BY STEVE SHUPERT
In using power tools, your goal is to assemble, operate, and maintain tools to efficiently and safely extricate victims and force entry to protect life and property. Inability to do so will cause the trapped victim further pain and suffering and will result in unnecessary property loss. As a professional firefighter/rescuer, you are also a professional power tool operator and must be proficient in quickly determining the proper tool for the application and a safe operation. Below are some typical fire/rescue power tools; appropriate fireground/rescue scene applications; and general operating principles and troubleshooting for gasoline engines, electrical power systems, and electric tools.
Selecting the proper tool for an operation is a major performance factor. Choose the right tool for the job. If you are forced to use an alternative tool, know its limitations. Sometimes the environment or your proximity to the victim dictates tool selection. As an example, when cutting metal, the excessive noise of a pneumatic air chisel or reciprocating saw may agitate the patient. Hydraulic shears may produce more of a reaction from the work piece when it cuts through it than can be reasonably controlled.
Working in confined spaces often limits the kinds of tools you can use. Gasoline-powered tools produce carbon monoxide, which may require monitoring and ventilation. Cutting/grinding tools create sparks and involve additional safety considerations if used around spilled fuels. In cutting through multiple barriers of different materials (e.g., plastic, insulation, rubber, steel), each material may require a different tool. Which tools can you safely operate around water or even partially submerged? Extremes in environmental temperature can change the operating envelope of tools. You must consider these limits when selecting your tools and techniques for an operation.
Always perform your morning checks; someone’s life may depend on it. Ensure that you have the proper and complete inventorypower sources, fuels, cords, hoses, and maintenance/repair tools. Keep everything ready for immediate operation. Memorize the location of all equipment on your rig. Know which tools need support tools, such as special wrenches to change saw blades and adapters for mutual-aid electric or pneumatic tools. Maintain fresh fuel and a field repair kit to sustain operations. Figure out how far away you can park your rig so the tool power transmission lines (hydraulic, electric, and pneumatic) will reach the job without your having to dismount the power units. Pre-rig saws and chisels so they are ready to deploy. Group tools in kits to minimize assembly/deployment time, and literally count the number of steps around your rig needed to assemble a tool system. By saving a minute here and there, you can buy the victim several more minutes for the “Golden Hour.” Every step saved is less time for the fire to grow and a step closer to the trauma center for the patient.
MAXIMUM TOOL SPEED/FEED RATE
When running a saw, drill, or jack, whether electric-, pneumatic-, hydraulic-, or gasoline-powered, do not load or apply so much pressure on the tool that it reduces the revolutions per minute (rpm) to an inefficient rate. With a saw, start slowly to establish a kerf (space created by the saw blade); this will make it easier to hold the tool/blade in place. Once the saw is fully engaged in the work piece, keep it cutting at full speed.
If you press too hard and slow down the tool too much, typically the motor, pump, or saw blade will overheat and compromise performance. If the tool cannot cut quickly enough, assess whether you are using the right tool/bit/blade, or put multiple tools in operation. By maintaining around at least 85 percent of full speed rpm or beats per minute (the number of times the tool bit moves back and forth striking the work piece), the tool/bit will cut/grind as efficiently as possible.
However, to find out a tool’s maximum feed rate or loading pressure, you must train with the tools and develop a touch so you can know from the tool’s vibration whether it’s running correctly and train your ears to recognize the pitch of a properly tuned engine or motor. You may not always have the luxury of good lighting and a low-noise environment.
Heat, one of the by-products of our systems, must be controlled. Overheating the teeth on saw blades causes them to soften and round off. Curved pneumatic chisel bits (which keep the work piece centered) also concentrate heat in one spot, fatiguing the bit prematurely. Carbide tips will overheat and break off and can also get knocked off from vibration and impact loads. Diamond segments (used for grinding) will mushroom, and cutting edges will round off. Electric motor insulation can break down if the tool becomes too hot and damage the mechanical bearings.
Some techniques to keep your tool and blade/bits cool include the following:
- Ensure adequate lubrication, water or oil, as appropriate.
- If dry-cutting through thick material (especially concrete), pull the tool blade/bit out of the cut every 10 to 20 seconds; let it run in ambient air to cool.
