Nail guns are used every day on many construction jobs, especially in residential construction.
The most common nail guns used are pneumatic, but nail guns can also use gas (explosive) or electricity. Nail guns may boost productivity, but they also cause a number of serious injuries each year from unintended nail discharge.
Nail gun injuries can happen due to unintentional discharges while carrying, moving, setting down or repositioning. Injury can also happen when using the gun in a restricted area or when rapidly fired nails strike other nails or timber knots causing them to ricochet. Nail gun injuries are common among young apprentice carpenters.
The risk of a nail gun injury is higher when using a contact trigger (bump fire or multishot) compared to using a full sequential trigger (single-shot). Most injuries occur when the nail gun is set to ‘bump fire’ mode, resulting in penetrating wounds to the operator or nearby workers.
While contact triggers may offer a slightly quicker response, workers and others in the vicinity are more likely to be injured when using this type of trigger. The type of nail gun trigger system and the extent of training are important factors in reducing injuries.
Trigger type is less important to overall productivity than who is using the tool. Therefore, productivity concerns should focus on the skill of the user rather than on the trigger.
A full sequential trigger is always the safest trigger mechanism for the job. It reduces the risk of unintentional nail discharge and double fires, including injuries from bumping into co-workers. If the trigger is pressed first and the muzzle is bumped or held against the work piece, the gun will not fire.
Builders, contractors and Group Training Organisations (GTO) need to consider restricting apprentices to using full sequential trigger nail guns when starting out and until deemed competent.
Bump fire trigger
A bump fire or bounce fire nail gun allows nails to be driven by holding the trigger in the firing position and pressing the barrel or muzzle against the work piece. Where possible, choose a nail gun with sequential (only) operation instead of a bump fire gun.
For some high volume production and manufacturing jobs, bump fire nail guns may be in use to help reduce the risk of musculoskeletal injuries (e.g. strains and sprains). A bump fire or bounce fire nail gun allows nails to be driven by holding the trigger in the firing position and pressing the barrel or muzzle against the work piece.
Operators can get into the dangerous habit of carrying the nail gun with the trigger depressed. If the muzzle bumps onto an object, the nail gun may inadvertently discharge.
This can result in operators discharging nails into their legs, hands and other body parts. Nails can also inadvertently ricochet around the work area, with the risk of hitting and injuring others.
In such cases, nail guns in the bump fire mode should be used with the aid of specially laid out work areas and jigs to hold the work pieces.
This will reduce the need for an operator’s hands and legs to be near the job while nailing is carried out.
Workers must take all practicable steps to keep themselves safe in the workplace and ensure they do not place others at risk of harm.
Risk control measures
There are a number of ways to reduce the risk of injuries by:
- providing workers with training and instruction in their safe use, including what to do if the nail gun malfunctions
- apprentices should only use nail guns under strict supervision
- replacing bump fire nail guns with sequential (only) firing nail guns, wherever possible
- avoiding the use of bump fire nail guns, including those with a switchable trigger mechanism, where the operator is required to climb ladders or other elevated areas with a loaded nail gun
- when working at height, operators work from a platform as nail guns are designed to be used with two hands and recoil when fired
- ensuring nail guns are not held above the line of the workers shoulders
- regularly checking and maintaining nail guns according to manufacturer’s specifications
- inspecting timber surfaces for cracks or knots prior to their use
- placing signage appropriately to warn that a nailing tool is in use
- excluding other workers from the area where the nail gun is being used, wherever possible
- wearing eye protection, hearing protection and additional personal protective equipment
- workers take regular breaks to address the ergonomic risks associated with their long-term and repetitive use.