23-9.4 Testing and Certification.

23-9.4.1 The manufacturer of the enclosed air refill station
shall test a standard production model. The test shall include
pressurizing a 1-hour SCBA cylinder rated at a gauge pressure
of 4500 psi (31,027 kPa) to failure. If the system provides for
simultaneously refilling of multiple cylinders, the other cham-
bers shall contain air cylinders of equal size filled to a gauge
pressure of 4500 psi (31 ,027 kPa) during the test. These cylin-
ders shall not rupture during the test.

23-9.4.2 The testing shall prove that the air refill station is
capable of containing all fragments of a failed cylinder so as to
protect the operator and not rupture cylinders in adjacent
chambers and prove that the venting provisions are adequate
to direct the air concussive release away from the operator.

23-9.4.3 All test results shall be certified by an independant
third-party testing organization.

23-9 SCBA Fill Station.

23-9.1 If SCBA or SCUBA air cylinders are to be refilled from
a vehicle-mounted air system, the system shall meet the follow-
ing requirements:

    (1) The system shall fully enclose the cylinder during filling
    to contain the fragments if a cylinder ruptures.

    (2) The system shall fully enclose the refill lines to the cylinders.

    (3) The system shall direct the concussive air blast away from
     the operator and bystanders. A fill station within an enclosed crew
     area shall have provisions to vent the concussive air blast to the
     exterior of the vehicle.

    (5) A warning sign shall indicate the hazards inherent in the
    operation of filling SCBA or SCUBA cylinders.