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The Door Silencer

An unassuming rubber pad, the door silencer is a paragon of passive, often unrecognized importance. Its moniker dubs it a preventer of noise, but in addition to a silencer it is also a door aligner for which space is made and receiving apertures cut in hollow metal door frames. When present they are all but totally unnoticed. When they are not, their absence can be keenly felt.

Door silencers are installed on the face of the stop. When the door is closed, it rests against the silencers. What many contractors and other hardware installers may not realize is that the silencers take up space.

Door hardware is all designed to work together in precise alignment. In the absence of door silencers the door travels an extra fraction of an inch. All other hardware is thereby put out of alignment by that fraction of an inch.

Perhaps the most significant consequence of this loss of alignment occurs when in single openings that are equipped with locking cylindrical locks equipped with dead-latches. Dead-latches have a deadlocking feature that may slip into the keeper of the strike if the door is allowed to travel that extra fraction of an inch allowed by the absence of the silencers, causing the latch to bind in the keeper and be difficult or maybe even impossible to retract. In order to enter from the push side of the door, users may have to first pull hard on the lever or knob to decrease the tension enough to allow the latch to withdraw from the keeper before they can twist the handle and push the door open. From the pull side, users may have to push on the door near the handle to decrease this tension. You can see where this could be a serious impairment to people needing to exit a space in an emergency.

Left: Wood Door Silencer. Right: Hollow Metal Door Silencer

Above: Installing a door silencer in a hollow metal door frame.

Door Problems

If the space between the door and the frame is different at the top than it is at the bottom, you've either got a door problem, or you're going to have a door problem.

As a locksmith I was called many times to fix what the customer thought was a lock problem only to find that the problem was with the door, not with the lock.   “What’s the difference?” you may well ask, proving to me that you are no locksmith.  “Well,” I would smugly reply, relishing my brief moment in the spotlight of useful knowledge.  “I’ll tell you.”  And I will, too.


Hardware and doors age together and develop different and sometimes incompatible symptoms of aging.  Like people, doors are subject to the prolonged effects of gravity.  Things start to sag, and for a while you can tighten things up and slow down or even perhaps reverse the effects, but eventually Newton will have his way and what was put up will come down.  That is to say the door, suspended an eighth of an inch (ideally) above the threshold, will eventually come to rest on that threshold.  If left to the ravages of time it will eventually cut a groove in the threshold.

Locks, meanwhile, start having trouble finding their strikes.  (A strike is to a lock what a tunnel is to a train or the side pocket to the eight ball.)  Usually (but not always) the strike stays put, but the lock travels downward along with the lock side of the door.  Eventually the lock may not line up with the strike at all, but before that there will be friction between the bolt or latch and the strike, making the lock difficult and eventually impossible to lock and/or unlock.

Besides sagging, wooden doors may warp and door frames of any construction may move as the building shifts and settles over time.  These changes may also result in locks that no longer line up and do not work properly.

Diagnoses and Remedies

The Sagging Door

Looking at the closed door from the ‘pull’ side, it is often easy to see if it is sagging.  If the jamb has not moved and was installed correctly, it is perfectly square.  Ideally there will be a one eighth inch gap between the top and the left and right edges of the door and the frame.  If the door hangs at an angle to the frame, it is probably sagging.

Marks on this ANSI 4-7/8 strike plate show that the latch has traveled down as it has traveled through time because of gravity.

If a door is sagging enough, there will be marks on the lock edge of the door where it is rubbing against the frame.

Often this is because the top hinge is loose.  If you tighten all the hinge screws this may solve the problem.  On a wooden door and/or frame you may find that the screws for the top hinge are stripped – that is, the screw hole has become enlarged because the weight of the door has pulled the screw out.  The solution for this situation may be longer screws.  Be sure you replace the screw with one of the same wire size so it fits flush in the countersunk screw hole of the hinge.  Commercial hinges use a size 12 screw, but bring one of the screws to the hardware store to match it up if you have any doubts.

Many times longer screws do not solve the problem because the wood door is not solid would, but particle core or gypsum core, or the frame is shimmed out from the studs so far that that there is nothing for a screw less than five inches long to grab.  In this case it might be necessary to relocate the top hinge (not generally a good result), install an additional hinge or hinges above and/or below the existing top hinge, install a reinforcing pivot hinge at the top of the door, or replace all the hinges with a continuous hinge.

