How antimicrobial coating works: Bacteria can be transmitted from human host to just about any surface that person touches.  Some surfaces are more conducive to bacterial growth than others.  Hard surfaces are typically good places for bacteria to begin multiplying.  The less porous (harder) a surface, the faster bacteria can multiply.  Bacteria that have been transferred to a hard surface, like a door, can then be transferred back to other humans, and the cycle continues.

This puts door hardware at a distinct disadvantage over many other surfaces for two major reasons: their surfaces are not very porous, and they tend to experience a lot of human contact.  Because institutions have such a high rate of traffic and human-to-surface contact, their door hardware tends to be the most vulnerable.  Combine this with the fact that those within the walls of the building live, work and study in very close contact, these institutions are ideal places for the spreading and growth of bacteria.

Bacteria must be able to take in nutrients from the environment in order to reproduce.  Von Duprin’s antimicrobial coating is made from ionic silver.  The ions in the silver coating surround the individual bacterial cells on their surfaces and prevent them from taking in the nutrients necessary to grown and multiply.  Door hardware treated with antimicrobial coating experience significantly less bacterial growth than uncoated surfaces.

Business and commercial building owners who have a significant investment in keeping those who work in and visit the premises healthy should consider Von Duprin door hardware, like exit devices, with antimicrobial coating.  Businesses and buildings that do not fall under the category of “institution” may still want to consider coated hardware, especially if buildings experience a high rate of traffic in and out every day.  The more people who come and go from a particular building in a given day increase the chances of depositing and spreading bacteria within the building.  Installing exit devices and door hardware with antimicrobial coating is a highly effective way to keep staff and patrons healthy.

To understand how electric latch retraction works, it helps to first get an idea of how a regular (mechanical) exit device works.  An exit device consists of a bar which extends across the width of the interior side of a door. It may be a crossbar (raised, arm-style) or it may be a flat, push bar.  The bar is connected to a rod, which may be concealed (mounted inside the door) or exposed (mounted on the outside of the door’s interior side.)

The exit device renders the door locked.  It cannot be opened from the exterior except with a key.  From the inside, the door can be opened quickly and easily by simply pushing on the bar.  As soon as the door closes, it re-locks automatically.  Exit devices are sometimes referred to as “panic bars” because they are much easier and quicker to open in an emergency situation (i.e. fire) than a knob or lever.  In fact, most building codes in the industrialized world mandate that doors on public buildings cannot be locked from the inside except with the use of a panic bar.

Ordinary panic bars typically come with a dogging feature.  This allows for the device to be disengaged (unlatched) if desired.  This would allow for people on the exterior of the building to enter without a key or having someone from inside open the door manually.

Fire-rated exit devices, on the other hand, cannot be produced with a dogging feature.  Building and fire codes have specific regulations regarding the locking and unlocking of fire doors.  These are typically not installed on a building’s exterior, but rather inside, often to separate the main office of a business from its warehouse, or to separate one unit from another in a multi-unit commercial building.

By law, fire doors must remain locked at all times. This helps to prevent the spread of fire from one part of a commercial building to another (i.e. between units in a multi-unit building/complex.) This is why fire-rated mechanisms are not sold with a dogging feature.  This ensures that fire doors are not inadvertently left unlocked.

Electric latch retraction allows a door to operate with some extra features.  Doors outfitted with electric latch retraction can be remotely unlocked.  One example of this is a residential, multi-unit building where visitors must be “buzzed in” by someone who lives in the building.  This feature allows the building owner/occupants to control who enters.  Other features include remote dogging (except in the case of fire doors) and automatic door operator.  When power is cut to the system, the door latches automatically until power is restored.  Doors can still be opened manually even in a power outage.

The Von Duprin EL conversion kit allows a user to retrofit a number of Von Duprin’s manual exit devices and convert them to electric latch retraction.  The kit can be applied to the 33, 35, 98 and 99 series of Von Duprin panic devices.  The kit can even be applied to fire doors and will maintain its fire rating and UL listing.

The Von Duprin EL Conversion Kit

One feature to consider when choosing an exit device/crash bar is the need for a dogging feature.  Essentially, the dogging feature allows the locking nature of the crash bar to be over-ridden and the door left unlocked, or able to function as a regular locking door.

The nature of an exit device is such that it allows the door to which it is applied to remain locked at all times.  However, anyone on the interior side of the door can open the door easily and quickly simply by pressing on the crossbar, crash bar or touch pad, depending on the type of device it has.  This increases a commercial building’s level of security but still allows those on the inside of the building to escape quickly during an emergency, such as a building fire.

