Active GH2 sensors should be installed and continuously monitored in all enclosed buildings near GH2 sources. All buildings near areas where hydrogen is used should be designed to preclude GH2 entrapment (e.g., sloping roof with ventilation at the highest point).
Underground carbon steel lines beneath concrete pad areas should not be used for GH2 transmission. All GH2 lines are now stainless steel and above ground. - Any GH2 transmission lines buried underground should be proof-tested and leak-checked on a periodic basis.
Any below-grade piping installation should be in open trenches covered by grating.
Facilities should be protected from GH2, at a safe distance, by manual isolation valves. If remote-operated valves (ROVs) are required for operational isolation purposes, the ROVs should be in series with and downstream of the manual isolation valve.
The pressure between isolation valves and stand shut-off valves should be routinely monitored on a daily basis.
Field repair of mechanically severable valves in high-pressure systems should be eliminated.
Valves repaired in the field should be subjected to functional and leak checks, including actuator and valve seals at simulated operating conditions. A written procedure should be prepared and used.
Valves utilizing pneumatic actuators should have actuator piston and piston nut staked (or locked by other positive means) in the installed condition.
All high-pressure gas lines scheduled to be inactive for periods greater than 6 months should be physically isolated by blind flanges from active systems.
Supply system status of pressure vessels and lines (pressure and/or quantity) should be recorded at the start and completion of operations each day. All reservoirs should be isolated at close of business each day, and before weekends and holidays.
Corrosion protection systems for underground lines should be reviewed and tested to confirm the adequacy of the systems.
Operational and support buildings at hazardous sites should be isolated (i.e., interconnecting air conditioning systems should be avoided). Buildings connected to hazardous sites by tunnels and/or conduits should be physically isolated by seals. If physical isolation is not practical, then positive air flow should be maintained in tunnels and conduits.
Explosive gas detection meters should be included in the equipment carried by firefighters and emergency medical personnel.
Fire alarm transmitters should be located at all hazardous locations.
Emergency instructions for isolating GH2 and utilities for hazardous locations should be permanently posted with names and telephone numbers of key individuals to be contacted.