Vertical combustion testing service

Vertical Combustion Testing Service – Comprehensive Flame Retardancy and Fire Safety Evaluation for Plastics, Textiles, Electrical Components and Building Materials

As an ISO/IEC 17025 accredited independent testing laboratory, we offer specialised vertical combustion testing services to manufacturers, quality assurance teams, and regulatory authorities across the electrical and electronics, automotive, aerospace, construction, textile, and consumer goods sectors. Vertical combustion testing is a fundamental method for evaluating the flame retardancy and fire safety performance of materials – measuring the afterflame time, afterglow time, flame propagation rate, and dripping behaviour of vertically oriented test specimens under controlled flame exposure. These test results are critical for material selection, product certification, regulatory compliance, and ensuring the safety of end‑users. Our test protocols are executed in accordance with UL 94 (Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances), IEC 60695‑11‑10 (Fire hazard testing – Test flames – 50 W horizontal and vertical flame test methods), ASTM D3801 (Standard Test Method for Measuring the Comparative Burning Characteristics of Solid Plastics in a Vertical Position), ISO 3795 (Road vehicles – Textiles – Determination of flammability), GB/T 2408 (Plastics – Determination of burning characteristics – Horizontal and vertical test), and GB/T 8332 (Test method for flammability of cellular plastics – Vertical burning method). Our inspection and test reports are recognised by the National Medical Products Administration (NMPA), the State Administration for Market Regulation (SAMR), the Ministry of Industry and Information Technology (MIIT), and international certification bodies for product registration, type approval, and quality assurance.

Materials and Products We Regularly Test

Our vertical combustion test facilities accommodate a wide range of materials and finished products. Typical test articles include:

Plastics and polymer materials – thermoplastics (ABS, PC, PA, PP, PE, PS), thermosets (epoxy, phenolic, polyurethane), and engineering plastics for electrical enclosures, automotive components, and consumer goods
Electrical and electronic components – housings, connectors, switches, circuit breakers, and insulating materials for appliances and industrial equipment
Textiles and upholstery fabrics – curtain fabrics, furniture coverings, automotive interior textiles, and protective clothing materials
Wiring and cables – cable insulation, jacketing materials, and wire harnesses
Building and construction materials – insulation foams, wall panels, roofing membranes, and acoustic materials
Foams and cellular materials – polyurethane, polystyrene, and polyethylene foams for cushioning and insulation applications
Composite materials – glass fibre and carbon fibre reinforced composites for automotive, aerospace, and marine applications
Personal protective equipment (PPE) – flame‑retardant coveralls, welding aprons, firefighter gloves, and balaclava hoods

UL 94 Vertical Burning Test – V‑0, V‑1, V‑2 Classification

Test specimen preparation – standard bar specimens (125 mm × 13 mm × thickness) – We prepare specimens from the supplied material, conditioned at 23 °C and 50 % RH for 48 hours (or as specified by the standard). The thickness of the specimen is determined by the application (typically 0.8 mm, 1.6 mm, or 3.2 mm) and is measured and recorded. The specimens are marked with reference lines at 25 mm and 100 mm from the bottom end.
Test procedure – two 10‑second flame applications – We mount the specimen vertically in a test cabinet, with the lower end clamped and the upper end free. A calibrated gas flame (20 mm high, 50 W heat input) is applied to the bottom of the specimen for 10 seconds. The flame is then removed, and we record the afterflame time (t1) – the time that the specimen continues to burn after the first flame application. As soon as the specimen stops burning, we immediately apply a second 10‑second flame application and record the afterflame time (t2) and the afterglow time (t3). We also observe whether flaming drips fall from the specimen and whether they ignite the cotton indicator placed below the specimen.
Classification criteria – V‑0, V‑1, and V‑2 ratings – Based on the recorded times and the dripping behaviour, we assign a UL 94 V‑rating:
- V‑0 – afterflame time (t1 or t2) ≤ 10 seconds for each individual specimen, total afterflame time for all five specimens ≤ 50 seconds, afterflame plus afterglow time (t2 + t3) ≤ 30 seconds for each specimen, and no flaming drips that ignite the cotton indicator.
- V‑1 – afterflame time (t1 or t2) ≤ 30 seconds for each individual specimen, total afterflame time for all five specimens ≤ 250 seconds, afterflame plus afterglow time (t2 + t3) ≤ 60 seconds for each specimen, and no flaming drips that ignite the cotton indicator.
- V‑2 – same as V‑1, but flaming drips are permitted that ignite the cotton indicator.
Test acceptance – pass/fail criteria – A material is considered to have passed the test for a specific V‑rating if all five specimens meet the requirements. If any specimen fails (e.g., afterflame time exceeds the limit, or the flame reaches the 125 mm mark), the material is classified as not meeting that rating.
Effect of specimen thickness on classification – testing at multiple thicknesses – For materials intended for different applications, we test specimens of varying thickness (e.g., 0.8 mm, 1.6 mm, 3.2 mm). The classification is thickness‑dependent; a material may be rated V‑0 at 3.2 mm but V‑2 at 0.8 mm. We report the classification for each thickness tested, helping you select the appropriate grade for your application.