Many exit devices come with a dogging feature.  The feature is activated by using a hex wrench or even an ordinary key.  When the mechanism is dogged, the crash bar is inactivated and the door works just like an regular push-pin style door.

A dogging feature is useful during periods of time when it might be inconvenient for a door that is normally locked from the exterior to remain locked.  One example of this is when an outside group is renting space in a commercial building and must be able to enter and exit frequently and freely but building owners do not wish to loan out keys to the building in the interest of long-term security. 

In this type of situation, the dogging feature can be activated.  Renters/users can come and go out of that one door freely (usually with the expectation that they visually monitor who is entering the building.)  No other doors need be used, and no keys have to be distributed.  Once the renters have left the building, the dogging feature can be deactivated and the door remains locked again.

Not every door needs to have an exit device with a dogging feature, especially if building owners are worried about compromising building security due to tampering with dogging devices or accidentally forgetting to deactivate a dogging feature.  Von Duprin exit devices are manufactured with and without dogging features, so choices are flexible.

However, exit devices with dogging features should NEVER be applied to fire doors.  By law (no matter where you live and/or build in most every industrialized country) fire doors must remain locked at all times.  This is to ensure that fire cannot spread from one part of a commercial building to another due to doors in fire walls being accidentally left open.  The chances for this to happen would increase significantly if exit devices were outfitted with a dogging feature.

So, “To Dog, or not to Dog” is really a matter of preference when it comes to exterior doors and non-fire doors.  But when it comes to fire doors, be sure to read the product information on any exit device you intend to purchase to make sure that it cannot “dog.”

Typically, commercial buildings which exceed a certain size or have multiple units housed within (i.e. condo/apartment buildings, shopping centers, industrial buildings, etc.) are required by building code law to have fire walls.  Fire walls are walls which separate sections of the building from one another.  They are made from materials which are highly resistant to combustion and smoke transfer.  In the event that a fire breaks out in one section or unit of the commercial building, fire walls are intended to keep the flames from spreading to other sections of the building.

Fire walls won’t contain flames forever.  A typical fire wall will hold flames at bay for around three hours.  This is usually enough time for the local fire department to respond and put out the fire before it endangers the rest of the building.

Any doorways that are cut into fire walls must be outfitted with doors which also resist the spread of flames and smoke.  These are known as “fire doors.”  All materials which are used to construct them, including door hardware like exit devices, door closers, locks, knobs, etc. must also be combustion-resistant.

Devices which are not fire-rated cannot be installed on fire doors.  They are usually made with less expensive, more flammable materials, and are best suited for exterior doors and doors which don’t have to maintain fire integrity.

Fire-rated exit devices, on the other hand, are constructed of flame resistant materials.  They are composed of metals and other materials which will not melt or break under extreme heat for at least 1-3 hours.  All components, including screws, must be heat and flame resistant.

These devices tend to cost a little bit more.  Both non-fire and fire-rated models perform equally well in all other aspects of function, so building owners can use non-fire-rated models on non-fire doors to save money without compromising performance or safety.  Many models, such as the Von Duprin 99 Series can be purchased in both a fire and non-fire rated version.  Users can maximize their budgets this way while still maintaining a cohesive and uniform look throughout the building.

The Von Duprin 99-F Rim Device. This particular model is fire rated.

Prior to its development of the 33A Series, the only style of exit device/panic bar on the market was the crossbar style.  The crossbar device  is still in use and being installed in many commercial buildings today.  The Von Duprin 88 Series of crossbar devices was its original line of panic bars, and remains one of the company’s best-selling product lines.

The Original Von Duprin 88 Series Crossbar-Style Exit Device

The new pushpad exit device was developed for two major reasons.  First, it was a new, more modern look.  It eliminated the need for protruding parts, and allowed for an overall sleek and contemporary style.  The pushpad is relatively flush with the door itself, and still remains easy to operate, particularly in a panic/emergency situation.

The second, and main reason it was invented was for its ability to be electrified.  The new pushpad was able to be wired for electric latch retraction, security alarm monitoring, remote locking control, and request-to-exit features.  It also functions with a building’s smoke/fire detection system, locking and unlocking in response to triggered fire alarms.

The introduction of the 33A Series brought a whole new dimension of security possibilities to commercial building.  Within a few years, the product line was joined by the new Von Duprin 99 Series.  The new series featured a wider-stile pushpad.  New features and improvements have been added to both the 33A and the 99 Series since they were first marketed.  New technologies have made significant design improvements possible, making both product lines perform better and more efficiently and to last longer.  Today the 99 Series is also one of Von Duprin’s top sellers.

