Smoke density Chamber

A smoke density chamber is an instrument designed to measure the smoke density generated by a sample subjected to a heat source or open flame within a controlled test chamber. This test assesses the behavior of materials in terms of smoke emission during combustion or under thermal exposure conditions, providing fundamental data for applications where smoke visibility and toxicity are critical safety factors.

The sample, of a determined thickness, is exposed to a defined heat flux, typically 2.5 W/cm2 (25 kW/m2) using the Mod. E 662 radiant furnace, or to a direct flame, depending on the applied standard. For more advanced tests, the conical radiant heat furnace according to ISO 5659 allows the heating intensity to be varied from 10 kW/m2 up to 50 or 70 kW/m2, enabling customized tests based on the material type and application sector.

The smoke density chamber is compatible with a wide range of international standards, including:

• ASTM E 662 – Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials.

• BS 6401 – British Method for Measuring Optical Density of Smoke in Laboratory.

• ISO 5659 – Plastics — Smoke generation — Part 2: Determination of optical density by a single-chamber test.

• NES 711 – Determination of the Smoke Index from the Combustion or Decomposition of Small Specimens of Material.

• NFPA 258 – Standard Test Method for Determining Smoke Generation of Solid Materials.

Notably, in tests according to NES 711, combustion and non-combustion conditions are distinguished, with different test parameters compared to those stipulated by ASTM E 662.

This technology is increasingly applied in material control for rolling stock, low-smoke cables, plastic components, and films used in critical environments. Interfacing with data acquisition systems also allows real-time monitoring of smoke optical density, ensuring precision, repeatability, and traceability of results.