LISUN ZY-3 Needle Flame Test Apparatus: A Core Tool for Fire and Flammability Testing of Electrical and Combustible Materials

Abstract
Fire and flammability testing plays a critical role in ensuring the safety of electrical equipment and combustible materials, as small flames resulting from internal faults can trigger catastrophic fire hazards. The LISUN ZY-3 Needle Flame Test Apparatus is a specialized instrument designed to simulate such fault-induced small flames and evaluate ignition risks. This paper elaborates on the design principles, technical specifications, testing procedures, and application scenarios of the LISUN ZY-3, with a focus on its compliance with international standards. By analyzing its structural components and performance parameters, the paper demonstrates its significance in fire and flammability testing for lighting equipment, low-voltage electrical appliances, insulation materials, and other products. Practical test cases and data are presented to verify its reliability and accuracy, providing a reference for researchers and industry practitioners in material safety evaluation.

1. Introduction

1.1 Background of Fire and Flammability Testing

Electrical equipment and combustible materials are ubiquitous in industrial production and daily life, but their flammability poses inherent fire risks. Internal faults such as short circuits or overheating in electrical devices often generate small, localized flames that can ignite surrounding materials, leading to large-scale fires and casualties. Fire and flammability testing, as a key link in product safety certification, aims to simulate potential fire sources and assess the ignition resistance of materials and equipment, thereby preventing fire accidents from the source. Among various fire testing methods, the needle-flame test is widely recognized for its ability to replicate small fault flames, making it an essential part of safety evaluation systems for electrical and electronic products.

1.2 Overview of LISUN ZY-3 Needle Flame Test Apparatus

Developed by LISUN GROUP, the ZY-3 Needle Flame Test Apparatus is tailored to meet the rigorous requirements of fire and flammability testing for a wide range of products. It is primarily used for testing lighting equipment, low-voltage electrical appliances, household appliances, power tools, electronic instruments, and electronic meters. Additionally, it is suitable for evaluating insulation materials, engineering plastics, and solid flammable materials. The apparatus consists of three core components: a needle flame burner, a working chamber, and a temperature measuring device, which work together to simulate fault flames and accurately record test data. With compliance to international standards such as IEC 60695-2-2:2021 and IEC 62368-1:2023, the ZY-3 has been widely applied in industries worldwide for over a decade, establishing a reputation for reliability and precision.

2. Fundamental Principles of Needle Flame Test in Fire and Flammability Testing

The needle-flame test is a simulation-based fire and flammability testing method that evaluates the ignition hazard of small flames generated by equipment internal faults. The core principle involves using a needle-shaped burner of specified size to generate a stable small flame, which is applied to the test specimen at a fixed angle for a predetermined duration. The test assesses fire risk by monitoring three key indicators: whether the specimen and the underlying ignition pad ignite, the duration of combustion (including burning time and afterflame time), and the length of the flame.

For the LISUN ZY-3, the burner uses 95% butane (or propane) as fuel and has a diameter of 0.9mm, which is standardized to ensure consistency in flame size. During testing, the burner is oriented at 45° to the specimen surface, and the flame height is strictly controlled at 12mm±1mm—dimensions chosen to replicate the small, concentrated flames typical of electrical faults. The temperature measuring device, a Φ0.5mm K-type thermocouple, tracks the flame temperature, which must rise from 100℃±2℃ to 700℃±3℃ within 23.5 seconds±1s to meet standard requirements. This precise temperature profile ensures that the test flame accurately simulates real-world fault conditions, making the results of fire and flammability testing actionable for safety certification.

3. Technical Specifications and Structural Design of LISUN ZY-3

3.1 Core Structural Components

The LISUN ZY-3’s design is optimized for efficiency and accuracy in fire and flammability testing, with three integrated components:

• Needle Flame Burner: The heart of the apparatus, featuring a 0.9mm diameter needle-shaped nozzle. It can be adjusted to two angles: 45° for testing and 0° for flame height calibration, ensuring precise flame positioning relative to the specimen.
• Working Chamber: A enclosed space that isolates the test environment from external draughts, which could invalidate fire and flammability testing results. It is typically used with a ventilation system (mandatory for the compact ZY-3S model) to remove toxic fumes generated during testing, as specified in IEC 62368-1:2023 Annex S.
• Temperature Measuring Device: Equipped with a high-sensitivity K-type thermocouple (Φ0.5mm) that provides real-time temperature data with minimal error, supporting the critical temperature rise requirement for valid flame simulation.