Both the 33A and the 99 Series of exit devices are available in rim, surface and vertical concealed rod mounting styles, as well as fire-rated models.  The 33A Series fits nearly any door, even doors with stiles as narrow as 1 and 3/4 inches.  It is manufactured in seven different finishes, making it easy to coordinate with any building decor.

The Von Duprin 33A Rim Device

The trim is an important part of the aesthetics of the outside of the door, though.  More importantly, you can usually choose from a number of handle styles, depending on the model of the device that you choose.  Typical door trims for exit devices include:

1) Night latch:  This type includes a key cylinder and a straight handle.  The latch is engaged with the key.  The handle is for the convenience of pulling the door open rather than for unlatching.

Night latch trim

2) Thumbturn: This type includes a key cylinder and a small swiveling lever.  The key is used to unlock the cylinder.  The latch is disengaged by rotating the thumbturn. 

3) Thumbpiece: This trim looks like the night latch, with a straight pull-handle.  However, it has a small thumbpiece above it which must be pressed with the thumb to engage the latch before pulling the handle.

Thumbpiece trim

4) Lever:  The lever trim has a key cylinder, and must be locked/unlocked with a key.  The lever is depressed with the hand to engage the latch.

Lever trim

5) Knob: This style consists of an ordinary door knob.  The key cylinder is located within the knob.  The key is used to lock and unlock the door.  The knob is turned to engage the latch.

The type you choose is usually a matter of preference.  The lever style tends to be the easiest to operate for most people (children, adults and seniors.)  The night latch type is usually recommended for exterior utility-type doors (i.e. delivery doors) which don’t get used regularly, especially by the general public.

Most exit devices consist of two major components: the touch bar and the rod.  The touch bar is the part of the exit device that is used to unlock and simultaneously open the door.  Touch bars come in two major styles: touch pad and crossbar styles.

Both styles of touch bars are attached to a rod device.  As their names imply, this rod may be concealed, or it may rest on the surface of the door.  In either case, the rod functions in the same way.  When the touch pad is pressed, the rod mechanism is activated and releases the lock, allowing the door to be opened.

There are three main considerations to make when it comes to choosing one style over the other:

1) Aesthetics: Concealed rod devices look more aesthetically pleasing than surface rod devices.  If looks are important, a concealed vertical rod mechanism is the best choice.

2) Cost: Surface rod devices are more easier to install.  Concealed rods must be buried within the door, so installation costs will be higher.

3) Durability: Concealed rod devices will last longer.  Rods mounted on the door’s surface are exposed to abuse and may require more frequent repairs and need replacing more often.

New buildings or office spaces which are in the construction phase should choose concealed over surface rod exit devices.  The extra cost is minimal when compared to the overall cost of construction.  They look more professional, and will perform better in the long run.

When it comes to replacing an old exit device, it may be more cost effective to stick with the original design, especially if the doors have already been outfitted with surface rod exit devices.

*Design:  Though they are operated in a similar manner, they look quite different from one another.  A typical crossbar exit device, like the Von Duprin 88 Series (the company’s original design) consists of an arm-like mechanism which is raised off of the surface of the door. 

The Von Duprin 88 Series Crossbar exit device.

To execute the device, force is applied in a slight downward and forward motion.  This action retracts the latch bolt, unlocking and opening the door.  Crossbar exit devices were first invented and manufactured in the early 1900′s, and eventually became mandatory pieces of hardware on commercial doors in North America and other industrialized countries.

Touchbar style devices were a later invention.  They work at least as well as crossbar style mechanisms.  Their design, however, results in some inherent and distinct advantages over the crossbar device.  The raised design of the crossbar arm leads to quicker wear and tear on and degeneration of the device as a whole, and on its individual components.  The touchpad exit device eliminates most of those problems, resulting in a product that is more durable and therefore will last longer and require less maintenance in the long run.

*Ease of installation: Touchpad devices are less onerous to install than crossbar mechanisms.  The main reason for this is that crossbar devices are forged in a number of different parts.  They may, in fact, consist of up to ten separate parts.  Touchpads, on the other hand, typically have three or fewer separate parts, making installation faster and more foolproof.

*Ease of operation: Touchpads are slightly easier to operate than crossbar devices.  However, the difference is usually so insignificant that this fact alone would not be a compelling enough reason in and of itself to choose touchpads over crossbars.

*Optional features: Touchpads have electrical options which crossbar devices do not.  One such option is the ability to be wired into a central fire detection system.  This is usually recommended for modern commercial buildings, especially high rises, residences (apartments, residential care facilities, etc.) and even schools.

