Manufacturer: RAE Systems
Order / Quote

The QRAE Plus is a full-featured, compact, one-to-four sensor confined space gas detector. Its features include easy-to-change, externally accessed battery packs (available in both alkaline and rechargeable versions) and water-resistant case design. The rechargeable, Lithium-ion battery pack provides up to 20 hours of continuous operation. The QRAE Plus includes 16,000 datalogging points of storage capacity for download to PC compatible with Windows 98, NT, 2000, and XP.

Key Features

  • One-to-four plug-in "smart" sensors: Combustible, Oxygen, Hydrogen Sulfide, Carbon Monoxide
  • Optional substance-specific toxic sensors: Sulfur Dioxide, Nitric Oxide, Nitrogen Dioxide, Chlorine, Hydrogen Cyanide, Ammonia, Phosphine
  • 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


  • 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

Sensor Specifications

Range  Resolution 
Oxygen 0-30.0% 0.10%
Combustible 0-100% LEL 1% LEL
Carbon Monoxide 0-500 ppm 1 ppm
Hydrogen Sulfide 0-100 ppm 1 ppm
Sulfur Dioxide 0-20.0 ppm 0.1 ppm
Nitric Oxide 0-250 ppm 1 ppm
Nitrogen Dioxide 0-20.0 ppm 0.1 ppm
Chlorine 0-10.0 ppm 0.1 ppm
Hydrogen Cyanide 0-100 ppm 1 ppm
Ammonia 0-50 ppm 1 ppm
Phosphine 0-5.0 ppm 0.1 ppm


  • 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 with 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

  • Instantaneous reading of up to four sensors
    • 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
  • Low Flow Alarm Auto shut-off pump at low flow condition

Hazard Area

  • US and Canada: UL, CSA (pump only), Approval 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 Approval


  • -4 to 113o F (-20 to 45o 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
Specifications are subject to change

  • Confined Space Entry
  • Waste water treatment plants
  • Marine and off-shore oil wells
  • Landfill operations
  • Trenches, silos, railcars
  • Coal mines
  • Cruise ships
  • Sewers and manholes
  • Tunnels
  • Refineries and petrochemical plants, including off-shore drilling and plant shut downs
  • Power plants
  • Pulp and paper industry
  • Steel mills