Portable air supply
The ever increasing use of synthetic materials and the frequent transport of chemicals across roads, rails and water makes the use of selfcontained breathing apparatus (SCBA) at most incidents mandatory. For large incidents, fire departments often have to call in mutual aid for extra air tanks and then transport empty tanks to refilling stations. In addition, the lack of a ready air supply can reduce the number of SCBA drills.
These problems forced the Shelburne, VT, Volunteer Fire Department to search for a portable air supply. When evaluating portable air systems, it was determined that:
- Portable air compressors, that fit the department’s “needs, were too bulky, costly, and delicate for the fireground.
- Fill times directly off the portable compressors were unacceptable. Even though four air tanks could be filled at a time, each took approximately six minutes.
A committee consisting of Captain Tim Thomas, Lieutenant Ed Vizvarie, Firefighters Gary Kirby and Chris Bissonitte, and Harold Simpers decided to tackle this problem. They designed a three-tank cascade system filled by a stationary compressor at the fire station. This system, built onto a utility truck, was mounted near the truck’s center, since the three tanks weigh a total of about 600 pounds when full.
The tanks were piped to the rear of the truck where the necessary gauges and fittings ’were mounted for the filling and discharging of air. Because the system is so compact, an additional six SCBA units and five extra SCBA tanks also can be mounted on the truck. An explosion shield will be added to the back of the truck for safety when filling the tanks.
System fill time at the station is about two hours, from empty to 3,600 psi, and is usually done while the equipment is being readied for the next call. Fill time for the portable SCBA tanks is about 30 seconds when the system is full, to four minutes when the system is down to 1,500 psi. The system is capable of refilling approximately 24 SCBA tanks.
This portable system has been successfully tested and has been made available for mutual aid to neighboring communities.
The total system cost $7,500, the major purchase being the stationary compressor. The other components were the three cascade tanks, plumbing, gauges and tubing.