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Electric Strike Monitors: LBM and LBSM

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Exploded view of Von Duprin 6211 with Dual Switch option.
From Von Duprin 6211 installation instructions.

LBM stands for Latch Bolt Monitor. LBSM stands for Latch Bolt and Strike Monitor, also known as LBCM and DS, depending on the manufacturer. There are probably other variations as well.

In the illustration above is shown the Von Duprin 6211. The labeled parts, “Tripper” and “Extension,” are used when the strike is equipped with the DS (dual switch) option. The DS option is Von Duprins version of LBSM. The Tripper is a piece of metal that changes the state of a switch when it is depressed by the spring-loaded force of a latch bolt when it drops into the keeper. Most other strikes use similar mechanisms to detect the presence of the latch bolt.

LBM will tell you if there is not a latch bolt present in the keeper. LBSM will tell you if there is no latch bolt present in the keeper and/or the strike itself is not in the fully locked position. Neither of these would tell you if the door is ajar. So LBM and LBSM are not true substitutes for a door position switch.

And, if someone stuffs the keeper with something to effectively keep the door unlocked or fool it into thinking there was a latch bolt there, it won’t tell you anything. On the other hand, if you don’t have LBM, someone can tape the latch back with duct tape you would have no way of knowing. The door position switch will tell you the door is closed, but you need the LBM to tell you it’s latched. The LBSM can provide you with the additional information that the electric strike is not properly locked; perhaps the keeper is not closed all the way or the internal parts are not all the way in the locked position.

Choosing a Power Supply for Electric Locking Devices

February 24, 2019 access control / electric locking

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Allegion PS904 Power Supply with optional boards.

There are many ways to lock a door electrically. Here are a few of the most popular:

Electric Strike
Electromagnetic Lock
Electrified lock
Electric Latch Retraction exit device

Voltage and Current

Two main factors are universal in choosing a power supply, but some kinds of electric locking devices require special considerations. The first universal consideration is the voltage required by your electric devices. The second is the amount of current drawn by these devices.

As of this writing, most strikes, magnets and locks are field selectable for a variety of voltages, mostly 12 or 24 VDC. Some are not field selectable. Almost all electric latch retraction exit devices are 24 VDC. The important factor is, what voltage will be used to power the devices. Voltage is important (aside from the fact that running an electric device on the wrong voltage may cause a fire) because voltage affects current draw. Current draw (measured in Amperes, or ‘Amps’) determines the need for power supply capacity.

Following are examples of how the voltage affects current draw:

HES 1500 series electric strike:

.24 Amps @ 12 VDC
.12 Amps @ 24 VDC

Schlage Electronics M490 electromagnetic lock:

.65A @ 12 VDC
.35A @ 24 VDC

SDC 7800 series electrified mortise lock:

600 mA @ 12VDC
300 mA @ 24VDC

Yes, there is a trend here. 12VDC draws twice as much current as 24VDC. Good to know. A little clarification may be in order:

.24 Amps = 240 mA

Now that we have that cleared up, let’s say that we have a six-door access control project and we’re using 24VDC. On four of the doors we’ll use the HES 1500; on one door we’ll use the M490 mag and on the last door we’ll use the SDC 7800 electrified mortise lock.

Just for variety, let’s add a Sargent 80 series exit device with motorized latch retraction:

1 amp @ 24VDC

The arithmetic looks like this:

.12 + .12 + .12 + .12 + .35 + .30 + 1 = 2.13 Amps total current draw

You want to allow at least a 25% cushion so that the power supply does not have to work too hard. Therefore, rounding up, a 3-Amp power supply would be a safe bet.

Distance of Wire Run

The distance between the power supply and the appliance to be powered is also an important factor. It may determine how many power supplies you need.

Using an online voltage drop calculator I was able to determine that a 1,000-foot wire run (one-way) using 18-gauge two-conductor wire, with a current draw of 120 mA, the voltage drop will be less than 1 percent. With a 1-Amp current draw, and all other parameters the same, the voltage drop would be about 27 percent. Therefore, whereas the 1,000-foot wire run would not be a factor to run one HES 1500 strike a 120 mA, it would be a factor in powering the Sargent exit device with electric latch retraction at 1 Amp at that distance. This might mean that a separate power supply would be installed much closer to the Sargent and another power supply could power all the other devices.

Voltage drop can be managed to a degree by increasing the gauge of the wire. Using the Sargent electric latch retraction example, this time using 12-gauge wire instead of 18-gauge wire, voltage drop on a 1,000-foot one-way wire run would be 14 percent instead of 27 percent. Using thicker wire combined with moving the power supply closer to the device can mean the difference between a system that works well for years and one that soon fails.

