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Tech behind the gear: Scott 5.5 Cylinders

After surveying hundreds of fire departments, Scott Safety listened and provided a lighter more versatile cylinder

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The 5.5 cylinder shifts the center of gravity, providing more comfort.

This following is paid content sponsored by Scott Safety

By Greg Bogosian

In an effort to continually improve their products for the sake of firefighter safety and survival, Scott Safety recently asked over 200 fire departments and other SCBA users what could be done to that most central piece of equipment, the Air-Pak, in order to help firefighters perform their duties more effectively. The answer from all of them was simple: reduce the weight and size of the bottle. Now, while that might sound simple in theory, the modern composite tank is a highly sophisticated piece of engineering, and a reduction in both areas required a creative solution which utilized the most recent advancements in the field of composite materials. That solution was recently released to production in the form of Scott’s new 5.5 line of cylinders.


Working with Luxfer, the leading gas-cylinder manufacturer, Scott redesigned the Air-Pak cylinders with advanced composites to be able to withstand an internal pressure of 5,500psig, as opposed to the current industry-standard 4,500psig. The construction is composed of an advanced aluminum alloy interior, with a total overwrap of carbon fiber, fiberglass, and epoxy resin, and was built around DOT and TC specifications. By having a higher internal pressure, the cylinders could be made smaller in diameter while still maintaining the same time durations, thereby reducing not only the size of the cylinder, but also the weight by more than 10% overall. In terms of real weight, that means the cylinder is up to 1.23 pounds lighter, depending upon its time duration.

With the smaller cylinder design, Scott was also able to add an industry-first larger-duration cylinder with a 75-minute capacity ideal for RIT teams, in addition to the standard 30-, 45-, and 60-minute models available. The design also shifts the center of gravity, increasing comfort for the operator. Helmet clearance was carefully studied, and in some cases the overall length of the cylinder was reduced in order to help avoid interference. All of this, of course, had to be done with both safety and reliability in mind, and Scott’s extensive in-house testing provided a rigorous framework upon which the design was refined until ready for use by working firefighters. As a result, all of the 5.5 cylinders in their final design have now received approval from DOT, NIOSH, and the NFPA laboratories.


With budgets tight across the country throughout all sizes of department, Scott also recognized the need to have the 5.5 line remain compatible with existing infrastructure, and worked with leading manufacturers during the design and refinement process to ensure that the cylinder works with the truck seats and brackets currently deployed by agencies. This was done to eliminate the increased infrastructure and training costs which would have been incurred by a radical shift in cylinder design, and allows firefighters more peace of mind and security in knowing that the 5.5 line will operate and function in a familiar manner . Charging the cylinders can be accomplished either with the current RevolveAir Charging Station, or with standard 6000psi-or-larger air compressors. A five-year hydrostatic testing schedule remains in place, as well.

In terms of integration with existing Air-Pak SCBA, the cylinders themselves are approved on the Air-Pak 75, the Air-Pak NxG7, and RIT-Pak III, with further approvals anticipated as integration of the new cylinders continues. In order to account for the higher internal pressure of the cylinder, and ensure accuracy during operations, the pressure gauge in the console will need to be replaced, along with the pressure reducer and pressure relief valve, and the HUD software must be reprogrammed. Upgrade kits will be available from Scott to facilitate this transition, along with a trade-up program which may prove simpler for some agencies.

AVAILABILITY, ADOPTION, AND CONCLUSIONS Adoption of the new cylinders has already begun by some agencies, and manufacturing is currently in-progress, with widespread availability ramping up . The Rochester, N.Y. Fire Department recently made the transition from older 2.2 cylinders to the 5.5 series, and is in the process of training and deployment to field personnel, with other agencies beginning their transitions as well.

Overall, when considering the amount of additional equipment modern firefighters need to carry, the reduction in weight and size in the 5.5 cylinder line will prove to be a major benefit in terms of operational safety and capabilities, with the additional benefit of a change in center of gravity potentially helping to reduce back and hip injuries on a long-term basis. If your agency has been considering or requires an upgrade to its SCBA cylinders, the Scott 5.5 is the clear and advantageous choice on many levels for both administrator and front-line member alike.