ASTM D3801 Vertical Burning Test – Comparative Burning Characteristics

Test procedure – single flame application – Similar to UL 94, we apply a specified flame to the bottom of a vertically mounted specimen. However, ASTM D3801 uses a single flame application and records the time to reach the 25 mm and 125 mm reference marks, the afterflame time after flame removal, and the burning rate (in mm/min).
Burning rate calculation – for materials that do not self‑extinguish – If the flame progresses beyond the 125 mm mark, the burning rate (in mm/min) is calculated from the time taken for the flame to travel from the 25 mm to the 125 mm mark. A higher burning rate indicates a higher flame spread hazard.
Comparative rating – classification based on burning behaviour – The test results are used to classify materials into categories such as "slow‑burning", "self‑extinguishing", or "fast‑burning" for comparative purposes.

IEC 60695‑11‑10 – 50 W Vertical Flame Test

Test method – aligned with UL 94 V‑rating – IEC 60695‑11‑10 specifies a 50 W vertical flame test method that is technically equivalent to the UL 94 V‑0, V‑1, and V‑2 tests. The test uses the same specimen dimensions, flame application, and classification criteria. We perform the test in accordance with the IEC standard, providing a classification that is accepted for global markets.
Global acceptance – for IECEE and CB Scheme certification – The IEC 60695‑11‑10 standard is the basis for many international product safety certifications, including the IECEE CB Scheme. Our test reports, performed to this standard, are accepted by certification bodies in over 50 countries, facilitating global market access.

Automotive and Textile Testing – ISO 3795 / GB/T 8410

Vertical flame test for automotive interior materials – ISO 3795 (formerly DIN 75200) / GB/T 8410 – We test automotive interior materials (seat fabrics, headliners, floor coverings, instrument panel materials) using a vertical flame test with a defined flame application (typically 38 mm high, 15 seconds). We measure the burn rate (in mm/min) and compare it to the requirements specified by automotive OEMs or regulatory standards (e.g., FMVSS 302). A burn rate of ≤ 100 mm/min is typically required for passenger car interior materials.
Flame propagation and self‑extinguishing behaviour – For materials that self‑extinguish before reaching the specified end‑point, the time to self‑extinguish and the burn length are recorded. This information is used to classify the material and to determine its suitability for use in vehicle interiors.
Sampling and conditioning for automotive materials – for realistic test results – We test specimens from actual production batches, conditioned to the specified temperature and humidity. For materials with different colours, finishes, or surface coatings, we test each variant individually, as the flame retardancy can vary significantly.

