## Security Screening Requirements for Intruder Alarm Personnel

The integrity and trustworthiness of individuals working with security systems, especially intruder alarms, is paramount. BS 7858:2019 (Screening of individuals employed in a security environment) is the British Standard that sets out the requirements for the security screening of personnel in the UK security industry. Compliance with this standard is a mandatory requirement for companies approved by accreditation bodies like NSI (National Security Inspectorate) and SSAIB (Security Systems and Alarms Inspection Board). These bodies ensure that security companies meet high standards, including the rigorous vetting of staff.

## Purpose and Scope of BS 7858

The primary purpose of BS 7858 is to mitigate risks associated with personnel having access to sensitive information, customer premises, or security equipment. It aims to ensure that individuals are reliable, honest, and suitable for their roles, thereby protecting customers, their property, and the reputation of the security industry.

Who needs to be screened?

• All employees whose duties involve access to customers' premises, security equipment, sensitive information (e.g., alarm codes, system designs), or key holding responsibilities.
• This includes directors, managers, engineers, sales personnel, administrative staff, and subcontractors who meet the access criteria.
• The standard applies to both new hires and existing staff, with ongoing rescreening requirements.

## The Screening Process

BS 7858 mandates a comprehensive screening process covering several key areas:

• Identity Verification: Robust checks to confirm the individual's identity, including proof of current and previous addresses.
• Right to Work: Verification of the individual's legal right to work in the UK.
• Employment History: Verification of employment for the past 5 years (or 10 years for specific roles), including explanations for any significant gaps.
• Financial Checks: A basic credit check to identify any history of bankruptcy or insolvency, which could indicate financial vulnerability.
• Criminal Record Check: A Basic Disclosure and Barring Service (DBS) check (or equivalent for Scotland/NI) to reveal unspent convictions.
• Character References: Obtaining references from previous employers or reputable individuals who can attest to the applicant's character and reliability.
• Self-Declaration: A declaration regarding mental health, drug/alcohol use, and any unspent criminal convictions.

## Ongoing Requirements and Record Keeping

Screening is not a one-off process. Companies must:

• Maintain comprehensive records of all screening checks for the duration of employment and for a specified period after an employee leaves.
• Conduct rescreening at regular intervals (typically every 5-10 years, or if there's a significant change in role or circumstances).
• Have clear policies for managing adverse screening results and ensuring compliance.

Failure to comply with BS 7858 can lead to loss of accreditation, reputational damage, and potential legal or insurance implications.

## Relevant Standards for Security Systems (Intruder Alarms)

Understanding and applying relevant standards is fundamental for the design, installation, and maintenance of intruder alarm systems in the UK. These standards ensure system performance, reliability, safety, and facilitate appropriate police response and insurance acceptance.

BS EN 50131 Series: European Standard for Intruder Alarms

This is the core European standard for intruder alarm systems. It defines various aspects of system components and overall system performance. Key concepts include:

• Grades (1-4): These classify the level of security and resistance to attack.
• Grade 1: Low risk, simple systems (e.g., residential with low value items).
• Grade 2: Low to medium risk, common for residential and small commercial. Requires some resistance to basic attack.
• Grade 3: Medium to high risk, for commercial and high-value residential. Requires sophisticated attack resistance.
• Grade 4: High risk, for critical infrastructure or very high-value assets. Designed to withstand highly skilled intruders.
• Environmental Classes (I-IV): Define the environmental conditions a component can operate in (e.g., indoor, outdoor, harsh conditions).

PD 6662:2017: British Application of BS EN 50131

This Publicly Available Specification (PAS) is crucial for applying the BS EN 50131 series within the UK. It provides guidance on the selection, installation, and maintenance of intruder alarm systems to meet specific Grades. PD 6662:2017 details how to combine EN 50131 components and system requirements to achieve a compliant system for a given Grade. It's essential for installers to follow this for UK installations.

BS 8243:2017: Police Response to Alarms

This standard specifies the installation and configuration requirements for intruder alarm systems to enable an appropriate police response. It defines methods for alarm confirmation, which is critical for obtaining and maintaining a Unique Reference Number (URN) from the police. Systems must comply with BS 8243:2017 to qualify for a Level 1 or Level 2 police response. It works in conjunction with PD 6662:2017.

Certification Bodies and Police Policy

• NSI (National Security Inspectorate) & SSAIB (Security Systems and Alarms Inspection Board): These are the primary UK certification bodies. Approved installers (e.g., NSI NACOSS Gold/Silver, SSAIB Intruder Alarm) are audited to ensure their systems comply with BS EN 50131, PD 6662, and BS 8243. This compliance is often a requirement for insurance and police response.
• NPCC (National Police Chiefs' Council) Security Systems Policy: This policy outlines the police approach to responding to alarm activations, including the criteria for URNs and different response levels based on alarm confirmation.

