Critical entrances in commercial buildings subject to criminal attack are often monitored and controlled by an access control system. As such, these portals must be equipped with keypads or card readers that automatically establish the identity of those who are authorized to enter. Typically, the identification (ID) of all system users is stored at the door as well as within a centralized computer which is often called a “host.”
Although all this high-tech electronics and computerization is handy to have, all of it would be virtually useless without a simple electric door strike. Without them, a live security officer would still be standing guard at every door in town checking the ID of everyone who wants to enter.
Electric strikes come in a wide variety of shapes, sizes, voltages, and other varied yet important parameters. To select the right electric strike, the first step is to know the type of door, frame, and mechanical lock involved. For example, whether the frame is wood or metal is important. Electric strikes also operate on 12 VDC, 24 VDC, 24 VAC and sometimes 16.5 VAC.
Door & Frame Materials
The first factor to consider when selecting an electric door strike is what kind of material is the door and door frame made of. There usually are three basic materials to consider: 1) Wood, 2) Hollow Metal, and 3) Aluminum. Wood frames usually call for an electric strike that contains a longer faceplate than is used on metal doors. Check the specifications of the electric strike you intend to use to assure that wood is listed.
Hollow metal doors are usually anything but hollow. During construction, many times these hollow frames are filled with pieces of brick, mortar, and other materials. One sure bet is to use a low-profile electric strike that houses the electric coil(s) up inside the door strike itself. By contrast, this coil(s) in most electric strikes are contained external to the strike body—which means they essentially reside inside the door frame. If you use a traditional electric strike, you will have to chisel out any construction materials that happen to be there. The expenditure of extra time and material can be avoided by using a low-profile electric strike in cases like this.
Aluminum frames are usually not a problem, but when there’s a window in the equation, be sure to pay attention to where you drill. If you catch the edge of the glass, it will likely crack and you’ll be responsible for replacing it.
Listed Ratings
It’s also important to note whether the door(s) in question has a fire rating. If it’s an outside door, it likely will not carry one. But if it’s an inside door, such as a computer room, storage room, or a door within a fire-rated wall, you must match the rating of the electric strike to that of the door.
The rated strength of the mechanical lock also must be considered when choosing an electric door strike.
There are three basic strength ratings to consider: 1) Grade 1, 2) Grade 2, and 3) Grade 3. Grade 1 is commonly used in commercial applications, Grade 2 in commercial and high-end residential, and Grade 3 in residential only. If the lock carries a Grade 1 rating, the electric strike must carry a Grade 1 rating, too. If the door lock is rated as a Grade 2, then the electric strike must carry at least a Grade 2 rating. In this case, a Grade 1 electric strike would also work.
The Grade rating system comes from the work of two organizations, the American National Standards Institute (ANSI) and the Builders Hardware Manufacturers Association.
Door(s) and Lock(s)
Another issue to consider is whether the door on which you’re installing an electric strike happens to be a single or double. Double doors many times include an optional center mullion that can be used to house the strike. In this case you can usually drop the wire down the hollow center channel. This is a great location for electric door strikes, although there will be times when this will not work.
In cases where there is no mullion to work with, you may be forced to install it in the edge of the inactive door. The latter requires more work as well as a special boring jig, a 1-inch mortise pocket extension drill bit, as well as a transition hinge to transfer the four wires that usually come with such a lock.
The next consideration is what kind of mechanical lock that is now on the door. There are three to choose from. They are: 1) cylindrical, 2) mortise and 3) rim.
The center point of an electric strike must coincide with that of the latch-bolt on a cylindrical lock. Also watch for alignment with the deadlatch, for as you know, this small spring-loaded latch prevents someone from prying or jimmying the deadlatch open. If this should occur, the door could be opened without the customary card, token, PIN, key, etc.
Alignment also is important when working with a deadbolt lock. The keeper in an electric strike must be aligned with the deadbolt in order to maintain security of the door. In this case, when a valid user presents an authorized credential to the access control system, or when a receptionist knows the individual asking for access, the electric strike can be made to allow the deadbolt to pass over the keeper, usually by way of an electromagnetic device called a solenoid. Here the depth of the cavity inside the strike is important in order to assure proper security of the deadbolt.
