, the result is an optimized air monitoring package that exceeds the requirements, while enhancing packaging by eliminating many individual gas sensors. Rel-Tek’s unique automatic sensor calibration utility maintains sensor accuracy for years, unattended, thus virtually eliminating the cost of maintenance.
The “AwAir” trademark succinctly describes this system, as it addresses the life-support environmental safety of miners residing inside an RA. It provides reliable information to the occupants and to the surface and other support personnel on the air quality in and around the RA living quarters.
Basic System -- Physically, AwAir comprises two, steel explosion-proof boxes. Sample-draw gas tubing entering through flame arrestors cascades through 4 gas sensors, continuously sampling the gases inside the living chamber, inside the air lock, and outside the RA. The fifth sensor (H2) draws its sample from the battery box. Gas sensors inside the XP control housing analyze the sequenced gas streams for air quality. The sensor readings are viewed through a polycarbonate window on the enclosure lid, showing the detected levels of oxygen, carbon monoxide, carbon dioxide, methane and hydrogen. Miners inside the shelter are alerted of any hazardous condition by a visual (amber flasher) and an audible (bleeper) alarm. An alarm silence switch is provided. A hydrogen sensor and fourth sample tube are included for monitoring the battery enclosure. An isolated auxiliary relay is provided for controlling an external oxygen supply (for use by others.) An embedded PC controls the gas sampling and monitoring processes, providing digital displays of values and alarms and optical fiber cable link for digital communications with other RA units and with the surface station.
An optical fiber cable provides 2-way data communications with a surface computer running Millennia software. Also, NIOSH is developing “through-the-earth” communications that can access the AwAir system computer.
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use in your Refuge Alternatives (emergency underground shelters.) This electrical approval also covers use as a stand-alone system for monitoring gob areas and other hazardous mine locations. For nearly a decade Rel-Tek has worked to develop and perfect this unique gas monitoring system to satisfy the demanding RA monitoring requirements, per 30 CFR, Parts 7 and 75. Conferring with MSHA and NIOSH for assessment of safety issues along the way, the result is an optimized air monitoring package that exceeds the requirements, while enhancing packaging by eliminating many individual gas sensors. Rel-Tek’s unique automatic sensor calibration utility maintains sensor accuracy for years, unattended, thus virtually eliminating the cost of maintenance. 
flame arrestors cascades through 4 gas sensors, continuously sampling the gases inside the living chamber, inside the air lock, and outside the RA. The fifth sensor (H2) draws its sample from the battery box. Gas sensors inside the XP control housing analyze the sequenced gas streams for air quality. The sensor readings are viewed through a polycarbonate window on the enclosure lid, showing the detected levels of oxygen, carbon monoxide, carbon dioxide, methane and hydrogen. Miners inside the shelter are alerted of any hazardous condition by a visual (amber flasher) and an audible (bleeper) alarm. An alarm silence switch is provided. A hydrogen sensor and fourth sample tube are included for monitoring the battery enclosure. An isolated auxiliary relay is provided for controlling an external oxygen supply (for use by others.) An embedded PC controls the gas sampling and monitoring processes, providing digital displays of values and alarms and optical fiber cable link for digital communications with other RA units and with the surface station.
An optical fiber cable provides 2-way data communications with a surface computer running Millennia software. Also, NIOSH is developing “through-the-earth” communications that can access the AwAir system computer.
