Investigation Guideline

Investigation Guideline
Product: Nailers/Nail Guns
Appendix #: 132
Date amended: October 2004
I. Introduction
A. Background Information
Portable pneumatic fastener driving tools, commonly known as nail guns or
nailers, have been identified as a product with an increasing trend in injury incidents.
Estimated injuries associated with nailers have steadily increased from 8,970
emergency room-treated injuries in 1996 to 16,240 emergency room-treated injuries in
2002. There was a slight decrease in injuries in 2003. Staff will continue to monitor
the injuries to see if this trend continues.
A common hazard pattern is accidental firing of a nail into a body part (usually
hand or finger) or into another person. Many nail guns are activated by a trigger and a
contact piece on the muzzle of the nail gun (see Figure 1). It is common practice to
hold the trigger down and simply push the contact piece into the work material to fire
a nail. This practice is susceptible to unintentional firing of a nail by accidentally
contacting the nailer to a body part or nearby person, or unexpected recoil (backward
jerk of a gun when it is fired) of the nail gun that causes contact. Sensitive triggers in
conjunction with nailer recoil can also lead to inadvertent firing of an additional nail.
This second nail can ricochet off the first nail and cause injury, or miss the work piece
entirely to strike a body part or nearby person.

Figure 1: Nail Gun, finish nailer type

In May 2003, the latest revision of the voluntary standard for pneumatic nailers
became effective. The revised standard requires that most nailers be manufactured
with some type of sequential trigger.
CPSC staff is evaluating the adequacy of the current voluntary standard for
nailers to determine if the latest revision of the voluntary standard is adequately
addressing accidental contact hazards.

B. Product Descriptions
Pneumatic nailers should not be confused with powder-actuated nailers, which
use combustion of a powder to drive fasteners into the material. These products use
cartridges, much like a gun, and are known as stud guns. In general, powder-actuated
nailers are designed to fire fasteners into concrete and structural steel. Powderactuated nail guns are very easy to tell apart from pneuma tic nail guns. They do not
have a nozzle to hook up to an air compressor hose and look more like a gun.
Pneumatic nailers use compressed air to drive a piston that ‘hammers’ a nail out
the tool nozzle into the work material. The depth of nail penetration can be adjusted
either by the compressed air pressure (higher pressures result in deeper nail
penetration) or by adjusting the distance between the nail’s exit from the tool and the
surface of the work material (the closer the exiting nail is to the material, the deeper it
will penetrate).
The basic components of a pneumatic nailer are: a compressed air inlet, a
trigger, a workpiece contact, and a nail source. There are several trigger systems
defined in the current voluntary standard:
1) Contact Actuation -- Requires depression of the trigger and the workpiece
contact, in any sequence, to fire a nail. Additional nails can be fired by holding the
trigger down and depressing the workpiece contact. This trigger was the most
prevalent type used in nailers before the latest revision of the standard. It was popular
due to the ease of operating the nailer by holding the trigger down and firing by simply
pushing the contact against the work piece (also known as “bump firing”).
2) Single Sequential Actuation -- Requires depression of the trigger and
workpiece contact, in a specific sequence, to fire a nail. The trigger and workpiece
contact are considered operating controls, and at least two operating controls are
required to fire a nail. Additional nails can be fired only if the workpiece contact
remains depressed and another operating control, usually the trigger, is release and reactivated.
3) Full Sequential Actuation -- Requires at least two operating controls activated
in a specific sequence to fire a nail. Additional nails can be fired only when all
operating controls are release and re-activated in the same sequence.

4) Selective Actuation -- Allows discrete selection of single sequential, full
sequential, or contact actuation. At least one type of sequential actuation must be an
option.
5) Automatic Reversion Actuation -- Requires at least two operating controls
activated in any sequence to fire a nail. Regardless of the initial sequence, the tool
automatically reverts to a single sequential, full sequential, neutral or off position.
There are two types of nail-loading mechanisms (as shown in Figures 2 and 3):
coil feed and nail strip feed. Coils of nails are formed by welding nails to a wire
which is then wound up into a coil. The coil is loaded into a cylindrical holder, and
one end is fed to the “barrel” of the nailer. The compact size of coil nailers allows
access to tight areas. Strips of nails are formed by gluing nails together with paper or
by joining nails together with a plastic material. If the nails in the strips have a full
round head, the collation material is usually plastic. If the nails in the strips have only
half of the nail head, the nails can be lined up right against each other and are called
clipped nails. The nail strip is loaded into a magazine, which feeds into the “barrel” of
the nailer. Nailers that use strips of nails are referred to as stick nailers. They are
lighter and more balanced as the weight of the nails is distributed, but the length of the
magazine limits their use in tight working spaces.

Figure 2. Coil of nails

Figure 3. Strip of full round head nails.

