GNA-Brook Fire Protection designs, installs, inspects and certifies fire sprinkler systems, fire hydrants, UL 300 kitchen suppression systems and portable extinguishers across California. It publishes California contractor licence 782494 C-16 and State Fire Marshal licence E-1528 A. The firm runs its own shop for extinguisher servicing, CO2 and nitrogen refilling, hydrostatic testing and cylinder requalification, and has been family-owned since 1989.