- Ensure that the power tool has a properly dressed sharp bit/blade.
- If the tool motor is too hot to touch, you may need to switch it out or change tools.
- Keep the air vent passages on the tool unobstructed and clear not only from dust/debris but also from your gloved hands and bunker gear.
MATCHING THE TOOL WITH THE JOB
Choosing the right tool for the job begins with size-up. Everyone on the fireground has a size-up responsibility: The chief has the entire scene, the company officer his crew and its assignment, and the firefighter his task. After selecting a tool to perform the task, continuously assess the progress you made against the time needed to complete the task using that power tool. If necessary, be willing to change the tool to ensure meeting the objective.
Rotary saw. This air-breathing tool holds a flammable liquid fuel and produces carbon monoxide. Portable, but heavy (newer saws are more lightweight), this tool requires a skilled operator. An easy mistake to make with this versatile tool is neglecting to adjust the blade guard to match the angle of the saw as it is applied to the work piece. Take a moment to do this; it will pay off. Inspect the V-belt for any breaks from time to time.
A rotary saw and a carbide-tip blade can easily cut thin sheet metal (bendable by hand); this blade also works well for shingles and roof sheeting. Although it can handle the occasional nail, do not use this blade to cut heavy metal. The carbide tips fly off and become dangerous projectiles. Whenever possible, do not stand directly in line with the blade when cutting.
A composite abrasive wheel or blade is another choice for metal cutting with a rotary saw. These blades are inexpensive and very effective for short cuts. Because they reduce themselves as the wheel grinds on the work piece, the depth of cut becomes shallower and shallower.
While cutting with the carbide tip or composite abrasive blade, do not twist the blade while cutting; it can only be loaded radiallythat is, by pushing straight down.
Use caution if using the blade’s upper quadrant while cutting. This may cause an unwanted reaction force and make the saw climb up and away from the operator, possibly causing an injury. These blades have also been known to fragment and throw pieces, so always wear complete personal protective equipment (PPE).
Holding a running rotary saw is like holding a gyroscope: It will resist a change in orientation. Maintain control and the position of the saw at all times.
Blade pinching is another reaction that must be controlled. This happens when your work piece folds back in on the blade. Support the work piece so that the kerf will open instead of close.
Most metal-cutting operations have the potential to create sparks; sometimes an abrasive composite blade can create a large number of sparks. Use caution in assessing your work-site hazards, and be aware that you are creating a source of ignition. Take proper precautions.
Abrasive composite blades are designed for many applications, such as cutting steel, iron, and concrete. They look the same and perform the same but must be used for their specific application to get the best wear out of them. In a pinch, a concrete-rated (abrasive composite) blade will cut steel and vice versa. These blades are for dry cutting only.
If using carbide-tipped blades in a state covered by federal Occupational Safety and Health Administration (OSHA) workplace regulations, your saw may require additional safety guards. An OSHA-compliant saw that uses a carbide-tip blade has a retractable chip guard to catch anything flying off or from the blade. Check with your safety officer to make sure.
Currently, carbide blades for the mixed-gas powered saws are best used when cutting relatively soft material such as wood, tar, and shingles. However, some electric circular saw manufacturers have recently produced extremely effective steel-cutting carbide-tipped blades. They are noisy, but they quickly cut very thick metals up to two inches thick. These saws are equipped with a chip/debris catcher and run at 3,500 rpm, compared with gas-powered rotary saw carbide blades, which are rated at 6,200 rpm (photo 1).
(1) These rotary saw blades are each designed to cut specific materials (left to right): diamond (concrete), silicone-oxide (metal), and carbide-tipped blades (wood). Use the right tool for the job! (Photos by author.)
Reciprocating saw.There are many types of saw blades for this power tool that can cut wood, plastic, or metal. The so-called “rescue” blades are rarely worth the extra money. Buy a quality industrial blade. Make sure the extra thickness of the blade will allow it to slide into your blade chuck. As soon as the blade’s performance slows, change it out. Keep a small pouch on the saw to keep extra blades within easy reach, and get a chuck that doesn’t require a tool to change the blade. Control vibration by holding the shoe of the saw firmly against the work piece. Blade lubrication also helps control this problem. As with most saws, start this tool slowly, and develop the cut before increasing speed.
