Flameless combustion time testing service

Flameless Combustion Time Testing Service – Evaluating Smoldering and Afterglow Hazards for Brazilian Fire Safety Compliance

As an ISO/IEC 17025 accredited independent testing laboratory, we offer specialised flameless combustion time testing services to Brazilian manufacturers, importers, and safety regulators. Flameless combustion – including smoldering and afterglow – occurs when a material continues to oxidise and release heat without a visible flame, often generating toxic gases and initiating secondary ignition long after the original ignition source is removed. This phenomenon is a critical risk factor for upholstered furniture, bedding, thermal insulation, cable bundles, and polymeric components. Our test protocols quantify the duration and extent of such flameless burning under controlled conditions, providing essential data for product safety certification. All methods are aligned with ABNT NBR standards, UL 94, IEC 60695‑11‑10, ISO 12952, ISO 4880, and ASTM D635, and are recognised by INMETRO (for product safety), ANVISA (for healthcare materials), and Brazilian fire authorities for building and transport applications.

Product Samples We Regularly Test for Flameless Combustion

Our fire laboratory accommodates a wide variety of materials and finished products that may exhibit smoldering or afterglow behaviour. Typical test specimens include:

• Textiles and upholstery fabrics – curtains, furniture coverings, mattress ticking, and automotive interior textiles
• Cellular plastics and foams – polyurethane, polystyrene, polyethylene, and phenolic foams for insulation and cushioning
• Electrical cables and wire insulation – PVC, XLPE, and low‑smoke halogen‑free materials
• Building insulation panels – rigid foam boards, mineral wool with facing, and composite sandwich panels
• Furniture and bedding components – foam cores, filling materials, and mattress covers
• Wood products and composites – plywood, particle board, and fire‑retardant treated lumber
• Consumer electronics enclosures – plastic housings and structural components

Textiles, Upholstery and Bedding Materials – Smoldering Resistance and Afterglow Measurement

• Cigarette ignition resistance (ISO 12952‑1/2 for bedding, ISO 8191‑1 for furniture) – We place a lighted cigarette on the surface of the test specimen (fabric+foam assembly) under controlled draft‑free conditions. The time until the cigarette self‑extinguishes or until the material begins to smolder is recorded. We also measure the total smoldering time and the maximum char length. A specimen that exhibits smoldering beyond 60 minutes or that propagates to the edge is considered a failure for Brazilian residential and hospitality furniture.
• Afterglow time in vertical flame tests (ISO 6941 / ABNT NBR 14641) – After applying a standard flame to the lower edge of a vertically mounted fabric specimen for 10 seconds, we measure not only the afterflame time but also the afterglow time (the duration of glowing combustion after the flame has ceased). The afterglow is recorded in seconds; a value exceeding 5 seconds is typically unacceptable for protective clothing and curtain materials.
• Smoldering propagation in mattress and pillow testing (ISO 12952‑3/4) – For complete mattress assemblies, we perform a gas burner ignition test (with a specified heat output) and then monitor the smoldering progression through the core. We report the time to penetration of the outer cover and the total smoldering duration before self‑extinction or full propagation.
• Effect of laundering on smoldering behaviour – For textiles that are washed, we repeat the cigarette or afterglow test after a specified number of washing cycles (e.g., 5 or 10) and report any increase in smoldering time, which indicates depletion of flame‑retardant additives.

Plastics, Foams and Cellular Materials – Afterglow Duration and Glowing Combustion Classification

• Vertical burning test for plastics (UL 94 V‑0/V‑1/V‑2 / IEC 60695‑11‑10) – We prepare standard bar specimens (125 mm × 13 mm × thickness) and apply two 10‑second flame applications. In addition to measuring afterflame times (t1, t2), we record the afterglow time (t3) – the time that the specimen continues to glow after the flame has disappeared. For a V‑0 classification, t3 must not exceed 30 seconds for each specimen, and total afterglow for all five specimens must not exceed 60 seconds. Our report provides the measured t3 values and the resulting classification.
• Horizontal burning test for cellular plastics (ISO 9772 / ASTM D635 adapted) – We test foam blocks (150 mm × 50 mm × thickness) horizontally, applying a flame to one end. The afterglow time is measured from the moment the flame is removed until all glowing combustion ceases. This is especially critical for flexible foams used in Brazilian automotive seating and packaging.
• Glowing hot wire test for insulation foams (IEC 60695‑2‑10 adapted) – For foam panels, we also perform a glow‑wire test to assess the material’s resistance to ignition from an electrically heated wire. The flameless combustion time is defined as the duration of glowing after the glow‑wire is removed. This simulates overheating faults in electrical installations.
• Effect of density and cell structure – We test foams of different densities and report the afterglow time as a function of density, helping Brazilian foam converters select optimal formulations for fire‑safe applications.