Electric Latch Retraction Exit Devices

In many cases the industry has shifted away from solenoid-driven electric latch retraction exit devices and moving more and more toward motor-driven latch retraction. Nevertheless, those solenoid-driven devices are still out there and many are still being sold. From a power supply point of view, it is very important to understand the difference.

When solenoids are activated, the draw an “inrush” of high current for a fraction of a second. For example, a Von Duprin EL99 rim exit device draws 15 Amps at 24 VDC for one third of a second, requiring it to have a special power supply. Their power supply for this application is the PS914-2RS, which will power up to two EL devices. What makes the power supply special is (1) the circuit board equipped with capacitors that gather the current and release it when it’s big enough to do the job and (2) a delay timer that allows the power supply to power up two devices one at a time, one-third of a second apart.

There are other power supplies that will work in this application: the Altronix STRIKEIT series power supplies, or the Command Access PS220 with PM300 power booster are two such. Each will power up to two solenoid driven electric latch retraction exit devices.

As shown earlier in this article, motorized latch retraction exit devices also draw more current than other kinds of electric locking devices. However, they draw much less current than solenoid driven latch retraction exit devices. Most manufacturers say to allow 1 amp per device. Check the install instructions for your particular device to be sure.

Options

Following are some accessories you can add to make your power supply easier to install and/or service, or to add functionality.

Power Distribution Board

If you have a power supply with one or two sets of outputs and need more outputs, you can add a power distribution board. The power distribution board distributes power evenly among several sets of output contacts. This can come in handy when troubleshooting a power supply that is powering multiple devices.

Relay Board

Relays are electrically operated switches. You flick the lights on in your room with your finger. Instead of a finger, the relay uses electricity. Relays typically draw a very small amount of electrical current. This can be useful in a variety of applications.

One example is in a simple access control system, where a receptionist pushes a button to activate an exit device with electric latch retraction that draws 1 Amp, 150 feet away. Instead of of running 1-Amp current from the power supply to the pushbutton, from the pushbutton to the device, and from the device back to the power supply, use the pushbutton to trigger a relay in the power supply to power the device. Only the few milliamps needed to power the relay will run back to the pushbutton. This makes the system much safer for the receptionist and avoids any voltage drop problems from the extra wire run back to the pushbutton.

Fire Alarm Relay

The fire alarm relay option allows connection to the fire alarm panel, so that in the event of an alarm the panel can shut off the power supply.

Logic Board

Logic boards are boards with multiple relays and internal switches. These are used to perform more complex functions, such as activating electric latch retraction exit devices and then, a fraction of a second later, activating an automatic door opener.

Timers

There are two main types of timers found in power supplies that are used with electric locking devices: 24-hour timers and delay timers.

24-hour timers are used to keep doors locked or unlocked for variable periods at specific times. Typically these timers can be programmed for a number of lock or unlock events. Simpler units might be used to unlock a door in the morning and then lock it back up at night every day. More versatile units can be programmed to behave differently on weekends and holidays.

Delay timers are used to time the re-locking of the electric device after it has been activated. For example, the receptionist pushes the button at her desk and immediately lets go. The timer powers the electric strike for six or seconds to allow the visitor time to push the door open.

EPT vs. Electric Through-Wire Hinge, Revisited

February 14, 2019 Uncategorized

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The choice between an electric through-wire hinge and an electric power transfer (EPT) is one of convenience vs. durability. Whereas the hinge requires almost no prep, the EPT does. However, the EPT is designed to minimize stress on the wires and the electrified through-wire hinge is not.

Every time the door is opened, the wire in the electric hinge is unbent and bent at least ninety degrees. With an EPT, the wire is bent at a much gentler angle. This difference translates into a big difference in durability in high traffic applications.

Command Access electric through-wire hinge

SDC electric through-wire hinges are UL Listed for 100,000 cycles. That means if the door were used 200 times a day for 500 days, one might expect the wires to break sometime after day 501 or so – or a life span of about a year and a half in this unusually high usage environment. Electric through-wire hinges, therefore, may not be the best choice for doors that experience very high traffic volume. The Assa Abloy EPT is rated at three million cycles, or fifteen times that of the hinge – that is, in the 200 cycles per day scenario, about twenty-two years vs. a year and a half.

