Gas detector - GX-3R (RIKEN KEIKI Co., Ltd.)

Gas detector - GX-3R
  • Monitoring 4 types of gas (LEL/O2/CO/H2S)
  • 3-year warranty
  • Only Approx. 100g
  • Water and dust resistant, IP66/68
  • Loud alarm buzzer 95dB at 30cm


Category Portable gas detector
Type Multi gas
Target gas LEL/O2/CO/H2S
Detection range 0~100%LEL(HC/CH4)
Sampling method Diffusion
Type of alarm Gas alarms, Fault alarms
Display of alarm Flashing light, buzzer, vibration
Explosion proof Intrinsically safe
Ingress proof rating IP66/68
Power source Lithium ion rechargeable battery unit
Continuous operation Approx. 40 hours after full charge(with long battery mode)
Dimensions & Weight Approx. 58(W)×65(H)×26(D)mm
Approx. 100g
Operating temperature & Humidity -40℃ to 60℃, (-40℃ to 140F)
0 to 95% RH, (Non-condensing)

You can understand at a glance! GX-3R

Model GX-3R
Detection gas 1 to 4 types
Battery Rechargeable battery
Detection method Diffusion type "Pump unit available as option(see next page)
Alarm setpoint Setting can be changed.
Combustible gas conversion function 26 types
Data logger function Records up to 3,600 data.
Confirmation beep function Can be changed (see section below for details).
Lunch break function Can be changed (see section below for details).
Protective cover Provided as standard
Heat-resistant case, leather case Optional accessories
Five-component detection ⇒We recommend the GX-3R Pro model.
Dry battery power ⇒We recommend the GX-3R Pro model.
Bluetooth ⇒We recommend the GX-3R Pro model.

Combustible conversion gas list

Conversion gas Gas name displayed Calibration gas conversion
CH4 i-C4H10
Methane CH4
Isobutane i-C4H10
Hydrogen H2
Methanol CH3OH
Acetylene C2H2
Ethylene C2H4
Ethane C2H5
Ethanol C2H5CH
Propylene C3H6
Acetone C3H6O
Propane C3H8
Butadiene C4H6
Cyclopentane C5H10
Benzene C6H6
N-hexane n-C6H14
Toluene C7H8
N-heptane n-C7H16
Xylene C8H10
N-nonane n-C9H20
Ethyl acetate EtAc
Isopropyl alcohol IPA
Methyl ethyl ketone MEK
Methyl methacrylate MMA
Dimethyl ether DME
Methyl isobutyl ketone MIBK
Tetrahydrofuran THF

Mounted with the new R sensors, which are long-term consistence sensors

GX-3R mounted with the new R sensor series, which have dramatically improved the performance from the previous sensors. The sensors have 5-year warranty*.

Gas detector - GX-3R

Wide range of safety functions

Combustible gas conversion function

Eliminates the need for complex calculations.
Allows direct readout of 26 different combustible gas types.

Lunch break

Enabling this function retains the TWA and peak values and allows integrating measurement whether power is on or off.

Alarm setpoints can be freely adjusted

You can now adjust alarm setpoints on the main unit.
Allows monitoring based on the customer's own standards.

Cal. Limit

Indicates the number of days until recommended regular maintenance when the power is turned on.
Reminds the user to perform maintenance on the product to ensure safe use.

Confirmation beep

This function provides audible notification that the device is functioning correctly.
Buzzer sounds at preset intervals while measurement is underway.

Optional accessories

Gas detector - GX-3R
1 Heat-resistant case Case for protection from heat resource.Uses a safety pin. Part No.4777 4259 40
2 Leather case Case for protection against dirt.Uses the clip on the unit. Part No.4777 4257 00
3 Belt clip Allows the product to be attached to a belt or pocket. Part No.4777 9202 40
4 Arm / Ankle belt Belt for securing the unit to your arm or ankle. Part No.4777 9293 30
5 Protective film Protects the display. (set of 5) Part No.4777 9296 50
6 Manual suction unit External manual pump. Draws in at greater flow rates than electric pump. (with sampling probe) Part No.4777 9302 80
(with 8m float-type tube) Part No.4777 9304 20
(with 30m weighted tube) Part No.4777 9305 00
7 Charging cradle Cradle for recharging the unit. Cradles can be interconnected. Part No.BC-3R 00
8 Five-unit AC adaptor One AC adapter recharges up to five units,
*Recharging times remain unchanged.
(with 22.5cm cable) Part No.4777 9329 70
(with 60cm cable) Part No.4777 9319 80
(with 120cm cable) Part No.4777 9333 20
9 Calibration adapter Adapter for applying gas to GX-3R during bump test and calibration. (with outlet nipple and rubber seal) Part No.4777 9311 00
10 Data management program Software for viewing and managing measurement data. Part No.9811 0870 60

Pump unit RP-3R

An external electric pump.Allows use for suction sampling.

