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This standard is one of the key documents of the EN series and provides clear guidance on systems requirements.

System components
For an installation to be defined as a system The EN standards requires that a system must include the following components:

• Control and indicating equipment
  
• One or more detectors
  
• One or more warning devices and or alarm transmission system
  
• One or more power supplies combined with other system components or housed separately.
  
• All system components must be classified according to their environmental capability and graded relative to their performance.
  
• Components of other applications may be integrated with a system providing the performance of the system components are not adversely influenced.

Security Grading
In the last article we discovered that there were four grades of system within the new European Standards:

Grade 1 low risk
Grade 2 low to medium risk
Grade 3 medium to high risk
Grade 4 high risk

Grade 1 is the basic grade and grade 4 the highest risk. The grading of the system determines the performance of the following:

• Authorisation
  
• Access levels
  
• Operations
  
• Processing
  
• Detection
  
• Notification
  
• Power supply
  
• Tamper security
  
• Monitoring of interconnections
  
• Event recording

When an intruder alarm system is divided into sub-systems, systems may include components of varying grades within each sub system. When this happens the grade of the sub-system is that of the grade of the lowest component within the system. This means that the grade of the intruder alarm system is that of the lowest graded sub-system. If a situation exists where components are shared by more than one sub-system then the overall grade of the system will be that of the highest sub-system grade.

Examples of components shared by sub-systems may be:

Environmental Classes
A further inclusion in European Standards (as we noted in the last article) is that components that are used for the intruder alarm system will be classified, and this will determine where they are installed.

There are four classifications of components that specify their environmental performance:

Class 1 indoors controlled temperature
Class 2 indoors uncontrolled temperature
Class 3 outdoors sheltered
Class 4 outdoors exposed

Operating requirements
Access Levels
Access levels are the varying levels that allow diff-erent users access to various functions of a system.

The four access levels that define who has access to operate the system are:

• Access Level 1. Anyone has access at this level. This may seem strange, but this is because no user code is required. As an example, if the keypad for the system has indication of time and date displayed or mains indication, anyone can have access to this.

• Access Level 2. This is the normal user codes which we are familiar with. Of course manufacturers will still provide the normal master, manager levels etc.

• Access Level 3. This will be the Installer/service code. As with some current panels on the market a level 2 user (Customer) code will be required to authorise the logging on of a level 3.

• Access level 4. This access level is a code for the manufacturer to make changes to software and not for programming the parameters of the system.

Notification
In addition to the four grades of system that determine levels of risk, alarm signalling and sounders, which in European Standards are defined as Notification, are specified once the grade of system has been determined.

For the following grades of system the types of Notification that will be required for each grade are:

• Grade 1 two warning devices, or one self-powered warning device, or one signalling system with 24 hour reporting.

• Grade 2 two warning devices and one signalling system with 24 hour reporting, or one self-powered warning device and one signalling system with 24 hour reporting, or one signalling system with 3 minutes reporting plus encryption.

• Grade 3 two warning devices and one signalling system with 5 hour reporting, or one self-powered warning device and one signalling system with 5 hour reporting, or two signalling system with 5 hour reporting, or one signalling system with 3 minute reporting.

All signalling systems require encryption.

• Grade 4 two warning devices and one signalling system with 3 minute reporting, or one self-powered warning device and one signalling system with 3 minute reporting, or two signalling system with 3 minute and 5 hour reporting.

Event Recording
The General Requirements also specify the number of events which a control units log should record and for how long the events are to be retained.

For the varying grades here are the number of events required and the retention time:

• Grade 1 event recording is optional
  
• Grade 2 one hundred events with a thirty day retention
  
• Grade 3 two hundred events with a thirty day retention
  
• Grade 4 five hundred events with a thirty day retention

Power supply requirements
Power supply requirements in the European Standards are considerably more stringent than those currently required by British Standards 4737 which states that a system must have an 8-hour standby capacity on the failure of mains supply. European Standards require that a 1A PSU must be capable of providing 1A continuously whilst at the same time recharging a flat battery when the mains voltage is reduced by 10per cent.

The requirements for the various grades are:

• Grade 1 & 2 12 hours standby capacity
  
• Grades 3 & 4 60 hours standby capacity

Although grades 3 and 4 are sixty hours this may be reduced by half if the system signals mains failure to an alarm receiving centre (ARC).