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Information on Scott AP 75 Model 4.5

Scott AP 75 Model 4.5

General- AP 75 Model 4.5 NFPA 1981 approved (2007 standard)


Engines have 4 BA’s with 4 spare bottles

Engine 652 has 4 BA’s with 4 30 minute spare bottles

Truck 54 has 4 BA’s with 8 spares bottles

Truck 57 has 4 BA’s with 4 spare bottles

Medics have 2 BA’s with 2 spare bottles

RIT packs on Engines 52 and 56


Numbering system- ie 51-1, 51-2, 51-3


Backpack frame made up of metal frame with Kevlar and nomex straps/pads. Has built-in Drag Rescue Loop for FF rescue. Tri-slide buckle to adjust for different bottles and cylinder latch with retention strap. Parachute style straps adjustable shoulder straps and breakaway Colorado belt by Fire Innovations. Pak alert sensor module is attached on either side of the bottle. Visual indicators on sensors with blue (during battery check)red (pre-alarm and alarm), green (sensing mode), and orange (low on air) lights. Takes 6 AA batteries and has an estimated life span of 6-9 months. Measures FF movement via a small metal ball bearing that moves in slide to indicate movement. After PASS is activated by either air being turned on or by using the PASS CONSOLE (personal alert safety system), Pak Alert will constantly sense movement. No movement for 20 seconds and PASS goes into pre-alert. If after 12 more seconds the pre-alarm is not canceled by either moving the lower body or by pressing the yellow button on Pass Console, the PASS goes into full alarm (95 dBa). When in full alarm, PASS sends out FF ID that can be located by the Pak Tracker.


The bottle is a 45 min bottle, holds 66 cubic ft of compressed air at 4500 PSI. Bottle made of aluminum core (70% of strength) wrapped by carbon fiber then layer of epoxy, fiberglass then layer of epoxy, then covered in durable gel coat (30% of strength). The bottle has a cylinder pressure gauge, tri-lobe hand wheel with ratchet design (2 ½ turns) to reduce the possibility of accidentally turning off the bottle. Locking Tab. Burst disc set to 7200 PSI. 15 year life span with Hydro every 5 years.


From bottle connects to high-pressure line via the Compressed Gas Association CGA nut. AKA High-Pressure Coupling. Stainless in 4500 PSI, Brass in 2216 and 3000 PSI. Nylon O-ring makes the connection airtight. Holes in threads to relieve pressure in case the wrong size bottle is placed in incorrect SCBA.


From CGA into RIC UAC. Designed for emergency operation only. Includes the UAC PRV. PRV set to 4950 PSI.

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