SUITABLE BASE MATERIAL
While powder actuated fasteners can be used successfully in concrete, certain masonry material and some
types of steel are completely unsuitable.
Fasteners should never be fired into hard or brittle materials such as cast iron, tile, glass or rock. These
materials can shatter easily resulting in a potential safety hazard. In addition, soft base materials such as
wallboard, plaster or wood are not appropriate as the fastener could pass completely through these materials.
The user should never guess when fastening into any base material. Failure to follow the recommended
installation and safety guidelines can result in severe injury or death to the tool operator and/or bystanders.
CENTRE PUNCH TEST
A centre punch test should always be performed to determine the suitability of the base material for a powder
actuated fastening. This test is relatively simple and can help to insure a safe, successful fastening. Be sure to
use eye protection properly in accordance with AS / NZS 1873.1:2003
To begin, select the fastener to be used for the job. Then, place the point of the fastener against the proposed
base material. Strike the fastener with a single hammer blow, then examine the point. If the point of the
fastener is not blunted and the base material has a clear point indentation, it is acceptable to proceed with
the first test installation.
Use of a powder actuated system is not recommended if the following occurs during the centre punch test:
1. The fastener point has been blunted. This indicates that the base material is too hard.
2. The base material cracks or shatters. This indicates that the base material is too brittle.
3. When using an average hammer blow, the fastener penetrates the base material easily.. This indicates that
the base material is too soft.
FASTENER INSTALLATION REQUIREMENTS
It is important to understand minimum base material thickness requirements along with minimum spacing
and edge distance requirements. Failure to follow these requirements can result in unsuccessful fastening and
create a safety hazard.
BASE MATERIAL THICKNESS
Concrete base material should be at least three (3) times as thick as the fastener embedment penetration.
If the concrete is too thin, the compressive forces forming at the fastener’s point can cause the free face of
the concrete to break away. This can create a dangerous condition from flying concrete and/or the fastener
and also result in a reduction of fastener holding power. For applications in the face shell of concrete masonry
block, select a fastener length which will not exceed the thickness of the face shell.
FASTENER PENETRATION GUIDE
The following tabe lists typical embedment or penetration depths expected in the base material listed.
Penetration will vary depending on the density of the material. This table should be used as a guide only since
the consistency of these materials varies. When in doubt, a job site performance test should be conducted.
EDGE DISTANCE
Do not fasten closer than 75mm from the edge of concrete. If the concrete cracks, the fastener may not hold.
Closer edge distances for applications such as sill plates may be permitted if specific fastener testing has been
conducted.
4 5
Model P3X Model P3X
FUNCTIONING IN CONCRETE
The performance of a powder actuated fastener, when installed into concrete or masonry base materials, is
based on the following factors:
1. Strength of base material 2. Hardness and concentration of the aggregate
3. Shank diameter of the fastener 4. Depth of embedment into the base material
5. Fastener spacing and edge distance.
In addition to these factors, installation tool accessories such as a stop spall, which reduces the tendency of
the concrete surface to spall during the driving action, can increase the performance of the fastener.
When a powder actuated fastener is driven into concrete, it displaces the volume of concrete around the
embedded area of the fastener shank. As this occurs, the concrete directly surrounding the fastener is
compressed and in turn presses back against the shank of the fastener.
Additionally, the driving action generates heat which causes particles within the concrete to fuse to the shank
of the fastener. This combination of compression and fusion holds the fastener in the concrete base material.
A similar action occurs when fastening into block masonry.
Generally, the performance of the fastener in a given concrete strength will increase with greater embedment
depths in a certain range. Depending on the fastener style and base material strength, embedment depths
range from 16mm to 38mm. In depths greater than this range, there is a possibility of the fastener bending or
fishhooking which may decrease expected load capacities and create a safety hazard.
During the driving action, some localised surface spalling of the concrete may occur. Normally, this is a surface
effect which does not effect the performance of the fastener. However, this may pose an aesthetic problem for
exposed applications where a fixture is not used. In such cases, two methods may be used to improve the
appearance of the fastening. A stop-spall adapter mounted on the powder actuated tool can help reduce
surface spalling. Another method used is to drive the fastener through a steel washer to improve the
appearance of the application.
FUNCTIONING IN STEEL
The load performance of a powder actuated fastener when installed into steel base material is based on the
following factors:
1. Thickness of the steel 2. Tensile strength of the steel 3. Shank diameter of the fastener
4. Depth of point penetration through the steel 5. Fastener spacing and edge distance
When a powder actuated fastener is driven into steel, it displaces the steel laterally 360° around the shank of
the fastener. Since steel is an elastic material, it presses back against the shank of the fastener to hold it in
place. As the diameter of the fastener shank is increased, the load capacity obtained will generally increase
provided the steel thickness is sufficient to accept the fastener. To further increase fastener performance in
steel, some fasteners have a knurled shank which allows the steel to form a key lock into the grooves to
provide higher capacities than those obtained with a smooth shank. For optimum performance, the fastener
point should completely penetrate the steel. Normally, a minimum of 6.5mm is allowed for the point length.
An increase in performance may be expected until the fastener no longer penetrates through the steel. At this
point, the elastic properties of the steel cause a compression force to be developed at an angle against
the fastener point which reduces load capacity. In thicker steel base materials, adequate load capacities may
be obtained for applications in which the point of the fastener does not fully penetrate the steel. Job site
performance tests are recommended.
Fasteners should not be used in areas that have been welded or cut with a torch as these procedures may
have caused local hardening of the steel. Over-driving of the fastener should be avoided as the rebound
created may reduce the load capacity or cause damage to the fastener.
When fastening into unsupported steel members, it may be necessary to provide support in the area of the
fastening to prevent spring action which can cause inconsistent penetration and a reduction in load capacity.
Washer
Stop Spall
P
Point
Flattens
P
Surface
Shatters
P
Fastener
sinks in
with
average
hammer blow
Penetration
3 x
Penetration
75mm
Density Typical Base Material Penetration
Soft Masonry Concrete Block 25 - 32mm
Average Poured Concrete 19 - 25mm
Dense Concrete Pre-stressed / Pre-cast Concrete 16 - 19mm
P3X Inst Manual Update 14-8-13.indd 4-5 8/14/2013 9:44:15 AM