ANSI/UL1638-2023 Safety Standard for Visual Signaling Appliances for Fire Alarm and Signaling Systems - Standard Requirements and Photometric Coordinate System Implementation

Effective light intensity is an important parameter for evaluating the optical characteristics of flash light sources. Therefore, it is necessary to measure the effective light intensity of these lamps to ensure they meet specifications. Flash light sources 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 mainly analyzes the standard requirements for minimum effective light intensity percentages at various angles according to the "ANSI/UL1638-2023 Safety Standard for Visual Signaling Appliances for Fire Alarm and Signaling Systems" and how to implement measurements in the photometric coordinate system.

(Video is for demonstration purposes only. Actual measurements must be performed in a darkroom without external light.)

I. Standard Requirements for Minimum Effective Light Intensity Percentages at Various Angles?

1. Standard Requirements for Minimum Effective Light Intensity Percentages of Wall-Mounted Alarms

(Screenshot from ANSI/UL1638-2023 Safety Standard for Visual Signaling Appliances for Fire Alarm and Signaling Systems, Pages 44-46)

1) Horizontal Direction:

2) Vertical Direction:

2. Standard Requirements for Minimum Effective Light Intensity Percentages of Ceiling-Mounted Alarms

(Screenshot from ANSI/UL1638-2023 Safety Standard for Visual Signaling Appliances for Fire Alarm and Signaling Systems, Pages 46-47)

II. How to Implement 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)

2. Both precision angle rotary tables can achieve measurement.

3. The difference between the two devices is that the A-plane precision angle rotary table meets the standard pitch test requirements, while the C-plane precision angle rotary table achieves this 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 luminaire axis in the coordinate system.

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

6. After engineers install the luminaire, the above process is automatically completed by YIMING test software. After the test is completed, a test report is provided and judgment results are given.