*Aesthetics: Touchpad devices tend to be more aesthetically pleasing.  They are less obtrusive and tend to blend in more discreetly with the door itself and with the surrounding decor.  However, crossbars are still manufactured and sold, so that crossbars from older buildings can still be replaced to maintain continuity in design, and so that entire mechanisms don’t have to be replaced (better cost efficiency.)

*Cost: Cost differences range from slight to significant between crossbar and touchpad devices.  Crossbars tend to be slightly cheaper than basic touchpad devices.  Touchpads which have more options (i.e. electrical) are significantly more costly than both crossbars and basic touchpad devices.

Whether you choose crossbar or touchpad devices, each will perform the job that they were invented and designed to do.  That is, they will allow doors to remain locked, keeping people on the outside from using them.  At the same time, those inside will be able to open doors quickly and easily, particularly during an emergency.

The Occupational Safety and Health Administration (OSHA) is the agency in the United States charged with regulating safety in the workplace, including public buildings.  According to OSHA [1] an exit route consists of three parts:

1) Exit access:  This is the portion of the exit route that leads to an exit (door.)  This would include entrances to hallways/corridors and entryways/vestibules, etc.

2) Exit:  This is the portion of an exit route that is generally separated from other areas to provide a protected way of travel to the exit discharge (i.e. hallways, vestibules, etc.)

3) Exit discharge:  The part of the exit route that leads directly outside to the street, a sidewalk, walkway, refuge area, public way or open space with access to the outside. 

These three aspects are critically important, and must all be functioning maximally together in order to ensure a safe escape during a fire or other emergency situation.  Maintaining safe and effective exit routes means evaluating all three of these aspects.

For example, exit accesses must be at least 28 inches wide at all points, according to OSHA standards.  Objects, whether fixed or not, (i.e. metal detectors, gates, etc.,) must not reduce clearance to less than 28 inches.  This allows enough clearance to help avoid people jamming exit accesses and becoming stuck, which frequently happens in mass panic situations.  Maintaining that clearance throughout the entire access also helps to avoid the “funnel effect” that can be detrimental to the flow of traffic.

Exits themselves are required to be outfitted with fire doors (one-hour or two-hour fire doors, depending on the style and size of the building.)  Exit doors must be able to remain closed but unlocked from the inside (i.e. outfitted with exit devices/panic bars.)  Exit doors must be self-closing (i.e. outfitted with door closers.)  All door hardware must be fire rated for the same duration of time as the door itself.

Exit discharges must be large enough to accommodate the number of people that are likely to use a particular exit.  In other words, exit discharges leading from the sales floor of retail business would need to be significantly larger than exit discharges leading from storerooms, employees-only areas, etc.

OSHA’s complete set of regulations regarding exit routes is available on its website.  Local fire marshalls/inspectors can be excellent sources of information and interpretation of fire and emergency exit rules.  Ask for an audit from your fire marshall if you are unsure how to interpret a particular rule.

[1]“Fact Sheet: Exit Routes.”  Occupational Safety and Health Administration.  U.S. Department of Labor.  2003.

Many cabinets can be finished without latches.  Instead, knobs are applied, and doors are held shut in other ways.  They may employ magnets, be fitted with cabinet catches, or may be held closed by adjusting the tension on hinges so that cabinets can’t pop open.  However, some circumstances may exist where latches might be highly recommended.  Some of these include:

1. There are likely to be young children present.  Whether commercial or residential, sometimes it’s advisable to install cabinet latches to prevent young kids from opening up cabinet doors.
2. Cabinets contain breakable items.  For example, it’s almost always a practical idea to use latches on China cabinets.  If you happen to live in an earthquake-prone region, cabinet latches will prevent doors from inadvertently swinging open and spilling out the breakables inside.  Other places where cabinet latches are practical are kitchen cabinets which house breakable cookware, hobby cabinets, etc.
3. Cabinets which contain poisonous chemicals/cleaning products.  Again, efforts should be made to keep these types of things inaccessible to children.  Sometimes even pets need protection, since some are able to open cupboard doors.
4. Cabinets which contain dangerous items.  Garage cabinets which house tools are a prime candidate for latches.

It may not be necessary to install latches on every cabinet in a room.  Pick one or two in which to keep all of your breakables or chemicals and apply latches to those cabinets only.

Cabinet latches come in a variety of finishes and can be easily matched to both the cabinet and to the rest of the door finishing hardware.  Or, choose invisible latches.  This type can be mortised into the door of the cabinet so it is flush with the door’s surface and virtually invisible to the eye.

Ives Invisible Latch

Ives Invisible Latches can be purchased at Popular Hardware.com.