(1) You must make sure the exhaust ventilation system is fully operational by checking the static pressure drop at the exhaust ducts leading from the equipment at both of the following times:

(a) When installation is completed;

(b) Annually after installation.

(2) You must repair or clean exhaust systems when either of the following occur:

(a) Dust leaks are found; or

(b) The pressure drop gauge indicates a change exceeding 20 percent.

(3) You must use an abrasive separator to separate larger particles for reuse on installations where abrasive is recirculated.

(4) You must set up dust collecting equipment to do both of the following:

(a) Empty and remove accumulated dust without contaminating work areas;

(b) Discharge the air used in blast cleaning equipment.