This difference in durability is illustrated by the evolution of continuous hinges with through-wire electrification. Because the wires eventually break, hinge manufacturers now offer removable panels that contain the wire, so that when the wire breaks the entire 7-foot hinge need not be replaced; just the panel. While it is fairly cheap and easy to replace a 4-1/2 x 4-1/2 electric hinge, replacing a full height electrified continuous hinge is not. Replacing the removable panel is not the easiest process either, but it is much less expensive than replacing the whole hinge.

With continuous hinges as well as regular hinges, the EPT remains the far more durable choice. All continuous hinge manufacturers offer their hinges prepped for EPT; most require handing and location of prep when ordering. The projected life span of an EPT in a continuous hinge is in numbers of decades. But if you ever do have to replace one, it’s relatively easy.

Electric Hinge vs. EPT (and oh yeah, Molex)

June 2, 2018 access control / door hardware / electric locking / security hardware

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McKinney Electric Thru Wire Hinge with Molex connectors

I was taking a class on Molex connectors a while ago and the teacher – a manufacturer’s representative from a major hardware manufacturer – expressed the opinion that for high traffic applications, a power transfer is preferable to an electric thru wire hinge. I confess that until that moment I had not actually thought about it much, but what he said made a lot of sense. After all, almost everyone prefers an electric hinge to an EPT because of the relative ease of installation.

But the rep made a good point. The wires that run through an electric through an electric hinge are pretty thin – usually 24 or 26 gauge wire – and every time the door is used these wires are bent back and forth. If you’ve ever bent a copper wire back and forth in your hands until it breaks you will know what I’m getting at here. When you bend a copper wire back and forth, over and over, first it heats up, then it breaks. The same process is going on in the knuckle of that hinge. There’s a whole lot o’ twistin’ goin’ on.

Von Duprin EPT10

When you open a door equipped with an EPT, however, there is less twisting happening. The wires must still bend with the motion, but only a fraction of the bending that occurs with an electric hinge. That’s why the rep always recommends EPT’s over electric hinges if the opening is to have any serious traffic through it. Sure, installing an EPT is a lot more work, but a callback to replace a failed electric hinge is at least as much work, especially considering travel time.

Yes, you’re right, I did mention Molex connector class. A few times now I’ve run into applications where the installer wants to convert a regular removable mullion into an electric mullion so they can install an electric strike on the mullion. Since the advent of the surface mounted electric strike for rim exit devices, it was inevitable that someone would want to do this. The problem? What do you do with the wire at the header? Well, if you just run a continuous wire, the mullion is no longer removable, is it?

But, aha! I said. We’ll use a Molex connector at the header. What is a Molex connector, you ask? Those would be those plastic connectors attached to the ends of the wires on the McKinney hinge above. Molex is a company that has created a system of plug-and-play wire connectors, and these connectors are becoming more and more common in the door hardware industry. Major door hardware manufacturers are now incorporating Molex connectors into all their electrified products and offering what are in effect extension cords with Molex connectors.

So a couple of connector-equipped extension cords would solve the problem of the suddenly non-removable mullion, right? Well, not so fast, buckaroo.

This is what I learned in Molex class. In Molex connectors, which connector will connect to what other connector is determined by the pin crimped onto the end of the wire. They give them genders, “male” and “female”, because the male can be inserted into the female. Okay, great. Where is the problem? The problem is that as of this writing, door hardware manufacturers’ extension cords all have connectors of the same gender on each end, so you cannot plug them into each other. They will only plug into an electric hinge or EPT that has Molex connectors.

The solution to the DIY electrified mullion problem: make your own DIY Molex connector for the wire in the header. To do this you will need a standard wire stripper, some 12-conductor cable, the special Molex crimping tool, Molex connector housings, and Molex male and female pins. There is a service kit available that contains all these parts. It is a fairly time consuming process to make your own Molex connector, and it requires skill, but it is the only solution that I know to the mullion problem.

Get your surface mount electric strike with Molex connectors (several electric strike manufacturers offer these) and an extension cable from Assa Abloy or Allegion to get the wire from the strike to the top of the mullion. Now you have the capability to connect your makeshift electrified mullion into the connector you must make. You can attach your homemade Molex to as long a cable as you like – long enough to reach the power supply or access control panel.

Does this solution comply with code? I do not know. Best check with your local AHJ before embarking on your Molex DIY mullion adventure.

Why is the industry moving to Molex connectors? They do not fall off, look ugly, or take up a lot of space like wire nuts, and if you need to trade out an electric hinge or electric strike they sure do make it a whole lot cleaner and easier.

That’s right. As usual, it all comes down to sex.