Regulatory Compliance and Certification – Supporting Product Approvals

UL certification support – for UL 94‑compliant products – We provide testing services that support UL certification for electrical and electronic components. Our test reports are accepted by UL for product submission, and we can assist you with the interpretation of the UL 94 requirements.
IEC and EN compliance – for European and international markets – We perform vertical combustion testing to IEC 60695‑11‑10 and EN 60695‑11‑10, which are accepted for CE marking and for compliance with the Low Voltage Directive (LVD) and the Construction Products Regulation (CPR).
Chinese national standard compliance – GB/T 2408, GB/T 8332 – We perform vertical combustion testing to the Chinese national standards, ensuring that your products meet the requirements for the Chinese market. Our reports are accepted by the National Medical Products Administration (NMPA) and the State Administration for Market Regulation (SAMR) for product registration and type approval.
Fire safety regulations for buildings and transportation – For building materials, shipbuilding, and railway applications, we perform vertical combustion testing in accordance with the relevant fire safety regulations (e.g., EN 13501‑1, IMO FTP Code, EN 45545). We provide the test data needed for classification and for meeting the specific requirements of these regulations.

Data Analysis and Reporting – Clear and Actionable Results

Afterflame time, afterglow time, and burn length – the primary results of the test – We report the afterflame time (t1 and t2), the afterglow time (t3), the total afterflame time (sum of t1 and t2), and the burn length (the distance from the bottom of the specimen to the point where the flame extinguished) for each specimen.
Classification and pass/fail verdict – against the specified rating – We provide a clear classification (e.g., V‑0, V‑1, V‑2) and a pass/fail verdict against the specified acceptance criteria (e.g., "Pass: V‑0" or "Fail: V‑0 – afterflame time exceeded the limit").
Statistical summary – for batch‑to‑batch consistency – For multiple specimens, we provide the mean, standard deviation, and coefficient of variation (CV) of the afterflame times, and the percentage of specimens that passed the test. This data helps you to monitor the consistency of the flame retardant performance across production batches.
Photographic and video evidence – for visual documentation – We provide high‑resolution photographs (and, where required, video recordings) of the test specimens during and after the test. The images document the flame propagation, the dripping behaviour, and the extent of the burn damage, providing a visual record that supports the numerical results.

Test Standards and Specification Compliance – Supporting Regulatory and Contractual Requirements

Our vertical combustion testing is performed in accordance with a wide range of national and international standards. The most commonly requested include:

UL 94 – Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances – the most widely used standard for plastics in North America and internationally
IEC 60695‑11‑10 – Fire hazard testing – Test flames – 50 W horizontal and vertical flame test methods – the international standard for 50 W flame tests
ASTM D3801 – Standard Test Method for Measuring the Comparative Burning Characteristics of Solid Plastics in a Vertical Position – for comparative testing of plastics
ISO 3795 – Road vehicles – Textiles – Determination of flammability – for automotive interior textiles
GB/T 2408 – Plastics – Determination of burning characteristics – Horizontal and vertical test – the Chinese national standard for flammability testing of plastics
GB/T 8332 – Test method for flammability of cellular plastics – Vertical burning method – the Chinese national standard for testing cellular plastics
EN 60695‑11‑10 – European standard for fire hazard testing – for CE marking and European compliance
FMVSS 302 – Flammability of interior materials – for vehicles sold in the United States

Report Acceptance and Regulatory Recognition

All vertical combustion tests are conducted under our ISO/IEC 17025 accreditation, using calibrated gas flow meters, timers, and temperature sensors, all traceable to national and international reference standards. Our final test reports include: a complete description of the test article (material, thickness, colour, manufacturer), the test method and conditions (flame height, flame application time, specimen conditioning), the individual test results (afterflame times, afterglow time, burn length, dripping behaviour), the classification (V‑0, V‑1, V‑2, or burn rate), a statistical summary (mean, standard deviation, CV), a clear pass/fail verdict against the specified acceptance criteria, and photographic/video documentation of the test. These reports are accepted by the National Medical Products Administration (NMPA), the State Administration for Market Regulation (SAMR), the Ministry of Industry and Information Technology (MIIT), and international certification bodies for product registration, type approval, and quality assurance. Bilingual (Chinese/English) versions are available to facilitate submissions to domestic and international authorities and to support your global market access.