Mortise locks are a little more complicated because they contain both a deadbolt and latch-bolt. Alignment with both elements with regard to the faceplate and keeper in an electric strike is important to consider.
Rim locks also must be considered when purchasing an electric strike. This type of locking device is used commonly in schools, commercial buildings, government institutions, and other kinds of construction. This type of electric strike is different from the others in that they usually are surface-mounted devices equipped with two gates/keepers..
The Right Electric Strike
Electric strikes are not a new phenomena in the world of electronic access control for they’ve been available to the security market for many years. Instead, there have been many improvements in the general operation of these most vital electromechanical devices. Less current flow than the electric strikes of yore is but one of them. Less current means lower operational temperatures, which translates to longer life expectancies.
The electric strikes listed below by manufacturer offers the best of the best. Use it to select an electric strike for your next access control job.
Camden Door Controls of Mississauga, ON Canada, features two universal electric strikes, Models CX-ED2079 and CX-ED1079, that allows you to stock one electronic strike instead of a dozen. It doesn’t matter what the voltage is, whether it’s fail safe or fail secure, what the frame type is or even if the door is out of alignment. These strikes are 12 or 24 volts, AC or DC, with selectable fail safe or fail secure operation, come with 3 stainless steel faceplates and have horizontal adjustment of the strike body. Best of all, installers can get the many benefits of Camden universal strikes at an incredibly competitive price. For more information, visit Camden's website at http://www.camdencontrols.com.
Dortronics of Sag Harbor, NY, offers seven reasons why you need the 3300 series electric strikes. Probably the biggest is that it’s one of the few electric strikes that allows you to stock a single electric strike for all your access control needs. The 3300 series features high strength through the use of a heavy-duty keeper. This electric strike series also features a stainless steel jaw and strike plate, both of which carries a rating of 1,000 lb. of static strength. Because of this, the 3300 series has earned UL's Burglary-Resistant Electric Locking Mechanisms. The second reason why you need to consider Dortronhics’ 3300 series electric strikes is that they require only a small screw driver to quickly change them from fail-secure (factory default) to fail-safe. A third universal feature is dual-voltage operating voltages of 12 and 24 VDC. For more information, go to: http://www.dortronics.com.
HES of Phoenix, AZ, offers the 1500 series electric strikes which feature a modular, low-profile design that works with every brand of cylindrical or mortise locks on the market. The 1600 series is designed for both latchbolt and deadbolt locks. In addition, the 1500 series works with 4-7/8 inch strike plates. Several features make both the 1500 and 1600 series electric strikes worth a look. First, both strikes feature voltage auto-sensing, which means you can use them with 12- and 24-VDC. In addition, both series electric strikes feature selectable fail-safe and fail-secure modes of operation. For more information, go to www.hesinnovations.com.
ROFU of Lakewood, WA, features the 2460 Series Rim Mount strike for crash bars. Designed for doors with crash bars requiring a rim mount strike, the 2460 offers latch monitoring and strike locked/unlocked status monitoring. This electric strike lock can easily be reversed from fail-safe to fail-secure modes. For more information, go to https://rofu.com/home/rofu-reps-usa/.
SDC’s UniFLEX™ 55 Series Universal Application Strikes are designed for installation in hollow metal frames for access control of cylindrical and mortise locksets and mortise exit devices. The choice of 6 application faceplates eliminates the need for centerline relocation, making them ideal for new or retrofit , high security access control applications. They are designed for use with 5/8'' latchbolt, or up to 3/4'' latchbolt with 1/8'' door gap, field changeable for failsafe or fail secure and non-handed. The strikes are constructed with all stainless steel parts with durable die case body for corrosion resistance, 12VDC/24VDC with 630 Satin stainless steel face plate and ANSI A156.31 compliant, Grade 1. For more information, visit www.sdcsecurity.com
Trine Access Technology of Bethel, CT, has manufactured a unique product they claim to be the smallest electric strike for vertical rod control available in the world. The 330VR mounts on top of a metal, aluminum, or wood frame. It works with exposed and concealed vertical rods. Rated Grade 1, the 330VR comes in satin stainless steel and dark bronze powdercoat finishes. Electrical options include 12 VDC/VAC and 24 VDC/VAC with selectable intermittent or continuous duty. For more information, go to: http://bit.ly/2icZuzn.