Damaged Hinges and Crooked Door Jambs

If hinge tightening does not solve the problem, the hinge or hinges may be bent or the door frame may have shifted.

Hinges are often bent when someone (who is not too bright) places a piece of wood between the door and the frame to hold the door open.  It is possible to bend a hinge back to almost its original shape, but when it is bent the metal of the hinge is fatigued and it will never be the same.  Since hinges vary by manufacturer, it is best to replace all the hinges if one is bent unless you can find an exact replacement for the bent hinge.

If the hinges are neither loose nor bent, the door frame may be out of alignment.  Use a carpenter’s square to check the corners of the frame and a level to check the legs and header.

If it is a three-piece, knock down hollow metal frame in a sheet rock wall, you may find an adjustment screw at about eye level on each leg of the frame.  These vary widely between door manufacturers, so see what kind of driver may be required to turn the adjusting screw.   You can experiment with the adjusting screw to see if turning one or the other either way has any desirable effect.  Sometimes the adjustment screws are not connected to anything that has contact with anything else.  In that case turning the adjustment screws will have no effect.

Hollow metal frames that are installed in interior sheet rock walls are often secured to the wall at the bottom of each leg with a screw.  If the floor has shifted beneath the frame so that one leg is now lower than the other, it is possible to remove the screws from both sides of the leg, gently pry the leg up off the floor a little and insert shimming material beneath the leg to hold it up.

Wooden Doors and Frames

Wooden doors and frames are generally susceptible to more movement than hollow metal.  In addition to sagging, there is warping, twisting and swelling that may occur.  Fortunately whenever finished wood rubs up against something, it tends to leave a mark.  These marks can tell you what the door is up to and help you fix the problem.

Unlike a hollow metal or Fiberglas door, you can plane a wood door down.  Careful, though:  make sure you iron out any hinge problems before you start to plane, otherwise you’ll plane, the door will sag more, you’ll plane some more, the door will sag some more – pretty soon you’ll have a big space between the frame and the door someplace and you won’t need a door viewer anymore because you’ll be able to see out the crack.

One has no choice but to plane a door that has swollen.  Plane carefully, a little at a time, and do your best to keep the door as square as possible.  After planing, finish the door with paint, polyurethane or varnish – especially the edges – so that it doesn’t swell again so fast.

This is not a complete list of door problems, but it is a good sampling.  I hope it serves as a starting point for you to solve your own.

Fail Safe and Fail Secure Electric Locking Devices



  • Fail Safe = power off, it’s unlocked
  • Fail Secure = power off, it’s locked

Electric locking devices include:

  • Electric strikes
  • Electromagnetic locks
  • Electromechanical locks
  • Electrified exit devices

Most electric strikes are sold fail secure by default. For example,
if you order a Von Duprin 6123 24V US32D, and architectural grade 1
electric strike, it will most likely come fail secure regardless if
it has Von Duprin’s “FSE” (standing for fail secure) in the part number
or not. The part number in the Von Duprin price book does not include
“FSE.” To be sure you are going to get a fail safe electric strike (not
the norm) if that is indeed what you want, in this instance you would
include Von Duprin’s abbreviation for fail safe, “FS”, for example,
6123 -24V-FS-US32D.

All electromagnetic locks are fail safe because they are always
unlocked when disconnected from the power source. Using a battery
back-up does not make an electromagnetic lock fail secure because
the magnet would still be unlocked if the power was disconnected.
Later in this article it should become apparent why this detail
is important for reasons of life safety.

Electromechanical locks include standard cylindrical or mortise
locks that have been electrified and locks that are designed to
only work electrically, such as an electric bolt lock. They are
sold in equal amounts fail safe and fail secure.

Electrified exit devices come in a variety of functions, including
those with electric latch retraction and those with electrified outside
trim control. Electric latch retraction devices are fail secure whereas
exit devices with electrified exterior trim control might be either
fail safe or fail secure.


Electric Strikes

Fail safe electric locking devices are used wherever doors must remain
unlocked in the event of a fire or other life safety emergency. If
the opening is fire rated, it must be positively latched by a fire
rated device in the event of a fire. Therefore there is no such thing
as a fire rated fail safe electric strike because if the power were
off (as it might very well be during a fire) the door would not be
positively latched. If you install a fail safe electric strike on
a fire rated opening, the inspector can require you to replace the
entire doorframe.