ZY-3 Needle Flame Test

3.2 Detailed Technical Specifications

The performance parameters of the LISUN ZY-3 are aligned with international fire and flammability testing standards, ensuring consistency and comparability of test results. The following table summarizes its key specifications:

3.3 Compliance with International Standards

The ZY-3 is fully compliant with major international fire and flammability testing standards, which is essential for global product certification:

• IEC 60695-2-2:2021: Defines the needle-flame test method for assessing fire hazards from small fault flames in electrotechnical equipment and materials.
• IEC 60695-11-5:2016: Specifies the apparatus, confirmatory test arrangements, and guidance for needle-flame testing, including specimen preparation and flame application protocols.
• IEC 62368-1:2023: Applies to audio/video, information, and communication technology equipment, requiring needle-flame testing for fire enclosure and barrier materials (Annex S).

Notably, the ZY-3 can automatically execute multiple flame applications as required by IEC 62368-1:2023 Annex S.1, which mandates reapplication of the flame for 1 minute and 2 minutes if the initial 10-second application results in flaming durations ≤30s. This automation eliminates human error in sequential testing and ensures strict adherence to standard protocols.

4. Application Scenarios of LISUN ZY-3 in Fire and Flammability Testing

The versatility of the LISUN ZY-3 makes it indispensable for fire and flammability testing across multiple industries. Below are its primary application areas, with specific test requirements and objectives:

4.1 Electrical and Electronic Equipment

The ZY-3 is widely used for testing end products such as:

• Lighting Equipment: LED bulbs, fluorescent fixtures, and street lamps. The test evaluates whether internal faults (e.g., ballast overheating) can ignite the lamp’s plastic housing or insulation, preventing fire spread.
• Low-Voltage Electrical Appliances: Switches, sockets, and circuit breakers. Testing focuses on the flammability of contact materials and insulating components, ensuring they do not sustain combustion after exposure to fault flames.
• Household Appliances: Refrigerators, microwaves, and washing machines. The apparatus assesses the fire resistance of control panels and wiring insulation, critical for preventing fires in domestic environments.
• Power Tools & Electronic Instruments: Drills, oscilloscopes, and multimeters. Testing ensures that mechanical or electrical faults do not generate flames that ignite the tool’s casing or internal components.

For these products, the test typically follows IEC 62368-1:2023, with three specimens per test (each representing the thinnest significant wall thickness of enclosures/barriers). The goal is to confirm that flames do not propagate beyond the test area and that afterflame time does not exceed standard limits.

4.2 Insulating and Combustible Materials

The ZY-3 is equally effective for fire and flammability testing of raw materials and components:

• Insulation Materials: PVC insulation for wires, mica sheets, and ceramic insulators. Testing verifies that these materials do not ignite or sustain combustion when exposed to small flames, ensuring electrical system safety.
• Engineering Plastics: ABS, polypropylene (PP), and polycarbonate (PC) used in equipment casings. The test classifies their flammability (e.g., HB classification in horizontal testing) to guide material selection for high-risk applications.
• Solid Flammable Materials: Fiberglass composites and phenolic resins. Testing assesses their ignition resistance, which is critical for use in industrial machinery and building electrical systems.

For material testing, the ZY-3 adheres to IEC 60695-11-5:2016. For example, in horizontal HB classification testing, specimens are 125mm (length) × 13mm (width) × ≤13mm (thickness), clamped at one end, and exposed to a 30-second flame application. A metal mesh is placed 10mm below the specimen’s free end to detect dripping and flame propagation.

4.3 Compact Model (ZY-3S) for Specialized Needs
To address the cost and space constraints of overseas markets, LISUN developed the ZY-3S compact version, weighing less than 50kg. It retains all the core functions of the ZY-3 but requires an external ventilation system (provided by the customer) to handle toxic fumes. This model is ideal for small laboratories or manufacturers with limited space, ensuring access to high-quality fire and flammability testing regardless of facility size.

5. Practical Operation and Data Acquisition of LISUN ZY-3

5.1 Standard Testing Procedure

The operation of the ZY-3 follows a structured workflow to ensure consistency in fire and flammability testing:

Pre-Test Preparation:
• Calibrate the flame height to 12mm±1mm using the 0° burner angle.
• Verify the temperature rise performance: confirm the thermocouple detects a temperature increase from 100℃ to 700℃ within 23.5s±1s.
• Prepare specimens according to the target standard (e.g., three specimens of the thinnest enclosure section for IEC 62368-1).
• Activate the ventilation system to remove toxic fumes.

