Appendix 7 – Intruder Sensor Selection
Types of Sensor - Advantages and Disadvantages
PIDS (Perimeter Intruder Detection System) – Fence mounted
Advantages
Will give the earliest notification of somebody scaling a fence.
Disadvantages
Not normally practicable for a cultural setting.
Expensive with limited cost benefit, especially if no immediate response is available.
Ongoing maintenance costs
PIDS (Perimeter Intruder Detection System) – Buried
Advantages
Will give the early notification of somebody walking over an area.
Discreet
Disadvantages
Not normally practicable for a cultural setting.
Expensive with limited cost benefit, especially if no immediate response is available.
Ongoing maintenance costs and difficulties if faults or damaged.
Prone to false activations especially if cattle are in the area.
PIDS - Microwave Beams
Advantages
Effective in most weather types
Effective up to 200 metres
More effective than IR beams
Disadvantages
Expensive
Hard-wired power is required.
Vegetation can still create false alarms
PIDS - Infrared
Advantages
Less expensive than microwave
Disadvantages
Still expensive with a questionable cost/benefit.
Impacted by weather
Precise installation/alignment needed
Prone to false alarms caused by animals and vegetation
Motion sensor with light combination
Advantages
Low costs
Provides a clear illumination of an area
Can be powered from inside a property
Disadvantages
False alarms
Not normally linked to an IDS and therefore passive
Door/window contacts
Advantages
Discreet
Effective if a door/window is opened.
Cheap
Good as an initial notification
Can be hard-wired or wireless[1]
Disadvantages
Can be damaged and/or cables removed
Potential to bypass.
Vibration/shock sensors
Advantages
Can provide an initial notification of a forced entry attack.
Can be used on/in display cases
Cost effective
Versatile
Can be used on doors to provide a confirmed alarm
Very effective when fastened to walls of secure storage facilities.
Disadvantages
No suitable when the public has direct access to the outside (windows) due to false alarms
Has a range of 2.5 metres sq. and then additional sensors need to be added.
Acoustic (break glass)
Advantages
Discreet
Can provide the initial notification of windows/glass being broken.
Cost effective
Disadvantages
Only works with glass
Not very versatile
PIR (motion sensors)
Advantages
Wide choice
Cost-effective
Good for spatial coverage
Discreet
Anti-masking capabilities
An ability to undertake a walk test to confirm if working.
Disadvantages
Can be accidentally obscured thereby reducing effectiveness
Dualtech sensors
Advantages
Less prone to false alarms
Good for spatial coverage
Wide choice
Cost effective
Good for spatial coverage
Discreet
Anti-masking capabilities
An ability to undertake a walk test to confirm if working.
Disadvantages
Slight cost increase over standard PIR sensors.
[1] Wireless sensors are only acceptable to Grade 2 systems and therefore would not be appropriate for the standard requirements of Grade 3 and Grade 4 (DP3/4) signalling.