2.3.4.2
Other System Success Considerations
**************************************************************************
NOTE: Select the most restrictive choice(s) based
upon the degree of IDS annunciation granularity
required.
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a.
False alarm: An alarm which does not result from a valid
intrusion by personnel, vehicles, other moving objects, or
nuisances, but rather as a result of an internally generated
sensor or other system component noise. The false alarm rate
shall not exceed one per [30] [_____] days for each sensor zone.
b.
Nuisance alarm: May result from sources external to the system
which provide sensor stimuli similar to those of personnel,
vehicles, or moving objects, such as wildlife and natural
phenomena. Nuisance alarm rate is a function of sensor adjustment
and shall not exceed a rate of one alarm per [7] [_____] days for
each sensor zone for the initial 90 days after acceptance by the
Government. Nuisance alarm rate shall not exceed a rate of one
alarm per [30] [_____] days for each sensor zone thereafter.
c.
Reliability and Availability: Reliability for IDS shall be based
upon reliabilities of equipment used. Reliability requirements
shall be as contained in equipment specifications, and when
equipment is combined in particular configuration, shall provide a
system-level mean-time-between-failure (MTBF) that is consistent
with both the system-level availability requirement stated below
and specific requirements for each defined functional area.
Inherent availability required (Ai) is based on an assumption of
no planned system downtime for preventive maintenance and shall be
calculated as:
MTBF
_____________
Ai =
MTBF + MTTR
Where MTBF is the mean-time-between-failure of the system as defined by:
1
=
1
________
________
MTBF
j
(MTBF) j
Where (MTBF)j is the achieved mean-time-between-failure of each individual
piece of equipment used in the given system configuration as demonstrated
in the individual equipment reliability qualification test.MTBF for this
system shall be not less than [5000] [_____] hours. System shall be
capable of pinpointing failures within [20] [_____] minutes.
MTTR is the weighted average mean-time-to-repair of the system as defined
by:
(MTTR) j
MTTR = MTBF x
________
j
(MTBF) j
Where (MTTR)j is the achieved mean-time-to-repair of each individual piece
SECTION 13703N
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