Technically, fire rated door frames cannot be modified in the field,
but must be prepared for hardware (including architectural grade electrified
hardware) in a fire rated shop. I have never heard of this being enforced,
nevertheless, the AHD (Authority Having Jurisdiction) could enforce
it, so if you plan to modify a fire rated opening in any way it might
be a good idea to get the local fire marshal on board during the planning

In general, a fail safe electric strike is a good choice for a “non-fire-rated
door that must be unlocked in the event of an emergency other than
a fire” kind of application.

Fail secure electric strikes are a good choice for exterior or other
non-fire-rated doors where remote release or electronic access control
is needed. They are pretty reliable, usually not difficult to install,
and relatively inexpensive. One of the chief disadvantages of an electric
strike is that, on out-swinging doors, they provide an opening into
which a burglar can insert a tool, such as a tire iron, to pry directly
on the locking device. A latch guard is a minimally effective deterrent
to this kind of attack.

(Exterior doors are almost never fire rated, and if they are, usually
it is because all the doors on the job were ordered to the same spec,
not because they have to be.)

Electromagnetic Locks

Some inspectors and fire marshals just don’t like electromagnetic
locks. This is another reason to get your local AHD on board from
the start. But if your AHD is not an obstacle, a mag can be a good
solution for existing fire rated doors with existing fire rated hardware
on them. The fire rated hardware can stay to keep the door positively
latched in the event of a fire, and the mag is inherently fail safe,
so it could be a good choice for stairwell doors, greatly simplifying
the application. The problem with mag locks is that they lock both
sides of the door simultaneously. That means you have to deal with
both a means to get in (access control) and a means to get out (presence
detector and redundant exit pushbutton, for example).

If the door already has an exit device, it is probably possible to
install a request-to-exit (RX) switch in the bar to allow exit by
a fully mechanical means – a factor which might make the AHD happier
with the installation. The AHD will also want to know that all electromagnetic
locks are wired so that the fire alarm will cut power to them in the
event of a fire.

Since a mag lock does not positively latch, it cannot be legally
used alone on a fire rated door. There must be a fire rated positively
latching mechanism in addition to the mag.

Delayed egress electromagnetic locks can also be used for access
control on egress doors while helping to prevent unauthorized exit.
For more information on delayed egress, please visit:

Electromagnetic locks are not too expensive and are very easy to
install. Because they are inherently fail safe, you may want to install
a battery back-up system so that they remain locked during routine
power outages.

Electromechanical Locks

Fail safe electrified standard locks are ideal for stairwell doors
(unless they already have exit devices) because they remain positively
latched when unlocked. Many states and localities require that stairwell
doors be unlocked in the event of a fire, and because all interior
stairwell doors are fire rated, they must also remain positively latched.

In order to replace a standard mechanical lock with an electrified
one, a raceway must be drilled through the door from lock side to
hinge side so that wire can be run to power the lock. If you guessed
that, technically speaking, this voids the fire rating on a fire rated
door, you were correct. Be sure to clear all modifications to fire
rated openings in advance with the local AHD.

Electric bolts are usually used as a last resort when no other application
will work, such as when retrofitting access control to automatic sliding
doors. Electric bolts are most commonly used in prisons, where egress
concerns are treated rather differently than commercial applications.
They can also be used in place of electromagnetic locks, however electric
bolts designed for commercial (rather than detention) applications
are less secure, less durable and more difficult to install than mag

Electrified Exit Devices

If a door has an existing exit device or an architect has specified
an exit device for an opening, it is because the capacity of the building
in terms of the number of people therein warrants the use of an exit
device. Therefore it is unwise to replace an exit device with another
kind of hardware.

Luckily, many exit devices can be electrified in the field either
by replacing internal parts of the device or by adding an electrified
trim (outside handle or lever).

As I mentioned earlier, exit devices can be electrified in one of
two ways:

  • Electric latch retraction
  • Electrified outside trim

Since electric latch retraction is always fail secure, it might not
be a good choice for stairwell doors unless it was always unlocked
from the stairwell side. If that were the case, the only probable
purpose for the electric latch retraction would be to unlatch the
door for a power operator (automatic door opener).

