Part 4: Martin Kane and Geoff Tate of the SSAIB introduce the new European Standards or ENs (European Norms). This month: Continuing General Requirements
Welcome to the fourth instalment of European Standards (EN). To keep you all informed since last month's article, there has been no change to the date of withdrawal for conflicting BS standards. However a meeting of TC79 is planned for June of this year during which the issue will almost certainly be discussed and a meeting of the technical board, which has the authority to change the date, is scheduled for July. If the date changes during this series of articles we will update readers.

In this article we would like to complete the discussion on EN50131-1 General Requirements. This standard, a key document of the EN series, provides clear guidance on systems requirements.

Set out in this article is a precis of some of the main areas within the standards that may be of particular interest to you.

Event recording
The number of events that are required to be recorded at various grades are defined. In addition to the number of events it also specifies the number of days that the recorded event should be retained. This is to ensure that the log information retained is protected against accidental damage, deliberate deletion or alteration of events. When the log reaches its full capacity of retained information for the required time period, the oldest event is erased and the newest event is clocked on. In the event of a mains failure the memory retention is maintained to meet the specified time periods.

The requirements for event recording at the four grades and the time period of retention are:

  • Grade 1. This is optional. No recording of information is required.
  • Grade 2. 100 event memory capacity with 30 days retention.
  • Grade 3. 200 event memory capacity with 30 days retention.
  • Grade 4. 500 event memory capacity with 30 days retention.

The events which are required to be recorded at the various grades, of which there are 21, are defined in terms of whether they are optional or mandatory. However at grades 2, 3, and 4 in addition to the event being recorded, the time and date at which the event occurred is also required. The time (clock) has to be accurate to within 10 minutes per annum. Finally, the events which are recorded may be within the system components, e.g. (at the control unit), or at an alarm receiving centre.

Power supplies
There are several types of power supplies within EN50131-1 and there are varying time requirements for standby supplies depending on the type of power supply. Power supplies are classified by type; A, B and C.

  • Type A. This is a conventional type and typically in use today. It's a prime source and a rechargeable battery which is automatically recharged by the intruder alarm system.
  • Type B. Is a prime source and an alternative power source which is not replenished by the intruder alarm system.
  • Type C. A prime source which has a finite capacity. This is typically a battery, which is not recharged by the intruder alarm system.

Power supplies can be located either within system components, e.g. control unit, or in separate housings. When a type C power supply is used as the prime power source it has to be capable, whatever the grade of system, of powering the system in all the conditions of use, for example alarm condition, set condition, test conditions, transmission of information for a minimum duration period of 1 year.

In all intruder alarm systems, in case of failure of the prime power source the alternative power source has to be capable of powering the system for the following periods:

  • Type A. 12 hours at grade 1 & 2
    60 hours at grades 3 & 4*
  • Type B. 24 hours at grade 1 & 2
    120 hours at grades 3 & 4*
  • Type C. 720 hours at grade 1 & 2
    720 hours at grades 3 & 4*
* However, as a national forward in EN 50131-6 the requirement of that standard for stand by periods maybe adopted in the UK.

Although the power supply requirements are quite stringent in grades 3 and 4, systems which are able to transmit the status of the power supply to an alarm receiving centre or alternative centre, can halve the standby power supply requirement. For example, a type A standby power supply for grade 3 and 4 can be halved to 30 hours. If a supplementary prime power source with automatic change over between the prime power source and the supplementary prime power source is used on a grade 2, 3 or 4 system, the required period for alternative power source, to power the system, can be reduced to 4 hours.

In all systems an indication is required when the voltage available from the alternative power source falls below the level required for the system to operate correctly.

Finally for this article and to complete the short tour of EN50131-1 we'll finish with documentation:

Documentation
The EN standards require that the documentation for the intruder alarm system is clear, concise, complete and unambiguous. Information has to be sufficient to install, operate and maintain systems.

Information relating to the operation of the system should be structured for ease of operation and reflect the access level of the user. As you know from the previous articles, this will take in to account, users, service personnel and manufacturers.

Documentation relating to system components also needs to be concise. It should ensure the implementation of the correct installation and the maintenance of the system components together with the integration of the other system components. Component documentation will consist of:

  • Name of manufacture or supplier
  • Description of equipment
  • Standard to which component claims compliance
  • Name or mark of the certification body. (If certified).
  • Environmental class.

Marking/Identification
All components are required to be clearly marked. Where space is limited on a component e.g. a door contact, codes can be used. When insufficient space is available for codes the component has to include cross-reference to documentation providing the required information.

The information required for system components are:

  • Name or manufacturer or supplier
  • Type
  • Date of manufacture or batch number or serial number
  • Security grade
  • Environmental class.

Once again we have covered a lot of ground in this article but hope it has been useful to you and we look forward to producing the next instalment. In the meantime we expect that the debate and speculation over the date of withdrawal will continue, however we will update you all in next month's issue if any changes occur.

Source

Security Installer