Security gradesInstallations of intruder alarm systems are covered by PN-EN 50131-1:2009 defining system requirements and PN-EN 50130-5:2002 defining environmental requirements.
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Table 1. EN50131-1 defines four grades of intruder alarm systems: Grade 1 | for installations with a low risk | Grade 2 | for installations with a low or medium risk | Grade 3 | for installations with a medium or high risk | Grade 4 | for installations with a high risk |
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Due to type of the intruder, the system is protecting against, the following grades are specified:
Grade 1 – the intruder is expected to have some knowledge of how alarm systems work and possibly carry some basic tools to allow him to overcome a simple alarm system.Grade 2 – the intruder is expected to have basic knowledge of how alarm systems work and possibly carry a wide range of basic tools (e.g. multi-meter).Grade 3 – the intruder is expected to have good knowledge of how alarm systems work and possess a number of specialized tools to overcome the system.Grade 4 – the intruder not only have complete knowledge of how alarm systems work but also possess a number of specialized tools but also could be expected to plan a burglary in advance and deactivate the intruder alarm system to prevent detection.
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The requirements of Grade 1 should be met by all devices and installations for use in apartment buildings and single-family houses. Public buildings will be required to meet the requirements of Grade 2 and 3. The highest (Grade 4) is required for buildings containing very valuable items, including galleries, museums and banks.
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The grades are also related with a servicing frequency criterium of the installation and its power supply. Grade 1 installations require annual service visits, Grade 2 and 3 require semi-annual service visits or one on-site service visit and one remote service. Grade 4 installations require semi-annual on-site service visits.
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All standards anticipate use of an auxiliary power supply with the intruder alarm system. Two types of auxiliary power supply are defined:
type A: mains supply + rechargeable batteries,type B: mains supply + batteries.
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The table shows alarm standby time (in hours) required for the installed battery to meet standard requirements.
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Table 2. Alarm stand-by time (hours) | Grade 1 | Grade 2 | Grade 3 | Grade 4 | A type | 12 h | 12 h | 24 h | 24 h | B type | 24 h | 24 h | 120 h | 120 h |
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For wireless transmission, to protect the communication against hijacking, each transmitter in the system must be assigned an identification code. The number of codes available in the system is defined in the standard.
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Table 3. Available codes Security grade | Number of codes available in the devices | Grade 1 | 100 000 | Grade 2 | 1 000 000 | Grade 3 | 10 000 000 | Grade 4 | 100 000 000 |
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The requirements on detecting the wireless communication loss, which must be treated as a fault, are also strictly set. The table shows wireless communication monitoring periods.
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Table 4. Wireless communication monitoring periods Security grade | Devices indicating, controlling and transmitting alarms | Grade 1 | 240 minutes | Grade 2 | 120 minutes | Grade 3 | 100 s | Grade 4 | 10 s |
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