Other Relevant Legislation

• Health & Safety at Work Act 1974 & Electricity at Work Regulations 1989: Ensure safe working practices and electrical safety during installation.
• Data Protection Act 2018 (GDPR): Relevant if the system involves recording personal data (e.g., integrated CCTV).

## Types of Security Systems (Intruder Alarms)

Intruder alarm systems are primarily categorised by their Grade (level of security) and their Monitoring Type (how alarms are communicated). Understanding these types is crucial for selecting and installing an appropriate system for a given risk, ensuring compliance with standards and client requirements.

System Grades (BS EN 50131 & PD 6662:2017)

The grading system defines the level of protection against intruders with varying degrees of knowledge and tools. Higher grades offer greater resilience against sophisticated attack methods.

• Grade 1 (Low Risk): Suitable for properties with a low risk of theft. Intruders are assumed to have little knowledge of alarm systems and use basic tools. Often basic "bells-only" systems.
• Grade 2 (Low to Medium Risk): For properties with a low to medium risk. Intruders are assumed to have some knowledge of alarm systems and use general tools. These systems often feature tamper protection and remote signalling capabilities.
• Grade 3 (Medium to High Risk): Designed for properties with a medium to high risk, protecting high-value assets or where intruders are expected to have considerable knowledge and a range of tools. Requires specific detection, robust tamper protection, and secure signalling.
• Grade 4 (High Risk): For properties with extremely high risk, such as military sites or banks, where intruders are highly sophisticated, well-resourced, and may attempt to compromise the system before entry. Requires advanced detection, multiple communication paths, and very high levels of resilience.

Monitoring Types

How an alarm activation is communicated determines the response, impacting the overall effectiveness of the security system.

• Bells-Only Systems: These systems activate a local audible alarm (siren) and/or visual alarm (strobe light) upon activation. They do not send signals to a remote location. Their effectiveness relies on neighbours or passers-by reacting to the alarm. They offer the lowest level of security and are typically Grade 1.
• Speech Dialler / GSM Dialler Systems: Upon activation, these systems automatically dial pre-programmed telephone numbers (landline or mobile) to deliver a recorded message or SMS. They notify keyholders directly but do not provide professional monitoring or automatic police response.
• Monitored Systems: These systems transmit alarm signals to an Alarm Receiving Centre (ARC). The ARC is a continuously staffed facility that processes alarm signals.
• Keyholder Monitoring: The ARC receives the alarm and contacts nominated keyholders (individuals authorised to attend the premises).
• Police Response: For systems meeting specific requirements (e.g., Grade 2 or 3, installed by an approved company, two confirmed activations, and a Unique Reference Number (URN) issued by the police), the ARC can directly request police attendance. This is governed by the NPCC (National Police Chiefs' Council) Security Systems Policy. Grade 4 systems almost always have police response.

## Siting of Security Detection Devices

Effective siting of security detection devices is fundamental to the performance of any intruder alarm system. The primary objective is to maximize the likelihood of detecting an intruder while simultaneously minimizing false alarms, which can lead to complacency and unnecessary call-outs.

Key Principles

• Layered Protection: Implement detection at various points: at the perimeter (doors, windows), within internal spaces (rooms), and for specific high-value assets (point protection).
• Coverage: Ensure each detector's specified coverage pattern fully protects its intended area without blind spots. Overlapping coverage is often preferred, especially for higher security grades.
• Environmental Immunity: Position detectors to avoid sources of interference that could trigger nuisance alarms. This is critical for system reliability.
• Compliance: All installations must adhere to relevant industry standards, primarily EN 50131 / PD 6662 in the UK, which defines Security Grades (Grade 1 to 4) and their respective requirements.

Passive Infrared (PIR) Detectors

These detect changes in infrared radiation (body heat).

• Avoid Heat Sources: Do not point PIRs directly at radiators, heaters, flues, ovens, or areas subject to rapid temperature fluctuations.
• Avoid Direct Sunlight: Direct sunlight can cause false alarms or desensitize the detector.
• Avoid Drafts: Air currents from open windows, vents, or air conditioning can create temperature changes that trigger PIRs.
• Avoid Moving Objects: Curtains, blinds, or foliage visible through windows can cause false activations.
• Mounting Height: Typically 2.1m to 2.4m for optimal volumetric coverage, but always follow manufacturer specifications.
• Pet Immunity: If required, ensure pets cannot enter the lower, insensitive zone of the detector's pattern.

