CENTER PUNCH TEST
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A center punch test should always be performed to determine the suitability of the base
Point Flattens
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
No Indent
blunted and the base material has a clear point indentation, it is acceptable to proceed
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Surface Shatters
with the first test installation.
the center punch test:
1. The fastener point has been blunted. This indicates that the base material is
Material Cracks
2. The base material cracks or shatters. This indicates that the base material is
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3. When using an average hammer blow, the fastener penetrates the base material
FASTENER INSTALLATION REQUIREMENTS
Fastener Sinks in with
Average Hammer Blow
It is important to understand the required minimum base material thickness
requirements along with the minimum spacing and edge distance requirements.
Failure to follow these requirements can result in an 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 fasteners point can cause the free face of the concrete to break away. This can
penetration
create a dangerous condition from flying concrete and/or the fastener and also results
in a reduction of fastener holding power. For applications in the face shell of concrete
3x
masonry block, select a fastener length which will not exceed the thickness of the
penetration
face shell.
FASTENER PENETRATION GUIDE
The following table lists typical embedment or penetration depths expected in the base
materials listed. The penetration will vary depending on the density of the material. This
table should be used as a guide since the consistency of these materials varies. When
in doubt, a job site performance test should be conducted.
EDGE DISTANCE
3"
Do not fasten closer than 3" (76mm) 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.
SPACING
3"
Setting fasteners too close together in concrete or masonry can cause cracking. The
recommended minimum distance between fasteners is 3" (76mm) center to center.
PA3500
Use of a powder actuated system is not recommended if the following occurs during
too hard.
too brittle.
easily. This indicates that the base material is too soft.
DENSITY
Soft Masonry
Average Concrete
Dense Concrete Pre-Stressed/Pre-Cast Concrete
TYPICAL BASE MATERIAL
Concrete Block
Poured Concrete
EN
PENETRATION
1" (26mm) -1-1/4" (32mm)
3/4" (19mm) - 1" (26mm)
5/8" (16mm) - 3/4" (19mm)
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