Air chisel.Small and lightweight, this tool can produce sparks. It will not cut heavy-gauge metal easily. It is effective for smaller jobs and is very portable, but this portability requires a steady supply of compressed air. This tool typically comes with bits to break up unreinforced concrete/masonry and a cold chisel bit that works well in shearing off bolt heads. Usually, air chisels come with two styles of sheet metal blades, a T-shaped bit that has a built-in depth control but tends to break frequently and a curved chisel that is more durable but takes a bit more training to learn. Like the reciprocating saw, this tool has a variable speed control operated by the triggerthe harder you pull the trigger, the faster the tool operates. Part of learning to use these tools is developing a feel for this trigger and how to develop the starting cut.
Hydraulic shears.Heavy and powerful, this reliable tool is sometimes limited by its size and the hose length from the power source. Keep the work as deep into the jaws as possible, and keep the jaws square to the work piece. It cuts by initially compressing and then shearing, or often by fracturing the work piece. However, typically with harder thicker metals, when the work piece breaks free, it can cause a violent reaction. Anticipate and prepare for this.
Versions with hand pumps are available and work quite well. Some newer versions are rated to cut boron steel; check with your manufacturer for your tool’s rating.
Chain saw.For shingles and plywood sheeting, the carbide-tipped chains work well. It takes a sizable saw to use this aggressive chain, but it is worth it. The number of links in your saw’s chain is directly related to the number of carbide tips you can lose before you must replace it. Although carbide segments on chains can be resharpened, a special machine is needed. Carbide-tipped chain does not cut green wood very well; a standard chipper-style chain is recommended for this purpose.
If plunge-cutting, begin your cut with the bottom half of the bar tip. Avoid cutting with the upper half of the bar/chain to help prevent kickback. Pull-in and push-back are other reaction forces to avoid. They can happen when you pierce a barrier not knowing what is on the other side and your chain catches on something. If possible, cut an inspection hole before making the larger cut. If your chain is making sawdust instead of thin chips or strips of wood, it is time to sharpen the chain. To maintain the sharpness of a chain saw blade, create a cover for the blade using a section of old supply hose (photo 2).
(2) A scrap piece of old supply hose helps to protect the saw chain and keep it sharp.
SAFE TOOL OPERATIONS
• Operator competence affects tool performance. Learn about the tool’s capabilities and limitations and the sound and feel of a properly operating tool. This enables you to select the right tool for the right job and use it properly.
• Inspect all tools carefully before use. Check for proper lubrication and operation. Look for loose, cracked, or broken components; loose fasteners; blocked vents; and cord damage. If the tool is not operating properly, place an “Out of Service” tag on it and turn it in for repair.
• When operating power tools, always wear the appropriate PPE, such as gloves, ear protection, safety glasses, helmet, respiratory protection, and clothing. Do not wear loose-fitting clothing or other items that could get entangled in the power tool.
• Never operate power tools when too tired or under the influence of alcohol or medication. A moment of inattention could result in a permanent serious injury. When operating tools, maintain a firm and balanced body position, and try not to overreach. Keep your work area as well lighted as possible.
• Refuel tools away from the work area.
• Keep tool power transmission lines (air hoses, hydraulic lines, and electric extension cords) as short as possible to reduce the possible loss of energy resulting from bends and kinks in hoses for hydraulic- or pneumatic-powered systems. Particularly when operating pneumatic systems with long hoses, consider jogging the tool against the work piece to counteract the friction loss and prevent outrunning the system’s ability to keep up with energy consumption.
• With electric extension cords, ensure the wire’s gauge and length are appropriate for the tools being powered.
• Anticipate long-term operations, and keep enough spare consumables on hand for replacements as needed (e.g., saw chains, spark plugs, filters). Include the necessary tools for replacing these items and performing field maintenance and repairs.
• Anticipate the action/reaction of the tool and the barrier. Be prepared to deal with rubble, weight of the cutout, and the speed of the release.
• Prepare to mitigate any hazard your tool operation may produce, such as dust, dirty water runoff, or exhaust fumes. When operating gasoline engines, anticipate the accumulation of carbon monoxide, and always monitor the atmosphere.
