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Portable Gas Detectors

GX-2012 Confined Space Gas Monitor with Internal Pump

4 Gas Sample Drawing Confined Space Detector with % Vol Combustible option

The Riken Keiki GX-2012 confined space gas monitor with pump, has multiple functions in one instrument. It has 3 operating modes. Customers can use the GX-2012 for Confined Space Monitoring, Leak Investigation in addition to underground leak checking using the Bar Hole mode.


Product Features

Sensor Technology

When selecting a flammable gas monitor, it is important to understand different sensor types and how they measure different conditions. Many Gases are flammable within a range of concentration known as the explosive or flammable range.

There are two limits to this range the lower explosive limit (LEL) and upper explosive limit (UEL). The Range differs for each flammable gas. At concentrations below the LEL, the mixture is too lean (insufficient fuel with respect to oxygen) to sustain combustion. In addition at concentrations above the UEL, the mixture is too rich (too much fuel with respect to oxygen) to sustain combustion.

Catalytic Bead (CB)

CB type sensors are intended for use below the LEL and are typically scaled from 0-100 % LEL. The full-scale indication therefore is the minimum concentration that could sustain combustion.

Thermal Conductivity (TC)

TC sensors do not require oxygen to operate. The most notable advantage of the TC type sensor is it’s ability to detect methane concentrations up to 100% by volume. This is well above the LEL and UEL ranges.

The GX-2012 Confined Space gas monitor with pump includes both catalytic bead and thermal conductivity sensors. These will automatically switch from a % LEL to a % Volume range.

Auto-ranging technology

Most dual range combustible instruments do not have the ability to automatically select the appropriate sensor. It is important to use the correct sensor based on the gas concentration encountered. If the instrument does not auto-range like the GX-2012 does, then the user must manually select the range. This may result in the user getting inaccurate readings or damaging the catalytic bead sensor.

When the GX-2012 detects high levels of methane, the display automatically changes from the % LEL to the % Volume. This is ideal for line purge testing. In Addition the catalytic sensor is protected from being exposed to a concentrated sample of methane that is well over scale. This auto-ranging combustible capability provides users with the flexibility to do general-purpose safety monitoring as well as detection of very high levels of flammable gases without any extra precautions or procedures.

The GX-2012 is built around high-quality micro-sensor technology, the GX-2012 is Riken Keiki’s  smallest personal 1-5 sensor gas monitor with a built in sample pump. Weighing only 350 grams, the GX-2012 can monitor the standard confined space gases (LEL combustibles, Oxygen content, Carbon Monoxide, and Hydrogen Sulphide).

The GX-2012 has a large LCD display that shows all gas readings, battery level and current time. In addition the screen will automatically back-light in alarm conditions. Users benefit from all Standard alarm types include vibration, visual in addition to audible alarms. the GX-2012 continuously checks itself for sensor connections, low battery, circuit trouble, low flow, and calibration errors. The GX-2012 operates with either Alkaline or Lithium Ion batteries. Users can change the battery packs without any special tools.


Gas Detected
Combustible Gases
(Methane as standard)
% Volume
Oxygen (O2)
Hydrogen Sulfide (H2S)
Carbon Monoxide (CO)
Detection Principle
Catalytic combustion
Thermal conductivity
Galvanic cell
Electrochemical cell
Detection Range
0 ~ 100% LEL
0 ~ 500 / 1,000 / 2,000 / 5,000 ppm
0 ~ 100% Vol.
0 ~ 40% Vol.
0 ~ 100 ppm
0 ~ 500 ppm
Accuracy Statement
(whichever is greater)
± 5% of reading or
± 2% LEL
(LEL mode only)
± 5% of reading or ± 2% of full scale
± 0.5% O2
± 5% of reading or ± 2 ppm H2S
± 5% of reading or ± 5 ppm CO
Sampling Method Internal sample pump, flow rate nominal 0.5 LPM, includes hydrophobic filter
Display Digital LCD with 7 segments, auto backlight during alarm
Preset Alarms
(User Adjustable)
1st alarm 10% LEL
2nd alarm 20% LEL
Over alarm 100% LEL
No alarms for
% Vol. CH4
Low alarm 19.5% High alarm 23.5% Over alarm 40.0% 1st 5 ppm
2nd 10 ppm
TWA 10 ppm
STEL 5 ppm
Over 100 ppm
1st 25 ppm
2nd 50 ppm
TWA 25 ppm
STEL 200 ppm
Over 500 ppm
Alarms Types Gas alarms: 1st and 2nd, STEL, TWA (user adjustable) and OVER
Trouble alarms: Sensor connection, low battery, low flow, circuit trouble and calibration error
Alarm Methods Gas alarms: Flashing lights, two tone buzzer, and vibration
Trouble alarms: Flashing lights, trouble displayed, intermittent buzzer, and vibration
Operating Temp. & Humidity -20°C to +50°C (-4°F to 122°F)
0 to 95% RH, non-condensing
Response Time Within 30 seconds (T90)
Continuous Operation Alkaline battery: 15 hours Li-Ion battery: 10 hours
21°C (70°F)
Power Source Li-Ion battery pack, or 3 “AA” Alkaline battery pack; interchangeable
Safety Rating ATEX, TIIS, IECEx, CE,
c CSA us classified as intrinsically safe. Class I, Division 1, Groups A, B, C, D
Dimension & Weight Approx. 143 (H) x 71 (W) x 43 (D) mm (5.6″ H x 2.8″ W x 1.6″ D), approx. 350 g (12.3 ounces)
Case Material High dust & water resistant design. RFI shielded high impact plastic with protective rubber over-molding
Controls Five buttons: POWER / ENTER, DISPLAY, AIR, RESET, SHIFT
Standard Accessories • Belt clip • Rubber nozzle, 5cm (2.5″) • Manual
Optional Accessories • SDM-2012 calibration stations • Calibration kit
• Li-Ion battery pack • AC or DC Charger
• Sample draw hoses (3m standard, up to 10m max. available)
• Carrying case
• Datalogging software
• 25cm (10″) Probe
Configurations 1, 2, 3, 4, or 5 sensor units
Li-Ion or alkaline battery pack options
Warranty Two years material and workmanship

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