Electric latch retraction is ideal on exterior pairs of doors where
fail secure access control is required. Since exterior pairs of doors
are often equipped with concealed vertical rod exit devices, installing
electric latch retraction is often the easiest and best alternative.
Electric latch retraction (or electric remote dogging) is also very
compatible for use with power operators.

The down side of electric latch retraction, in addition to being
expensive in its own right, is that it often requires a special and
expensive power supply. Sargent 56 prefix exit devices are an exception,
requiring only a minimal power supply for activation.

Fail safe electrified exit device trim is a good alternative for
stairwell doors whether they already have an exit device or not. For
one thing, since the wire powering the trim is run through the exit
device, no modification of the fire rated door is necessary.

Electrified exit device trim is also available fail secure, and is
often a less expensive alternative to electric latch retraction where
simple access control is the goal.

Note on “Continuous Duty”

I have been asked, ‘What is the difference between fail safe and
continuous duty?’ Fail safe applies to the function of the device
as described above whereas continuous duty simply means the strike
is built to be constantly powered if so required. The confusion arises,
I think, because all fail safe locking devices are continuous duty.
This is because a fail safe device must have power to be locked. Fail
secure electric strikes that are connected to a timer and powered
all day to remain unlocked also must be continuous duty rated. Therefore,
not all continuous duty electric strikes are fail safe, but all fail
safe strikes are continuous duty.

Rule of thumb: almost every kind of electric locking device that
runs on DC current is continuous duty.

Hinge Basics ‐ Architectural and Residential Hinges

There is a huge variety of door hinges available in today’s commercial hardware market. Which hinge is right for your application? This article discusses hinge types, hinge characteristics, and basic guidelines
on how to choose a hinge for your application.

Parts of a Hinge
At right is an illustration that details the components of a full mortise hinge. Pictured is the most common hinge used in the United States, a five knuckle, full mortise ball bearing architectural grade template hinge, four-and-a-half by four-and-a-half inches.

  • The leaves are fastened to the door and door frame.
  • The bearings keep the hinge alligned help the hinge last longer by reducing wear
  • The pin (shown slightly withdrawn from the knuckles as if being removed) holds the leaves together and provides the axis on which the door will turn
  • The knuckle is a loop of metal through which the pin passes
  • The top tip rests on the top knuckle of the hinge, stabilizing the pin; the bottom tip is attached to the bottom knuckle and helps keep the interior of the knuckles clean.

Some Variations

The leaves could be equal widths, or unequal; the leaves could be “swaged”, meaning bent to compensate for a door with a beveled edge; the bearings could be ball bearings, concealed bearings, lube bearings, or “plain bearings”, indicating no bearings at all; the pin could be non-removeable or fixed; there could be five knuckles, three knuckles, or in some cases, no knuckles; and hinge tips could be decorative or could serve a purpose, such as hospital tips, which are beveled to prevent things from getting caught on them.

Commercial architectural grade hinges could be standard weight or heavy weight; they could have square corners or round; and they could be “template” or “non-template” hinges, indicating whether its screw pattern matches architectural conventions so as to fit in standard hollow metal door preps or not.

Electrical options are also available, such as electric though wire, concealed magnetic contact, exposed electrical conctact, and others.

Hinge Sizing

To measure a full mortise hinge, also called a butt hinge, lay it on a flat surface.  Measure the height, then the width.  When you specify full mortise hinge sizes, always refer to the height first, then the width.

Heavy Weight vs. Standard Weight Hinges

Heavy weight hinges are used for very heavy doors or doors that are subjected to very high traffic. Hinge “weight” actually refers to hinge leaf thickness. Heavy weight hinges leaves run closer to .200 gauge thickness, while standard weight hinges are more in the range .150 gauge thickness.

Hinge thickness is also dependent on hinge size. For example, a standard weight hinge 6 inches by 5 inches will be thicker than a standard weight hinge that is 4-1/2 by 4-1/2 inches.

Wide Throw Hinges

At right is shown a wide throw full mortise hinge. Wide throw hinges enable a door to open 180 degrees when a decorative door molding might otherwise prevent it from doing so.

Types of Hinges

All the hinges lifted below are available in standard weightand heavy weight versions for different commercialapplications. Illustrations at right show various kinds ofhinges.