• Continuously assess the working end of your tool. Keep the bits dressed and sharp. Inspect carbide segments and diamonds for integrity and any deformation. Ensure bits/blades are compatible with the barrier and the desired result (e.g., the bull point of a jackhammer creates circular lines of force for general demolition; a chisel bit creates linear lines of force for a more precise/predictable break).
• Listen for the venting of pressure relief valves (hydraulic, pneumatic), indicating that the tool system may be overloaded. Stay within your tool packages’ operating envelope.
• Refer to your supervisor and operating manuals when you have questions or problems.
Understanding the principles of systems powering your tools is essential to proper maintenance and operation. This will ensure safe and reliable operations when you need them on the scene.
Two-Cycle Gasoline Engines:Typically used on chain saws, rotary saws, and some outboard boat engines, the two-cycle engine has no oil crankcase, which allows it to be operated in almost any position. The engine’s internal parts are lubricated through the fuel mixture, which is a combination of gasoline and oil. Ensure you are using the correct ratio of gas-to-oil in the fuel mixture. Too much oil will cause the engine to smoke excessively and will more quickly foul the spark plug. If there is not enough oil in the fuel mixture, the internal engine parts will be damaged. Check your tool’s operating manual for the proper gasoline-to-oil ratio.
Most saw manufacturers recommend using 89-octane gasoline that does not have any additives such as alcohol. Use quality two-cycle oil for your motors. Gas and oil will separate over time; if the refueling container or the tool has been sitting idle for some time, gently agitate to ensure the fuel components are mixed. Rotate your two-cycle fuel at least quarterly to ensure the fuel is fresh. Because these engines run hotter and faster than their four-cycle counterparts, they are more sensitive to stale gasoline and their spark plugs need to be changed more often.
Starting the tool properly the first time helps avoid flooding. Two-cycle motors tend to flood (accumulate too much fuel in the carburetor) easily, because every down stroke of the piston draws fuel and air into the cylinder. The easiest way to address this issue is to start the tool correctly the first time. To start a cold two-cycle engine, pull the choke (a butterfly valve that controls air into the carburetor) to full, set the throttle lock on full speed, and briskly pull the starter cord.
Some engines have a cylinder decompression valve that resembles a button; pushing it allows some of the air in the cylinder to escape during the startup. This makes it easier to pull the starter cord. The valve will reset itself.
Do not use drop-starting techniques to start tools! This practice is foolhardy and a sign of an inexperienced operator (photo 3). Place the chain/rotary saw securely on the ground or hold with your body to help ensure a safe startup (photos 4, 5). Once the engine “chugs” as if it were about to start, but stalls out, push the choke in (halfway or all the way, depending on your saw) and pull-start it again. If you have fresh fuel and a clean spark plug and air filter, the saw should take off and run.
(3) Never drop-start a saw or any other tool
(5) When starting a saw, maintain control of it to prevent accidents.
Once you have mastered this starting technique, develop a feel for the motor so you can feel when it chugs, especially in a high-noise environment. Know the sound so you can start it in the dark.
If the tool is flooded, try inverting the saw with the air filter removed, drain the excess fuel, change out the wet plug for a dry one, or wait until the excess fuel evaporates. Also, you may have some success alternately reducing and increasing the amount of choke based on how close the engine feels to turning over.
Make sure the air filter is clean. When changing the air filter, close the butterfly valve to prevent debris from falling into the carburetor during the filter change. Some tool fuel tanks have a vented cap to allow air in as fuel is pumped out; if your systems have this feature, make sure the vent is working. If you remove the cap and you hear air sucking in, check to see if the vent is clear.
During your morning equipment checks, start the saw up; ensure it is running properly and that everything is in order. Run the saw only long enough (one to two minutes) to confirm it is working. Allowing the saw to operate at idle only allows unburned fuel to collect in the cylinder, speeding up the spark plug fouling process inherent with two-cycle motors. The motors are tuned to run at working loads/speeds, not to sit at idle. Also, many two-cycle motors today have self-compensating carburetors that retune the carburetor as the air filter becomes clogged with debris.