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Aluminum Door Latch Electric Strike Retrofit

November 4, 2017 access control / door hardware / electric locking

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Adams Rite 4501 Strike – from the Adams Rite web site.

Often we find ourselves involved in someone’s second thoughts about the use of a particular aluminum storefront type opening, wherein someone remembers that, hey, this opening needs access control. Or, perhaps, the idea of access control comes to the opening later in its life. In any case, the door company provided their usual solution for the customer’s parameters: an Adams Rite latch with a lever handle or push paddle and the standard strike shown at right. Extra credit: What hand is the strike in the picture?*

From Adams Rite 4901 and 4902 install instructions

Above is a drawing of the prep for the 4901 double-hole strike. The prep is 4-5/8 x the width of the door frame less 5/32 inch (.15 inches) as shown – or about 1-7/8 inches wide or so, depending on the actual depth of the frame measured from the stop to the edge.

The most common (non-electric) strike that comes with the Adams Rite latch is the 4901 as of this writing. It was called the 4501 years ago, but it remains mostly the same: 4-5/8 inches tall, with two holes to accommodate left- or right-handed doors. It comes with a plastic insert to block off the unused hole as shown in the picture of the 4501 strike above.

Common electric strike face plate heights are 4-7/8 inches, 6-7/8 inches , 7-15/16 inches, and 9 inches, and common widths range from 7/8 to 1-7/16 inches. The problem lies in the differences. None of these common sizes will fully cover the width of the 4901 prep, and after you’ve installed the strike there are ugly gaps left to fill in the aluminum. You can use one of the following retrofit solutions to avoid this problem.

Retrofit Solutions

Trine 3458 electric strike, from the Trine web site.

Two companies have led the way in solutions to this very specific and often-occurring problem: Trine and Adams Rite. Trine has the quick fix and Adams Rite has the relatively heavy-duty fix.

Several years ago Trine redefined itself into a company of innovative solutions from a company that was much more focused on price point. They went from being the cheapest guy on the street (though in many cases they still have the best price) to being a great problem-solver. Case in point, the Trine 3458 electric strike (see pic at left), designed as a drop-in replacement for the Adams Rite 4901 with NO CUTTING. This is a big deal for installers.

Despite its tiny body, the strike boasts an ANSI Grade 1 rating and 1200 lbs. of holding force.

The downsides: not voltage selectable without a line conditioner, not field selectable for fail safe/fail secure, and keeper depth is 1/2 inch – fine for use with the Adams Rite 4510 latch which has a 1/2-inch throw, but could be an issue with the Adams Rite 4900 (5/8-inch throw) if the gap between the door and frame is less than the 1/8 inch it should be.

Adams Rite remains the premier manufacturer of locking hardware for aluminum storefront doors and frames as it has been for decades. They have consistently worked to improve product quality and performance and they have succeeded.

FPK45 Retrofit Kit by Adams Rite

The Adams Rite solution to the 4901 retrofit problem is actually two-fold because it applies to two very different models of strikes: the 7100 and the 7400. For the 7100 series, Adams Rite offers the FPK45-00 face plate kit, and for the 7400 series they offer the FPK7445 face plate kit. Installation of either one is largely the same: enlarging the prep on the top and the bottom, and keeping the bottom screw mounting tab.

At right you can see the overall dimensions of the FPK7445 or FPK45 and how it aligns with the 4901 (or 4501) strike. The mission is to line up the keeper of the electric strike to the active hole of the 4901. You can see that enlarging the prep represents a significant amount of work. You might well ask, “Why would I do this?”

First, as I mentioned, if you have a 4900 latch in the door and/or no gap between door and frame, you are going to want a deeper keeper than the Trine. Like the Trine, the Adams Rite are also ANSI Grade 1 burglary resistant but offer a slightly higher holding force of 1500 lbs. If you do not know the voltage in advance, the 7400 series is completely field selectable for a number of popular voltages – although one can get the Trine LC-100 line conditioner with the Trine strike and accomplish much the same thing. Both the 7400 and 7100 are field selectable for fail safe or fail secure operation whereas the Trine are not.

In the industry there remains a lot of loyalty to the 7100 series. In its time, the 7100 was a revolution in design and remains one of the most reliable and repairable electric strikes on the market today.

*The 4501 strike in the picture is left hand, or right hand reverse.

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Compact Electric Strikes

August 27, 2014 access control / builders hardware / door hardware / electric locking / hardware sales wars / security hardware

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A common problem with installing electric strikes is cavity depth – that is, how deeply you need to cut into the frame (or wall) so that the electric strike will fit. For most of the twentieth century electric strikes were, and most still are, designed without consideration for this factor. Instead they are designed for burglary resistance and durability.

