or isolating the frame from the wall substrate, and incorporating
weepholes and internal passages.
Anchorage. In typical wood frame construction, window
frames are nailed to the walls. Because security glazing systems
must resist attack, they have to be anchored to the walls.
Some frame designs, for concrete construction, use
anchor bolts for a dual purpose. They not only serve to anchor a
frame to a structure, but also serve as fasteners of the
removable stop. Since a glazing must be removable without
destroying the wall, careful consideration must be exercised as
to the type of anchor bolt used in this design. Sleeved anchors
and compression bolts which cannot be reinstalled are
unacceptable for this application.
Place anchorage and fasteners on the protected side for
security integrity and ease of replacement.
Anchor Bolt Types. Three types of anchors are
available for installing glazing systems:
a) Taper Bolt
b) Expansion Sleeve Anchor
Taper Bolt. Taper bolts have a uniform body diameter
construction. The taper bolt incorporates a tapered thread on
the bolt and a matching tapered thread in a nut. When screwed
into a nut, the bolt wedges or anchors into concrete. Once the
taper bolt is installed, it can be removed and reinstalled again
without breaking up the wall. This allows replacement of the
window frame without major wall work. Figure 4 illustrates a
typical taper bolt design.
Expansion Sleeve Anchor. The expansion sleeve anchor
incorporates a reduced body and mushroom end (see Figure 4). The
reduced body fits inside a sleeve that wedges against the
Sleeved anchor bolts have only the strength of their
inner bolt diameter in tension. If the expansion anchor is a
multi-sleeved "spacer" design, its shear strength is only equal
to that of the diameter of the inner bolt at the plane between
the spacers. For this reason, the sleeved spacer design is not
recommended for security applications.