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TOPIC: Flat-Form Bags
OBJECTIVE: Understand the function and application of high-pressure "flat-form" airbags
TASK: Understand the unique operational differences between lifting a heavy load with flat-form high-pressure airbags as compared to conventional high-pressure airbags.
Sava High-Pressure Rescue Airbags
A new high-pressure rescue airbag system being introduced to the fire service in the United States has several unique operating characteristics. This column will detail this new system and explain the differences between conventional airbags and these new bags. Referred to as Sava Flat Form airbags, this new system is a product of Savatech Corp., an international manufacturer based in Slovenia; a country tucked between Italy, Austria and Croatia. The U.S. headquarters is in Port Orange, FL.
The Sava system used for this column included three rubber airbags reinforced with Kevlar, each rated at 20-ton capacity. The Sava controller used was an interesting three-outlet unit, allowing up to three airbags to be operated simultaneously. System operating pressure is 116 psi supplied through 16- or 32-foot-long hoses. Each 31-by-31-inch airbag weighs 38 pounds, starts out about one-inch thick and inflates to a height of eight inches
The Flat Spot
What is unique about the Sava Flat Form bags is that they start out flat and remain flat even when fully inflated; well, at least the working surface remains flat. With the Sava bags at full inflation height, only the sides curl. Approximately 40% of the center area of the bag's working surface remains flat. The 19-by-19-inch dimensions of this flat center section of the airbag (361 square inches)remains flat and in contact with the object being lifted. The bag doesn't crown as conventional high-pressure rescue airbags do.
Sava's flat-form design eliminates the loss of lifting capacity as lifting height increases. In other words, the theoretical rating of the airbag, 20 tons in this case, remains the real-world lifting capacity of the airbag throughout its entire inflation height. Conventional high-pressure airbags are only capable of lifting approximately 50% of their rated capacity when fully inflated. Conventional airbags also take on the familiar round basketball shape when fully inflated.
Because the Sava design allows the airbag to maintain a flat-top surface, the 361 square inches pressurized to 116 psi creates the rated 20-ton capacity.
The Triple Controller
A second capability that the Sava system presents that is not normally available with conventional airbag systems is the triple controller.
By having three outlets, each with its own integrated relief valve, rescue personnel can inflate or deflate up to three airbags at the same time. Triple-stacked as a single-point lift, the three Sava bags can lift 20 tons about two feet off the ground. With the capability of operating three bags, rescuers could create three single-bag, single-point lifts at multiple points along the load or a two-point lift; one double stacked and the third bag working alone. This would provide the rescue team with the capability of controlling the lift at two or three points, thereby balancing the load as the lift is accomplished.
RON MOORE, a FirehouseÂ® contributing editor, is a battalion chief and the training officer for the McKinney, TX, Fire Department. He also authors a monthly online article in the Firehouse.com "MembersZone" and serves as the Forum Moderator for the extrication section of the Firehouse.com website. Moore can be contacted directly at Rmoore@firehouse.com.