Oldham BM25 Transportable Multigas Monitor

Code: 6514842-L12301
  • Portable area monitor
  • Two-year warranty (excludes consumables sensors, filters etc)
  • Ideal For turnaround & shutdown work

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The Oldham BM25 Gas Detector is an area monitor that can detect up to five gases; flammable, oxygen and toxic gases can be monitored simultaneously. Suitable for temporary gas detection work, perimeter monitoring, or areas where fixed gas detectors cannot be installed. Pre-calibrated smart sensors can be swapped, providing versatility for deployment in various applications.

Multiple units can be daisy-chained to provide broad area coverage using alarm transfer kits 25m, 50m or 100m; if one BM25 detects gas, all connected units alarm. Alternatively, a wireless BM25 dispenses the need for cabling using a 2.4GHz signal.

Switch the BM25 on, and it automatically adds to an existing wireless mesh network. The connection is peer-to-peer, with no hierarchy, forming a virtual net allowing each detector on the network to transmit, receive and relay information. The MX 40 controller gives the operator wireless network access to perform alarm resets and view the status of detectors and readings. The data is automatically re-routed if a detector goes down or is removed for charging or maintenance. If an obstruction inhibits the line of sight signal, other detectors in the group will continue to operate, and the network will self-heal when the obstacle is removed.

The following gases can be detected: Combustible Gases, Methane, Propane, Butane, Isobutane, LPG, Ethanol, Pentane, Oxygen, Carbon Monoxide, Hydrogen Sulfide, Hydrogen, Sulfur Dioxide, Chlorine, Nitrogen Dioxide, Nitric Oxide, Hydrogen Chloride, Hydrogen Cyanide, Ammonia, Phosphine, Arsine, Silane, Ethylene Oxide, Carbon Dioxide, Isobutylene, Fluorhydric Acid, Ozone, Phosgene, Chlorine Dioxide and Hydrazine.


  • Standalone or multiple detector operation
  • Backlit graphic liquid crystal display
  • Pumped versions available
  • Infrared sensors for certain gases
  • Wireless communication distance: 0.6 mile/1000m line of sight
  • Alarms: Visual 360 and audible siren (103 dB @ 1m)
  • Four months of data storage, when memory is full, the oldest data is overwritten
  • Ingress Protection IP66
  • STEL and TWA values
  • Power (run time) up to 170 hours, 135 hours wireless
  • Up to 30 BM25 detectors on a single network
  • If overturned, product design ensures sensors are not blocked and will still read
  • Recharge time 4.5 hours
  • Safe trickle charger for longer-term monitoring in classified zones
  • Approvals ATEX & IECEx, CSA, INMETRO & EAC
  • By Teledyne, Oldham, GMI. Historic brand Industrial Scientific
  • Size: 470 x 180 x 190 mm (16.7 x 7.1 x 7.5”). Weight: 6.8 kg (15 lbs)
  • Included: Detector, instruction manual, charger with universal power cord, calibration adapter and maintenance tool.

Order Information

BM25 Gas analyser part numbers are custom-made according to the sensors and options required. Common configurations are detailed below; for others, please get in touch with us.


6514842-L12300 Detector ATEX approved, LEL Methane, CO, H2S, O2, no pump.
6514842-L12301 Detector ATEX approved, LEL Methane, CO, H2S, O2, with pump.
6514872-L12300 Detector CSA approved, LEL Methane, CO, H2S, O2, no pump.
6514872-L12301 Detector CSA approved, LEL Methane, CO, H2S, O2, with pump.


6514889-L12300 Detector ATEX approved, LEL Methane, CO, H2S, O2, no pump.
6514889-L12301 Detector ATEX approved, LEL Methane, CO, H2S, O2, with pump.
6514891-L12300 Detector CSA approved, LEL Methane, CO, H2S, O2, no pump.
6514891-L12301 Detector CSA approved, LEL Methane, CO, H2S, O2, with pump.

Replacement Sensors

LEL Catalytic Bead Sensors

6313888 LEL/Methane (BM 25 ATEX only)
6313969 LEL/Methane (BM 25A CSA only)

LEL Infrared Sensors

6314064 IR, 0-100% LEL CH4 (5% vol)
6314065 IR, 0-100% LEL CH4 (4.4% vol)
6314087 IR, 0-100% LEL (Propane)
6314088 IR, 0-100% LEL (Butane)
6314090 IR, 0-100% LEL LPG
6314091 IR, 0-100% LEL (Ethanol)
6314092 IR, 0-100%Vol. CH4

CO2 Infrared Sensor

6313818 IR, Carbon Dioxide (CO2, 0-5% vol.) medium

Electrochemical Sensors

6313811,  AsH3 (Arsine 0-1ppm), mini
6313809, Cl2 (Chlorine 0-10ppm), mini
6313843, Cl2 (Chlorine 0-10ppm), medium
6313841, ClO2 (Chlorine Dioxide 0-3ppm), medium
6313787, CO (Carbon Monoxide 0-1000ppm), mini
6313826, CO (Carbon Monoxide 0-2000ppm) (High), mini
6313868, CO null H2(Carbon Monoxide 0-500ppm),mini
6313823, CO/H2S (Carbon Monoxide/Hydrogen Sulfide), medium
6313812, COCl2 (Phosgen 0-1ppm), mini
6313821, ETO (Ethylene Oxide 0-30ppm), medium
6313820, F2 (Fluor 0-1ppm), mini
6313803, H2 (Hydrogen 0-2000ppm), mini
6313788, H2S (Hydrogen Sulfide 0-100ppm), mini
6314206, H2S null CO (Hydrogen Sulfide 0-100ppm), mini
6313804, HCl (Hydrogen Chloride 0-30ppm), mini
6313805, HCN (Hydrogen Cyanide 0-30ppm), mini
6313806, HF (Hydrogen Fluoride 0-10ppm), mini
6313879, N2H4 (Hydrazine 0-1ppm), mini
6313799, NH3 (Ammonia 0-100ppm), mini
6313800, NH3 (Ammonia 0-1000ppm), mini
6313802, NO (Nitric Oxide 0-300ppm), mini
6313856, NO (Nitric Oxide 0-300ppm), medium
6313801, NO2 (Nitrogen Dioxide 0-30ppm), mini
6313857, NO2 (Nitrogen Dioxide 0-30ppm), medium
6313780, O2 (Oxygen 0-30% Vol.), medium
6313817, O2 (Oxygen 0-30% Vol.) mini
6313807, O3 (Ozone 0-1ppm), mini
6313810, PH3 (Phosphine 0-1ppm), mini
6313998, PID (0-1500ppm), medium
6313808, SiH4 (Silane 0-50ppm), mini
6313819, SO2 (Sulfur Dioxide 0-30ppm), medium
6313822, SO2 (Sulfur Dioxide 0-100ppm), medium

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Title Size
bm25_commercial_brochure 246 KB
bm25_features_&_benefits 102 KB
bm25_wireless_faq 99 KB
bm25_user_manual 2 MB

Additional information

Weight 0.09 kg