It is common to have combustible materials and fuels in a building during construction activities. Commissioning is typically considered part of construction. It is good to see that fire suppression is available. However, given the lack of alarm capabilities, it would seem prudent to have a fire watch posted when hazardous materials are present or being used. Regarding requirements, the International Building Code (Chapter 33) and the International Fire Code are the primary applicable codes. NFPA 241 also provides guidance but may not be required by the local jurisdiction. It may also be beneficial to contact the contractor’s or owner’s insurance company to see if they have any specific requirements as a result of the increased risk. 

In particular and with regard to hydrogen, it is unusual that H2 would be needed for construction activity in the same way that other gases such as propane, natural gas, or acetylene might be used for welding, brazing, or cutting.  When bringing H2 into a building for commissioning activity, the building and fire codes should be followed with respect to maximum allowable quantities (MAQ), control areas, and ventilation. Consult with the local authority having jurisdiction for specific requirements from the model fire code and associated codes for the hazardous materials and processes planned for the premises. Occupancy certificates are typically issued by the AHJ upon final inspection and approval by several code Officers such as building, electrical plumbing, Fire etc. Typically all life safety systems required by codes must be functional regardless if the premises is occupied or not.