without compromise associated with turning off portions or all of the
intrusion detection system. The criteria here are time of day, day of week,
and 8-day calendar (includes holidays scheduled as the eighth day).
5.3.4 Fail Safe/Fail Soft. If the communication lines between the
controller and the central processor are severed, then the default
parameters within the system are exercised. Two schemes are available to
address this problem. The first, "fail safe," prohibits access even if the
criteria of correct facility code is met. The fail soft scheme is also
referred to as degraded mode. Access is granted normally upon correct
facility code entry. A caution must be observed; few systems in the
degraded mode record access information for later transmission to the
computer when the communication line is restored.
5.3.5 Occupant Listing. These programs are software functions which
process entry information and permit the report by area of occupants,
maximum number or load of personnel, or enforcement of the "two-man" rule.
Specific reader configurations and entry and exit readers must be used in
conjunction with anti-passback on tailgate or piggyback prevention controls.
The controls must be utilized to assure accurate representation of the data
gathered in conjunction with access authorizations. The computer compiles
useful lists only if all entries and exits are indicated. The safety
aspects and the "two-man" security aspect can be controlled with this
manipulation of information. Evacuation plans and evacuation assurance can
be realized by this feature.
5.3.6 Anti-Passback. Exclusion of access or egress approval in the event
of two successive "in" or "out" access requests is anti-passback. This
exclusion prohibits the unauthorized use of a single card by two persons
until an exit read is accomplished. This avoids the event where one
individual obtains access and, while inside, "passes back" the access
credential. Tailgating or piggyback is a fault in automated access control
systems where two persons gain access with one card at the same time. A
single authorized card is used and approved, but two persons enter during
the door unlock time window. This problem is critical in sensitive
facilities, particularly if duress situations are a threat. The problem can
be addressed by an interlocking man-trap with visual guard assessment
equipment, the use of closed-circuit television assessment in addition to
access control at portals, or the lesser effective beam break and personnel
counting devices with appropriate alarm/delay features. The best solution,
though, would be the use of a rotary gate (turn-style) connected to the
access control system.
5.3.7 Security Enhancement. The standard features of the automated access
control system provide enhancement of security operations, particularly
where the equipment outperforms the human. This creates a more secure
environment since the human element is permitted to perform in the area
where greater efficiencies are achieved. Definitions of whom is permitted
access based upon the criteria of area, portal, time zone, holiday schedule,
loading, two-man rule areas, and the subsequent recording of the information
relative to utilization can be essential to the mission of security. The