Circular Power Saw Safety
Tom Brennan’s Random Thoughts On…
Circular power saws provided a significant advance in offensive structural firefighting tactics when they were introduced in the late 1960s.
Unfortunately, they’re also responsible for some painful, disabling injuries during operations. Here are some tips from the field, learned from analyzing such injuries.
If visibility is low, roll the unstarted saw in front of you to the point of operations. Better for the saw to fall forward into an opening than for the firefighter to do so.
Start the saw only when you get to the point of operation. One of the most unsafe situations is having a few easily distractible firefighters walking around occupied areas with 6,000-rpm saw blades in their hands.
Establish and maintain a circle of safety around sawing operations. The operator and a properly equipped person guiding the operator should be the only humans within a 20-foot radius (if possible).
Gunning the motor may make you sound like you know what you’re doing, but it’s not good for the saw or your grip on it. Slowly build up to maximum revolutions per minute and keep it there while you’re cutting.
When not cutting, let the motor return to idle, the clutch disengage, and the blade rotation stop. You must verify that the idling saw isn’t turning the blade. Get in the habit of lowering the blade onto some woodwork nearby to ensure that the blade has stopped.
Drop starting—holding onto the cord and letting the saw drop—is a lumberjack trick, not a firefighter’s procedure. Wet, inexperienced hands, lack of visibility, and instability spell disaster for a firefighter. If you drop a started saw, it can easily ride around by itself, claiming parts of bodies.
Know what you’re cutting and where your feet are. The latter should always (if there is such a thing as “always”) be outside the perimeter of the cut. Otherwise you may cut yourself into the fire building, with the running saw following close behind.
Horizontal cutting is dangerous. Cutting above waist level magnifies the danger, and cutting above your head is insane. Numbed hands, oscillating machinery, and fatigue multiply the probability of injury.
With today’s lightweight building materials, it’s sometimes difficult to tell when you’re cutting not only the sheathing, but the supports with it; a stiff, numbed arm won’t know. Keep a light, floating touch on the saw. Let the saw cut through the sheathing and ride over any supports it finds.
In life-or-death situations, the carbide-tipped (wood-cutting) blade may be used to cut an opening in thin metal facades, rather than taking the time to change to the aluminum-oxide (metalcutting) blade. But firefighters should be aware that the teeth can come off like bullets. Full fire clothing can adequately protect the firefighter from these projectiles.
In cold weather, a carbide-tipped blade throws undetectable chips of frozen asphalt roof shingle under the operator’s feet. On a sloped roof, these pieces can become as dangerous to walk on as ball bearings, if they’re not noticed and swept away.