Cleanroom smoke exhaust systems have some "special" design requirements. In Class C cleanroom within the same fire compartment, if the personnel density is less than 0.02 people/m² and the safe evacuation distance is less than 80m, mechanical smoke exhaust facilities may not be required. Cleanroom with a cleanliness level stricter than Class 4 should not have mechanical smoke exhaust systems. Cleanroom with a building area greater than 2500㎡ and an air cleanliness level worse than Class 7 should have emergency smoke and heat exhaust facilities on the outer walls or roof of the production floor.
The core contradictions in cleanroom smoke exhaust systems:
(1) Airtightness VS Smoke Exhaust Requirements: Cleanroom require high airtightness to maintain cleanliness, while effective fire and smoke control requires opening smoke exhaust vents and supply air vents, which compromises airtightness.
(2) Airflow Organization Conflict: The airflow organization in cleanroom is designed to control particle flow, while the smoke flow direction during a fire and the airflow organization for fire and smoke control may conflict with this.
(3) Difficulty in Sealing Smoke Compartments: Cleanroom rooms contain many automated transportation systems, such as OHS. Due to the presence of automated transportation tracks, it is difficult to achieve sealed smoke compartments, meaning that multiple smoke compartments are interconnected.
The following methods can be used in engineering design to improve airtightness:
(1) Terminal: Use a plate-type smoke exhaust vent + 280℃ smoke exhaust fire damper, or use a smoke exhaust valve + 280℃ smoke exhaust fire damper + fixed single-layer louvered vent in the smoke exhaust branch pipe within this fire and smoke control zone;
(2) Pipe Airtightness: Must meet the relevant requirements of the acceptance specifications;
(3) Design within the Equipment Room: A smoke exhaust valve is installed in the main smoke exhaust pipe in the equipment room, and this valve is interlocked with the smoke exhaust fan; a maintenance bypass is provided in the main smoke exhaust pipe in the equipment room for maintenance and testing of the fan.
Design measures for unsealed smoke compartments:
Increase the smoke exhaust volume of the smoke exhaust system. For example, some projects amplify the calculated smoke exhaust volume by 1.2 times to accelerate the smoke exhaust rate and reduce the diffusion and accumulation of smoke.
Where should the smoke exhaust supply air be introduced into the cleanroom?
(1) The smoke exhaust and makeup air are supplied to the return air plenum of the cleanroom;
(2) The smoke exhaust and makeup air are supplied to the technical interlayer below the cleanroom;
(3) The smoke exhaust and makeup air are supplied to the smoke control zone within the cleanroom.
Suzhou Pharma Machinery Co.,Ltd.
2026/03/09
Icey