Dual Technology (PIR & Microwave) Detectors

These combine PIR (heat) and Microwave (motion) detection; both must trigger simultaneously to generate an alarm, offering enhanced false alarm immunity.

• Microwave Component: Be aware that microwave signals can penetrate thin walls, potentially detecting movement in adjacent, unprotected areas. Avoid pointing at large metallic objects that can reflect microwave signals.
• Follow general PIR siting rules regarding heat sources and drafts.

Magnetic Contact Detectors

Detect the opening of doors or windows.

• Alignment: Ensure the magnet and reed switch are perfectly aligned when the door/window is closed.
• Gap: Maintain the manufacturer's specified maximum gap between the magnet and switch. Recessed contacts offer better aesthetics and tamper resistance.

Vibration & Glass Break Detectors

• Vibration Detectors: Mount directly onto the surface to be protected (e.g., walls, ceilings, safes). Sensitivity adjustment is crucial to detect forced entry without nuisance alarms.
• Glass Break Detectors:
• Acoustic: Requires a clear line of sight to the glass, within its specified range. Avoid areas with high ambient noise or echoes.
• Shock/Piezoceramic: Mount directly onto the glass pane.

General Siting Considerations

• Intruder Path: Strategically place detectors to intercept the most likely entry routes and paths an intruder would take *before* they can access valuables.
• Tamper Protection: Ensure detectors are installed to resist tampering or bypassing.
• Maintenance: Consider accessibility for future testing and servicing.
• System Grade: Higher security grades (e.g., Grade 3 and 4) demand more robust detection strategies, often requiring multiple, overlapping detection zones and advanced environmental immunity.

## Control Panel (CIE) Overview

• Definition: The Control and Indicating Equipment (CIE), commonly known as the control panel, is the central processing unit and brain of an intruder alarm system.
• Function: It receives signals from detectors, processes them according to programmed logic, activates alarm outputs (sounders, strobes), manages system status (armed/disarmed), and facilitates communication with users or monitoring stations.
• Compliance: All CIEs installed in the UK must conform to relevant standards, primarily the EN 50131 series for intruder alarm systems, and PD 6662 for UK specific requirements and grading.

## Key Components of a CIE

• Microprocessor: The central processing unit that executes the system's programmed logic and controls all functions.
• Memory: Stores critical data including configuration settings, user codes, and the event log (a chronological record of all system activities, crucial for diagnostics and auditing).
• Power Supply Unit (PSU): Converts mains electricity, charges the standby battery, and provides regulated DC power to all connected system components.
• Input Zones: Terminals where detectors (e.g., PIRs, door contacts, shock sensors) are connected. Each zone is configured for specific response types (e.g., entry/exit, immediate, 24-hour).
• Output Relays: Control external devices such as external sounders, strobe lights, and Alarm Receiving Centre (ARC) communicators.
• User Interface (Keypad): Allows users to arm/disarm the system, view status, and access programming menus. Typically features an LCD or LED display and tactile buttons, often with audible feedback.
• Communicator: Enables the system to send alarm signals and status updates to an ARC or directly to users (e.g., via SMS, app notifications). Common types include PSTN (telephone line), GSM (mobile network), and IP (internet protocol).

## Operational Features

• Arming Modes:
• Full Arm: All zones are active.
• Part Arm (Set/Unset): Specific zones (e.g., perimeter) are active while others (e.g., internal living areas) are bypassed, allowing occupants to remain inside.
• Night Arm: Similar to part arm, often used for setting perimeter zones overnight.
• Timers:
• Entry Delay: Time allowed to disarm the system after entering a protected area.
• Exit Delay: Time allowed to leave after arming the system.
• Alarm Duration: How long external sounders activate (typically limited by local regulations, e.g., 20 minutes in the UK).
• User Codes: Different access levels (e.g., master user, standard user, engineer code) for varying permissions.
• Tamper Protection: Circuits designed to detect unauthorized opening of the control panel enclosure or disconnection/cutting of system wiring.
• Fault Indication: Alerts for issues like mains failure, low battery, zone faults, or communication failures.

## Installation Considerations

• Location: The CIE should be installed in a secure, accessible location for users, away from environmental extremes (heat, moisture, direct sunlight), and ideally discreetly.
• Power: A dedicated fused spur from the consumer unit, protected against accidental disconnection, is typically required. Proper earthing of metal enclosures is essential for safety.
• Standby Battery: Must be correctly sized to provide power for the required duration during a mains failure (e.g., 12 or 24 hours, depending on system grade and standard requirements).
• Wiring: Use correct cable types, ensure segregation from mains wiring, and secure all terminations to prevent faults and tampering.

