VAD Fire Alarm Effective Intensity & Light Distribution Testing

GMS-2000S fully automatic VAD light-distribution testing of EN 54-23 coverage volume, also covering GB 26851, ISO 7240-23, UL 1638-2023 and UL 1971. This article defines coverage volume and the Annex A goniophotometric method.

GB 26851-2026 raises quantitative optical bars for fire light alarms: wall-mount effective luminous intensity from 10 cd, ceiling-mount from 5 cd, with installation-specific light distribution (wide horizontal vs 360°), flash about 1–2 Hz, pulse width ≤0.2 s, red/white colour. This article maps clauses to a two-track lab workflow—temporal I_eff metrology plus goniophotometric angular grids per applicable standards—and links LUX-200D-F, GMS-2000S and VAD test systems for reproducible compliance next to EN 54-23, ISO 7240-23 and UL 1638.

GB 26851-2026 replaces GB 26851-2011 from 1 September 2027. Optical compliance shifts from subjective visibility to quantitative effective luminous intensity I_eff with Annex A measurement: instantaneous illuminance E(t) at 3 m, time-constant integration to E_eff, conversion to I_eff (cd), averaged over flash cycles. Impacts design, type testing and engineering. Yiming Technology flash effective-intensity solution, VAD fire alarm goniophotometer system and LUX-200D-F flash illuminance meter support reproducible VAD photometry alongside EN 54-23 and related standards.

BS EN 54-23:2010 specifies requirements for Visual Alarm Devices (VAD) in fire detection and fire alarm systems. Key parameters: Effective light intensity (Ieff, unit: cd, minimum values vary by angle: typically 0.4 cd at 0°, 0.7 cd at ±45°, ensures visibility), light distribution (luminous intensity at various angles, C-γ or A-α photometric coordinate system), coverage area (illuminated area meeting minimum illuminance, typically 0.4 lux minimum). Photometric coordinate systems: C-γ system (C=azimuth angle 0-360°, γ=elevation angle 0-90°, used for most VAD), A-α system (A=azimuth angle, α=elevation angle, alternative system). Test requirements: Measurement distance (typically 3-5 meters), ambient conditions (temperature, voltage variations per EN 54-23), test angles (full sphere coverage, typically 5° or 10° intervals). Coverage calculation: Based on light distribution data, calculate illuminance at various points, determine area meeting minimum requirements. Standard compliance: EN 54-23:2010 (European standard), equivalent to BS EN 54-23:2010 (British standard). Test equipment: Goniophotometer for light distribution, effective intensity tester for flashing characteristics. Yiming Technology provides comprehensive VAD testing solutions per EN 54-23 requirements.

Sound and Light Alarms (Visual Alarm Devices, VAD) are essential components of fire alarm systems per EN 54 series standards, widely used in commercial, industrial, and residential buildings. CE certification requirements: EN 54-23 (Visual Alarm Devices, effective light intensity, light distribution, coverage area), EN 54-3 (Fire detection and alarm systems - Part 3: Fire alarm devices - Sounders), EN 54-4 (Fire detection and alarm systems - Part 4: Power supply equipment). EN 54-23 key requirements: Minimum effective light intensity (varies by angle, typically 0.4-0.7 cd minimum), light distribution coverage (ensures visibility in designated areas), photometric coordinate system (C-γ or A-α system), test conditions (ambient temperature, voltage variations). Compliance path: (1) Testing per EN 54-23 (effective intensity, light distribution, coverage), (2) Technical documentation (test reports, design drawings, component certificates), (3) EU Declaration of Conformity (DoC), (4) CE marking. Test equipment: Goniophotometer for light distribution measurement, effective intensity tester (LUX-200D-F) for flashing characteristics. Typical applications: Fire alarm systems, emergency evacuation systems, building safety systems. Yiming Technology provides comprehensive testing solutions for EN 54-23 CE certification.

ANSI/UL1638-2023 specifies requirements for Visual Signaling Appliances (VAD) in fire alarm and signaling systems. Key requirement: Minimum effective light intensity percentages at various angles relative to maximum intensity. Typical percentages: 0° (100% reference, maximum intensity), ±15° (≥50% minimum), ±30° (≥25% minimum), ±45° (≥12.5% minimum), ±60° (≥6.25% minimum), ±75° (≥3.125% minimum), ±90° (≥1.5625% minimum). Photometric coordinate system: C-γ system (C=azimuth 0-360°, γ=elevation 0-90°), standard for UL1638 testing. Test method: Goniophotometer measures luminous intensity distribution, effective intensity tester (LUX-200D-F) measures flashing characteristics, calculate effective intensity per Allard or Modified Allard method. Coverage requirements: Minimum illuminance 0.4 lux at specified distances, full 360° horizontal coverage, vertical coverage typically ±60°. Standard scope: UL1638-2023 applies to visual signaling appliances for fire alarm systems, emergency signaling, building evacuation systems. Test equipment: Goniophotometer for spatial distribution, high-speed photometer for effective intensity. Compliance: UL1638-2023 certification required for US market, equivalent to EN 54-23 for European market. Yiming Technology provides comprehensive UL1638-2023 testing solutions including goniophotometer and effective intensity measurement systems.

VAD fire alarm effective intensity and light distribution test system; GMS-2020A for VAD photometric performance; C-x-y/W-x-y coverage volume measurement; compliant with GB26851, ANSI/UL1638-2023, AS-ISO-7240.23-2014, BS EN 54-23-2010

Widely used for effective luminous intensity measurement of traffic warning lights, aviation obstacle lights, aircraft anti-collision lights, navigation lights; also for transient photometry of flares, signal flares, pulse LEDs, explosives and other pulse light sources