How much time is safety worth? A comparison of trigger configurations on pneumatic nail guns in residential framing.

OBJECTIVE

Nail gun injuries are among the most common in wood frame construction. Despite evidence that the majority of injuries from unintentional firings could be prevented with a sequential trigger mechanism on the tools, the safer trigger has not been embraced in the fast-paced residential construction industry. An experiment was conducted in an attempt to realistically evaluate the magnitude of productivity concerns.

METHODS

Ten journeymen carpenters built a yard shed on two occasions, using nail guns with two different trigger configurations, alternately, under controlled conditions. Mean differences in time required, nails used, and proper placement were evaluated considering the trigger used and whether the building was the carpenter's first or second project.

RESULTS

The sequential trigger tool required a mean of 10 additional minutes of active nailing time, which represented 10% of mean nailing time (97 minutes) but only 0.77% of the total mean work time (1,298 minutes) to construct each shed. No significant differences were observed in nail count or placement. The majority of the time variability was related to who was using the tool, rather than the type of tool in the person's hand.

CONCLUSIONS

Productivity concerns should focus more on improving the skill of the carpenter rather than on the trigger mechanism. Failure to place tools with the safer trigger configuration, which requires the nose piece to be depressed before the trigger is pulled, in the hands of workers does not make sense given the frequency and potential repercussions of injuries associated with the use of these tools in wood framing.