Quick-cut Saws

Controls can reduce or eliminate hazards.

Increasing use poses hazards.

Quick-cut saws are hand-held, portable, gasoline-powered circular saws used to cut concrete, masonry products, and metal.

There are four main types of hazards in operating quick-cut saws:

cuts and entanglement
flying particles
airborne dust, carbon monoxide, and noise
fire from refueling and sparks.

Starting Position

Cuts and entanglement

Very serious injuries and even fatalities have resulted from the improper use of quick-cut saws.

Wounds and amputations can occur when the operator loses control of the saw or parts of the body get in the way of the blade.

Ensure that the saw has a working guard on the blade.
Never hold materials in place with your feet.
Maintain control by always keeping two hands on the saw when it's running.
Avoid using the saw when you are in an awkward position or off-balance.
Never cut above chest height. It is very easy to lose control of the saw and lacerations to the neck or face could result.

When starting, set the saw on a smooth, hard surface. Take a solid, well balanced stance put a foot on the rear handle and one hand on the top handle to lift the blade off the surface. Then use the other hand to pull the starter cord.

Cutting Stance and Grip

Never hold the saw in one hand and start it in a standing position. A slip could result in a serious cut to the leg.

Ensure that all material to be cut is supported so that it will not be thrown around by the blade and will not bind the blade.

If the top part of the blade contacts the work, kickback can result. Kickback has caused cuts, lacerations, and amputations.

The blade runs better and with less danger of kickback when the saw is operated at full throttle.

Injuries can occur when clothing catches in rotating parts of the saw and pulls the saw into the operator.When using a quick-cut saw always wear snug clothing. Never wear bracelets or loose neckchains.

Kickback

Flying particles

The quick-cut saw blade or disk can travel at up to 15,000 rpm. This can cause pieces of material being cut or shattered parts of the blade to fly out at up to 290 km/h (180 mph). One of these particles hitting the eye can cause severe injury and blindness. Cuts and burns to the face and other parts of the body may also result.

Particles have been known to pass under a faceshield and safety glasses to cause eye damage. Wear a faceshield and goggles when using a quick-cut saw.

Only use disks for the materials they are designed to cut. Never cut dry with blades recommended for wet cutting or use water with blades designed for dry cutting.
Special care is required with carbide-tipped blades. If the blade hits material harder than what it is designed to cut, the carbide tips may fly off.
Do not apply excessive pressure to a disk when cutting.
Do not make long continuous cuts with dry cutting blades. Disk damage will result. Abrasive disks may fly apart if they become damaged.
Never use the side of the disk for cutting or try to change the direction of a cut part way through.
Replace damaged disks immediately.

Use Proper Protective Equipment

Carbon monoxide and airborne dust

You breathe whatever you cut. Cutting blocks, bricks, or concrete without respiratory protection, you will breathe in large amounts of silica. Overexposure to silica can lead to long-term lung problems (silicosis) that can be fatal.

Lead paints are still found on some equipment and steel structures. Cutting or grinding through this paint can expose saw operators to lead. Excessive exposure may damage the blood and the digestive, nervous, cardiovascular, urinary, and reproductive systems.

Using water at the cutting surface will reduce exposure to silica. However, the disk must be designed for wet cutting. Use respiratory protection such as half- or full-face respirators with N100 filters for protection from silica and lead. These filters do not, however, provide protection from carbon monoxide.

Carbon monoxide (CO) is a byproduct of all internal combustion engines. In confined areas such as trenches, crawlspaces, bathrooms, basements, and tanks, carbon monoxide can build up to dangerous levels. Only cut for short periods and ventilate the space.

A recent alert from the Ontario Ministry of Labour recommends that all areas where fuel-burning equipment is being used must be ventilated by mechanical means to the outside.

CO levels in an enclosed area where a small engine is running can exceed the National Institute for Occupational Safety and Health (NIOSH) maximum exposure level (200 parts per million) in under a minute. To keep CO levels below this level, 120 air changes per hour are required for a 5hp engine.

Opening doors and windows will probably not provide enough ventilation. When ventilation is not adequate to remove CO, supplied-air respirators must be provided and worn.

Noise

Noise from quick-cut saws can exceed 105 db(A). Always wear hearing protection such as earplugs or muffs when using a quick-cut saw. There is no regulation limiting noise exposure in Ontario construction. However, the American Conference of Governmental Industrial Hygienists (ACGIH) recommends that exposure to this level of noise [105 db(A)] should not exceed 5 minutes on any day.

Fire from refueling and sparks

To prevent fires from starting when refueling,

refuel away from the work area
let the quick-cut saw cool for a few minutes before refueling
let spilled gasoline on the saw evaporate before starting up.

Sparks from cutting can ignite any flammable or combustible material in the area. Ensure that there are no flammable materials such as varsol, gasoline, and oil-based paints in the area. Sparks may also ignite rags, garbage, or paper. Clear all combustible material from the work zone.

Abrasive Disks - Types and Uses

Type	Uses	Materials
Concrete	All-around use, most economical for cutting concrete and masonry. Water-cooling is recommended to increase disk life and reduce dust.	Concrete, stone, masonry products, cast iron, aluminum, copper, brass, cables, hard rubber, plastics
Metal	primarily for steel, not suited for masonry products. Water-cooling is not recommended with metal abrasive disks.	Steel, steel alloys, other hard metals such as monel and iron.

Diamond Disks and Blades - Types and Uses

Type	Uses	Materials
Diamond Abrasive Disk	Faster cuts than with other abrasive disks and creates less dust. Water-cooling is absolutely necessary to prevent heat build-up that can make the disk disintegrate.	Stone, all masonry and concrete products. Not recommended for metals.
Dry-Cut Diamond Blade	ast cuts, lots of dust, very expensive. Let blade cool for 10-15 seconds every 40-60 seconds. Continuous cutting will damage the blade.	Stone, all masonry and concrete products. Not recommended for metals.

Checklist

Quick-cut saws are powerful tools that can make many jobs easier and more efficient.

However, if used improperly, the saws can be very dangerous. The following checklist will help ensure safe operation.

Always hold the saw with two hands and maintain a well-balanced position. It is important to be able to keep control if the saw pulls or kicks back.
Always start the saw on a flat, level surface. Ensure that all material to be cut is well supported.
Clothing should be snug and saw operators should not wear bracelets or neckchains.
Flying particles can cause blindness and other injuries. Always wear a faceshield and goggles when using a quick-cut saw.
Use the correct disk for the material to be cut.
Quick-cut saws can produce dust, noise, and carbon monoxide well above recommended exposure limits. Use eye, hearing, and respiratory protection. When cutting in an enclosed area, ventilate the area thoroughly.

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