The Advanced Photon Source
a U.S. Department of Energy Office of Science User Facility

Experiment Hazard Class 11 – Hydrogen


This hazard classification applies to all experiments and processes involving the use of gaseous hydrogen.  This class includes work performed in the Experiment Hall Beamline Stations and any preparatory/setup/testing work performed in the LOM laboratories.  Other hazard controls such as fire protection and life safety regulations may apply to experiments of this hazard class.  A summary of controls for hydrogen use is available in the hydrogen summary document.

Experiment Category

Experiments involving previously reviewed hazard controls are categorized as medium risk.

Experiments involving new equipment or modified hazard control schemes are categorized as high risk.

Experiment Hazard Control Verification Statements

Engineered Controls – Applicable controls for the storage and use of hydrogen.  The quantities of hydrogen used and/or stored must be limited to as small a quantity as possible.  Flash back arrestors must be provided on all hydrogen supplies and must be located immediately downstream of the first regulator or other location determined by a safety review.  Piping and tubing should be uncoated wrought steel or any 300-series stainless steel.  Cast iron pipe and fittings should not be used.  Flammable mixtures of hydrogen are to be used in a well ventilated, sprinkled area.  Avoid the use of spark producing equipment.

Procedural Controls – A SOP is required to define startup, shutdown, normal and emergency operations, purging, maximum flow rates for hydrogen, and PPE for handling gas cylinders.  The need for a SOP is also required for small quantities of hydrogen.  Beamline supervisors are responsible for the preparation and approval of the operating procedures

Design Reviews and Equipment Inspections – All experiments and operations involving the storage, use, or generation of hydrogen must undergo a documented safety review.  The review may include non-APS entities at Argonne.  Any safety reviews provided by Non-APS Argonne personnel must be documented and forwarded to the APS User Safety Officer.

Training – Sector specific training for the facility using hydrogen.

Signs and Labeling – Contact the ESH Divisional Coordinators for signs.

Personal Protective Equipment – Safety glasses with side shields and safety shoes when handling gas cylinders.  Heat resistant gloves for high temperature hazards.

Dosimetry and Monitoring – Continuous hydrogen detectors.

Experiment Authorization

Unless otherwise noted in the approved experiment safety plan, the PSC Deputy Associate Laboratory Director of Operations delegates the authority to authorize an experiment in this hazard class to a member of the APS Experiment Safety Review Board and resident beamline personnel having the authority to authorize experiments as listed in the ESAF system.  Approval by both the host beamline and APS Experiment Safety Review Board are mandatory prerequisites for experiment authorization.

Hazard Control Verification

The PSC Deputy Associate Laboratory Director of Operations delegates responsibility for verifying that required controls are in place to the experiment On-Site Spokesperson and Beamline Management.


ANL ESH Manual Chapter 4.8, Hydrogen Safety (Internal link)

OSHA Regulation 29 CFR 1910.103 - Hydrogen

LMS-PROC-332 Compressed Gas Cylinders

NFPA 55 Compressed Gas and Cryogenic Fluids Code

Contact the APS User Safety Program with any questions or if the internal links are not working properly.

Reviewed: May 15, 2020