SDC HiTower: Electric Frame Actuator Controlled Mortise Lockset

March 2, 2015
HiTower mortise locks use the SDC deadlocking plunger assemblies, operating in conjunction with the EFA, to electronically control access and/or egress by restricting or engaging the operation of the mortise lock's interior and/or exterior levers.

In 1976, Security Door Controls developed simultaneous, remote electronic access control for multiple mortise lock applications including stair doors in high-rise buildings. The HiTower locking system provides increased levels of security, satisfying what would become life safety considerations.

Prior to 1976, most stairwell doors were unlocked, having unrestricted stairwell access onto every floor. Today, according to code, high-rise stairwell enclosure doors must electronically unlock the inside (stair side) levers simultaneously without unlatching upon fire alarm or power failure. Unlocking the inside lever permits people to re-enter the building on any floor. HiTower accommodates the building, electrical and life safety codes by unlocking the inside lever while the lock is latched, keeping the door closed.

Over the years, a number of applications have implemented the SDC HiTower Lock System to raise the level of security and meet codes. These include elevator lobby doors, perimeter exit doors, communicating bathroom doors, private office doors, computer room doors, pharmacy storage doors, money room doors and mantraps.

Incorporating a mechanical mortise lock with an electric actuator installed into the frame provides the ability to use mechanical and electronic access control when setting up access and egress options. HiTower can be equipped with latch or latch and deadlocked status sensors. The latch status sensor indicates when the door is closed and latched, and unlatched or open. The latched and deadlocked status sensor indicates when the door is closed, latched and locked, and/or the door is unlatched or unlocked.

When power is removed, a Fail Safe electric strike or electromagnet will not maintain the positive latching required for the fire rated stair door openings. As a result, without positive latching, the pressure from a fire could push the door open, allowing smoke and flames to enter the stairwell, resulting in the chimney affect.

Security Door Controls (SDC) HiTower locks the inside (stairwell side) mortise lock assembly, preventing people from using the stairs to gain access onto different floors. Once in the stairwell, a person must descend to the main/ground level floor in a non-emergency situation to exit. I have heard of re-entry exceptions, and Chicago appears to be one city that incorporates them. The International Building Code (IBC) does not cover selected re-entry. During a fire, emergency or power loss, the HiTower simultaneously unlocks the all of the mortise locks to provide access to all of the floors.

The HiTower is a mechanical mortise lock operating in conjunction with an Electric Frame Actuator (EFA). In order to control access and/or egress, HiTower mortise locks have the SDC deadlocking plunger assemblies installed into non-deadbolt mortise lock bodies. The deadlocking plunger assembly operates in conjunction with the EFA to electronically control access and/or egress by restricting or engaging the operation of the mortise lock's interior and/or exterior levers.

For the stair doors in high-rise buildings, HiTower mortise locks are Fail Safe with the stair side levers locked by power. The building side can be equipped with lever trim or mortise exit devices. Cutting power unlocks the stair side levers, permitting people and fire personnel in the stairwell to access to any floor in a fire or emergency. In case of a fire or emergency, a fire life safety system will release all HiTower-equipped stair doors.

The Electric Frame Actuator mechanism is built onto a custom cutout ANSI (4-7/8") Strike Plate that accommodates a 1-3/4" - 2" face frames. The strike plate has a cutout just for the latch. The auxiliary deadlatch contact the face of the strike plate and retracts into the mortise body as the door is closed. When the auxiliary deadlatch retracts, the latch becomes fixed in the extended position within the cutout. As long as the auxiliary deadlatch is retracted, the latch will not retract from the strike plate cutout preventing the door from opening. The latch can be retracted using a key or rotating a lever if configured. The narrow backset EFA accommodates a 1-1/4" - 2" face frames using a modified strike plate.

The HiTower deadlocking plunger assembly controls retraction of the latch by locking or unlocking one or both sides of the mortise lock's split retractor hubs. The deadlocking plunger assembly is held in place within the mortise body. The 9/16" diameter deadlocking plunger extends through the front, entering the opening with the EFA. Because the deadlocking plunger extends out from the mortise lock front, a wire guide retracts the deadlocking plunger as the latch is being retracted, avoiding contact with the strike plate.