Full Mortise Hinges

As I said earlier, full mortise hinges are by far the mostcommon type of hinge. They come in a wide variety toaccommodate diverse applications.

Half Mortise Hinges

Half mortise hinges are hinges that have one leaf mountedto the visible front of the frame and the other leaf mountedin a hinge prep, or mortise, on the edge of the door.

Half Surface Hinges

Half surface hinges are hinges that have one leaf mountedto the surface of the door and the other leaf mounted intoa hinge prep on the jamb part of the door frame.

Full Surface Hinges

Full surface hinges have both leaves visible when the dooris closed. One leaf is fastened to the surface of the frameand the other to the surface of the door.

Swing Clear Hinges

Swing clear hinges are designed so that when the door isopened to 90 degrees, the door itself is completely out ofthe opening.  For example, if you needed to move a cartthrough a door that was 35-1/2 inches wide through a 36inch wide door, unless the door was hung on swing clearhinges, you would have to be able to open the door 180degrees in order to get the cart through the opening.

All of the hinges above are available in swing clear versions.

Template and Non-Template Hinges

“Template” hinges are full hinges that have a standard screw pattern and sizing to fit into an ANSI  standard hinge prep, usually on a hollow metal door andframe. Most architectural (commercial) grade hinges aretemplate hinges. Most residential hinges are nontemplatehinges.

Radius Corners

Radius corner hinges are hinges with roundedcorners. “Radius” refers to the radius of the circle thatwould exist if the curve of the rounded corner werecontinued to form a circle.Architectural hinges are available with 1/4-inch radius corners whereas residential hinges are available in 1/4-inch radius and 5/8 inch radius corners.

Residential Hinges

Residential hinges are very simliar to architectural hinges, but there are differences. As stated above,more often residential hinges are non-template hinges, but they are sized the same as architecturalhinges. Residential hinges also more often have radius corners than architectural hinges and areusually made of thinner gauge metal. Often one will see an architectural grade hinge used on exteriordoors and residential grade hinges used on doors within the dwelling.

Spring Hinges

Spring hinges are architectural hinges that are springloaded so as to shut the door. They are available in fullmortise, with or without radius corner, in most sizes inwhich other full mortise hinges are made, and areavailable in template and nontemplateversions. A full mortise spring hinge is shown at right.  Beneath the full mortise spring hinge is a picture of adouble acting spring hinge for a door that swings bothways. Bommer Industries is an excellent source for a wide variety of spring hinges, as well as other architectural and residential grade hinges.  It is important to note that spring hinges are not a substitute for a door closer, since spring hinges slam the door.

Continuous Hinges

Continuous hinges are hinges that extend the full height of the door. They are widely used on aluminumstorefront and hollow metal applications. They are a good alternative for high frequency of useapplications where added durability is necessary. Continuous hinges are available in aluminum, steel,or stainless steel, and, like architectural hinges, are available in different types to accomodate differentconditions. Many of these configurations match those discussed in this article.

Pivot Hinges

Pivot hinges are used on very heavy doors in high traffic applications and on many aluminum storefront doors.  Since the weight of the door rests on the bottom pivot, thedoor does not “hang” as it does with other types of hinges, therefore there is less risk that the door will sag over time.  At right is a drawing from Rixson Hardware’s pivot catalog.

Electrified Hinges

Full mortise, pivot, continuous hinges and others are available with electrical options such as:

  • Electric Through Wire:  a number of conductors arethreaded through the hinge in order to conduct electricity from the door frame into the door (or vice versa) to power electric locks or transmit contact closure from monitor switches in the door or in the locking hardware. Available with anywhere from 2 to12 conductors, typically 24 gauge wire. 2conductor,18 gauge wire is also available.
  • Concealed Magnetic Contact: a magnetic contact reed switch is concealed in the leaves of a full mortise hinge. When the door is opened, the leaves are spread apart, breaking or making the contact. HInges with concealed magnetic contact are handed.It is possible to have both the above options in the same hinge.

Non-Removable Pins

In situations where you have an out-swinging secured door, you can use hinges with non-removable hinge pins. Non-removable hinge pins are pins which have a groove milled in them in the middle. A set screw is threaded through the middle knuckle to mate with the groove (see picture at right) to inhibit burglars from pulling the pin and the door to gain entry.  (In the picture, the center knuckle is not shown so that theset screw can be seen.)