Von Duprin 6211 Electric Strike

Click on the dimensional diagram of the Von Duprin 6211 electric strike at right. You can see that its total depth is 1-11/16 inches. All of its internal parts are heavy duty, and it has a heavy cast body and a thick, finished face plate. Most of the parts are individually replaceable. To install the 6211 in a hollow metal door frame, the dust box must be removed and often material inside the door frame – sheet rock, wood, masonry, whatever – must be removed in order to accommodate the strike. If the strike must be installed in a grouted door frame the installer is in for perhaps an hour’s worth of work that may involve a masonry drill, a 2-1/2 lb. sledge hammer, a masonry chisel and safety goggles.

In more recent years a new generation of low profile (shallow depth) electric strikes has become available, offering unprecedented ease of installation. The HES 5000 (illustration at left) was one of the first strikes on the scene to offer a depth of only 1-1/16 inches, and advertised that it could be installed without even removing the dust box from the frame. I have found it is usually much easier to knock out the dust box for wiring reasons, but it is true that the unit will fit neatly inside most original equipment dust boxes in hollow metal frames.

More recent offerings in the shallow depth electric strike department include the Trine 3478, the HES 8000 and the Adams Rite 7440, illustrations shown at the end of this article. All are UL Listed burglary resistant. The HES 8000 offers 1500 lbs. holding force, the 3478 offers 1200 lbs. holding force and the Adams Rite, with its innovative double keeper design, offers 2400 lbs. of holding force. The Trine 3478 offers an install with a very tiny lip cutout, and the HES 8000 offers the advantage of needing no lip cutout at all. Each of them fit in a strike cavity only 1-1/16 inches deep.

These strikes have revolutionized electric strike installation. Before, a good installer might install six or ten electric strikes in a day. Now a really fast installer might be able to install 20 or more, greatly reducing labor and other costs associated with installation.

What’s the Trade-Off?

None of the internal parts of these strikes are available. When these strikes break, you throw them away and buy new ones. Also they do not last as long. Whereas it is not unusual to see a Von Duprin 6211 or a Folger Adam 712 still in use after 10 or even 20 years, 6 years of service is a long time for a low profile strike. In ten years you might be replacing a spring or solenoid in a Von Duprin, but you might be installing your second or third low profile strike in the same door frame in that same amount of time. This is a small inconvenience.

Upon installing that third strike in the same hole, you probably will not yet have equaled the price of a single Folger Adam 712 or Von Duprin 6211. If price up front is the primary consideration, low profile is definitely the way to go. But if in about 12 years you are installing the fourth replacement strike in the same prep, those expensive, harder-to-install, heavy duty strikes start to look like a much better value.

HES model 8000, Trine model 3478 and Adams Rite model 7440

Thank you.

Quest for the 24-Inch Exit Device with Electric Latch Retraction

June 30, 2013 access control / builders hardware / door hardware / electric locking / hardware sales wars / Life Safety Hardware / security hardware

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I had a lot of fun recently trying to meet a customer’s requirement for a 4-foot by 7-foot pair of doors in a hospital that needed to be fire rated and automated. I found that Corbin and Yale (sister companies whose exit devices are almost identical) offer fire rated surface vertical rod exit devices with electric latch retraction that meet this need. The installer will be able to put some kind of little power operator on each 24-inch leaf of this four foot pair and cram two fire rated surface vertical rod devices onto these same narrow leaves. Doubtless it will look odd, but it will work.

Admittedly the whole idea is a bit dubious. True, by having both leaves opened simultaneously by power operators will provide amply more than the minimum 32-inch clearance demanded by the American Disabilities act, but if anyone manually opens either leaf it certainly will not.

Sargent and Von Duprin offer 24-inch fire rated exit devices, but neither offer them with electric latch retraction. It is unfortunately necessary to call these companies’ tech support lines in order to verify this information, since their price lists both show 24-inch possibilities without disclaiming the electric latch retraction option. Neither the Sargent nor the Von Duprin has a note to say the 24-inch device is not available with electric latch retraction that I could see; if that is in fact the case, the buyer is left to beware the exit device order that bounces back because it was ordered with options that are mutually incompatible.

It’s good advice anyway to always call the manufacturer’s tech support whenever there is a question. Waiting on hold is a lot better than storing thousand-dollar exit devices that didn’t work out on the job.

