Combustion Performance Testing of Materials in Public Places: Standards, Methods, and Compliance

Combustion performance testing of materials in public places is a critical fire safety requirement that verifies whether decorative and functional materials—such as wall panels, curtains, seating foam, carpets, and cables—meet mandatory flame retardancy regulations before installation in crowded venues. This technical guide explains the key standards (GB 8624, GB 20286, EN 13501-1, ASTM E84), common sample types, measured parameters, laboratory test methods, and frequently asked questions to help manufacturers, contractors, and facility owners achieve regulatory compliance.

Technical Overview

Public assembly venues such as shopping malls, theaters, hotels, airports, hospitals, schools, and stadiums concentrate large numbers of occupants in environments densely furnished with combustible interior materials. In the event of a fire, wall coverings, curtains, upholstered seating, and polymer foams can act as the primary fuel load, accelerating flame propagation and generating lethal smoke and toxic gases within minutes. Combustion performance testing of materials used in public places therefore serves as the fundamental technical basis for controlling fire risk at the material selection and acceptance stage.

In the Chinese regulatory framework, the core standards governing this field include GB 8624-2012 (Classification for burning behavior of building materials and products), GB 20286 (Requirements of burning behavior of fire-retardant and fire-resistant products used in public places), and GB 50222 (Code for fire prevention in design of interior decoration of buildings). Under GB 8624-2012, materials are classified from A1 and A2 (non-combustible and limited-combustible) through B and C (flame-retardant, equivalent to the former B1 grade), D and E (ordinary flammable, equivalent to the former B2 grade), down to F (no performance requirement). GB 20286 additionally mandates that fire-retardant products used in designated public places—such as wires and cables, textiles, foam materials, and furniture components—achieve defined flame-retardant performance levels and be marked accordingly.

Internationally, equivalent classification systems include EN 13501-1 (Euroclasses A1 to F), ASTM E84 and UL 723 (flame spread index and smoke developed index from the 25-foot tunnel test), JIS A 1321 in Japan, and ISO-based reaction-to-fire methods such as ISO 1182, ISO 1716, ISO 11925-2, and the EN 13823 single burning item (SBI) test. Testing must be performed by accredited third-party laboratories holding recognized conformity assessment accreditations, with test reports serving as essential documentation for fire design review, product certification, and construction acceptance inspection.

Testing Samples

Building and Interior Decoration Materials

This category covers wall and ceiling panels, gypsum boards, calcium silicate boards, aluminum composite panels, mineral wool products, wood-based panels, wallpapers, decorative fabrics laminated to substrates, coatings, and adhesives used in interior finishing. These materials determine the early-stage fire behavior of a compartment and are typically classified under GB 8624 or EN 13501-1.

Textile Products

Samples include stage curtains, window drapes, blinds, upholstery fabrics, seat covers, carpets, and artificial turf installed in assembly halls, cinemas, and hotel ballrooms. Textiles are evaluated for ease of ignition, flame spread, char length, after-flame and after-glow time, and damage length using vertical, horizontal, or 45-degree flame test configurations.

Polymer and Foam Materials

Flexible and rigid polyurethane foams, polystyrene insulation boards (EPS and XPS), PVC sheets, polyolefin films, and engineering plastics are among the most hazardous materials in public venues due to rapid flame spread, dripping, and heavy smoke. These materials are tested for oxygen index, horizontal and vertical burning characteristics, melt dripping behavior, and smoke production.

Furniture and Seating Components

Theater and cinema seating, airport waiting chairs, sofas, mattresses, and their composite constructions (covering fabric over foam padding over frame) are assessed as complete assemblies using smoldering cigarette and flaming ignition source tests to simulate real-world ignition scenarios.

Wires, Cables, and Electrical Materials

Low-smoke halogen-free cables, fire-resistant cables, cable trays, and electrical enclosures installed in evacuation routes and concealed spaces are tested for flame propagation, smoke density, halogen acid gas emission, and circuit integrity under direct flame impingement.

Fire-Retardant Treated Wood and Products

Flame-retardant treated timber, plywood, and engineered wood products used for decorative ceilings, wall linings, and stage structures are verified for both initial and, where required, accelerated aging-conditioned combustion performance to confirm the durability of the flame-retardant treatment.

