Engineering Drafting for ELV Services: What Irish Projects Require

ELV (Extra Low Voltage) systems are the most drawing-intensive building services discipline in Ireland — and the one where drawing quality most directly determines compliance outcomes. A fire alarm drawing that fails to demonstrate IS 3218:2013 zone coverage will be rejected by Dublin Fire Brigade. A CCTV drawing that omits field-of-view analysis may fail the Garda evidential CCTV standard. A BMS schematic without a complete I/O points schedule cannot be commissioned. This guide covers the complete drawing requirements for every major ELV system on Irish projects — from statutory obligations to smart building integration.

What Are ELV Services? Defining the Scope

Extra Low Voltage systems are defined under IEC 60364 as systems operating below 50V AC or 120V DC. On Irish building projects, ELV typically encompasses:

• Fire detection & alarm (IS 3218:2013 — the Irish Standard)
• CCTV / IP surveillance systems
• Access control & intruder alarm
• Structured data cabling (ICT/IT networks)
• Building Management Systems (BMS / BAS)
• MATV / SMATV / IPTV distribution
• Public address & voice evacuation (PAVA)
• Nurse call & staff attack systems
• DALI / KNX smart lighting controls
• Audio visual & conference room systems

The regulatory framework is multi-layered: IS 3218 for fire alarm; ETCI Wiring Regulations (ET 101) for general ELV installation; Technical Guidance Documents (TGD B for fire, TGD E for sound) under the Building Regulations; BS 5839, BS EN 50133, EN 54 series for specific systems.

Fire Alarm Drawings — IS 3218:2013 Requirements

Fire alarm drawings for Irish projects serve two purposes: design documentation and regulatory submission. The Fire Safety Certificate (FSC) application to the local fire authority (Dublin Fire Brigade, Cork City Fire Service etc.) must demonstrate IS 3218 compliance through the submitted drawings.

Required fire alarm drawing types:

• Site plan: building location, hydrant positions, fire brigade access routes
• Floor plans (all floors): detection device positions, sounder/flasher positions, manual call points, zone boundaries — each device labelled with type code and address number
• Riser diagram: floor-by-floor schematic showing loop routing, panel locations and battery/PSU distribution
• Zone schedule: table listing each zone number, zone description, floor, area (m²), travel distance (m) to nearest detector
• Addressable loop wiring diagram: complete loop schematic showing device sequence, address numbers, end-of-line resistors, isolator positions
• Panel schematic: fire alarm control and indicating equipment (FACIE) wiring, power supply calculations, battery sizing, network connections

IS 3218 zone layout rules: maximum zone area 2,000m² (Category L/P systems), maximum travel distance to detector 30m from zone boundary, single staircase or lift shaft per zone, no zone to extend across more than two floors without a riser zone. These rules must be demonstrably met in the floor plan drawings.

CCTV and IP Surveillance Drawings

CCTV drawing requirements in Ireland are shaped by two overlapping frameworks: technical performance and data protection compliance. Since the Data Protection Commission (DPC) Ireland's CCTV guidance was updated in 2023, CCTV drawings are now reviewed by privacy counsel on enterprise Irish projects, not just by the security consultant.

Required CCTV drawing types:

• Camera location plan: all camera positions, types (dome, bullet, PTZ, fisheye), mounting heights
• Field of view (FOV) diagram: coverage footprints for each camera at the specified mounting height, resolution and lens — JVSG IP Video System Design Tool is the industry standard for FOV calculation on Irish projects
• Network topology diagram: IP network architecture, PoE switch locations, NVR/VMS server location, WAN/remote monitoring connections
• Cable schedule: camera-by-camera cable run reference, type (Cat6A, fibre), length, switch port assignment
• NVR/VMS rack layout: server rack elevation showing NVR, UPS, PoE switches, KVM

DPC GDPR requirement: A Data Protection Impact Assessment (DPIA) must be referenced in the CCTV drawing package for systems in public-facing areas. The drawing set should include a camera coverage map that demonstrates proportionality — no camera should capture more than the minimum area necessary for the stated purpose.