Parameter Setting:
• Use the touch screen or remote control to set test parameters: burning time (e.g., 10s, 30s), number of burns (single or multiple), and temperature thresholds.
• Save the program to ensure repeatability for batch testing.

Test Execution:
• Place the specimen in the working chamber and adjust the burner to 45°.
• Start the test; the apparatus automatically ignites the burner, applies the flame for the set duration, and retracts the burner.
• The thermocouple and timing sensors record real-time temperature, burning time, and afterflame time.

Post-Test Analysis:
• Check if the specimen or ignition pad ignited.
• Review recorded data (e.g., afterflame time ≤30s for compliance with IEC 62368-1).
• Generate a test report with parameters and results.

5.2 Data Acquisition and Analysis

The ZY-3’s integrated data system ensures accurate and reliable fire and flammability testing results. Key data points include:

• Burning Time: The duration the flame is applied to the specimen (adjustable from 0 to 999.9s).
• Afterflame Time: The time the specimen continues to burn after the test flame is removed (auto-recorded with ±0.1s accuracy).
• Temperature Data: Real-time tracking of flame temperature, including the critical 100℃ to 700℃ rise time.

For example, in testing a PC plastic enclosure for a microwave oven (per IEC 62368-1), the ZY-3 applies a 10-second flame. If the afterflame time is 12.3s (≤30s), the flame is reapplied for 1 minute. If the second afterflame time is 8.7s (≤30s), a final 2-minute application follows. The specimen passes if no ignition of the pad occurs and all afterflame times are within limits. This sequential testing aligns with Annex S.1 and provides a rigorous assessment of fire resistance.

6. Maintenance and After-Sales Support for Sustained Testing Reliability

The LISUN ZY-3’s longevity (over a decade in the market) is attributed to its robust design and comprehensive after-sales support, which are critical for consistent fire and flammability testing performance.

6.1 Routine Maintenance

• Burner Cleaning: Regularly remove residue from the 0.9mm nozzle to maintain flame stability.
• Thermocouple Calibration: Recalibrate the K-type thermocouple annually to ensure accurate temperature measurement.
• Gas System Inspection: Check for leaks in the butane supply line to prevent safety hazards and inconsistent flame output.
• Ventilation Maintenance: Ensure the working chamber’s ventilation (or external system for ZY-3S) is unobstructed to remove fumes and avoid draughts.

6.2 After-Sales Support

LISUN provides a dedicated FAQ page for the ZY-3 (linked at https://www.lisungroup.com/products/electrical-safety-tester/needle-flame-test.html), summarizing common issues and solutions (e.g., flame height calibration failures, thermocouple errors). The engineering team updates the page regularly, enabling users to troubleshoot independently. For complex issues, LISUN offers technical consultation to minimize downtime, ensuring uninterrupted fire and flammability testing operations.

7. Conclusion
Fire and flammability testing is a non-negotiable aspect of product safety, and the LISUN ZY-3 Needle Flame Test Apparatus stands as a leading tool in this field. Its compliance with international standards, versatile application range (from electrical equipment to combustible materials), and precise performance make it indispensable for manufacturers, laboratories, and certification bodies. The apparatus’s structural design—integrating a standardized needle flame burner, enclosed working chamber, and high-sensitivity temperature measuring device—ensures that small fault flames are accurately simulated, and test results are reliable.

Whether using the standard ZY-3 or the compact ZY-3S, users benefit from automated testing capabilities, user-friendly operation, and robust after-sales support. As fire safety regulations become increasingly stringent globally, the ZY-3 plays a vital role in helping products meet certification requirements and protecting lives and property from fire hazards. For future development, LISUN is likely to enhance the apparatus’s connectivity (e.g., cloud-based data management) to further streamline fire and flammability testing workflows, solidifying its position as a core tool in material and equipment safety evaluation.

References
IEC 60695-2-2:2021, Fire hazard testing – Part 2: Test methods – Section 2: Needle-flame test.
IEC 60695-11-5:2016, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method – Apparatus, confirmatory test arrangement and guidance.
IEC 62368-1:2023, Audio/video, information and communication technology equipment – Part 1: Safety requirements.