Power Saw Basics
There was a time when a determined “truckie” armed with an eight-pound axe (yes, I said EIGHT pounds) and a pike pole, would make his way to the roof to ventilate. Once there, he would relentlessly strike the decking until an adequate-sized hole appeared to release the smoke, heat and flames. Yesterday’s firefighter could accomplish for two reasons. One, structures were built from “real” wood. Carpenters used native lumber species cut to actual dimensions — often much larger than what would have been required from an engineering standpoint. Second, in the absence of plastics, the contents of a building produced a considerably lower BTU output and the smoke was no comparison to that of today. This was also the same time period when most American homes and businesses were secured with little more than a wooden door equipped with a simple lock. Most doors easily yielded to a well placed mule-kick or a blast from an axe.
That was yesterday. The modern ladder company is plagued with under-staffing, lightweight building construction, hotter burning and faster spreading fires, and ever-increasing forcible entry issues. All of these place even higher demands upon our limited personnel. Today the power saw can literally be a lifesaver. Where time is of the essence and personnel at a premium, power saws often plays a vital role in the success of an operation.
Fire Service Power Saws
The most common types of power saws used on the fireground are the rotary saw and chain saw. The type and brand are matters of preference. When choosing a model, look for brands that have a long and respected reputation in the fire service or that have been specifically designed for our line of work. Some saws are not designed for the rigors of fire service use. Carefully review saw choices, interview other departments, and have a dealer loan you a “demo” saw for a period so your department can test it and make the right choice its needs.
Contrary to popular belief size does matter, at least when it comes to power saws. The ability to rotate the cutting edge through some material quickly requires sufficient horsepower. Underpowered saws stall when cutting, delaying operations. Choose the saw that is the largest (horsepower) your personnel can safely operate.
Smaller rotary saws are well suited for most forcible-entry and light-ventilation operations. For heavy ventilation work on built-up flat roofs, a higher horsepower saw is needed. A rotary saw's greatest attribute is versatility wherein you can easily change blades to cut almost any material.
Initially, chain saws in general were restricted to light-ventilation and overhaul operations. Modern fire service chain saws are much improved over their predecessors and are entirely designed for ventilation and some forcible entry operations. Chain saws also tend to be easier to operate, especially on peaked roofs.
Power Saw Safety
Firefighting is inherently dangerous, and power saws operated by untrained or inexperienced firefighters add to the risk. Start by reading the owner's manual. It covers all of the saw’s technical aspects and its limitations. Blades and chains must be rated for use on your specific saw. Never modify any component of the saw or force a blade or chain to fit. Serious injury, or worse, could result from such actions. Most all manuals include safe-operation guidelines. Remember: this book is full of important information, but it will not benefit you if you do not read it.
Saw operators must remain constantly aware of their surroundings. Anytime a saw is in operation, personnel are exposed to a rotating cutting edge. The edge does not differentiate between wood, metal, or flesh. For this reason, wear full protective equipment at all times. Wear safety glasses to protect against flying debris. During training and whenever else possible, use hearing protection. Safe saw operations begin and end with personnel who thoroughly understand the saw’s capabilities and limitations and have been trained adequately in its use.
Maintaining Power Saws
Just like the firefighters who operate them, power saws are expected to work on a moment’s notice and to continue through to the incident's conclusion. Failure to perform could have serious and negative consequences for the outcome of the incident. For this reason, maintaining power saws is extremely important. Remember that owner’s manual? It will help in this area too. Also, using one brand of saw will help to alleviate numerous maintenance headaches and standardize operating procedures.
Maintenance should be performed at the beginning of each shift or weekly drill. Check over the entire saw before starting it. Look for any damage, debris build-up, and check the condition of the blade or chain. Run the saw until the motor is warm. Listen to how it sounds and feels. If the saw is not operating normally have a qualified person check it out. Allow the saw to idle for a short period before shutting it off. A properly tuned saw will idle smoothly without stalling. Finish by refueling the saw and give it one last “once over” before returning it to the rig. Spending the extra time now will save time on the fireground.
How the saw is stored on the fire apparatus greatly affects how fast it can be put in operation. Saws need to be stored in a single compartment with their associated parts and equipment.
The compartment should be well vented, large enough to accommodate all of the items in an orderly fashion, and low enough so that a firefighter can remove the saw easily. Saws should not be stored inside boxes within the compartment. These storage boxes take up valuable compartment space and delay saw operations.
Starting the Power Saw
Starting a power saw while wearing full turnout gear and SCBA requires a different technique than when wearing your station uniform. Fire boots, even leather ones, many times are too large to fit into the rear handle of the saw. Forcing the toe of a fire boot into the handle could damage the controls, which usually are made of plastic. Furthermore, bending over the saw in full PPE to pull the starter cord is awkward and creates the potential for back injuries.
To prevent potential injuries and equipment damage, use a crouching starting position. Developed by Fire Department of New York Lieutenant Michael Ciampo, the technique and its variations involve squatting, like a baseball catcher, and using a knee to hold the saw firmly to the ground.1 This method of starting works equally well for both types of power saws.
