P3500
EN
4
FUNCTIONING IN STEEL
The load performance of a powder actuated fastener when installed into steel base
materials 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 1/4" is allowed for the point length. An
increase in performance can be expected until the fastener no longer completely
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 long 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.
SUITABLE BASE MATERIAL
While powder actuated fasteners can be used successfully in concrete, certain masonry
materials, and A 36 steel, some materials 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.
CENTER PUNCH TEST
A center 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 wear the appropriate eye protection
when performing this test. 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 center 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.
Surface Shatters
Material Cracks
Point Flattens
No Indent
2
1
