Pneumatic nail guns are common tools in residential construction. The tools allow increased productivity, but also create serious injury risks. They are typically energized by air pressure supplied by a compressor, requiring a hose from the compressor to the gun. The tools are then loaded with magazines of nails joined together. Framing nailers are capable of driving 3.5 inch nails into dense wood in less than a 10th of a second!
The two most common triggering mechanisms on these tools are contact trip and sequential triggers. The more popular contact trip design allows nails to be discharged from the tool anytime the nose and the trigger mechanism are both depressed. Workers are able to hold the trigger down and do rapid fire “bounce” nailing to speed up progress. The sequential design requires that the nose be depressed before the trigger in order to discharge a nail, making it more difficult to unintentionally discharge nails because the trigger has to be pressed every time a nail is discharged.
Most nail gun injuries occur when the gun is equipped with a contact trip trigger. Contact trip triggers allow the gun to discharge a nail anytime the gun’s nose piece and the trigger are pressed, so the user can hold the trigger down and bump fire the gun repeatedly by simply pushing down on the nose piece rather than repeatedly pressing the trigger. Carpenters prefer using contact trip triggers because they are faster and do not require the repetitive movement of pulling the trigger. However, contact trip triggers also make it much easier for the operator to accidently shoot themselves or anyone standing close by if the nose piece bumps up against someone or something while the trigger is depressed. Injuries often occur when climbing up and down ladders while holding a nail gun with a finger on the trigger.
ALERT: The two types of nail guns look exactly alike, so workers often cannot tell the difference between the contact trip and sequential triggers. A number of manufacturers now have models that allow the triggering mechanism to switch back and forth from contact or sequential, which can also be confusing.
Because of the dangerous nature of these tools, it is important to be trained in safe handling practices before using them. The facts contained in this Hazard Alert will give you basic information, good work practices, and helpful resources to prevent injuries.
GENERAL SAFETY GUIDELINES:
- Review the owner’s manual carefully with all operators. Be aware of the type of gun being used!
- Use manufacturer’s specified pressures for the tool.
- Supervisors should observe each employee demonstrating safe operating procedures.
- Always wear safety glasses.
- DO NOT touch the trigger unless firing the tool against a work piece.
- Use extreme caution when using an air tool around other workers.
- Never point the tool at anyone. Treat the tool like a firearm and assume that it is loaded!
- Disconnect the air hose before clearing a jam or making adjustments.
- Keep your free hand safely out of the way of the tool.
- Secure the hose when working on scaffolding to prevent the weight of the hose from dragging the tool off the scaffold if you set the tool down.
Pneumatic nail guns are extremely helpful tools, but must be treated with respect and handled carefully in order to reap the benefits! Injury will slow a job down much more significantly than any safety measure ever could.
A Real Workforce Hazard
Compressed gas cylinders pose an ever-present threat to workers who use them. Dangers associated with damage to cylinders containing compressed gases include oxygen displacement, fires, explosions, and toxin exposures, as well as the physical hazards associated with high pressure systems. Special storage, use, and handling precautions are necessary in order to control these hazards.
Compressed gas and equipment safety measures are addressed with specific standards for particular environments including the general industry, shipyard employment, marine terminals, and the construction industry. Each compressed gas cylinder is a sleeping giant which must be used, maintained, and handled with great care. Some of the most noteworthy recommendations and regulations are described below.
The following are general precautions that should be observed when handling any compressed gas cylinder:
- Never identify contents by container color, except in the case of medical gases, as color codes are not standardized throughout the compressed gas industry.
- The contents of a cylinder should be identified by a decal, label, tag, or stenciling. If an identifying label is missing or illegible, return the container to the supplier, unused.
- Industrial gas containers are fitted with outlet connections that are compliant with Compressed Gas Association’s standards for Compressed Gas Cylinder Valve Outlet and Inlet Connections. These fittings are specifically designed to prevent the connection of a gas container to a gas system with an incompatible gas. Never bypass this protection measure by using an adapter!
- Always use a pressure-reducing regulator that has been properly conditioned for the gas being used.
- Never attempt to transfer gas from one cylinder to another, or mix multiple gases in one cylinder.
- Do not misuse gas cylinders by using them for rollers, blocks, striking arcs, etc.
- Do not attempt to lift a gas cylinder by the valve protection cap.
- Always use a hand-truck specifically designed for the job when moving large cylinders.
- Be sure to secure cylinders when storing or transporting to prevent tipping over, which may lead to damage of the valve or cylinder itself, resulting in a leak or even explosion.
- Never move or store compressed gases in a closed van or automobile.
State and local building and fire codes will apply to the installation and storage of compressed gases. The following information covers some of the major requirements for the storage of compressed gases.
- Store all cylinders in designated areas that are secured.
- Flammable, Toxic and Oxygen (or any Oxidizer) gas cylinders must be separated from each other by at least 20 feet, or by a non-combustible barrier at least 5 feet high with a fire resistance rating of at least one-half hour. Inert gases such as Argon, Nitrogen, Helium, and Carbon Dioxide may be used within the separation distance since they are chemically inert and compatible with all other gases.
- Outdoor storage must be kept clear of dry vegetation and combustible materials for a distance of at least 15 feet.
- Cylinders stored outside may not be placed on the ground (soil) or any other surfaces where water can accumulate and cause rust, which may weaken or damage the cylinder, causing a leak or explosion.
- Storage areas must be provided with physical protection from vehicle damage.
- Do not store cylinders near elevators, truck loading platforms, gangways, under operating cranes, or other areas where they might be damaged by falling objects.
- Never expose cylinders to temperatures exceeding 125F.
- Smoking and open flames are not permitted in Oxygen and Flammable gas storage areas or within 20 feet of these areas.
- Always observe local code limits set for the storage of flammable gases in buildings.
Hazards of Industrial Gases
There are certain properties, hazards and precautions associated with each of the major industrial gases, as well as mixtures of same. These gases are: Acetylene, Air, Argon, Carbon Dioxide, Helium, Nitrogen, Nitrous Oxide, Oxygen, and Propane. Each of these gases has at least one of the following hazards:
- High Pressure
- Extreme cold
- Asphyxiating (Inert)
It is the responsibility of the employer to be certain that all employees using a gas are familiar with its specific properties and are properly trained to handle that gas. Proper labeling, handling and storage of compressed gas cylinders are imperative in order to prevent personal and property damage and to ensure overall workforce safety!