Environmental Monitoring Equipment & Supplies • Sales, Rental & Service by Enviro-Equipment — Charlotte, North Carolina USA

RAE Systems QRAE Plus 4 Gas Meter
  • One to four plug-in "smart" sensors.
  • Oxygen, Combustibles, and 9 toxic sensor options.
  • Integrated sampling pump.
  • Rugged housing for harsh environments.

This item is no longer available.

The QRAE Plus 4 gas meter is a one-to-four confined space gas detector/monitor with an intrinsically safe rating which is perfect for use in harsh environments due to its resistance to water, dust, and EMI.

It's tough, compact design has several user-friendly features such as simple button operation, a rechargeable/easily changeable battery pack (available in both alkaline and rechargeable versions) that provides up to 20 hours of continuous operation, and the option of substituting the H2S and CO sensors for SO2, NO, NO2, Cl2, HCN, NH3, or PH3 and a 16,000 point datalogging storage capacity for downloading to a PC.

One-to-four plug-in “smart” sensors:

Combustible, Oxygen, Hydrogen Sulfide, Carbon Monoxide

Optional substance-specific toxic sensors:

Sulfur Dioxide (SO2 ), Nitric Oxide (NO), Nitrogen Dioxide (NO2 ), Chlorine (Cl2 ), Hydrogen Cyanide (HCN), Ammonia (NH3 ), Phosphine (PH3 )

Rechargeable Lithium-ion battery pack

Provides up to 20 hours (more than 2 work shifts) of continuous operation

Rugged housing

Withstands use in harsh environments with a water and dust resistant case and strong protective rubber boot

Highly resistant to radio frequency and other electromagnetic interference

Strong, built-in sample draw pump with optional collapsible sample-probe

Also available in diffusion configuration

One-button calibration with auto-zero capability

Loud audible alarm

Bright visual alarm

Interchangeable Lithium-ion and alkaline battery packs





0-100% LEL



0-100% Vol


Oxygen (O2)



Carbon Monoxide (CO)

0-500 ppm

1.0 ppm

Hydrogen Sulfide (H2S)

0-100 ppm

1.0 ppm

Sulfur Dioxide (SO2)

0-20 ppm

0.1 ppm

Nitric Oxide (NO)

0-250 ppm

1.0 ppm

Nitrogen Dioxide (NO2)

0-20 ppm

0.1 ppm

Chlorine (Cl2)

0-50 ppm

0.1 ppm

Phosphine (PH3)

0-5 ppm

0.1 ppm

Ammonia (NH3)

0-50 ppm

1.0 ppm

Hydrogen Cyanine (HCN)

0-100 ppm

1.0 ppm


4.5"L x 3.0"W x 1.8"H (11.5 x 7.6 x 4.6 cm)


15 oz (425 g) with battery w/o rubber boot


  • Combustible: Protected dual-mode catalytic bead
  • Oxygen: Electrochemical fuel-cell
  • Toxic: Interchangeable electrochemical for CO, H2S, SO2, NO, NO2, Cl2, HCN, NH3, and PH3


  • Interchangeable Li-ion and alkaline battery packs
  • Rechargeable units include Li-ion battery pack with internal smart charging, 120V AC/DC wall adapter, and spare alkaline battery pack

Operating Hours

  • Diffusion: Up to 20 hours continuous operation with Li-ion battery, up to 18 hours wi h alkaline battery (typical without alarm)
  • Pump: Up to 16 hours continuous operation with Li-ion battery, up to 12 hours with alkaline battery (typical without alarm)


2 line, 16 digit LCD with LED back light automatically in dim light or alarm condition


1 operation and 2 programming keys

Direct Readout

  • Oxygen as percentage by volume
  • Combustible gas as percentage of lower explosive limit (LEL) (scalable using Correction Factors) - Thermal conductivity mode as percent volume (option)
  • Toxic gases as parts per million by volume
  • High and low values for all gases
  • STEL and TWA values of toxic gases
  • Battery and shutdown voltage
  • Date, time, elapsed ime, temperature


95dB buzzer (at 30 cm) and flashing red LED
to indicate exceeded preset limits

  • High: 3 beeps, vibra ions and flashes per second
  • Low: 2 beeps, vibrations and flashes per second
  • STEL and TWA: 1 beep, vibra ion and flash per second
  • Alarms latching wi h manual override or automatic reset
  • Additional diagnostic alarm and display message for low battery and pump stall


Highly resistant to EMI/RFI. Compliant with EMC Directive 89/336/EEC

IP Rating

IP-55, protected against dust and low-pressure jets of water from all directions


Standard 67 hours at one-minute intervals, with serial number of unit, user ID, site number, calibration date


Two-point calibration for zero and span, userselectable three-point calibration for oxygen

Sampling Pump

Optional, internal pump with user selectable flow-rate: High: ~250cc/min, Low: ~150cc/min

Hazardous Area Approval

  • US and Canada: UL, CSA (pump only),Classified as Intrinsically Safe for use in Class I, Division I Groups A, B, C, D, T3C
  • Europe: ATEX II 2G EEx ia d IIC T3 & T4


-4 to 113 F (-20 to 45 C)


0% to 95% relative humidity (non-condensing)


Belt Clip on rugged black rubber boot


  • Lifetime on non-consuming components (per RAE Systems Standard Limited Warranty)
  • 2 years for O2, LEL and CO, and H2S sensors
  • 1 year for all other electrochemical sensors
  • 1 year for pump and battery