(1) You must ensure that dry chemical agents are compatible with any foams or wetting agents with which they are used.

(2) You may not mix together dry chemical extinguishing agents of different compositions. You must ensure that dry chemical systems are refilled with the chemical stated on the approval nameplate or an equivalent compatible material.

(3) You must provide a predischarge employee alarm which will give employees time to safely exit from the discharge area prior to system discharge when dry chemical discharge may obscure.

(a) Your predischarge employee alarm systems must:

(i) Provide enough warning to allow employees to safely escape from the workplace or the immediate work area or both.

(ii) Be capable of being perceived above ambient noise or light levels by all employees in the affected portions of the workplace before system discharge.

(iii) Be distinctive and recognizable as a signal to evacuate the work area.

(iv) Be kept in operating condition except when undergoing repairs or maintenance.

(b) You must explain to each employee how to report emergencies in your workplace. Methods of reporting emergencies include manual pull box alarms, public address systems, radio, or telephones. Post emergency telephone numbers near telephones, or employee notice boards, or other conspicuous locations if you use telephones to report emergencies.

(c) If you use a communication system that also serves as an employee alarm system, all emergency messages must have priority over all nonemergency messages.

(4) You must sample the dry chemical supply of all but stored pressure systems at least annually to assure that the dry chemical supply is free of moisture which may cause the supply to cake or form lumps.

(5) You must ensure that the rate of application of dry chemicals is such that the designed concentration of the system will be reached within thirty seconds of initial discharge.