Smoke tightness S is the ability of the component to reduce or eliminate the transmission of gas or smoke from one side of the door to the other. The following performance levels are defined:
The Sa index relates to smoke tightness at ambient temperature only.
The Sm index relates to smoke tightness at ambient temperature and at 200°C.
In the case of fire-resistant components, S must be added to the fire-resistance classification (e.g. EI2 60 – Sm).
- Smoke tightness Sm – when the maximum flow rate measured at one of the temperatures (ambient and 200°C) and up to a pressure of 50 Pa does not exceed 20 m³/h for a single-leaf door set or 30 m³/h for a double-leaf door set.
- Smoke tightness Sa – when the maximum flow rate measured at ambient temperature and at a pressure of less than or equal to 25 Pa only does not exceed 3m³/h per metre of clearance between the fixed and mobile components of the door set.