The fill station shall be designed for filling three SCBA/SCUBA cylinders simultaneously or separately. The enclosure shall be designed to contain the impact of suddenly expanded high pressure air and all displaced fragments in the unlikely event of a cylinder or fill component rupture. The loading door must be designed to be trapped inside the fill enclosure cabinet frame when closed. The design must include an automatic, safety interlock to prevent filling unless the loading door is completely in the closed position and a safety relief valve to protect operators in the event that the SCBA/SCUBA fill pressure exceeds 4750 PSIG.

The external construction of the high pressure, breathing air fill station shall be appliance-like; using formed, fabricated steel structures and panels without visible welds, burrs or grinding marks. All structure fasteners shall be concealed and all access panels shall include concealed hinges and pushbutton latches. Two full height, maintenance access doors shall be located on each side of the appliance allowing complete access to all components. The fill control panel shall be illuminated.

The fill station must allow the fill process to be accomplished from the front. The front loading door shall be designed so that, when opened, the SCBA/SCUBA cylinder holder sleeves tilt forward to ease loading and minimize operator fatigue. Three (3) fill whips, each fitted with a cylinder fill adapter and shut-off valve, shall be located within the enclosure.

The access door control shall include an air actuator handle designed to operate a pneumatic cylinder to open and close the access door. For opening, the handle shall lower the access door, releasing it from behind the cabinet frame and allowing the operator to pull the door forward to load and unload SCBA/SCUBA cylinders. For closing, the access door is rotated up to the vertical position and the handle shall then raise and trap it behind the cabinet frame. When fully raised, the door trips the safety interlock allowing air to flow to the fill station.

The access door shall be supported on the enclosure frame with an adjustable bearing bushing on each side assuring a balanced, smooth rotation and effortless operation when opening and closing. A gas strut shall secure the assembly to the enclosure so that it does not require operator support when opening or closing and to cushion the access door landing when opened.

In order to minimize operator handling of pressurized components, a bleed valve shall be located on the control panel to relieve all fill hoses of pressure after opening the front loading door and before disconnection from the SCBA/SCUBA cylinders(s).

All air flow components and indicators must be labeled and mounted on a steel control panel on the front of the unit and located above the fill enclosure. The panel shall be painted in a matte shade with a textured finish to eliminate glare and enhance the visibility of gauges and indicators.

II. Integral Air Storage System

When specified, the breathing air storage system shall be integral to the appliance and include all the cylinders, plumbing and hardware installed in accordance with all current ASME or DOT codes, as specified below:

Two (2) DOT 4500 PSI cylinders each with a capacity of 444 cubic feet of air at 4500 PSI. The piping of air storage shall be arranged for bulk filling.
Two (2) DOT 4500 PSI cylinders each with a capacity of 444 cubic feet of air at 4500 PSI. The piping of air storage shall be arranged for cascade filling.
Three (3) DOT 4500 PSI cylinders each with a capacity of 444 cubic feet of air at 4500 PSI. The piping off air storage shall be arranged for bulk filling.
Three (3) DOT 4500 PSI cylinders each with a capacity of 444 cubic feet of air at 4500 PSI. The piping of air storage shall be arranged for cascade filling.
Four (4) DOT 4500 PSI cylinders each with a capacity of 444 cubic feet of air at 4500 PSI. The piping off air storage shall be arranged for bulk filling.
Four (4) DOT 4500 PSI cylinders each with a capacity of 444 cubic feet of air at 4500 PSI. The piping of air storage shall be arranged for cascade filling.
Two (2) DOT 6000 PSI cylinders each with a capacity of 509 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for bulk filling.
Two (2) DOT 6000 PSI cylinders each with a capacity of 509 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for cascade filling.
Three (3) DOT 6000 PSI cylinders each with a capacity of 509 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for bulk filling.
Three (3) DOT 6000 PSI cylinders each with a capacity of 509 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for cascade filling.
Four (4) DOT 6000 PSI cylinders each with a capacity of 509 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for bulk filling.
Four (4) DOT 6000 PSI cylinders each with a capacity of 509 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for cascade filling.
Two (2) ASME 6000 PSI cylinders each with a capacity of 525 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for bulk filling.
Two (2) ASME 6000 PSI cylinders each with a capacity of 525 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for cascade filling.
Three (3) ASME 6000 PSI cylinders each with a capacity of 525 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for bulk filling.
Three (3) ASME 6000 PSI cylinders each with a capacity of 525 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for cascade filling.
Four (4) ASME 6000 PSI cylinders each with a capacity of 525 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for bulk filling.
Four (4) ASME 6000 PSI cylinders each with a capacity of 525 cubic feet of air at 6000 PSI. The piping of air storage shall be arranged for cascade filling.

III. SCBA Cylinder Fill Enclosure Flow Control System

The SCBA/SCUBA cylinder fill control system shall include a regulated panel with all the components, devices and piping arrangement necessary to direct the compressed high pressure breathing air to an air storage system and the SCBA/SCUBA cylinders being filled. An auxiliary outlet to fill remote air storage systems shall also be provided.

A cascade control system shall be included for the number of banks specified below. The cascade control system shall permit filling or drawing down each air storage cylinder, independently of each other, while filling SCBA/SCUBA cylinders. An air storage by-pass valve shall be included to permit filling SCBA/SCUBA cylinders or through the auxiliary outlet directly from the compressor. (A)

The control system shall include a dual regulator package for safely filling SCBA/SCUBA cylinders at two (2) different pre-set pressures. The package shall include installation of the standard and an additional regulator behind the panel at pre-set pressures. A selector button located at the control panel shall be required to select air flow from the regulator with the highest pre-set pressure. A pneumatic actuator valve shall return the air flow to the low pressure regulator after every high pressure fill cycle. (B)

An additional "dedicated fill circuit" shall be included to safely fill SCBA/SCUBA cylinders at a different pressure that that flowing from the main control panel regulator(s). The "dedicated fill circuit" shall include an adjustable, pre-set regulator installed behind the control panel plumbed directly to a dedicated fill whip and adapter located in the fill enclosure and a separate panel mounted flow valve and gauge. (C)

All air flow components and indicators must be labeled and mounted on a steel control panel on the front of the unit and located above the fill enclosure. The panel shall be painted in a matte shade with a textured finish to eliminate glare and enhance the visibility of gauges and indicators. The panel shall be illuminated.

As a minimum, the air control panel must include the following:

• Inlet pressure gauge.
• Adjustable, 0-6000 PSI self-relieving regulator.
• Regulator outlet pressure gauge.
• Storage fill/by-pass (A) valve.
• SCBA/SCUBA cylinder(s) fill control valve.
• SCBA/SCUBA cylinder(s) fill pressure gauge.
• Auxiliary outlet with flow control valve and CGA fitting.
• Two (2) bank cascade control with a single valve and gauge per bank. (A)
• Three (3) bank cascade control with a single valve and gauge per bank. (A)
• Four (4) bank cascade control with a single valve and gauge per bank. (A)
• Six (6) bank cascade control with a single valve and gauge per bank. (A) 
• Two (2) bank cascade control with “To” & “FROM” valves and gauge per bank. (A)
• Three (3) bank cascade control with “To” & “FROM” valves and gauge per bank. (A)
• Four (4) bank cascade control with “To” & “FROM” valves and gauge per bank. (A)
• Six (6) bank cascade control with “To” & “FROM” valves and gauge per bank. (A)
• Dual regulator high pressure selector button. (B)
• "Dedicated fill circuit" flow valve and gauge. (C)