Note: A reader named Rick writes in with this about Sargent electric latch retraction: “Tom, I just stumbled across your site this evening, while doing a search for Fail Secure mag locks of all things (IR says there is one). But I saw your latest article on latch retraction units and had to clarify the Sargent restrictions. These can be found within the catalog pages, specifically the page showing the 56 option (toward the back). It says:

MinimumDoorWidths:

-Wide Stile Door 28″

– Narrow Stile Door 26″

Thank you, Rick, for this bit of info. I should add that it is always good to check all the literature at your disposal for any information you are looking for. Some manufacturers have more detail in their price list than in their catalog, and others vice versa. Thanks again.

Hot Stuff: Continuous Duty Electric Locking Devices

January 12, 2012 access control / Lock Repair / security hardware

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The Ohm Symbol

I regularly hear complaints about electric strikes, cylindrical locks or mortise locks that are hot to the touch. When I ask, I am always answered that, yes, the device is being used in a continuous duty application.

Continuous duty means that the electric lock or strike is powered continuously, usually for several hours a day. Most fail safe locks and strikes are run continuously, since they are usually locked part of the day and they require electric power to lock. Whenever a door is kept unlocked by using an electrical timer, the lock or strike that is controlled by the time is run continuously for part of the timing cycle.

Heat in an electric lock or strike is caused by resistance in the electrical circuit as it passes through the coil of the solenoid inside the device. Often this heat is sufficient to “burn out” the solenoid. The solenoid does not actually catch fire, usually. The term, “burned out” refers to a solenoid that has been ruined by excessive heat so that it no longer functions.

Heat from electrical resistance is exacerbated when there are problems with the supply of power. For example, if the power supply provides less than sufficient amperage to constantly power the solenoid, the solenoid will ‘run’ hotter. Similarly if there is a current drop because of a long wire run with inadequate wire gauge, the solenoid will not get sufficient current and will run hot. Also if the voltage supplied is significantly higher than the solenoid is rated to accept, that could create a heat problem as well.

Often, however, there is no detectable reason for the solenoid to run hot. Sometimes, it seems, they just do.

A great way to mitigate the problem of the hot lock or strike (when all power supply problems have been solved) is to use an electrical device in line with the electric lock or strike that provides it with a full inrush voltage and current upon activation and then reduces the voltage and/or current to a holding level, allowing the solenoid to run cooler.

Several companies offer these units. Here are some examples:

HES: Model 2005M3 Smart Pack controller
COMMAND ACCESS: CRU-2 current reduction unit
TRINE: LC-100 line conditioner

Glass Door Electric Locking Solutions

September 21, 2011 access control / door hardware / security hardware

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Installing an electric locking system on an existing, currently unsecured all-glass or Herculite door can be a challenge for the security professional, but there are solutions. Here are a few:

Electromagnetic Locks

Securitron Glass Door Solution

The Securitron solution to the glass door locking problem is… glue. When I sell this solution, I usually use:

M62G (1200 lb. holding force electromagnetic lock with conduit fitting)
AKG (adhesive kit for glass doors)
GDB (glass door bracket for armature)

For all glass doors with all glass headers, I also use the HEB-G header extension bracket. This can also be glued in place using the Securitron AKG. Since the AKG includes enough glue to do 10 glass-door mag installs, there is more than enough to do one all-glass door and one all-glass header.

Everybody Else’s Mag-Lock-for-Glass-Door Solution

As far as I know, no one besides Securitron really deals with the situation of an all glass header. For all-glass doors, all the other companies that make electromagnetic locks use variations of the HDB, or Herculite Door Bracket. This bracket is a U-channel that slides down over the top of the door. It’s a clip-on system:

Illustration from Rutherford Controls web site

The Herculite door bracket concept seems to work well except in cases were there is a reduced gap between the top of the door and the header. In that case the U-channel idea is out because the HDB bracket will keep the door from closing. Then it’s the Securitron and the glue or something else altogether.

RCI Cushion-Lok

A pricey but classy and easy to install alternative to the electromagnetic solution is the Rutherford Controls Cushion-Lok. The Cushion-Lok is a specially constructed, fail safe electric strike and passive latch that gently locks the door upon closure. Shown below is the RCI 3360 which is pre-installed on patch fittings that slide onto the glass of the door and “frame” when the entire doorway – door, lintels and header – is made of glass.

Not shown is another version for use with a wood or metal frame and Herculite door.

It is worthwhile to note that the reason security professionals are faced with installing electric locks on existing all-glass doors is because of a lack of planning on the part of the architect or project manager. It is much easier for a glass door manufacturer to pre-install a locking system than it is for a security professional to install it after the fact.