Access Control and Intruder Alarm Drawings

Access control installations in Ireland are regulated by the Private Security Authority (PSA). System designers and installers must hold the appropriate PSA licence category. The drawing package must support the PSA commissioning and inspection process:

• Door hardware schedule: every controlled door listed with door number, location, reader type, lock type, REX device, door controller reference
• Reader/controller location plan: floor plan showing reader positions, door controllers, electric strikes/maglocks, request-to-exit devices
• Panel wiring schematic: controller block diagram, power supply, input/output assignments, network connection
• Zone map (intruder alarm): detection zones per floor, panel location, keypad positions, sounder/strobe positions
• Integration drawing: access control → fire alarm inhibit interface; access control → BMS event logging interface

Structured Cabling and ICT Room Drawings

Structured cabling drawing requirements are governed by ISO/IEC 11801 (international) and the European adoption EN 50173. Irish data centre and enterprise office projects increasingly specify TIA-942 Annex compliance for the data centre cabling infrastructure.

• Floor plan with outlet positions: workstation outlets, conference room outlets, WAP positions — each outlet numbered and cross-referenced to patch panel schedule
• Patch panel schedule: port-by-port listing of all horizontal cabling — outlet ID, cable label, patch panel, port number, floor, room
• Rack elevation drawings: all IDF and MDF racks shown with equipment, patch panels, cable management — rack units assigned to each item
• Fibre run schedule: fibre backbone cables listed with fibre type (OS2 single-mode, OM4/OM5 multimode), core count, route, length, termination point
• Cabinet layout drawing: equipment floorplan showing server rack positions, cooling layout, cable trays

Future tech — OM5 wideband multimode fibre: Irish data centre operators are specifying OM5 fibre to support 40GbE and 100GbE shortwave WDM (SWDM) applications. Drawing annotation must specify OM5 (lime green jacket) clearly, distinguishing from OM4 (erika violet), as incorrect installation cannot be identified visually after installation.

BMS Schematics and Points Schedules

Building Management System documentation is the most complex ELV drawing type — it sits at the intersection of electrical, mechanical and IT engineering:

• Sequence of Operation (SoO) diagrams: control logic for each plant item — AHU, chiller, DOAS, VAV boxes, FCUs — showing sensor inputs, control outputs and setpoint logic
• Points schedule (I/O list): every monitoring and control point listed with signal type (DI, DO, AI, AO), description, BMS controller address, panel reference, associated plant item
• BMS controller layout: controller panel drawings showing I/O card configurations, power supply, network connections (BACnet/IP, Modbus, LON)
• Network architecture diagram: supervisory network topology — BMS server, operator workstations, IP network connections, gateway to LV switchboard (SCADA interface)

Coordinating ELV with BIM on Irish Projects

On ISO 19650 Irish NDP projects, ELV systems are modelled in Revit at LOD 300 alongside architectural, structural and MEP elements. The key coordination issue is ELV containment — cable trays, basket trays, trunking and conduit — which competes for ceiling and wall space with mechanical ductwork, pipework and structural steel.

• ELV containment is modelled in Revit as MEP Cable Tray and Conduit families
• Navisworks federated model clash detection isolates ELV containment clashes against HVAC, pipework and structure
• Clash reports are issued back to the ELV designer for routing revision — the CAD drawing is updated and the Revit model is revised accordingly
• IFC export from Revit ELV discipline model is published to the project CDE (ACC, Aconex) per ISO 19650 issue cycle

The Future of ELV Drafting — Smart Buildings and NIS2

The ELV drawing landscape is being reshaped by two converging trends: smart building convergence and cybersecurity documentation requirements.

Smart building convergence: Power over Ethernet (PoE) is replacing separate power circuits for ELV devices — cameras, access readers, VAV controllers and luminaires all on a single IP network. The drawing implication: combined data/power schedules replace separate cable schedules; VLAN segmentation drawings become part of the ELV package; QoS configuration tables are drawing deliverables alongside physical layouts.

NIS2 Directive (effective in Ireland 2024): The EU NIS2 Directive requires operators of essential services to implement and document cybersecurity measures. For Irish healthcare, utilities and financial sector clients, this now means the ELV/BMS drawing package must include network segmentation diagrams showing OT/IT separation, firewall rules documentation, and evidence of cybersecurity impact assessments for building systems that connect to operational technology networks. ASDV includes OT network architecture diagrams in BMS and CCTV/access control drawing packages for clients subject to NIS2.

ELV Drawing Package — Reference Table