There are a variety of pneumatic nailers, but the most common categories are
roofing nailers, framing nailers, and finish nailers. Roofing nailers, as the name
implies, are designed to nail roofing material. They are typically coil nailers that use
shorter nails with wide heads to maximize surface area. Due to the hazardous
applications involved in roofing, it’s not expected that many consumers would
purchase this type of nailer.
Framing nailers are designed to drive 2 to 3.5 inch nails. These nailers are
typically used to build any type of framing (drywall, home construction, etc.) and most
come equipped with a touch trip trigger. Framing nailers are readily available as both
coil and stick nailers. Because these nailers are particularly useful in refinishing
basements, deck building, and framing of additions, it’s expected that many consumers
would purchase this product.

Finish nailers are designed to drive small nails or brads in applications such as
trim work or picture frame fabrication. These nailers are lighter, and require slightly
less air pressure to operate. The smaller volume and pressure of air required to operate
the finish nailer results in lower nail velocity, less noise, and less recoil during
operation. Most finish nailers use the sequential trigger, while some small gauge
nailers (in the range of 19 gauge) have no contact piece at all and only require
depression of the trigger to fire a nail.

C. Specific Items of Interest
Incidents involving nailers require information on nailer type, trigger
mechanism, brand, model, serial number, as well as detailed information on the use of
the nailer at the time of the accident. Of particular interest is the type of trigger system
on the nailer and whether or not the actuation system meets the current voluntary
standard.
Also of interest is if the nailer recoiled or if recoil contributed to the accident.
Recoil occurs when the nail is fired into the workpiece and the nail gun jerks back,
towards the user. Depending on the nailer and the amount of pressure in the tank, the
user might let the nailer recoil on purpose. An air compressor pumps air into the tank
to reach the maximum PSI, often 120 PSI. As the air tool is being used, the pressure
in the tank falls to a predetermined level, say 70 PSI, before the air compressor kicks
on again and pumps more air into the tank. If the tank is full, at the maximum PSI, the
nail may sink too deep into the wood. If the tank is at the lower end of this range, the
nail head may stick out of the wood. If the nail gun has a depth-of-drive feature, it
may account for this variation in pressure. Otherwise, the user may attempt to account
for the difference in pressure. If the tank just filled up, then the pressure is high and
the user may allow the nail gun to recoil a little. That will keep the nail from sinking
into the workpiece too far. Although, this is a technique only an experienced user will
know.

D. Headquarters Contacts
Natalie Marcy, EHHA (301) 504-7329
Caroleene Paul, ESME (301) 504-7540

II. Instructions for Collecting Specific Information
If the injury was work related, i.e. a hired contractor on a jobsite, only obtain
basic information about how the injury occurred and the triggering mechanism of the
nail gun. There is no need to conduct an on-site investigation; a telephone
investigation should be sufficient.

A. Synopsis
It is important to describe clearly the sequence of events. Describe what
happened immediately before, during, and after the incident. Include location of the
victim, and a detailed description of how the nailer was being used. Describe whether
the victim is the operator, helper, or bystander. Where the incident occurred (home,
school, at work, etc.). What the injury was and how severe was the injury. Include the
following important information:
•
•
•
•
•

Explain in a step by step manner the tasks required to set up and use the nailer
(i.e. attach compressed air hose, verify air pressure in the compressor, set
trigger switches, etc.).
Describe in detail the exact task being performed by the victim such as type of
structure being built
Did the nailer fire a nail more than once? Was this expected?
Provide details of the victim’s hands, feet, and body in relation to the material
being nailed. Was the victim reaching with the nailer? Was the victim nailing
overhead? Did the victim have a firm grasp of the nailer?
Use ATTACHED DATA RECORD SHEET to obtain specific information
associated with nailer related incidents.

B. Description of Incident Environment
Describe all relevant information on environmental factors such as lighting, its
location and intensity, slippery floor/debris on the floor, standing on a ladder, or
uneven footing. Visually examine the product of signs for abuse, modified safety
devices, or other problems on the nailer.
Inspect the nailer, owner manual, or other available material for ANSI labeling
or other listings of certification. Report presence or absence of the ANSI labeling or
listings of certification. Photograph these indications and transcribe information on
them. If none of these indications are found, include a statement indicating this in the
investigation report.

C. Description of Interaction between Injured Person(s) and Product
•
•
•
•
•

Determine the incident sequence and the exact position the victim was in when
injured.
Describe the position of the victim’s left and right hands with respect to the
nailer and material, just before the incident, and right at the time of the
incident.
Specify if the victim was reaching.
Specify whether the victim was holding the nailer firmly or loosely.
Describe whether the victim is right-handed or left-handed or he/she uses both
hands interchangeably.

•
•

Indicate whether the victim was wearing safety goggles, gloves, or other
special clothing at the time of the incident.
In the victim’s opinion what caused the accident?