When the door is closed and latched, the deadlocking plunger is either retracted into the mortise body or extended beyond the gap into the EFA's access hole. If the deadlocking plunger is retracted, one or both sides of the hubs are either disengaged or fixed. Rotating the lever on the disengaged retractor hub will not retract the latch. If the deadlocking plunger is extended into the access hole, both sides of the hub are engaged, permitting the latch to be retracted by rotating a lever.

The EFA controls the position of the deadlocking plunger as it extends through the armored front. This is accomplished by the EFA's solenoid operated bolt head that moves in and out in the EFA Strike Plate opening. The HiTower is available with 12 VDC, 24 VAC, 24VDC or 115VAC. The advantage of 115VAC solenoid is there is no concern regarding voltage drop having to simultaneously power multiple Electric Frame Actuators.

The bolt head in the EFA is adjustable in order to fully retract (disengage/fix lever) or extend (engage lever). When the bolt head is fully extended, the deadlocking plunger is press back into the armor front of the mortise lock. In addition, the bolt head adjustments can compensate for changes in the door gap.

The HiTower System provides the end user with mechanical and electronic access control for an additional level of security. The deadlocking plunger locks the retractor hub to prevent a lever from retracting the latch. HiTower locks depending upon the application, control the inside lever, outside lever, or the outside and inside levers. They can be configured for Fail Safe or Fail Secure operation.

The two standard Fail Safe HiTower lock configurations are the 7530 and the 7550. The 7530 Mortise lock is unlocked by a remote switch or by means of a key from either side. Fail Safe locked both sides. This configuration can be used for man traps, communicating locks and bathrooms. The 7550 Mortise lock is unlocked by remote switch, by means of a key, or by rotating the lever or pressing the exit device on the non-secured side. Fail Safe locked on one side only. This configuration can be used for stairwell doors, classrooms, laboratories, offices, and mantraps.

Older HiTower systems are equipped with the 5000 Series mortise locks and Electric Frame Actuators. The 5000 Series can easily be identified, as the auxiliary deadlatch and the deadlocking plunger are part of the Electric Frame Actuator, not the mortise lock. The 7500 Series mortise locks and EFAs can replace the 5000 Series locks.

HiTower Electric Frame Actuator prep is the standard door hardware dimensions for an ANSI Strike Plate. No frame face modifications are required for the installation. Arrow, Best, Cal-Royal, Corbin Russwin, DORMA, Falcon, Marks USA, PDQ, Schlage and Yale mortise locks can be modified by SDC for a HiTower application. Contact SDC for more information.

One of the HiTower advantages is the electronics are installed into the frame, so there are no wires running into the mortise lock or trim. This eliminates the need to drill a raceway or to require a power transfer product to provide electricity.

A maintenance consideration for a HiTower installation is the powder build-up that can result from the grout-filled frame. The powder can accumulate in the mortise lock and the Electric Frame Actuator. This problem normally occurs when the grout-filled frames were not sealed once a portion of the grout had been removed to accommodate the EFA and the wire run. If grout is not sealed inside the frame, the powder will eventually get into the mortise body and the EFA. The best solution is to remove the EFA, clean out the dust and spray paint the inside of the frame to prevent future dust problems. Take your time and spray enough paint to fully seal the area.

Use only compressed air to clean the EFA including the bolt head area. Do not use spray lubricant in the bolt head opening or any other part of the EFA, as this can result in damaging the solenoid. Also, remove the mortise lock body; spray it with compressed air to remove any grout powder. There should not be a need to remove the cover, as there are sufficient openings through which to spray.

Like just about every other electronic locking mechanism, it is extremely important to keep the power supply producing the proper amount of voltage. This is because a Fail Safe solenoid is powered to remain locked. Overpowering the Fail Safe solenoid causes excess heat, which can shorten the operational life. If the power supply is not charging backup batteries, the voltage should be exactly 12 VDC or 24VDC. If there are backup batteries, the DC voltage should be no more than 10 percent higher to charge the batteries.

Before selling, installing or modifying stair doors, contact the local Authority Having Jurisdiction.

For more information, contact your local locksmith distributor or SDC , 801 Avenida Acaso, Camarillo, CA 93012. Telephone: 805-494-0622. Web Site: www.sdcsecurity.com.