Mark IV Hydrogen Gas Detector
Protects life, property and profits against hydrogen gas explosions

All our products are proudly made in the United States of America.

Mark IV Hydrogen Gas Detector

The hydrogen gas detector protects battery charging rooms and other locations where motive and stationary batteries are present by monitoring hydrogen gas levels. Lead-acid batteries on charge emit hydrogen gas after reaching the 80% recharge point. Concentrations of 4% to 75% mixed with air can be explosive. Sparks or hot surfaces can ignite them. The hydrogen gas detector will provide a warning and facilitate dissipation of the hydrogen, by operating alarms and exhaust fans before it reaches the lower explosive limit of 4%.

In addition to protecting your property and employees, cost savings are also realized. Insurance premiums may be reduced as a result of a hydrogen gas detector installation. Electricity costs decrease as a result of controlled exhaust fan operation rather than continuous fan operation. Air conditioning and heating costs are also reduced as a result of the controlled fan operation.

Two models are available: AC or DC, Optional accessories include steel junction box for mounting on wall or ceiling, remote panel for eye level placement, and modular cable for connecting the remote to the detector.


  • 099133 HGD Mimic Panel, single, w/buzzer (remote)
  • 099135 HGD Mimic Panel, double. w/buzzer
  • 099136 HGD Mimic Panel, triple, w/buzzer
  • 099137 HGD Mimic Panel, single, (no buzzer)
  • 099117 25 Foot Interconnect Cable
  • 099128 Interconnect Cable, Custom Length up to 1000’
  • 099127 Junction Box HGD


  • Continuous monitoring of hydrogen gas levels
  • Automatic operation
  • An 80-db warning alarm, and remote excaust fan with alarm activation
  • LED status display
  • Simple Installation
  • Reliable, highly sensative, highly stable, solid state sensor
  • Simple Installation
  • Long operating life


  • Protects against battery charging room explosions
  • Inexpensive protection for your property and employees
  • Decreases electricity costs as a result of controlled exjaust fan operation
  • Insurance premium reduction may be realized
  • Reduces air conditioning and heating costs as a result of controlled fan operation
  • Reliable, uninterupted 24/7 monitoring and control
  • Simple operation

Technical Specifications

  • Dimensions (LXWXH)
    7” X 4 1/2” X 2 1/4”
  • Mounting
    Four 3/16-inch screws
  • Warranty
    Five year warranty

Models & Part Numbers

  • 099140 HGD-DR Mark 4 85 to 265 VAC 50/60 Hz
  • 099141 HGD-DR Mark 4 17 to 60 VDC
  • 099142 HGD-DR Mark 4 12 VDC