Gas detector - GX-3R


Model RP-3R
Suction flow rate High mode : 0.4 L / min or more
Low mode : 0.25 L / min or more
Battery AA alkaline battery×1
Continuous operating time High mode : Approx. 10 hours
Low mode : Approx. 16 hours
Temperature range -20℃ -+ 50℃ (at a constant condition)
Humidity range 0-95% RH (non-condensing)
Explosion-proof class Inherently safe explosion-proof construction
ATEX : Ⅱ1G Ex ia ⅡC T4 Ga
IECEx : Ex ia ⅡC T4 Ga
Japan Ex : Ex ia ⅡC T4 Ga
Structure Drip-proof and dust-proof performances compliant to IP67 level
Dimensions / Weight Approx. 82mm(W) × 96mm(H) × 29mm(D) /
Approx. 120g
Optional accessories 8m float-type gas sampling tube
Filters (set of 10)
Meshes (set of 10)

* Cannot be connected to other models GX-2009, GX-3R Pro and others.

Docking station SDM-3R

Allows the user to perform a simplified pre-work check (bump test) and gas calibration automatically.

Gas detector - GX-3R


Model SDM-3R
Power supply 100 to 240 V AC ±10%, 50 / 60 Hz
Suction flow rate Approx. 0.25 L/min
Temperature range 0-40℃ (at a constant condition)
Humidity range 0-95% RH (non-condensing)
Dimensions / Weight Approx. 130mm (W)×110mm(H)×250mm(D) /
Approx. 800g
Optional accessories Connecting fixture, wall-mounting fixture, exhaust tube

Also consider the high-spec [GX-3R Pro] model!

[GX-3R Pro] model
  • Up to 5 gases can be detected
    Detects carbon dioxide and sulfur dioxide in addition to combustible gases, O2, H2S and CO.
  • Connects with Bluetooth
    Allows connection to a smartphone. Use the dedicated app iOS, Android to send alarm notifications by email.
  • Runs on either dry cell or rechargeable batteries
    Unit system for easy replacement.
  • Easy-to-read full-dot display
    Supports a total of 11 different languages.


Model GX-3R
Detection method Diffusion type (Changeable to sampling type by attaching RP-3R)
Gas alarm indication Lamp flashing, continuous modulating buzzer sounding, gas concentration display blinking, vibration
Reset operation : Self-latching
Fault alarm System abnormality, sensor abnormality, battery voltage drop, calibration failure
Fault alarm indication Lamp flashing, intermittent buzzer sounding, detail display
Reset operation : Self-latching
Displays LCD digital, backlight, operation status, clock, battery level, temperature, peak reading, calibration notification
Buzzer volume Approx. 95dB (30cm)
Data logger function Maximum number of items : 3,600 Interval : 5 minutes (adjustable) Communication system : IrDA
Explosion-proof class ATEX
Ⅱ1G Ex da ia ⅡC T4 Ga / IM1 Ex da ia I Ma (With combustible gas sensor)
Ⅱ1G Ex ia ⅡC T4 Ga / IM1 Ex ia I Ma (No combustible gas sensor)
Ex da ia ⅡC T4 Ga / Ex da ia I Ma (With combustible gas sensor)
Ex ia ⅡC T4 Ga / Ex ia I Ma (No combustible gas sensor)
Japan Ex
Ex ia ⅡC T4 Ga
Protection level Equivalent to IP66/68 (2m, 1h)
Power source Lithium ion rechargeable battery unit Charging time : Approx. 3 hours
Continuous operating time*1 Long-life battery mode on : Approx. 40 hours (25℃, fully charged, no alarm, no lighting)
Long-life battery mode off : Approx. 25 hours (25℃, fully, charged, no alarm, no lighting)
Temperature range / humidity range*2 -40℃~+60℃ (no sudden changes), 0~95% RH (non-condensation)
External dimensions / weight Approx. 58mm (W) × 65mm (H) × 26mm (D) (excluding protrusions) / Approx. 100g
Warranty 3 years (optional 2 years extension available)

*1 Varies depending on sensor type installed. Please contact Riken Keiki for more information.
*2 In temporary ambient conditions for approximately 15 minutes. The operating temperature and humidity ranges for continuous ambient conditions are as follows : Temperature : -20℃ to +50 ℃ (no sudden changes) / Humidity : 10 to 90 % RH (no condensation)

Detection gas

Detection target gas Combustible gas
(HC or CH4)
Oxygen(O2) Carbon monoxide (CO) Hydrogen sulfide(H2S)
Detection principle New ceramic type Electrochemical type
Detection range
(service range)
0~100% LEL 0~25.0 vol%
(~40.0 vol% )
(~200.0 ppm)
1 digit 1% LEL 0.1 vol% 1ppm 0.1 ppm
Gas alarm setpoint
(can be set by user)
1st alarm : 10% LEL
2nd alarm : 25% LEL
3rd alarm : 50% LEL
OVER alarm : 100%LEL
L alarm : 19.5vol%
LL alarm : 18.0 vol%
H alarm : 23.5vol%
OVER alarm : 40.0vol%
1st alarm : 25ppm
2nd alarm : 50ppm
3rd alarm : 1200ppm
TWA alarm : 25ppm
STEL alarm : 200ppm
OVER alarm : 2000ppm
1st alarm : 5.0 ppm
2nd alarm : 30.0ppm
3rd alarm : 100.0 ppm
TWA alarm : 1.0 ppm
STEL alarm : 5.0 ppm
OVER alarm : 200.0 ppm

Standard accessories

Gas detector - GX-3R

Type list

TYPE Detection gas

*CO sensor with reduced H2 interference