What are B1 and B2 flame retardant wires? In fact, ZB, B1, and B2 are completely different cables. With the increasing number of high-rise buildings and electrical equipment, the electrical safety standards are gradually improving. B1 flame-retardant wires and cables will appear more and more in the world. in engineering applications.

The referenced standard is different

The ZB flame retardant grade refers to GB/T 19666-2019 "General Rules for Flame Retardant and Fire Resistant Wire and Cable or Optical Cable", which is divided into four categories: ZA, ZB, ZC, and ZD according to the combustion characteristics;

The B1 flame retardant level refers to GB 31247-2014 "Classification of Combustion Performance of Electric and Optical Cables", which is based on the flame spread length, peak heat release during combustion, total heat release, burning speed, peak smoke generation speed, and smoke generation within 20 minutes Indicators such as total amount and smoke concentration are divided into four levels: A, B1, B2, and B3;

different standards

GB 31247 "Classification of Combustion Performance of Electric and Optical Cables" is a national mandatory standard with mandatory binding force. Products and services that do not meet the mandatory standards shall not be produced, sold or imported. GB/T 19666-2019 "General Rules for Flame Retardant and Fire Resistant Wire and Cable or Optical Cable" is a recommended standard encouraged by the state. Compulsory standards are uniform standards throughout the country, standards to ensure human health, personal and property safety, and national standards that are enforced by laws and administrative regulations; recommended national standards are voluntary standards, mainly for production, inspection, and use. etc.

different technical requirements

Next, we will introduce the technical requirements of B1 level flame retardant in detail, from which you can clearly understand the excellent performance of these indicators in terms of safety performance.

1. Standards of combustion performance

1. Flame spread FS≤1.5 m;

2. The peak heat release rate is ≤30 kW; the total heat release within 1200 s of fire is ≤15 MJ;

3. The combustion growth rate index FIGRA≤150 W/s;

4. Peak smoke production rate ≤0.25 m2/s; total smoke production within 1200 s of fire ≤50 m2

5. Smoke density (minimum transmittance) It≥60%

6. Vertical flame spread H≤425 mm

2. B1 and B2 flame retardant products must provide additional 3 items of information

1. Droplet level: The burning droplet/particle level is divided into three levels: d0, d1, and d2

2. Toxicity level of flue gas: According to the degree of damage/damage caused by toxic and harmful substances in flue gas, it is divided into three levels: t0, t1, t2

3. Corrosive grade: according to the ability of the surrounding medium to corrode the material, it is divided into three grades: a1, a2 and a3

pay attention

B1, B2 level flame retardant products must indicate additional information; such as: GB 31247 B1 (d0, t0, a1), if not marked, it is regarded as B3 level flame retardant products, that is, ordinary low-smoke halogen-free wires and cables.

Applicable occasions for Class B1 flame retardant wire and cable

GB 51348-2019 "Electrical Design Standards for Civil Buildings" When using direct lay wiring in indoor places, the following requirements should be met

1. Insulated wires with flame-retardant sheaths not lower than B2 should be used, and their cross-sectional area should not be greater than 6mm2;

2. For the wiring of fire-resistant cables and mineral insulated cables, fire-resistant cables and mineral insulated cables should have a flame-retardant performance not lower than B1

The selection and laying of fire-fighting distribution lines shall meet the requirements for the continuous operation of fire-fighting electrical equipment (750°C, 90min) and meet the following requirements

1. For the alarm bus of the automatic fire alarm system in the evacuation channel of densely populated places, the cable with combustion performance B1 should be selected;

2. The alarm bus in other places should choose cables with combustion performance not lower than B2 level;

3. The fire-fighting linkage bus and linkage control lines should choose fire-resistant copper core cables; the combustion performance should meet the requirements of GB 31247;

The selection of power cables for non-fire-fighting load cables and communication cables in civil buildings should meet the following requirements

1. Public buildings with a building height of more than 100m: wires and cables with combustion performance level B1 and above, smoke production toxicity level t0, and combustion drip/particle level level d0;

2. Refuge floor (intermediate) exposed application: electric wires with combustion performance not lower than B1 level, smoke production toxicity level t0 level, and burning drip/particle level level d0 level

3. Finance, provincial power dispatching, provincial and municipal radio and television, telecommunications and crowded public places in a class of high-rise buildings:

The combustion performance level should be B1, the smoke production toxicity should be t1 level, and the burning drop/particle level should be d1;

4. Other types of public buildings: cables with combustion performance not lower than d2 level, smoke generation toxicity level t2 level, and combustion drip/particle level level d2 level should be selected;

5. For underground buildings where people stay for a long time, cables with a smoke toxicity level of t0 and a burning drop/particle level of d0 should be selected;

6. The combustion performance of the wires and cables selected for horizontal wiring and vertical wiring in the building should be consistent;

The basic knowledge of B1 flame-retardant products is introduced here. Fire-fighting systems, high-rise buildings, financial information hubs, and densely populated public places must use high-grade safety flame-retardant wires, and they will surely enter thousands of households in the future. Escort for our happy life!