Small-Capacity Hydrogen Generators for Laboratory Use

Electrolyzer-based hydrogen generators are often used to reduce laboratory gas inventory by generating hydrogen only as needed, especially when commercial hydrogen delivery and/or storage is not practical. Use of a suitable electrolyzer/hydrogen generator will allow automated generation of flow/pressure demand and can minimize concerns about gas purity and safe handling attributed to gas cylinder supply change reconnection.

To prevent the possibility of pumping hydrogen into a non-ventilated space, the electrolyzer should automatically shut down if

• there is a ventilation system outage, or
• a laboratory sensor detects hydrogen in the air.

Best practice includes use of agency certified/listed units (e.g., ISO 22734, CSA/ANSI 22.2 No. 22734, or IEC 61010-1).

Cord-connected bench-top appliances typically have very small H₂ generation capacities useful for laboratory chemical analysis. Larger capacity direct-wired systems may be specified where greater hydrogen generation rates are required, such as sub-scale fuel cell testing.

Electrolyzer-based hydrogen generators should be installed in accordance with manufacturer instructions. General guidance for installation includes the following:

• Install in a non-classified area that is ventilated with fresh air per manufacturer requirements – for instance, not in an enclosed unventilated equipment closet.
• Vent waste hydrogen to a safe hydrogen exhaust vent. See Venting.
• Vent waste oxygen to a separate safe exhaust vent or assure that local air ventilation provides sufficient dilution (less than 23.5% O₂ in air per NFPA 2 2020, 13.3.1.2.2.
  • Small units often dilute waste oxygen with enclosure vent air.
  • Larger units may require oxygen-compatible vent piping to a safe exhaust vent.
• Interlock with lab alarms – ventilation, combustible gas, fire – to stop hydrogen and oxygen generation.