The Proper Technique
Begin by grasping the forward handle with your right hand, keeping the arm straight. Kneel and place either knee on top of the power head, normally over the air cleaner. With the left hand, set the controls, and then release the compression from the motor. Releasing the compression will help prevent the embarrassment of having the saw roll out from under you, or worse, breaking the starter cord when you pull it. There are two methods for releasing the compression. Some saws are equipped with a decompression valve that opens when it is depressed and closes when the motor begins to fire. If the saw fires but does not start, you will have to reopen the valve. The second method requires a little practice, but will be quick and easy once you get the feel. Grasp the starter cord handle with your left hand and slowly pull it until you feel the cylinder reach the top of its stroke and break over top dead-center. Stop once you feel the cylinder start the down stroke. The exhaust valve will have opened, releasing the pressure which now will allow you to pull the starter cord without compression. Repeat this process for each new pull of the starter cord. Most people are right-handed, and it may feel strange to pull the starter cord with the left hand, but with practice this method of starting a power saw will begin to feel natural.
Blade and Chain Selection
The type of blade or chain on the saw will determine which materials can be cut and how fast. Initially, just like the saws, blades and saw chains were adapted to our purposes from some other trade. Most of the blades and saw chains used by the fire service are designed and manufactured specifically for fireground operations and are only available to the fire service.
Ventilation blades for rotary saws should have an aggressive tooth design and long and wide carbide tips. The larger carbide tips create a wider cut, or kerf, which prevents the blade from binding. Additionally, a major benefit of the aggressive tooth design is that even if several of the carbide tips are broken or missing, the blade will continue to “rip” the roof decking. This will enable a firefighter to complete ventilation without having to stop and change the blade under most circumstances. This type of blade will also cut the light sheet metal used in some residential and commercial roof systems. “Vent” work can be very rough on blades. Hidden structural components made of heavy steel can destroy a ventilation blade on contact, and the materials used in modern shingles often will dull carbide teeth. If there is any usable life remaining in the blade that has been removed, that blade can be saved for training. Since the saw will always have a new blade installed, there will never be any question relative to the quality of the blade the next time the saw is needed.
Some fire departments carry only the aluminum-oxide abrasive discs for steel cutting; others carry the aluminum-oxide and the silicon-carbide blades to add masonry-cutting capabilities to their operations. These blades look similar and are very difficult to differentiate by appearance alone. It is extremely important to clearly label abrasive discs with a paint pen or by some other fashion to ensure that a firefighter does not inadvertently put the wrong type of blade in the saw. Mixing up these two types of discs can have disastrous results and will cause delays and potential serious injuries. There are “multi-purpose” blades on the market that claim to cut numerous materials found on the fireground, while this may be true, they tend to cut very slow. Speed is important for safe and effective operations, therefore, it is better to match a specific blade to a specific function.
For chain saws selecting the proper chain for fireground duties is critical for effective operations. Unlike a rotary saw blade, once a saw chain is dulled or has lost its carbide tips, no matter how hard you force the saw, it will no longer cut. Standard saw chains (the type used for tree cutting) are not suited for the majority of fireground functions. They will dull quickly when cutting through shingles and are easily damaged from fasteners such as nails or screws. At a minimum, fireground chain saws should be equipped with carbide-tips.
Carbide-tipped saw chains will more than adequately cut through the shingle-over-wood or rubber-over-wood roofing systems found on residential and older commercial buildings. This type of chain will last for numerous ventilation operations as long as they are not misused. However, since the carbide tip is attached on only one side, it is prone to breakage as a result of repeated contacts with fasteners and other metal objects.
The best saw chains for fireground use are those specifically designed for the fire service. Although these saw chains use carbide tips, their design makes them superior to regular saw chains. They also have a wider kerf, which helps prevent binding of the chain bar and a larger raker (the piece of steel on the chain that extends up in front of the carbide tip) which helps protect the carbide tip from damage. The most important design feature is that the carbide tip is attached on both sides by two side plates or is attached to a single solid chain link, which helps prevent breakage. These features make this type of saw chain extremely durable and capable of cutting through almost any material found on the fireground.
Power Saw Accessories
The appropriate accessories make a good power saw even better. When ordering a new saw, consider all of the optional accessories available and determine which could help to improve efficiency and safety from an operational standpoint. You could also purchase many of the options separately from a local dealer and add them to older saws. A few of the most useful ones are the D-style pull starter handle, carrying sling, chain guard/depth limiter, and wrench holder.
Training with the Power Saw
Safe and efficient operations depend on how much and how well the firefighters using the saw are trained. Just like riding a bike, once you have mastered the techniques, you are able to pick up a saw and go to work even after long periods of non-use with little trouble. However, the best saw operators understand the saw intimately and practice frequently through realistic training scenarios.
The fireground is not the place to receive saw training. Firefighters should be trained and should practice their techniques under controlled conditions. One of the safest methods is to use training props such as a roof simulator and the security bar simulator. Acquired structures also present an abundance of training opportunities for saw operations. However, the structure must be sound, and safety precautions must be in place before training takes place. (See three photos below.)
For the modern ladder company, power saws can be a great asset on the fireground when they are thoroughly maintained, readily accessible, properly equipped, and used by well-trained personnel.
1. “Simple Saw Starting,” Michael N. Ciampo, Fire Engineering, July 1998. (Back to Text)