Another typical problem is a fouled spark arrestor (a small screen that suppresses any sparks produced by the engine), located on the exhaust muffler. It accumulates sludge, which hampers performance, and will require periodic cleaning.
Chain saws have a chain oiler. While running the saw, hold the chain/bar close to the ground; in a couple of seconds, you should see a small strip of oil. If you do not, check the bar oil reservoir. If the reservoir is full, the bar oil outlet could be blocked by sawdust. The bar oil outlet is built into the bar and mates up to an outlet in the saw body under the sprocket cover. Keep this oil-dispensing outlet clean. This bar oil has special viscosity characteristics that help keep it adhering to the chain and groove in the bar. Regular motor oil will spin off too quickly, underoiling the chain and bar.
The chain must be adjusted properly. Ensure that the chain is installed in the proper direction and seated in the groove of the bar. Pull up on the nose of the bar; adjust the droop out of the chain with the adjusting screw. Tighten until the chain is in full contact on the bar; then give it an additional quarter turn. Adjust the bar nuts snugly.
Some chain saw bars have a nose sprocket; others are solid. The sprocket nose bar will typically hold the chain on the bar better, but the solid nose has no moving parts. Maintenance on the bars includes keeping the bar oil port clean and occasionally filing off any mushrooming along the length of the bar caused by the chain.
Regularly check for fresh, properly mixed fuel, clean spark plug and filter, solid compression on the starter cord, and clear exhaust to keep your two-cycle engine running properly. Check fluid levels; ensure that blades are free of chips and nicks and that the chain is tightened properly.
Four-Cycle Gasoline Engines: These engines use straight gasoline and typically run electric generators and hydraulic power tool pumps. They have an oil sump or crankcase that circulates oil within the engine for lubrication. This means that four-cycle engines (unless they have a pressurized oil crankcase) must be upright to run properly. Aside from this, four-cycle engines operate similarly to the two-cycle engine.
Every four-cycle engine needs three things to start and run: proper (fresh) fuel, a good spark, and piston compression.
Electric Generators: Electric generators are a vital part of almost any assignment. Generators are sized according to the amount of wattage they can generate, usually in kilowatts (kw) or thousands of watts. A 2.5-kw generator is rated to produce 2,500 watts of electricity. But our power tools are rated in volts and amps.
Since most electrical appliances are rated at 120 volts of alternating current (VAC), they will draw or consume approximately 1,000 watts for every eight amps delivered from the power source. For example, if your 120-VAC reciprocating saw is rated to operate at four amps, the saw will burn 500 watts of the total capacity of the generator. With this information, you can convert the amperage rating on your tools to watts and figure out how much of a load you are placing on your generator.
Startup current is another consideration. Appliances such as lights draw the same amount of current regardless of how they are used. Electric motors are different; when the motor is not spinning and the voltage is turned on, for an instant, the motor is essentially a short circuit. This creates a momentary increase in the current draw until the motor starts to run. You may experience brownouts, or circuit breakers may trip, turning off your circuit. Also, when you bear down on the tool, forcing it to slow down, the electric motor draws more current from the generator to make up for the drop in voltage.
Electrical generators with a 5,000-watt capacity and larger often have a 120/220 VAC selector switch. This means the generator has two windings to produce electrical power as the windings spin. Each winding can produce 120 VAC; if they are combined electrically through the selector switch, you can tap into the 240 VAC. You can use the 120 and 240 at the same time. If you do not need the 240, turn the switch to the 120 position.
Electrical systems like balancethat is, equal loads applied to each winding. If you plug your tools into one winding only (120 VAC), as these bundles of wires spin, they will not be balanced electrically. Although this is not a fatal issue, over time it can cause some problems and you will not be getting all the power available to you.
Some generators have an “auto-throttle” mode. It helps conserve fuel by running at low-speed idle until an electrical tool is turned on but will not respond to electric loads of less than one amp. This mode is not effective for tools that require only momentary power (e.g., if you are turning a saw off and on as you work through the barriers). If this is the case, keep the auto-throttle off. If you decide to use the auto-throttle, wait until the engine reaches operating temperature.
Most generators have an “Oil Alert” safety switch, which will shut the unit off if the oil pressure is too low. These sensors can be very sensitive.