Exit Devices with Electric Latch Retraction

April 9, 2011 access control / builders hardware / door hardware / Life Safety Hardware / security hardware / Uncategorized

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Overview

Almost all exit device manufacturers offer the option of electric latch retraction on their touch-bar style exit devices. Different manufactures may call it by other names such as ‘latch pull-back’ or ‘remote dogging’. Some people refer a device with electric latch retraction as an ‘electrified exit device’, but that could also refer to electric unlocking of outside trim – a different animal altogether. Electric latch retraction is accomplished by using a solenoid or electric motor to actually retract the latch or latches of an exit device.

Below are some characteristics of electric latch retraction:

Electric latch retraction is fail secure. When power is supplied, the latches retract. When power is shut off, the latches extend, securing the door.
Electric latch retraction works well with power operators because when the latches are retracted, the doors can swing free.
With electric latch retraction, pairs of doors can continue to be latched top and bottom.

Cheaper alternatives, such as using an electromagnetic lock or an electric strike, would result in double doors that are only locked at the top. If they happen to be aluminum narrow stile doors locked only at the top, a person could actually pull the bottom of the locked door open several inches with very little effort. Such installations are at best sloppy, at worst not secure.

Solenoid vs. Motorized Latch Retraction

Solenoid driven electric latch retraction usually requires a specialized power supply due to the high inrush of current required (between 12 Amps and 16 Amps at 12 or 24 Volts DC). Motorized latch retraction generally requires just over 1 Amp of current for activation.

Solenoids are generally louder than motors, since solenoids move abruptly whereas motors retract at a slightly slower pace, and are therefore quieter.

Global Considerations

Check door width. Electric latch retraction devices may not fit if the door is too narrow.
A means of getting current from the door frame into the device, such as a door cord or electric power transfer will be needed.
Voltage drop due to length of wire run could be an issue with high current inrush devices.

Following are examples of electric latch retraction exit devices by different manufacturers.

Please keep in mind that any of the part numbers shown may change without notice at any time.

Adams Rite

Adams Rite makes hardware primarily for aluminum-and-glass storefront type doors, but also for standard hollow metal and wood doors. All of their exit devices are available with MLR (motorized latch retraction) or solenoid latch retraction (EL for rim devices and LR for all other devices). They make rim, concealed vertical rod, surface vertical rod, and mortise exit devices.

MLR motorized option draws 850 mA during retraction and 370 mA when maintained in dogged hold position at 24 VDC. Available in 24 VDC only. (ex. part number 8xxxMLR)
EL solenoid driven option (for rim devices, example part number 8801EL-36-12) draws 1.5 Amps at 12 VDC and 600 mA at 24 VDC
LR solenoid driven option (example part number 8xxxLR-36) draws 16 Amps at 24 VDC (inrush) and 500 mA (holding current) at 24 VDC

They do not offer a retrofit kit for field conversion of existing devices as of this writing, but aftermarket kits are available from other manufacturers.

Falcon / Doromatic

Falcon makes Doromatic exit devices primarily for aluminum storefront doors. All of their touch-bar style devices are available with electric latch retraction. Currently they use the Von Duprin-type solenoid for latch retraction, and use the Von Duprin PS914-2RS power supply to handle the 16-amp inrush current these solenoids draw.

The PS914-2RS will power up to 2 exit devices with electric latch retraction.

Doromatic offers a solenoid driven electric latch retraction field retrofit kit for their 1490 series concealed vertical rod and 1590 series rim devices as well as factory installed electric latch retraction. The EL1690 concealed vertical rod device and EL1790 rim device can be used field retrofit kits to electrify the 1990 and 2090 series crossbar “pipe-type” exit devices for latch retraction since they have the same latch side footprint and the vertical rod devices can use the existing rods.

Falcon offers their grade 1 series 24 and 25 exit devices with electric latch retraction or motorized latch retraction and field conversion kits.

Falcon exit device example part numbers:

EL solenoid latch retraction (EL25-R-EO 3 US32D)
MEL motorized latch retraction (MEL25-R-EO 3 US32D)

Example field conversion kits:

ELK-3 or ELK-4 (or 650147 or 650148) solenoid latch retraction kit for 3- or 4-foot 24 or 25 series exit devices. Specify finish.
25-MELK-3 or 25-MELK-4 (or 47266630 or 47266631) motorized latch retraction kit for 3- or 4-foot 25 series devices only. 24 series MEL devices are factory only. Specify finish.

Precision

Precision makes exit devices for hollow metal, aluminum storefront, and wood doors, fire rated and non fire rated. All of their touch bar-style exit devices are available with electric latch retraction, and they offer both solenoid driven and motorized electric latch retraction for their grade 1 devices.

