SIST-TP CLC/TR 50469:2006

Overview

CLC/TR 50469:2005 - "Lightning protection systems - Symbols" is a CENELEC technical report that defines standard graphical symbols for lightning protection system (LPS) drawings. The report specifies simple, consistent symbols to be used on design and construction diagrams for air-termination systems, conductors, earth electrodes, bonding, surge protection devices (SPD) and structural components. It also gives guidance on legend use and colour conventions for coloured drawings (building: black; lightning protection: red; metal sheets: green; metal structure: blue).

Key topics and requirements

• Scope: Standardizes graphical symbols for presenting lightning protection systems in technical drawings and plans.
• Structure components: Symbols for building contours, roof heights, roof coverings (metallic/non‑metallic), chimneys (metallic/non‑metallic), poles, gutters, prefabricated concrete parts, insulating parts and hazard zones (flammable, explosive, radioactive).
• LPS parts: Symbols for air-termination rods/studs, horizontal conductors (exposed/hidden), earth/foundation electrodes (including vertical and accessible types), bonding conductors (flexible and rigid), conductor connections/terminations, test joints and surge protection devices.
• Symbol annotation: Many symbols include optional characters to indicate size, material, type and specific measurements (e.g., roof height in metres, distance from roof surface).
• Legend and documentation: All symbols must be simple and explained in a legend on the LPS design drawings. For isolated protection systems, drawings must indicate that isolation and list required separation distances (referencing IEC 62305-1 and IEC 62305-3).
• Colour coding: Recommended colour usage for clearer presentation in coloured diagrams to distinguish building elements and LPS components.

Practical applications

• Producing consistent, unambiguous LPS design drawings and installation plans.
• Communicating lightning protection details to architects, electrical contractors, structural engineers and safety assessors.
• Preparing as-built documentation and maintenance schematics for buildings and industrial installations.
• Integrating LPS layouts into permit, compliance and inspection reports where standardized symbols reduce misinterpretation.

Who uses this standard

• Lightning protection designers and consultants
• Electrical and structural engineers
• CAD/draughting technicians and BIM modelers
• Installation and maintenance contractors
• Safety managers, building owners and regulatory authorities

Related standards

• IEC 62305 series (risk management and design rules for lightning protection) - referenced for isolated protection systems and separation distances.
• CENELEC TC 81X publications - committee responsible for lightning protection guidance.

Keywords: lightning protection systems, LPS symbols, CLC/TR 50469, lightning protection drawings, surge protection device, earth electrode, bonding conductor, IEC 62305.