Rescue tools: Pros and cons of 3 power sources
Whether hydraulic, pneumatic or electric, each extrication tool power source has advantages and disadvantages; here's how they break down
By Robert Avsec
Remember the days when pry bars, hacksaws and axes were pretty much the only tools available for vehicle extrication? Those human-powered tools still have application, but today's responders can pick from a wide variety of hydraulic, pneumatic and electrical tools.
Nearly every fire department across the United States is involved in a vehicle extrication incident, and every firefighter should have a good working knowledge of the powered extrication tools their department carries.
So let's take a look at the three predominant operating systems being used in today's powered vehicle extrication equipment: hydraulic, pneumatic and electric.
Hydraulic-powered tools first came to the fire service from the automobile body and fender world. Port-a-power spreaders and cutters, along with hydraulic jacks, were the first mechanical extrication tools to find a place on fire and rescue apparatus.
The big leap in hydraulic-powered extrication equipment came with the introduction of Hurst's Jaws of Life. The Jaws of Life was first used in 1963 as a tool to free race car drivers from their crashed vehicles.
Hydraulic rescue systems have three basic components: an electrical or gasoline engine power unit, a hydraulic fluid pump, and a reservoir with associated valves to control direction and pressure. The hoses transmit the pressurized fluid to the cutters, spreaders, rams, etc.
This is a closed system as opposed to a pneumatic system, which is open and vents/consumes its power transfer medium. Hydraulic systems have a pressure port (output of the pump), and a return port for hydraulic fluid to flow back into the reservoir. For best operations the fluid temperature should be between 60 and 140 degrees F.
- It's proven technology that has been around for many years.
- The tools are among the most powerful.
- It provides big power for incidents that involve heavy metal construction.
- The equipment is heavy.
- It relies on caustic hydraulic fluid for operation.
- Gasoline-powered models create noise pollution on scene.
Pneumatic rescue tools are powered by pressurized air from SCBA cylinders, vehicle-mounted cascade systems or vehicle-mounted air compressors. Whizzer saws and air chisels are examples of pneumatic-powered tools.
Pneumatic tools weigh less than hydraulic tools, are very portable and have many excellent applications.
Air tools, with the exception of air bags, are often measured in not only in operating pressure but also cubic feet per minute. This is the amount of air the tool uses to work; the speed of the air is expressed as feet per second. These factors can be affected by friction loss in the hoses.
- They are lightweight.
- They are easily transportable.
- They have quiet operations.
- There are a wide variety of appliances.
- They are limited to available air supply.
- They have limitations on cutting and prying for heavier metal construction.
Electrical power has been used with vehicle extrication tools first through power cords linked to electricity generators and more recently through batteries. These can serve as both a primary set of tools or as a redundant system alongside gasoline-powered hydraulic tools.
Electric tool systems have three general parts: power generation, transmission and tool. Users should understand the operation of each part and know where it fits in the operational envelope.
It is also important to understand some terms and units of measure concerning electricity. This information is often displayed on the tool.
One helpful way to think of these parameters is to liken them to fireground pumping operations. Volts are comparable to the pressure the pump creates to flow the water; amperage compares to the gpm of water flowed. Volts, whether from alternating current like our house outlets or direct current like that from a battery, is power. Voltage is the pressure or amplitude of the energy of the electricity.
All appliances have a specific amount of amps required to make them work efficiently, which is measured in amperage or amps. The operator can influence the amount of amps or load that the tool draws. For example, if you push your reciprocating saw till it bogs down and stalls in the cut, the amps will increase probably causing a circuit breaker or similar protection device to trip or shut the tool off.
A watt is the amount of energy consumed by the tool. You can calculate the amount of watts used by a tool or appliance by multiplying its amps and volts.
- They are lightweight and easily transportable.
- They have quiet operations.
- They have a wide variety of appliances.
- Newer, long-lasting battery technology is improving duration of operation capabilities.
- They are limited to available electrical supply, particularly for battery-powered units.
- There are some limitations on cutting and prying capability for heavier metal construction (however the technology is constantly improving in this regard).
Regardless of the extrication tool technologies used by your department, the successful use of a tool and its components is predicated on several factors. First, is the initial and ongoing training for personnel in the safe, effective, and efficient use of the tool.
Second, the knowledge and experience of the individual operator in using the tool so that they are always using the right tool for the job — operating within the tool's capabilities.
And last, but certainly not the least importantly, the tool is adequately maintained according to the recommendations of the tool's manufacturer.