## Warning Devices and Signalling

Warning devices and signalling are crucial components of any intruder alarm system, designed to alert occupants, deter intruders, and notify relevant authorities or keyholders. Understanding their operation and regulatory requirements is essential for compliant and effective installations.

## Warning Devices

External Sounders: These are typically mounted on the exterior of a building, serving as a primary deterrent and to alert neighbours or passers-by. Key features include:

• Audible Duration: In the UK, the audible alarm from an external sounder is legally limited to a maximum of 20 minutes to prevent noise nuisance.
• Visual Indication: Often incorporate a strobe light or flashing LED to provide a visual alert, which remains active after the audible alarm ceases.
• Tamper Protection: Must be robustly protected against physical attack, removal, or interference.
• Power Supply: Often self-contained with a rechargeable battery backup to ensure operation during a mains power failure or deliberate power cut.
• Location: Installed at a height to prevent easy access and ensure maximum visibility and audibility.

Internal Sounders: Located within the protected premises, their primary purpose is to alert occupants to an intrusion and to disorient the intruder, potentially encouraging them to leave. They are typically loud and can be strategically placed for maximum effect.

## Signalling to an Alarm Receiving Centre (ARC)

Remote signalling involves transmitting alarm activation signals from the protected premises to a dedicated Alarm Receiving Centre (ARC). The ARC then verifies the alarm and contacts designated keyholders or the police, if appropriate.

• ARC Role: ARCs operate 24/7, monitoring alarm systems and acting as a central point for alarm verification and response coordination. For police response, the ARC requires a Unique Reference Number (URN) for the premises.
• Signalling Paths: Various technologies are used for transmitting signals:
• PSTN (Public Switched Telephone Network): Traditional landline dial-up.
• GSM/GPRS/3G/4G: Mobile cellular networks, offering wireless transmission.
• IP (Internet Protocol): Utilising broadband internet connections.
• Radio: Dedicated radio networks (e.g., BT Redcare Secure, CSL DualCom) for high-security, resilient signalling.
• Path Supervision (Polling): Signalling paths are constantly monitored (polled) by the ARC to ensure their integrity. Any fault or failure of the path is reported promptly.
• Dual-Path Signalling: For higher security grades (Grade 3 and 4), dual-path signalling is mandatory. This uses two independent communication paths (e.g., IP and GSM) to provide redundancy, ensuring that if one path fails, the other can still transmit signals. This significantly increases resilience against deliberate attack or accidental failure.
• Police Response: For police attendance, the alarm system typically needs to be installed and maintained by an approved company (NSI or SSAIB) and connected to an ARC with a URN. Most police forces require confirmed alarms (e.g., two separate detection devices activating) to dispatch officers, to reduce false alarms.

## Legal and Standards Compliance

All intruder alarm installations, including warning devices and signalling, must comply with relevant British and European standards, primarily the BS EN 50131 series and the associated UK implementation standard PD 6662. Additionally, police response policies are governed by the NPCC (National Police Chiefs' Council) security systems policy (formerly ACPO policy).

## Wiring for Intruder Alarm Systems

Effective wiring is fundamental to the reliability and compliance of intruder alarm systems. The choice of cable, installation methods, and termination techniques all contribute to system integrity and resistance to tampering or interference.

Cable Types and Selection

• Multi-core cables: Commonly used, typically 4, 6, or 8 cores. Cores are colour-coded for easy identification (e.g., red/black for power, yellow/blue for data/zones).
• Shielded cables: Essential in environments with high electromagnetic interference (EMI) to prevent false alarms or system disruption. The shield (foil or braid) must be correctly terminated, usually at one end, to an earth point.
• Cable Sizing: Must be adequate for the current draw and to minimise voltage drop, especially over long runs. Undersized cables can lead to device malfunction or battery drain.
• BS EN 50131: Specifies requirements for cable types, installation, and segregation from other services (e.g., mains power) to prevent interference and ensure safety.

Wiring Configurations

• End-Of-Line (EOL) Resistors: Used to supervise the integrity of a detection zone. A resistor is placed at the furthest point of the circuit (e.g., inside the detector). The alarm panel monitors the resistance, differentiating between an open circuit (cable cut), a short circuit (tamper), and an alarm condition (detector activated).
• Double Pole (DP) Wiring: Provides enhanced tamper protection by using two separate circuits for each detector – one for the alarm contact and one for the tamper switch. This offers better supervision than single-pole wiring.
• Fully Supervised Loop (FSL) Wiring: The most secure method, using two resistors at the EOL to provide multiple states (normal, alarm, tamper, short, open) for comprehensive supervision.
• Tamper Circuits: All detectors, junction boxes, and the control panel must have tamper switches. These are normally closed (NC) circuits that trigger an alarm if the cover is removed or the device is disturbed.

