Overview
ISO 340:2022 - "Conveyor belts - Laboratory scale flammability characteristics - Requirements and test method" specifies a small-scale test to assess how conveyor belts react to an ignition flame source. Applicable to conveyor belts with a textile carcass and steel cord conveyor belts, the standard defines specimen preparation, apparatus, test conditions and pass/fail criteria. Note: this laboratory method helps assess ignition behaviour but is not intended to be the sole measure of fire safety for a product.
Key topics and technical requirements
- Scope: Laboratory-scale assessment of conveyor belt reaction to a gas flame for belts with textile carcasses and steel cords.
- Specimen size & sampling:
- Typical test pieces: (200 ± 5) mm × (25 ± 1) mm.
- Samples taken at least 50 mm from belt edges.
- For textile carcass belts: 12 specimens (covers intact and removed, longitudinal and transverse) or 6 specimens if covers are to remain intact.
- For steel cord belts: six longitudinal specimens, minimum 20 mm wide, containing at least two cords.
- Burner and flame conditions:
- Bunsen-type burner with 10 ± 0.5 mm bore; propane fuel (ISO 9162).
- Total flame height 150–180 mm, inner flame ~50 mm.
- Thermocouple (NiCr/NiAl per ISO 8056‑1) set to 1000 °C ± 20 °C in the hottest part of the flame.
- Pass/fail criteria:
- Sum of afterflame times for a series of six tests < 45 s.
- No individual afterflame time > 15 s.
- No reappearance of flame when a controlled air current (1.5 m/s ± 0.1) is applied after testing.
- Environmental & safety controls:
- Test atmosphere 10 °C to 30 °C, 15 %–80 % relative humidity.
- Ambient air movement