Building Design and Construction Handbook - Merritt - Ventech!

11.134 SECTION ELEVEN
that may be made in the drawings as the job progresses, or any changes that may
have to be made later are simplified, and special hardware is avoided.
Unit locks (Fig. 11.80) are complete assemblies that eliminate most of the adjustments
during installation that would otherwise be necessary. These locks have
merely to be slipped into a standard notch cut into a wood door or formed in a
metal door.
Bored-in locks are another type that can be installed by boring standard-size
holes in wood doors or by having uniform circular holes formed in metal doors.
These bored-in locks are often referred to as tubular-lock sets or cylindrical-lock
sets depending on how the holes have to be bored to accommodate them.
Tubular locks have a tubular case extending horizontally at right angles to the
edge of the door. This type of case permits a horizontal hole of small diameter to
be bored into the door at right angles to the vertical edge of the door; another small
hole is required at right angles to the first hole to take care of the latching mechanism.
Most tubular locks now produced fit the standard bores in steel doors con-
forming to ANSI A115.2 and A115.3, just as do cylindrical locks.
Cylindrical locks (Fig. 11.81), the
other type of bored-in lock, have a cylindrical
case requiring a relatively
FIGURE 11.81 Cylindrical lock.
large-diameter hole in the door, bored
perpendicular to the face of the door.
This hole accommodates the main body
of the lock. A hole of smaller diameter
to take the latch bolt must be bored at
right angles to the edge of the door.
When bored-in locks are used in hollow
metal doors, a reinforcing unit is required
in the door. This unit is generally
supplied by the door manufacturer.
Exit devices are a special series of
locks required by building codes and the
National Fire Protection Association ‘‘Life Safety Code’’ on certain egress doors
in public buildings. On the egress side, there is a horizontal bar running a minimum
of one-half the width of the door. When pressed against, the bar releases the locking
or latching mechanism, allowing the door to open. These devices are required to
be labeled for safe egress by a nationally recognized independent testing laboratory.
When used on fire doors, they must carry an additional label showing that the
devices have also been investigated for fire. They then bear the name ‘‘fire exit
hardware.’’ These devices are available with various functions, including arrangements
for having them locked from the outside and openable with a key. For all
functions, however, they must be openable from the inside by merely depressing
the cross bar.
Locking Bolts (Doors and Windows). Various types of bolts and rods are fastened
to doors and windows for the purpose of securing them in closed position or to
other doors and windows. Flush bolts and surface bolts, manual or automatic, are
often used.
Top and bottom vertical bolts operated by a knob located at convenient height
between them are known as cremorne bolts.
Keys. Locks are further classified according to the type of key required to retract
the bolts. On all but the cheaper installations the principal type of key used is the
cylinder key, which operates a pin-tumbler cylinder.