## Power Supplies for Intruder Alarm Systems

Reliable power is critical for continuous operation, even during mains failure. Intruder alarm systems require both a primary and a standby power source.

Primary Power Supply

• Mains Supply: Typically 230V AC, connected via a fused spur. This powers the control panel and charges the standby battery.
• Power Supply Unit (PSU): Converts the mains AC voltage to the required low DC voltage (e.g., 12V DC) for the system components. It also manages battery charging.

Standby Power Supply

• Rechargeable Battery: Usually a Sealed Lead-Acid (SLA) battery, providing power during a mains failure. The battery capacity (measured in Ampere-hours, Ah) must be sufficient to power the system for the required standby duration (e.g., 12 hours for Grade 2 systems, 60 hours for Grade 3/4) plus a specified alarm duration (e.g., 5 minutes).
• Battery Calculation: System current draw (mA) x Standby hours + Alarm current draw (mA) x Alarm hours. A safety margin is typically added.
• Charging Circuit: The PSU incorporates a charging circuit to maintain the battery at full capacity without overcharging.
• Fault Monitoring: The control panel continuously monitors the mains supply, battery voltage, and charging status, reporting faults such as mains failure or low battery.

Compliance

• BS EN 50131-1: Mandates specific requirements for power supply standby durations and fault monitoring to ensure system resilience.

## Commissioning Intruder Alarm Systems

Commissioning is the critical process of bringing a newly installed or significantly modified intruder alarm system into full operational service. Its primary purpose is to verify that the system functions precisely as designed, meets all relevant British and European standards (e.g., BS EN 50131 series, PD 6662:2017), and fulfills the client's specific requirements.

Key stages of commissioning include:

• Pre-commissioning checks: Verifying correct wiring, power supply, device placement, and overall installation quality.
• Functional testing: Thoroughly testing every component, including all detectors (PIRs, contacts, break glass), control panel, sounders (internal/external), keypads, and communication devices (e.g., to an Alarm Receiving Centre - ARC).
• System configuration: Confirming correct zone programming, timing settings (entry/exit delays), user codes, and system attributes like Grade and Environmental Class.
• Battery backup test: Ensuring standby batteries provide adequate power during a mains failure.
• Communication path testing: Verifying successful transmission of alarm signals and status updates to the ARC or designated recipients.
• Handover: Providing comprehensive user training to the client and issuing all required documentation.

A Commissioning Certificate is issued upon successful completion, confirming the system's compliance and operational status.

## Auditing Security Systems

Auditing involves an independent and systematic examination of an intruder alarm system and the company's procedures to ensure ongoing compliance with standards, contractual obligations, and best practices. Audits are crucial for maintaining the integrity and effectiveness of security systems and for certification bodies like NSI (National Security Inspectorate) and SSAIB (Security Systems and Alarms Inspection Board).

Types of audits include:

• Internal audits: Conducted by the installing company to monitor its own quality control and adherence to standards.
• External audits: Performed by independent certification bodies (NSI/SSAIB) to verify compliance, competence, and adherence to scheme requirements, leading to or maintaining accreditation.

Audits typically cover:

• System design, installation quality, and adherence to BS EN 50131 and PD 6662.
• Completeness and accuracy of all system documentation.
• Effectiveness of maintenance procedures and records.
• Company operational procedures, staff competence, and training.

## Essential Documentation

Accurate and comprehensive documentation is fundamental for any compliant intruder alarm system. It supports installation, commissioning, maintenance, and auditing processes. Key documents include:

• Risk Assessment: Determines the appropriate Grade of the system based on the perceived threat and risk.
• System Design Specification (SDS): Outlines the system's requirements, chosen equipment, and how it meets the risk assessment and standards.
• Installation Certificate: Confirms the system has been installed according to the SDS and relevant standards.
• Commissioning Certificate: Verifies the system has been fully tested and is operational.
• Logbook: A mandatory document for all compliant systems, recording all events, tests, maintenance, faults, and changes throughout the system's life. It must be kept on-site.
• User Manual/Operating Instructions: Provides the client with clear guidance on system operation.
• Maintenance Agreement: Details the agreed service schedule and responsibilities.

All documentation must be readily available and kept up-to-date.