The generators should not operate at full capacity for more than 30 minutes. When transporting, turn off fuel valves. Other operator switches include the main circuit breaker engine on/off switch and a fuel valve. Four-cycle generators run on regular gasoline; however, they may not perform as well if using fuel that has alcohol additives. Most manufacturers recommend a fuel with a minimum of 86 octane.
Electric tools: The length and gauge (wire diameter) of a tool’s extension cord can affect its performance. Tool amperage is another big factor. A 12-gauge, three-wire extension cord powering an appliance drawing 20 amps and that is 100 feet away from the generator will lose more than six volts in electrical resistance. This is more than enough to burn up an electrical motor over timea somewhat extreme example, but it does show the inherent inefficiency of portable power cords. Use this same cord to power an eight-amp tool, and the voltage drop is only three volts, which should not cause an appreciable loss in power.
When working around damp or wet areas, use a ground fault circuit interrupter (GFCI) to prevent electric shock. Regularly open the plug connections and check for corrosion and any loose connections.
Ensure your safety by knowing how to operate all your power tools and understanding their power systems for maximum efficiency. The ability to troubleshoot and sustain field operations with these powerful systems will make a positive impact on the safety and security of your community.
Troubleshooting Power Tools
When your tool is malfunctioning, typically only one thing might be wrong; most troubleshooting analysis operates from this premise. The most efficient way to find the problem is to start at one end (usually the power source) and work toward the tool while inspecting, isolating, and testing each component. It’s usually something simple. This way, even if there are multiple problems, you are likely to find them.
Resist starting in the middle of your system to troubleshoot. This will often result in your going back and forth looking for the problem; if there are multiple problems, you will be quickly frustrated. Additionally, you will lose irreplaceable time that could otherwise be applied to mitigating the initial incident. As stated, begin at the power source or at the tool itself, isolate and test system components in a logical order, and do not make assumptions. Trace out the flow of energy; find where it stops and why. Be prepared to change your mind when looking for the problem. Below is a sample of basic tool problems and solutions.
Two-cycle gasoline engines
Trouble: Hard starting/power loss.
Dirty air filter: Replace filter.
Carbon/oil buildup on spark plug: Clean or replace spark plug.
Wrong fuel mixture: Retune carburetor.
Engine flooded: Dry spark plug. Engine may be flooded because of excess fuel in the carburetor. Allowing the engine to sit for 10 minutes may allow the fuel to evaporate enough to try a restart. Make sure you are using fresh gasoline.
Four-cycle gasoline engines
Trouble: Engine won’t start.
Engine switch off: Turn switch on.
Oil alert light on: Check oil level, add oil.
No fuel: Check fuel level, add fuel.
No spark at the spark plug: Check spark plug connection.
Note: Before starting or restarting an electric generator, first unplug or turn off all electrical appliances connected to it so the generator is not trying to start itself and power the connected equipment at the same time. Although an electrically overloaded generator could start and try to run, it will either shut itself off or trip off circuit breakers to shed electrical load to protect itself.
Trouble: Engine starts but immediately shuts down.
Oil alert lamp on: Check oil level, add oil.
No fuel: Check fuel level, add fuel.
Trouble: No electricity at receptacles.
GFCI tripped: Check tools connected to generator for proper operation. Check extension cord plug connections and the electric appliances for excessive moisture; dry tools and connections before attempting a restart.
Trouble: Tool does not start.
Electric supply disconnected: Check electric supply continuity.
Defective trigger/on-off switch: Tag tool “out of service” and send to repair.
GFCI tripped at electric generator: Check tool for proper operation by plugging into a known good outlet.
Trouble: Tool motor cuts out.
Motor strained, overload interrupt activated: Allow tool to cool off for at least 10 to 15 minutes. Many modern electrical tools have sophisticated motor overload sensors that detect dangerous overuse of the tool, such as pressing too hard against the reciprocating saw blade as it is running. This slows down the tool and effectively stalls out the motor.
STEVE SHUPERT is a 17-year veteran of and a lieutenant in the Miami Township Fire Department in Montgomery County, Ohio. He is assigned to the second platoon, Engine/Rescue Company #48. He is a task force leader with OH-TF-1 and serves on the DHS/USAR Rescue Working Group.