Explosion Proof Oxygen Monitor with 10+ Year Sensor

Explosion Proof Oxygen Monitor with 10+ Year Sensor

Item #: 99020 (IN-STOCK)


Product Summary

The AirCheck Explosion Proof Oxygen Deficiency Monitor is perfect for facilities that use inert gases including, but not limited to, nitrogen, helium, and argon. The enclosure is specifically designed to prevent the ignition of an explosion. The monitor is well suited for environments such as corn and grain processing facilities, powder coating plants, and the oil and gas industry where combustible dust and ignitable fibers are present. The monitor will remain accurate at temperatures as -40C. PureAire’s durable, non-depleting, zirconium oxide sensor will last up to 10+ years in a normal environment needing to be replaced.



Two-Year Extended Warranty Available for this product in the US, Canada, and Mexico
  • 99020 – Suitable for Class 1, Div 1 & 2, Groups B, C, D, Zones 1 & 2, Groups IIB+H2, IIA
  • 99045 – Suitable for Class 2, Div 1 & 2  Groups E, F, G
  • Long-life 10+ year average sensor life
  • Two-alarm relay setpoints available or alarm defaults are set for 19.5% and 18.0%
  • No scheduled maintenance required
  • 3-year warranty
  • Digital display
  • 4-20mA analog output (Active)
  • No Drift due to thunderstorms or barometric pressure changes
  • Wall mounting brackets
  • Built-in flow sample pump up to 100ft
  • CE, UL, and C UL approval on enclosure

The Explosion Proof Oxygen Monitor offers long-lasting O2 deficiency detection. PureAire’s oxygen monitors are reliable, affordable, low maintenance, and provide continuous monitoring for an average of 10 years and more.

Ideal for use in electrically classified locations, confined spaces, analyzer shelters, petrochemical plants, cryogenic gas storage, and locations requiring remote sampling. The EX oxygen monitor can detect leaks of inert gases such as nitrogen, helium, and argon. The explosion-proof oxygen monitor can detect gas leaks at temperatures as low as -40C.

The monitor features an easy-to-read local display, visual LEDs, and an audible alarm. The oxygen monitor can be linked to fire alarm systems for notification of all employees.

The zirconia sensor is not sensitive to temperature, humidity, or barometric pressure changes (including thunderstorms). Unlike other oxygen monitors, replacement sensors are not required, since we use a zirconium sensor, rather than a disposable electrochemical sensor lasting 1-2 years on average. “Supervised watchdog,” software runs 24/7 checking electronics and components. Any errors or inconsistencies are reported on the display.

By installing PureAire’s explosion-proof oxygen monitor, you can save as much as $400 annually and reduce the time-intensive cycle of replacing sensors.


Sampling Method Sample Draw
Range 0 – 25 %
Accuracy Delivers ±0.2%O2 accuracy (± 1% of full range)
Operating Temperature -40° to 140°F (-40° to +60ºC)
Display 3/4” backlit digital display
Sensor Type Long-life zirconium oxide sensor cell
Sensor Life 10+ years under normal conditions
Signal Outputs 4-20 mA Analog Output (Active)
Dual-Level Alarm Relay Contacts
Power Requirements 24 VDC
300 mA
Dimensions 266.7 x 190.5 x 177.8 mm
10.5(W) x 7.5 (H) x 7.0 (D) inches
Weight  16 lb
7.3 kg
Enclosure 99020 – Explosion-proof Class 1, Div 1 & 2, Groups B,C, & D, Zones 1 & 2, Groups IIB+H2, IIA
99045 – Explosion-proof Class 2, Div 1 & 2, Groups E, F, G
Calibration Calibration is not required. Periodic span adjustment as needed.
Country of Origin USA
Harmonized Tariff Code 8531.10.0045


Additional O2 Monitor Accessories List Price
8 Channel Controller $3,35.00 US (P/N # 99196)
Horn and Strobe  $190.00 US (P/N # 42002)
Remote Display $435.00 US (P/N # 99091)

Connects to DCS and PLC Controls

PureAire’s Explosion Proof Oxygen Monitor continually checks oxygen concentration levels and relays information to the distributive control system, PureAire’s single or multichannel controllers, or a programmable logic controller. The Explosion Proof Oxygen Monitor can be operated remotely over a 0.6-mile or 1,000-meter radius.

Improved Oxygen Sensor Cell

Rather than the electrochemical sensor used by most companies, PureAire uses a current limiting zirconium oxide sensor. This sensor runs reliably without a reference gas, so it can be used in all-nitrogen environments. The earth provides calibrated oxygen. When everything is at an ambient state, the sensor is challenged by approximately 20.9 percent oxygen. PureAire’s Explosion Proof Oxygen Monitor checks 0 to 100 percent oxygen levels and can operate at a lower temperature than the competition while needing no calibration. A simple, periodic span adjustment may be necessary. No scheduled maintenance is required to use the sensor; however, you may wish to subject it to nitrogen to test its response periodically.

Features of the Explosion Proof Oxygen Monitor 

PureAire’s Explosion Proof Oxygen Monitor comes with several configurations. All units have a built-in CPU and a low-cost, basic display-only monitor. For additional capabilities, a full-featured dual-level monitor is available. The unit features built-in alarm relays and an air check program that monitors sample flow, sensor cell, and electronics. For full transparency, fault information is transmitted to the alarm relay, front panel LED, and mA output.

99020/99045-Explosion-Proof Oxygen Monitor Literature

O2 Sample Draw Monitor Manual – Rev 5.04 (Post Summer 2023)

Safety Risks of Oxygen Deficiency 

NIH – Protocol for Use & Maintenance of Oxygen Monitoring Devices 2021

O2 EX Monitor Relays and Remote

Comparison O2 Zirconium Oxide vs EC cell

Comparison of 10-Year Sensor vs. Electrochemical

O2 Test Against other Companies

Oxygen Monitor Sales Presentation

Remote Digital Display p/n 99091

Horn/strobe 24VDC Red

horn and strobe

Flameproof / Hazardous Location Strobe with Optional Horn



8-Channel Programmable Controller for Oxygen, Carbon Dioxide, or Toxic/Combustible Gas Monitors

Domestic 24VDC Power Supply 45101


International 220V Power Supply 45102


Replacement Filter 90115