VAD Fire Alarm Visual Alert Device Goniophotometer

The LSG-1930 VAD Fire Visual Alarm Distributed Photometer | Fire Alarm Photometric Testing System is specifically developed for fire visual alarm devices (VADs). It can perform a full range of photometric tests, including flash frequency, flash duration, effective luminous intensity, spatial light distribution, light output drift, and consistency. It outputs complete test data such as C-x-y/W-x-y coverage volume, effective luminous intensity in each direction, light output timing variation, and maximum/minimum effective luminous intensity. It automatically compares the data with standard limits to determine pass/fail results. It is widely used in the research and development, type testing, and factory testing of fire audible and visual alarms and visual alarm signal devices.

1 Standards:

System Configuration List (LSG-1930 includes all the following devices and accessories):

2 Laboratory Environment Requirements:

• Darkroom: Recommended dimensions ≥ 3m(H) * 4m(W) * 6m(L), customizable according to the sample being tested and available space; used to house the rotary table and photometric probe; walls and ceiling painted with matte black paint, floor covered with high-absorption black carpet; ambient stray light ≤ 0.2lx; test optical path distance not less than 3 meters; ambient temperature controllable to meet standard testing conditions.
• Control Room: Recommended dimensions ≥ 2.5m(H) * 3m(W) * 4m(L), used to house the control cabinet, computer, and printer peripherals.

3 Main Standard Technical Judgment Requirements:

GB 26851-2026 Fire Alarm and/or Light Alarm
• Flashing Frequency: 1Hz～2Hz
• Flashing Duration: ≤0.2s
• Effective Luminous Intensity: Wall-mounted ≥10cd; Ceiling-mounted ≥5cd
• Effective Luminous Intensity of VAD in Any Direction: 1cd ~ 500cd, and not lower than the manufacturer’s nominal value for that direction|
• Wall-mounted: Effective luminous intensity in the horizontal 75° direction ≥30% of the nominal value directly in front; Effective luminous intensity in the vertical 45° direction ≥34% of the nominal value directly in front
• Ceiling-mounted: Effective luminous intensity in 8 directions at 75° angles ≥3cd, and ≥30% of the nominal value directly in front
• Luminous Intensity Consistency: Maximum / Minimum ≤1.5

EN 54-23:2010 / ISO 7240-23:2013 Visual Alarm Devices (See EN 54-23:2010 Test Report)
• Light Output Stability: After sample preheating for 30 min, the effective luminous intensity change within 30 min is <25%; record the effective luminous intensity at 1 min, 10 min, 20 min, and 30 min respectively; Pmax / Pmin ≤1.33 is acceptable.
• Light Intensity Distribution: 70% of measurement points have an effective luminous intensity ≥1 cd; the total luminous intensity at all measurement points does not exceed 500 cd.
• Flash Parameters: Flash frequency 0.5 Hz～2 Hz; flash duration ≤0.2 s
• Tests are conducted in three ranges according to the product’s nominal effective distance: <10m, 10m～17m, >17m, to complete the coverage characteristic evaluation.

ANSI/UL 1638:2023 (See UL 1638:2023 test report)
• Effective luminous intensity of VAD in any direction: 15cd ~ 1000cd
• Flash frequency: 1Hz～2Hz
• Flash duration: ≤200ms
• Supports equivalent correction of light output based on a 20ms pulse width
• Completes minimum percentage testing and judgment of horizontal and vertical dispersion

4 Core Component Technical Specifications:

4.1 Photometer Main Unit

4.2 Flash Light Source Illuminance Meter: Specifically developed for photometric measurement of flash and pulse transient light sources; suitable for testing pulse light sources such as fire alarms, traffic warning lights, aviation obstruction lights, and pulsed LEDs.

Technical Features:
• High-speed 16-bit A/D acquisition, maximum sampling rate of 1MS/s, capable of recording 20 million sampling points;
• High-performance microprocessor with strong anti-interference capability;
• V(λ) human visual function matching, meeting Class A photometer requirements;
• Adaptable to any flash waveform, not limited to square waves; supports pulse train flash measurement;
• Threshold-triggered testing, supports background light subtraction;
• Built-in 4 effective light intensity algorithms: Blondel Rey Douglas, Form Factor, Allard, and Modified Allard.

Specifications: