Full set of classification standards for combustion performance levels of EPS molded polystyrene board

1、 Core Execution Standards

1. Basic classification national standard: GB-8624-2012 "Classification of Combustion Performance of Building Materials and Products" (currently widely used in engineering; the new version of GB8624-2025 will be implemented on January 1, 2027)

2. EPS board product standard: GB/T 10801.1-2021, which specifies that EPS combustion levels are divided into three levels: B1, B2, and B3. EPS cannot reach level A non combustible

3. Mandatory specifications for insulation materials: GB 46520-2025 and GB50016 "Code for Fire Protection Design of Buildings" control the selection level of external wall insulation

2、 Definition of 4-stage combustion level (GB8624-2012)

|Grade | Name | EPS Board Characteristics | Combustion Behavior|

|Grade A | Non combustible material | EPS does not meet this grade, rock wool and foam cement are Grade A | No fire, no smoke, and no melting droplets when exposed to open flames|

|B1- Flame retardant grade | Flame retardant | High quality EPS with high-efficiency flame retardants added, mainstream in exterior wall engineering | Difficult to ignite, self extinguishing immediately after ignition, almost no molten droplets, low smoke; Oxygen index ≥ 30%|

|B2- Flammable grade | Ordinary flame-retardant EPS, universal for construction sites | Can burn when exposed to open flames, slow flame spread speed; There are molten droplets present|

|B3 ‑ Flammable grade | Original foam board and packaging foam without flame retardant | Extremely easy to be ignited by open fire, fast flowing burning, dripping and igniting surrounding materials, and use of external walls is strictly prohibited|

Molded polystyrene board

3、 Official testing and judgment indicators (EPS) for B1/B2/B3

1. B1 (flame retardant)

1. Flammability vertical test: residual combustion length ≤ 50mm, no droplets igniting filter paper, continuous combustion ≤ 30s

2. Single combustion FIGRA ≤ 250 W/s; Total heat release ≤ 7.5MJ

3. Smoke density rating SDR ≤ 75; Oxygen index ≥ 30%

2. B2 (flammable)

1. Vertical combustion: The remaining length of combustion is ≤ 250mm, and droplets can ignite the filter paper

2.FIGRA≤750 W/s

3. Oxygen index ≥ 26%

3. B3 (flammable)

Not up to all B2 indicators, ordinary non flame retardant foam bead shaped plate

4、 Mandatory selection rules for engineering

1. Exterior wall insulation for high-rise residential buildings with a height of ≥ 27m: B2 and B3 are prohibited in most areas, and B1 grade EPS is mandatory

Multi story buildings below 2.27m: B2 grade flame-retardant polystyrene board can be used

3. Personnel intensive public places, basements, internal insulation, upgraded fire prevention standards, priority given to B1/A grade materials

4. GB/T10801.1-2021 requirement: The minimum insulation EPS for buildings shall not be lower than B2 level, and B3 level is prohibited from being used for building insulation

5、 New version GB8624-2025 changes (to be implemented in 2027)

The new standard cancels the traditional A-B1-B2-B3 simple label and changes it to:

A1/A2 (non combustible) B、C、D、E、F；

EPS organic foam plate generally corresponds to C/D grade, and at the same time, it is mandatory to bind three additional indicators, namely, smoke production grade, combustion drip grade, and smoke toxicity. In the future, the fire detection standard will be more stringent

Do you need me to compile a comparison table of EPS, XPS, graphite polystyrene board, rock wool board combustion grade, parameters, and applicable floors?

Shandong Huaneng Insulation Materials Co., Ltd. is a pipeline insulation manufacturer in Linyi. As an integrated insulation and decoration manufacturer in Shandong, our main products include integrated insulation and decoration, pipeline insulation, exterior wall insulation materials, extruded polystyrene board, thermosetting polystyrene board, and rubber insulation. If you need it, you can contact us by phone.

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