ELR solenoid latch retraction (ex. part number ELR2103 630 36)
MLR motorized latch retraction (ex. part number MLR2103 630 36)

Precision makes retrofit solenoid electric latch retraction kits specific to various device characteristics.

Non-fire rated 3- or 4-foot wide stile exit device: ELRK-3 / ELRK-4
Fire rated 3- or 4- foot wide stile exit device: ELRKF-3 / ELRKF-4
Non-fire rated 3- or 4- foot narrow stile exit device: NELRK-3 / NELRK-4
Fire rated 3- or 4-foot narrow stile exit device: NELRKF-3 / NELRKF-4

They make one kit to convert any of their touch bar devices to motorized latch retraction:

RPMLR-K

Sargent

Sargent offers a wide variety of exit devices in various functions and configurations to accommodate diverse applications. All 80-series models are available with “Remote Dogging / Latch Retraction”. Sargent recommends the Securitron BPS-24-1 power supply, a simple 1-amp, 24VDC power supply, to power electric latch retraction devices.

To designate Remote Dogging / Latch Retraction they use a prefix 56- to the exit device part number.

Example part number: 56-8810F 32D

Sargent offers two kinds of retrofit kits to convert existing Sargent exit devices to motorized latch retraction in the field. The R56A kit includes a complete touch bar (specify finish) whereas the M56A consists of a motor and control module unit that is unfinished. Rail size (according to door width) must be specified for either. Sargent uses letter designations for rail size:

E = 24 to 32 inch door width
F = 33 to 36 inch door width
J = 37 to 42 inch door width
G = 43 to 48 inch door width

Example part numbers:

Modular kit: M56AF
Push Rail Assembly Kit: R56AF 32D

Von Duprin

Von Duprin offers two kinds of electric latch retraction in rim, surface vertical rod, concealed vertical rod, mortise, and three-point exit devices for narrow stile aluminum storefront, standard hollow metal, and wood door applications. To order exit devices with latch retraction use prefix EL for solenoid latch retraction or QEL for motorized latch retraction.

EL prefix devices require the PS914-2RS power supply. PS902-2RS are the manufacturer’s recommendations for QEL prefix devices, but any regulated and filtered power supply 2 Amps or greater will do. If powering 2 devices simultaneously, the PS902-2RS will stagger the inrush, firing one QEL at a time. Since each draws 1 Amp, simultaneous activation of two devices might max out a standard 2 Amp power supply. If another manufacturer’s power supply will be used to power two devices, I suggest using a 3 Amp power supply.

Wire run/current drop factors apply.

Example part numbers:

Solenoid latch retraction: EL99EO 3 26D
Motorized latch retraction: QEL99EO 3 26D

Von Duprin offers a variety of retrofit kits to field convert existing exit devices to electric latch retraction. Options include motorized latch retraction kits, kits that include rail backplate (specify door 3 or 4 foot door width), kits with motorized latch retraction and hex key dogging, etc. Here I list part numbers for the most common variations:

Solenoid Latch retraction (EL) kits:
- For 3-foot door width: 050070
- For 4-foot door width: 050078
Motorized latch retraction (QEL) kits:
- For 3-foot door width: 958003
- For 4-foot door width: 040065

Dorma

Dorma offers solenoid and motorized latch retraction for their 9000 series exit devices. ES is the designation for solenoid driven latch retraction and MLR for motorized latch retraction. They offer full replacement touch bar and rail assemblies that can be used to field convert devices to ES or MLR.

Example exit device with latch retraction part numbers:

With solenoid latch retraction: 9x00B RHR 630 ES
With motorized latch retraction: 9×00 RHR 630 MLR

ES option requires Dorma PS501 power supply.

MLR option, Dorma DKPS-2A power supply recommended, but any 2 Amp regulated and filtered power supply will work.

Rail size designations:

A – for door width 34 inches to 48 inches
B – for door width 28 inches to 36 inches
C – for door width 25 inches to 30 inches

Touch bar and rail assemblies, example part numbers:

MLR option motorized latch retraction: MLRTBR 630 B
MLR option fire rated motorized latch retraction: MLRFTBR 630 B
ES option solenoid latch retraction: ESTBR 630 B
ES option fire rated solenoid latch retraction: ESFTBR 630 B

Electric Strike Monitors: LBM and LBSM

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Everybody Else’s Mag-Lock-for-Glass-Door Solution

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Exit Devices with Electric Latch Retraction

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