Section R. 408.10975 - SafeguardsRule 975.
(1) Where there is a possibility that an employee may be trapped in, or may enter into, an atmosphere made hazardous by the discharge of a halon 1301 extinguishing agent, the following safeguards shall be provided: (a) A predischarge and a discharge alarm in a normally occupied area, except an explosion suppressant system, does not require a predischarge alarm if the concentration of the discharge agent does not exceed 7%. If evacuation of the area by personnel can be accomplished within 1 minute, the concentration may be increased to 10%.(2) Where an alarm, audible or visual, is provided to indicate system failure, it shall be distinctive from an alarm indicating operation or hazardous conditions, and shall operate continuously until manually shut off.(3) Before an employee enters an area where halon 1301 has been discharged, the area shall be purged of that substance. In an emergency and before purging has been accomplished, an employee may enter the area while wearing approved respiratory equipment.Mich. Admin. Code R. 408.10975