Testing Items

Depending on the product category and applicable standard, combustion performance testing of public place materials typically includes the following parameters:

• Burning behavior classification (A1, A2, B, C, D, E, F under GB 8624-2012 or EN 13501-1)
• Ignitability under small flame impingement and sustained flaming duration
• Lateral flame spread and critical heat flux at extinguishment
• Heat release rate (HRR), peak heat release rate, and total heat release (THR)
• Fire growth rate index (FIGRA) used for classification in the SBI test
• Smoke production rate (SPR), total smoke production (TSP), and smoke growth rate index (SMOGRA)
• Smoke density expressed as light transmittance or optical density in a closed chamber
• Formation of flaming droplets and particles
• Gross heat of combustion (calorific value) determined by bomb calorimetry
• Mass loss and temperature rise in the non-combustibility furnace test
• Limiting oxygen index (LOI)
• Horizontal and vertical burning characteristics of plastics (after-flame time, after-glow time, drip ignition)
• Char length, damaged length, and melt-through behavior of textiles
• Acute toxicity and irritancy of fire effluents, including yields of CO, CO2, HCN, HCl, HF, and other gases
• Flame spread index (FSI) and smoke developed index (SDI) for tunnel method classifications
• Smoldering and flaming ignition resistance of upholstered furniture composites

Testing Methods

Accredited third-party laboratories apply a coordinated set of standard test methods to generate the data required for classification. The principal methods are summarized below.

Non-Combustibility and Calorific Value Tests

For A1 and A2 class determination, GB/T 5464 (identical to ISO 1182) subjects specimens to a 750 °C cylindrical furnace to measure furnace temperature rise, sustained flaming time, and mass loss, while GB/T 14402 (ISO 1716) determines the gross heat of combustion using an oxygen bomb calorimeter. These methods establish whether a material can be considered non-combustible or limited-combustible.

Single Burning Item (SBI) Test

GB/T 20284 (equivalent to EN 13823) exposes a specimen corner assembly to a 30 kW propane burner while oxygen consumption calorimetry records heat release and smoke production. The derived FIGRA0.2MJ, FIGRA0.4MJ, THR600s, SMOGRA, and LFS (lateral flame spread) parameters directly determine classes B through D under GB 8624-2012.

Single Flame Source Test

GB/T 8626 (harmonized with ISO 11925-2) applies a small diffusion flame to the bottom edge or surface of a vertically mounted specimen for 15 or 30 seconds, recording ignition, flame tip spread beyond a defined gauge line, and flaming droplets. It is the screening test for classes B through E.

Radiant Panel and Spread of Flame Tests

GB/T 11785 (EN ISO 9239-1) evaluates floor coverings by measuring critical heat flux at extinguishment under an inclined radiant panel, while ASTM E84 and UL 723 use the 25-foot Steiner tunnel to determine flame spread and smoke developed indices for building materials in North American markets.

Oxygen Index and Small-Scale Burning Tests

GB/T 2406.2 (ISO 4589-2) and GB/T 5454 determine the limiting oxygen index of plastics and textiles respectively, providing a quantitative measure of relative flammability. GB/T 2408 and GB/T 5455 assess horizontal and vertical burning behavior of plastic and textile specimens under a defined Bunsen-type burner flame.

Smoke Density and Toxicity Tests

GB/T 8627 measures smoke density in a closed chamber by light attenuation, whereas GB/T 20285 evaluates the acute inhalation toxicity of combustion products using animal exposure protocols, generating a toxicity hazard classification required for B1 flame-retardant products in public places under GB 20286. Gas chromatography and ion chromatography techniques quantify CO, HCN, HCl, and other species yields.

Furniture and Composite Assembly Ignition Tests

GB 17927 and equivalent BS 5852 methods apply smoldering cigarettes and small flaming ignition sources to complete furniture composites, verifying that fabric-foam-interliner combinations resist realistic ignition. GB/T 20285 and smoke tests are frequently combined with these methods for a complete fire hazard profile.