D. Description of Product (Involved in the injury)
Provide the following detailed information on the nail gun:
• Type of nailer, manufacturer, model number, and serial number or any other
identification number.
• Nail gun air pressure (PSI) and tool air volume (SCFM or CFM) required.
• Type of trigger system on the nailer. Does it meet the current voluntary
standard actuation requirements? (current standards require some type of
sequential trigger, types 2-5 described on pages 2 and 3)
• Air compressor used with the nail gun:
• Manufacturer, model number
• Capacity- expressed in gallons
• Air pressure- number of pounds per square inch (PSI)
• Air volume- standard cubic feet per minute (SCFM or CFM). The
measure of how much air a compressor can deliver or the amount of air
required by a tool. Air delivery should be higher than the nail gun’s air
requirement.
• Horsepower (HP)
• Length of air hose used between air compressor and nail gun.
• Manner in which the nailer was acquired: new, used, rented, or borrowed.
• Age of the nailer (if acquired used, state number of years owned and total age,
if known).
• Condition of the nailer, maintenance level, or previous repairs or
modifications (pay special attention to repairs made shortly before the
incident)
• The depth setting on the contact piece (if applicable).

III. Photographs/ Diagrams of Incident Scene
•
•
•

Photograph the nailer front, side, and top views and how the nailer was
positioned at the time of the incident.
Provide close-up photos of labels, controls, contact piece, and off-on switches.
Have victim pose for photo that depicts his/her position (WITHOUT AIR
PRESSURE TO THE NAILER), as well as the position of the material
being nailed, at the time of the incident.

IV. Obtaining samples and documents related to the investigation
• Photocopy the owners’ manual and attached it to the report.
• Collect any official records associated with this incident that may be available.
• Only collect the nail gun as a sample if it malfunctioned in some way. If there
was no product malfunction photographs and detailed information should be
sufficient.

(DATA RECORD SHEET – Attached)

DATA RECORD SHEET
Investigation Guideline
PRODUCT:

Nailer/Nail Gun

TASK NUMBER __________________________ INCIDENT DATE ___________________________

1. Describe the nailer involved in the incident. Does the nailer use "compressed air" or a
"powder cartridge" to drive or shoot the nail?

2. Was it a coil or stick nailer?
_____ Coil
____ Stick
_____ Other, Specify:_____________________________________________________
______ Don’t Know
3. Was it a framing or finish nailer?
_____ Framing
_____ Finish
_____ Other, Specify:_____________________________________________________
_____ Don't Know
2. What type of trigger mechanism is on the nailer?
_____ Contact Actuation --> can you hold the trigger and "bump" the workpiece
contact as many times as you need to fire a nail?
_____ Single Sequential --> after you depressed the trigger and the contact to fire a
nail, can you fire additional nails as long as the workpiece
contact remains depressed? (i.e. slide the nailer along and
fire the trigger)
_____ Full Sequential -->
do you have to release the trigger and contact, and reactivate each in sequential order to fire another nail?
_____ Selective Actuation --> can you select between a sequential and contact
actuation? (usually a switch)
_____ Automatic Reversion-> does the nailer have a micro-chip that automatically
reverts to a "safe mode" once you finish firing nails in
"bump" or sequential mode? (you use the nailer in
"bump" or sequential mode depending on the sequence
you use to depress the trigger and contact)
_____ Other, Specify: _____________________________________________________
_____ None
_____ Don’t Know

3. About how old is the nailer?

4. What is the brand name (manufacturer), model name and number of the nailer?
___________________ Manufacturer/brand name
___________________ Model name/number
5. What is the air pressure and air volume required to operate the nailer?
___________________ PSI
___________________ SCFM / CFM
6. Air compressor information:
___________________ Manufacturer/brand name
___________________ Model name/number
___________________Capacity- expressed in gallons
___________________ Air pressure- expressed in PSI
___________________ Air volume- expressed in SCFM or CFM
___________________ Horsepower (HP)
___________________ Length of air hose used to attach nail gun to compressor
7. Had the nailer been changed, modified, or repaired in anyway since you got it? How
was the nailer changed or modified? Who did it?

8. Does the nailer have a trigger lock switch or something similar?

9. How long had the operator been working with the nailer that day before the accident
occurred?

10. What type of material was being nailed?

11. What type of structure was being built?

12. Was the operator nailing at an angle?

13. Was the operator nailing near the edge of the material?

14. Did the nailer fire more than one nail?

15. Was the victim the operator, helper, or bystander?

16. Where was the operator's index finger at the time of the incident? Did the operator
release the trigger after operation?

17. Did the nailer recoil? Did the recoil contribute to the accident?

18. Did the nailer malfunction or act strangely in any way prior to the accident?

19. Is the operator right-handed or left-handed or ambidextrous?

20. Was the operator wearing eye glasses, safety goggles, gloves or any other special
clothing at the time of the accident?

21. How much experience did the operator have with this nail gun? With nail guns in
general?

22. In the victim’s opinion, what caused the accident?