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FORMING A NEW ATTACHMENT FOR CORRECTIONAL FACILITIES
Prison furniture takes a lot of abuse. To maintain security and inmate safety,
prisons and detention centers must provide solid attachments for all furniture and fixtures. For
this reason, beds, shelves, sinks and desks are typically welded or bolted to steel embeds.
Plate embeds are most commonly used. In concrete masonry construction, the
tongue of the embed is typically placed in a horizontal mortar joint of the concrete masonry
wall. When the height of the attachment does not align with a mortar joint, however, the concrete
masonry unit must first be notched to accommodate the embed. To install plate embeds, they must
be held tightly against the concrete masonry wall while a steel reinforcing bar is threaded
through the perforated tongue and while it is grouted in place. Because this is physically
difficult for one person to accomplish, a variety of problems can occur-the plate on the interior
wall surface can end up canted, rather than flush against the wall; embeds can be worked loose
if the cells behind are not grouted fully or correctly; and the embeds can be installed crooked.
With precast concrete cells, embeds can be even more complicated.
Although it may seem trivial, standards for prison embeds are strict-a necessary
precaution to prevent the unintentional formation of concealed spaces, which could be used to
hide contraband or weapons. In fact, if the embed is more than 1/4 in. (6.4 mm) away from the wall
surface, it must either be cut out and reinstalled, or the mason must slush behind the embed with
nonshrink high strength grout. Both options are expensive and time-consuming.
This product provided a unique solution for correctional facilities,
allowing quick secure attachements for furniture and others fixtures and futher increasing the inherint
flexibility of the concrete masonry wall system.
Tillman County Law Enforcement Center in Frederick, Oklahoma, is designed using
reinforced concrete masonry for security, durability and long-term low maintenance. On this
particular project, the contractor, CDBL, Inc., suggested a new product for making attachments to
the concrete masonry walls. Designer Larry Goldberg, principal of Lawrence Goldberg Architects,
Inc., found that this product provided a unique solution for correctional facilities, allowing quick
secure attachments for furniture and other fixtures and further increasing the inherent flexibility
of the concrete masonry wall system.
The new product is a basic unit that has the same overall dimensions and design
as a traditional concrete masonry unit (see Figure 1), but is manufactured of steel rather than
concrete. The unit is laid in the wall, as a concrete unit would be, with bottom flanges on the
faceplates to facilitate placement on mortar beds. The units are also sized to meet standard
concrete masonry unit dimensions, so coursing is uninterrupted. In fact, Goldberg has found that
once the masons know where the steel units need to be located in the wall, they don't require
special installation considerations.
Once installed and the wall is grouted, the steel unit is an integral part of
the wall and cannot be loosened. Items are attached to the units by welding, by using weld nuts
or by drilling and tapping the steel face. During manufacture, weld nuts are aligned with a hole
in the faceplate and welded to the inside at specified locations for bolt attachment of a specific
device, eliminating the need for welding on site. When a device requires two blocks for attachment,
and the blocks are spaced relatively far apart, such as an 82-inch (2,083-mm) spacing for setting a
steel bunk, the steel unit provides a template (a rod with pins at both ends that establishes the
correct distance apart) to aid installation. The manufacturer also recommends using products with
slotted bolt holes when weld nuts will be used.
When a designer orders these units, all weld nut and bolt fastener locations are
specified so units arrive on site with the proper connection accessories. Units are available
in 6-, 8-, 10- and 12-inch (152-,203-,254- and 406-mm) widths to correspond with concrete masonry
unit thicknesses. Unit strength and stability is controlled by specifying adequate steel thicknesses
to carry the heavy attachment loads, withstand induced vibration from intermittent use such as that
seen by handrails, and to prevent individual units from racking during shipment. Unless otherwise
specified, 6- and 8-inch (152 and 203 mm) units are manufactured with 1/4-inch (6.4-mm) steel
faceplates and 10-gage steel webs, while the 10- and l2-inch (254- and 406- mm) units have 1/4-inch
(6.4-mm) steel plate for all webs and faceplates.
The steel units include several features to specifically accommodate steel
reinforcement - a security requirement in all corrections facilities. All unit webs are manufactured
with a 3-3/4-inch (95-mm) square hole to help grout flow between cells and completely fill the cores.
In addition, the web height, at 7 inches (178 mm), allows placement of horizontal reinforcement
without modifying the units.
The steel units are available in several finishes to protect the steel from corrosion.
Several powder-coated color options are available as well as electro- deposition coated, hot-dip
galvanized, prime coated and stainless steel. When units are epoxy powder-coated, attachment by bolting
is recommended since products attached to the steel unit cannot be easily welded with this coating.
When items must be attached by welding, the manufacturer recommends using the prime-coated units. The
steel unit is testing several new powder-coating materials which accept welds much more readily and
have high scratch resistance.
Inmate Cells
Cell design is governed by either the prevailing state jail standards or by the American Correctional
Association Federal guidelines. Certain furniture and fixtures are required in each cell, depending on
cell configuration. Goldberg found that he used 14 to 16 embeds per cell for items such as a wall
mounted stool (l embed), desk (3), bunk (2 or 3), double bunk (4), plus a shelf, hooks and other
fixtures, all of which can be replaced with the steel units.
Products Designed Specifically for Correctional Facilities
The steel unit manufacturer has worked closely with various clients to design a number of products
to specifically address the needs of correctional facilities. For example, at the request of a state
department of corrections, the company recently designed a stainless steel block with a 1-1/2 in.
(38-mm) stainless steel rod welded to the face, similar to a grab bar. Because weapons are not
permitted inside the facility, when a prisoner was brought in, the officer had to remove and lock his
weapon in a gun cabinet outside while handcuffed to the prisoner. With the new block design, the
officer simply handcuffs the prisoner to the steel handcuff unit, stores the weapon, then takes the
prisoner back into custody and enters the facility.
Installing fire sprinkler heads can also be a challenge. Inmate cells typically
have wall-mounted sprinklers in each cell because of the difficulty installing the necessary piping
in the poured concrete slab above (the piping cannot be left exposed below the slab). To install
the sprinkler head in a concrete masonry unit, a hole is made in the block face shell, a pipe is
threaded through, and the sprinkler head is attached. The steel unit manufacturer developed a block
with the pipe already in it to accommodate the sprinkler head and hence speed installation.
Although the purchase price of these special steel units is higher than plate embeds,
Goldberg has found that the labor savings offsets the higher purchase price and results in a lower
overall cost. In his experience, masons also prefer using the steel units. Concrete masonry is the
material of choice for correctional facilities because of its economy, design flexibility, durability
and low maintenance needs. Now, products such as this steel unit are further enhancing these benefits
by improving construction productivity and quality. The end result is a better, more secure attachment
for prisons and detention centers.
Copyright 2001 by National Concrete Masonry Association (NCMA).
Concrete Masonry Designs is published monthly by the National Concrete Masonry Association and distributed
through the NCMA Foundation, dedicated to advancing and supporting the conrete masonry industry and the
public interest through research and educatonal programs designed to meet the future needs of the
industry.
Check out our Web site at www.ncma.org. |
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