Cone Calorimetry

ISO 5660-1 cone calorimetry provides comprehensive research-grade data—heat release rate, effective heat of combustion, mass loss rate, smoke yield, and ignition time—at controlled irradiance levels. It is widely used in product development and fire hazard engineering analysis of public place materials.

Applications

Combustion performance testing reports and flame-retardant product certifications are applied across the full lifecycle of public facilities:

• Fire design review and interior decoration plan approval for cinemas, theaters, KTV venues, and auditoriums where stage curtains and seating must meet B1 grade requirements
• Construction acceptance and fire safety inspection of shopping malls, supermarkets, and exhibition centers before opening to the public
• Material compliance verification for hotels, restaurants, and leisure venues, including textiles, carpets, and upholstered furniture
• Transportation hub projects at airports, railway stations, and metro systems, including platform screen doors, seating, and low-smoke cable systems
• Healthcare, education, and eldercare facilities where smoke toxicity and evacuation time constraints demand stricter material grades
• Flame-retardant product certification and mandatory marking for wires, cables, foams, textiles, and furniture components supplied into public places
• Research and development of flame retardants, fire-resistant coatings, and low-smoke polymer formulations
• Fire accident investigation and post-incident material performance analysis
• Export compliance, where manufacturers align GB test data with EN 13501-1, ASTM E84, or JIS requirements for international projects

FAQ

What is the difference between Class A, B1, and B2 materials under GB 8624?

Under GB 8624-2012, Class A1 and A2 materials are non-combustible or limited-combustible (stone, mineral wool, gypsum), Class B and C materials correspond to the former B1 flame-retardant grade with restricted contribution to fire, Class D and E correspond to the former B2 ordinary flammable grade, and Class F materials have no demonstrated performance. Public place regulations generally require B1 (Class B/C) or better for interior finishes, depending on the occupancy and location within the building.

Why is GB 20286 specifically important for public places?

GB 20286 establishes mandatory burning behavior requirements and grading for fire-retardant products—wires and cables, textiles, foam materials, and furniture components—used in public places such as hotels, cinemas, hospitals, schools, and internet cafes. Products must pass testing at accredited third-party laboratories and carry the designated flame-retardant marking before being installed.

Which test methods are combined to obtain a GB 8624 classification?

A typical classification sequence combines the non-combustibility furnace test (GB/T 5464) and gross heat of combustion (GB/T 14402) for Class A1, the SBI test (GB/T 20284) and single flame source test (GB/T 8626) for Classes B to E, and, for floorings, the radiant panel test (GB/T 11785). Smoke production and flaming droplets observations form part of the classification criteria.

What sample sizes and quantities are required?

Sample requirements depend on the test method. The SBI test typically requires multiple specimen sets of approximately 1500 mm × 500 mm and 1500 mm × 1000 mm, the single flame source test requires replicate specimens of 250 mm × 90 mm, the oxygen index test requires specimens of 80–150 mm in length depending on material rigidity, and smoke density tests use 25 mm × 25 mm × thickness cubes. Laboratories generally request surplus material and, for finished products, samples cut from actual production lots.

Do flame-retardant treated materials need retesting after aging?

Yes. For certain fire-retardant treated wood and textile products, standards require testing both in the initial conditioned state and after durability conditioning (water leaching or accelerated hygrothermal aging) to confirm that the flame-retardant performance is retained throughout the service life of the product.

Can GB 8624 test reports be used for international projects?

No single report satisfies all jurisdictions. GB 8624 classifications are used in the Chinese market, while EN 13501-1 Euroclass reports are required in Europe, and ASTM E84 or UL 723 tunnel data are accepted in North America. Although many test methods are technically harmonized with their ISO and EN counterparts, most projects require separate testing or classification reports issued for the specific target standard by an appropriately accredited laboratory.

How long does combustion performance testing take?

Standard single-method tests such as oxygen index or vertical flame testing can typically be completed within one to two weeks including conditioning. Full GB 8624 classification campaigns combining SBI, single flame, non-combustibility, and calorific value tests generally require three to six weeks, extended further when smoke toxicity testing under GB/T 20285 or durability preconditioning is included.