Electrical Cables and Wire Insulation – Afterglow and Smoldering Under Power Overload

• Flame propagation test for single cable (IEC 60332‑1‑2 / ABNT NBR 13249) – We mount a cable vertically and apply a 1 kW flame for 60 seconds. After the flame is removed, we measure the afterglow time (any visible glowing on the insulation or sheath) and the total time until all combustion ceases. The standard requires that the charred length does not reach the upper mark, but we also report the afterglow duration, which can be an indicator of oxygen‑index performance.
• Bunched cable test (IEC 60332‑3‑24) – smoldering in the bundle – For cable trays, after the 20‑minute flame application, we monitor the cable bundle for any smoldering that continues for more than 60 minutes after the burner is removed. We report the smoldering time and the maximum temperature recorded inside the bundle using thermocouples.
• Smoldering resistance of low‑smoke zero‑halogen (LSZH) compounds – For LSZH materials, we apply a small flame (20 mm) to a vertical insulation strip and measure the afterglow time, as per EN 50305 (adapted). A pass requires afterglow ≤ 10 seconds.
• Thermal ageing effect on afterglow – We condition cable samples at elevated temperature (100 °C) for 7 days and then repeat the afterglow test to simulate ageing; any increase beyond 20 % of the original value is reported as a warning.

Building and Construction Insulation Materials – Smoldering Propagation and Burn‑Through Time

• Smoldering resistance of foam insulation (ASTM C739 / ISO 11925‑2 adaptation) – We expose vertical foam panels to a small flame for 15 seconds, then measure the smoldering propagation distance and the total smoldering time (from ignition to self‑extinction). For Brazilian building applications, the smoldering time must not exceed 30 minutes for a thickness of 50 mm.
• Radiant panel test for floor covering (ASTM E648 / ABNT NBR 15553) – We determine the critical radiant flux at which the flame extinguishes, but also record the afterglow duration on the charred surface. This is relevant for carpet and floor insulation in public buildings.
• Smoldering in duct insulation (UL 181) – For air‑duct insulation, we perform a smoldering test where a heated wire is embedded in the insulation. The flameless combustion time is measured until the temperature drops below 200 °C. Our report includes the time‑temperature curve.
• Effect of moisture on smoldering – We condition insulation materials at 90 % RH and 30 °C for 48 hours before testing, as moisture can significantly extend smoldering time. The comparison between dry and conditioned results is provided for Brazilian tropical climates.

Furniture and Composite Panels – Smoldering Ignition from Small Ignition Sources

• Upholstered furniture – cigarette ignition (ISO 8191‑1 / ABNT NBR 15883) – We assemble a mock‑up of fabric over foam and place a burning cigarette on the surface. The time until smoldering ceases or propagates is recorded. A smoldering time exceeding 90 minutes without propagation is considered a pass for domestic furniture.
• Match flame equivalent ignition (ISO 8191‑2) – For more severe testing, we apply a 20‑second gas flame and then measure the smoldering time and char length. This simulates a match or small flame.
• Composite panel smoldering (EN 16755) – For wood‑based panels with flame‑retardant treatments, we apply a radiant heat source and measure the glow time after the heat source is removed. The afterglow time is reported as a criterion for fire classification.
• Resistance to smoldering from electrical faults – For furniture near electrical outlets, we also perform an arc‑ignition test and record any flameless combustion duration.

Report Acceptance & Compliance with Brazilian Regulatory Bodies

All flameless combustion time tests described above are conducted under our ISO/IEC 17025:2017 accreditation, using calibrated timers (±0.1 s), thermocouples, gas flow meters, and certified cigarette references (when applicable). Our environmental chambers are maintained at standard conditioning conditions (20 ± 2 °C, 65 ± 5 % RH) per ISO 554 to ensure reproducibility. The final test reports include: detailed description of the specimen preparation and test method, recorded afterglow and smoldering times (in seconds) for each replicate, statistical summary (mean, standard deviation), observations of char depth, propagation length, and any droplet/melt behaviour, photographic documentation (before/after), a clear pass/fail verdict against the client’s specified limit or the relevant standard, and an uncertainty statement for time measurements. These reports are widely accepted by INMETRO for product safety certification of furniture, electronics, and building components, by ANVISA for healthcare bedding and textiles, by ABNT for normative compliance, and by Brazilian civil defense and fire brigades for building material approvals. Bilingual (Portuguese/English) versions are available to streamline submissions to regulatory agencies and customer audits. With our rigorous flameless combustion testing, you can demonstrate that your products resist the hidden danger of smoldering and afterglow, thereby reducing fire risks in Brazilian homes, workplaces, and public spaces.