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Welcome to the fifth instalment of European Standards (EN). Notwithstanding the concerns expressed by the BSI committee responsible for electronic security systems over the withdrawal of British Standards conflicting with BS EN 50131-1: 1997, the date of withdrawal remains 1 September 2003.

The BSI are bound to comply with regulations associated with the publication of European Norms and is preparing to withdraw standards conflicting with BS EN 50131-1: 1997 and at the same time prepare a revised version of PD 6662: 2000 which will allow intruder alarm systems, complying with the requirements of BS EN 50131-1: 1997, as specified in PD 6662, to be published after 1 September.

Discussions have also been held between the security industry, the ABI and the inspectorates to provide a "dual running" period during which systems could be installed in accordance with existing British standards or as specified in PD 6662.

Set out in this article are some of the contents of part 7 of the EN 50131-1 series of standards.

Alarm system
TS 50131-7 Application Guidelines for intruder alarm systems, includes recommendations relating to the design, installation, operation and maintenance of intruder alarm systems similar to those given in BS 4737 Part 4.

It basically aims to ensure that systems perform and operate correctly with the twin objective of fulfilling its function as an intruder alarm system while minimising false alarms. The document is set out in seven main clauses:

System design

• Installation planning
  
• System installation
  
• Inspection, test, commissioning and acceptance
  
• Documentation and records
  
• Operation
  
• Maintenance and repair

The Application Guidelines provide guidance to assist people who are responsible for intruder alarm surveys and installations in terms of the extent of supervision required, the grade of the system and selection of equipment. Therefore this article is appropriate for Installers and surveyors.

Guidelines
The main processes in the application guidelines operate in the following ways:
System Design:

• Location survey risk
  
• Location survey of other influences
  
• From the above it produces a "System Design proposal".

Installation Planning:

• Pre-installation survey
  
• Amended system design proposal
  
• From this it provides the "Installation Plan".

Intruder Alarm Installation:

• Installation process
  
• Inspection test and commissioning
  
• Finally producing the "As Fitted Document".

The "As Fitted Document" will be an accurate record of the installed system and will include information relating to the installed equipment and its location. In large complex systems the document should also include types of cables installed and their routing. This document should also be made available to maintenance and service personnel.

System Design Proposal
Unlike the system specification which we have at present, we will now be required to produce a system proposal.

The system proposal will consist of:

• Grade of the system, and grade of any subsystem
  
• The environmental class of all components
  
• Schedule of equipment. Depending on the complexity of the system this may require a sketch of the location and type of equipment and the expected coverage of detectors.
  
• System configuration. This will detail how the system is configured in terms of its programming, e.g. circuit types, entry route detectors etc.

Part 7 requires equipment to be installed and maintained in accordance with manufacturers' recommendations and in environmental conditions in which it is expected to operate.

The standard also requires the person responsible for any of the following to hold an appropriate qualification:

• Risk assessment and design
  
• Installation
  
• Maintenance
  
• Repair of systems

This typically means that surveyors, installers and service personnel will have to prove competency, e.g. hold a relevant qualification. However details of how competency will be reached or when they will be required have not been agreed. Any such scheme will need to provide a method for existing installers to gain the qualification, if that is what is required. Addressing this requirement may take several years and the required infrastructure must be in place to provide access to any such qualifications with adequate time to obtain them.

System Design
The system design stage will be to establish the extent of the intruder alarm system and suitable grades of system components. A risk survey is also required which determines the grade of system. You may recall from previous articles that the Risk Analysis is one of the most significant changes to the way in which surveyors will be expected to approach the design of the system.

Siting of Equipment
Control indicating equipment (CIE) is required to be sited within the supervised area, (this really isn't any different to BS4737, which asks for CIE to be sited within the protected area). If systems are divided into subsystems of various grades the CIE needs to be located in the highest graded subsystem. You will also need to take into account the location of ancillary control equipment (ACE).

The considerations are:

• Location and ease of operation
  
• Siting to prevent observation of operation of a keypad (if used) unless shielded or scrambled

Consideration of environmental conditions if mounted externally.

When siting Alarm Transmission Equipment (ATE) it should be located as above but you must also take into consideration:

• Concealing wiring where practicable
  
• Causes that might prevent transmission of an alarm signal such as; PABX switchboards, incoming calls and disconnection of plug in transmission lines
  
• Monitoring of the dial tone
  
• Lightning protection devices
  
• ATE installed in supervised premises in discrete locations

Siting of warning devices are to be located in positions which are not readily accessible.

Interconnections
There is no restriction on the interconnection of components. It can be by cable, wireless or any other method providing it can provide the required monitoring for the appropriate grade of system.

When specific wired interconnections are used the main factors that must be taken into consideration are:

• Size and type of cable
  
• Concealment of cable. Cable to be kept inside supervised premises whenever possible. Where cables are outside of the supervised premises/area appropriate level of tamper protection is required
  
• Voltage drop
  
• Application of current IEE regulations
  
• Mechanically secure, and mechanical damage, if less than 2 meters above floor level
  
• Tamper considerations for cable and junction boxes, dependent on grade of system
  
• Jointing methods and Junction boxes
  Crimping and soldering must only be used when junction boxes are impractical
  
• Flexible door loops must be used where necessary.

Non-specific wiring connections are also employed within the standards. They must take into account the factor for specific wired interconnection but also consider:

• Effects of other signals using common wiring
  
• Faults on the common wiring that may affect operation of the intruder alarm system
  
• Effect of modifications to the other systems sharing the common wiring

Finally there are wireless interconnections. Factors which should be considered for these connections are:

Siting of the antennae


• RFI interference
  
• Objects blocking signal communication paths.

This is a very short pr茅cis of some of the sections within the TS 50131-7 standard. In the next article we will consider minimum levels of supervision for the grade of system. We will also update you on documents in the European series currently at a late stage of development, including PD 6662: 2000, which is being revised.