UFC 4-021-02NF
27 September 2006
change 1, 23 October 2006
9-4.7.2.1 Electric strikes should be protected with a cover guard. Exposed electric
strikes can be over-ridden (pried open) by an intruder with a pocket knife screwdriver.
9-4.7.3 Magnetic locks. The magnetic lock is popular because it can be easily
retrofitted to existing doors. The magnetic lock is surface-mounted to the door and
doorframe. Power is applied to magnets continuously to hold the door closed. Magnetic
locks are normally fail-safe (they can be fail-secure through the use of a solenoid). This
may be a problem for unstaffed facilities in the event of a power disruption that will leave
the site unsecured until security personnel arrive or power is restored.
9-4.7.3.1 Magnetic locks do have a security disadvantage. In the United States,
continuous locking of exit doors is not permitted. (For more information refer to NPFA
101, Life Safety Code.) Doors equipped with magnetic locks are required to have one
manual device (such as a Request-to-Exit, or REX button) and an automatic sensor
(typically a passive infrared sensor, PIR) to override the door lock signal when someone
approaches the door in the exit direction. While enhancing overall building safety, the
addition of these extra devices allows possible compromise of the door lock in the
following scenario:
1.
Person A in on the secure side of the door and walks into the field-of-view
2.
The door lock signal is shunted by the activated automatic sensor.
3.
Person B (located on the public side of the door) can open the door and
breach the security of the locked opening.
Magnetic locks should be the designer's last choice for door locking mechanisms and
should probably only be used on a retrofit project.
9-5
LIFE SAFETY CODE CONSIDERATIONS
9-5.1
Applicable life safety and existing codes/standards must be met. In the event
of an emergency, building occupants must be able to follow emergency procedures
quickly and safely. The ESS designer must coordinate with the building architect (for
items such as exit plan considerations) and the building fire protection engineer (for fire
alarm system integration) to implement security without comprising life safety code
standards. This requires close coordination and at times creative architectural and
security design solutions to implement the requirements of both safety and security.
Physical security system designs need to be coordinated with and comply with NFPA
101 and the Americans with Disabilities Act (ADA).
9-6
ELECTRICAL COORDINATION
9-6.1
Electrical issues that need to be considered include power, backup power,
grounding, bonding, lightning protection, cable type, electromagnetic interference,
tamper protection, voltage drop considerations, power reliability, harmonics, raceway,
labeling, shielding, fire alarm system interface, and lighting. These are discussed in the
following sections.
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