Commercial-quality locks have added features that provide facilities
with heightened security, such as heavier-gauge metal, a longer
throw on the latch, and additional locking functions.
Mortise locks, which are rectangular and embedded in the edge of a
door, are stronger than other types and more expensive to purchase
and install. They provide the highest level of security. The lockís
body is recessed into the door. Handles and cylinders, if required,
are installed through the door into the lock body.
Cylindrical locks, which come in light-, medium-, and heavy-duty
grades, are appropriate for many applications, though mortise locks
tend to be more suitable when tight security is required.
Cylindrical locksets are the most popular. The standard strike plate
for these locks is the 497 ANSI, which is 47/8
inches long, but other sizes are available to meet specific facility
Managers in commercial and institutional applications have a variety
of different lock functions to consider for the application at hand,
but four types are used most often:
Locks that address this function have no key or push button on
either side. Instead, they consist of two blank handles, and both
sides of the door are always unlocked. This type of lock sometimes
is used on stairwell doors and other doors where the only
requirement is to have the door latch behind the user but not lock
so it can be opened at all times.
Locks that address this function require a key on one side and a
push button on the other. When the button is depressed, the lock
can be unlocked from the outside with a key. Turning the handle on
the inside unlocks the door until either the button is depressed
again or it is locked from the outside with a key. This lock is
mostly used on doors that require some type of security, such as
exterior and office doors.
Locks that address this function have a push button on one side
and an emergency release on the other. Such locks are made so they
can be locked from the inside, but they can be opened from the
outside with a coin or a screwdriver in case of emergency. This
type of lock is used commonly on bathroom doors.
Locks for this function have a key on one side and a blank handle
on the other side, with no key or button. The lock remains locked
all the time and requires a key to open it. This lock is mostly
used on storage and janitorís closets and utility rooms.
Handles and hinges
Lever handles are most
commonly used in institutional and commercial applications to meet
guidelines established under the ADA. This component is the most
visible and touched portion of the assembly, so a good, lasting
finish is important. Brass is probably used most often for
decorative applications. Steel, however, offers both higher strength
and lower cost. Many facilities are installing touch-sensitive bars,
which can provide one-way, keyless access to a door that must remain
The type of hinge used in a particular application depends on the
door mount and function. For example, spring hinges use a spring as
an automatic closer and are best used on doors that donít receive
heavy traffic. Swing-clear hinges are bent so a door can open fully,
allowing a clear opening.
Among conventional hinges, five knuckles used to be standard, but
many installations have moved to three-knuckle hinges. Spring hinges
close a door automatically after it has been opened, like a door
closer, but they have no sweep and latch control. The only
adjustment is the speed with which the door will close.
The types of hinges most commonly used in commercial and
institutional facilities are these:
- Butt hinges are used with
wood and hollow metal doors. These hinges only use the pin
housing, called the knuckle, when a door is closed. If security is
required, managers can specify that the pin be non-removable.
- Surface hinges are used
when it is not possible to mortise the door and jam.
- Invisible hinges are
concealed in a mortise hole in the door and jam.
- Floor hinges are inserted
into a mortise in the door head and bottom for a double-swinging
door. This type of application might include a closer device.
- GravityĖtype pivot hinges
are used for applications such as cafť doors swinging in both
- Pivot-type hinges are used
primarily for cabinet doors.
- Electric hinges supply
electric power continually between the door and jamb for alarm
systems or electric locks. Electric hinges are mounted in the
center, non-load-bearing hinge position for three-hinge doors.
On exterior out-swing
doors, it is a good idea to have some kind of means of security so
the hinge pin cannot be removed to gain entry. This precaution
usually is addressed with a non-removable pin hinge.
Closers ó hydraulic and pneumatic ó control the closing of doors and
reduce shock to doors and hardware. Hydraulic closers, common in
commercial applications, contain an oil reservoir and cylinder with
an adjustable nut that controls flow of oil into the cylinder to
adjust the closing speed and the impact against the door frame when
closing. Pneumatic closers have an adjusting nut to control the air
flow and rate of closing.
Door closers are required on fire-rated doors so the door will close
after someone has passed through it. Most closers have a sweep and
latch adjustment. Sometimes, facilities need the door to close
quickly and then slow down right before closing to avoid slamming.
Other applications require the door to close slowly and then speed
up at the very end to ensure it actually latches.
Closers control a door throughout its opening and closing swing.
Electronic controls bring a different type of security to doors. One
group of operators is designed for standard-duty applications on
interior and exterior doors, providing free entry and exit to all
types of commercial and institutional facilities, including
assisted-living facilities, schools, universities, office buildings,
convention centers and hotels.
Another group of door operators have 28 programmable control points,
allowing adjustments for opening and closing forces, hold-open time,
safety function, force to keep the door closed, and push-and-go
features. When in a manual mode, the door must be opened slightly by
hand. The operator then opens the door the rest of the way. Many of
these operators offer lower energy use, which is attractive to
Knowing the Codes
Building codes and
facility access guidelines can have a tremendous impact on
managersí decisions on door hardware specification and
installation. Hardware installation, particularly on fire doors
and building exits, is governed by local and national codes.
Managers must be familiar with the Americans with Disabilities
Act (ADA) and the National Fire Protection Associationís life
safety code as they relate to door hardware. Fire codes and the
ADA also guide managers on the placement of panic door hardware.
For example, some states require a mounting height of 30-44
inches. Others prohibit placing panic bars below 36 inches. Many
jurisdictions require a 32-inch clear opening for wheelchairs,
but in some applications, panic hardware can stick out and
become an obstruction.
Also, some panic hardware isnít allowed on a 3-foot door, but
codes provide that anything mounted above 34 inches may extend 4
inches into the width of the door.
The bottom line is that when it comes to the actual installation
of the hardware, it is essential to know and understand