BS EN 54-23:2010 Fire Detection and Fire Alarm Systems - Part 23: Visual Alarm Devices (VAD) - Standard Requirements and Photometric Coordinate System Implementation

Effective light intensity is an important parameter for evaluating the optical characteristics of sound and light alarms (VAD, Visual Alarm Devices, also written as V.A.D). Therefore, it is necessary to measure the effective light intensity of these sound and light alarms to ensure they meet specifications. Sound and light alarms have instantaneous characteristics in the time domain, and their brief stimulation to the human eye has special visual effects. In a previous article: "Effective Light Intensity and Measurement of Flash Light Sources", we have described the overview of flash light sources, the definition of effective light intensity, calculation methods of effective light intensity, and the measurement of flash light sources. This article discusses standard requirements and how to implement effective light intensity and light distribution measurements in the photometric coordinate system based on the standard "BS EN 54-23:2010 Fire Detection and Fire Alarm Systems - Part 23: Fire Alarm Devices - Visual Alarm Devices".

(Video is for demonstration purposes only. Actual measurements must be performed in a darkroom without external light. This video demonstrates the effective light intensity and light distribution measurement process of sound and light alarms (VAD/V.A.D) to evaluate whether the coverage area meets EN 54-23 standard requirements.)

I. Standard Requirements:

1. Sound and Light Alarms (VAD/V.A.D) shall meet the coverage volume requirements of at least one of the following three categories:

According to EN 54-23 standard, sound and light alarms (VAD, Visual Alarm Devices, also written as V.A.D) need to meet coverage area and coverage volume requirements. The following are detailed regulations on coverage volume requirements for sound and light alarms in EN 54-23 standard (Screenshot from BS EN 54-23:2010 Fire Detection and Fire Alarm Systems - Part 23: Fire Alarm Devices (VAD) - Visual Alarm Devices, Page 13):

2. Variation of Light Output for Sound and Light Alarms:

EN 54-23 standard has strict requirements on light output variation of sound and light alarms to ensure stability of effective light intensity (Screenshot from BS EN 54-23:2010 Fire Detection and Fire Alarm Systems - Part 23: Fire Alarm Devices (VAD) - Visual Alarm Devices, Page 13):

3. Minimum and Maximum Effective Light Intensity for Sound and Light Alarms:

EN 54-23 standard clearly specifies the minimum and maximum effective light intensity requirements for sound and light alarms (VAD/V.A.D), which are key indicators for evaluating the performance of sound and light alarms (Screenshot from BS EN 54-23:2010 Fire Detection and Fire Alarm Systems - Part 23: Fire Alarm Devices (VAD) - Visual Alarm Devices, Page 13):

4. Light Color for Sound and Light Alarms:

EN 54-23 standard has clear regulations on light color of sound and light alarms to ensure visual alarm effects (Screenshot from BS EN 54-23:2010 Fire Detection and Fire Alarm Systems - Part 23: Fire Alarm Devices (VAD) - Visual Alarm Devices, Page 13):

5. Light Time Pattern and Flash Frequency for Sound and Light Alarms:

EN 54-23 standard specifies the light time pattern and flash frequency of sound and light alarms (VAD/V.A.D), which directly affect the measurement of effective light intensity and calculation of coverage area (Screenshot from BS EN 54-23:2010 Fire Detection and Fire Alarm Systems - Part 23: Fire Alarm Devices (VAD) - Visual Alarm Devices, Page 15):

II. How to Implement Effective Light Intensity and Light Distribution Measurements for Sound and Light Alarms in the Photometric Coordinate System?

1. Control Turntable Models: A-Plane Precision Angle Rotary Table (Figure 1) and C-Plane Precision Angle Rotary Table (Figure 2)

To accurately measure the effective light intensity and light distribution of sound and light alarms (VAD/V.A.D), precision angle rotary tables are needed to control measurement angles. The following are two commonly used turntable models:

2. Both precision angle rotary tables can achieve effective light intensity and light distribution measurements for sound and light alarms.

3. The difference between the two devices is that the A-plane precision angle rotary table meets the EN 54-23 standard pitch test requirements, while the C-plane precision angle rotary table achieves light distribution measurement of sound and light alarms through algorithm control.

4. Coordinate System Conversion Algorithm:

The conversion equations listed in Table A.1 of the national standard GB/T 39585-2020 "Photoelectric Measurement - Performance Requirements and Test Methods for Photometric Distribution Test Systems" can be used for coordinate conversion between different systems, and are effective when representing the orientation of the sound and light alarm axis in the coordinate system. Through the coordinate system conversion algorithm, the effective light intensity and light distribution of sound and light alarms at different angles can be accurately calculated, thereby determining the coverage area.

5. Simulation Diagram of Conversion from A-Plane to C-Plane

Through coordinate system conversion, measurement data from A-plane can be converted to C-plane light distribution data, thereby comprehensively evaluating the effective light distribution and coverage area of sound and light alarms (VAD/V.A.D):

6. After engineers install the sound and light alarm, the above process is automatically completed by YIMING test software. After the test is completed, a test report containing key parameters such as effective light intensity, light distribution, and coverage area is provided, and judgment results are given according to EN 54-23 standard requirements.