Guide to the Design and Installation Specifications of Fire Smoke Exhaust Ducts

 

Fire smoke exhaust ducts are a core component of building fire safety engineering. Their design and installation must strictly follow national standards to ensure that the system can efficiently exhaust smoke and delay the spread of fire during a fire. The following comprehensively analyzes aspects such as design standards, installation key points, and fire - resistance performance in combination with the latest specifications.

 

I. Design Standards for Fire Smoke Exhaust Ducts

1.Wind Speed and Material Requirements

   - The design wind speed of metal smoke exhaust ducts should be ≤20m/s, and that of non - metal ducts should be ≤15m/s to reduce air flow resistance and prevent noise from exceeding the standard.

   - Smoke exhaust ducts must be made of non - combustible materials, such as galvanized steel sheets, fire - resistant boards, or flexible fire - resistant coiled materials, to ensure structural stability at high temperatures. The inner wall of the duct should be kept smooth to avoid dust accumulation or increased resistance.

 

2.Duct Thickness and Fire - Resistance Limit

   - The duct thickness must comply with national standards such as the "Test Methods for Fire Resistance of Ventilation Ducts" to ensure mechanical strength and fire - prevention performance.

   - Fire - resistance limit requirements:

     - When the horizontal duct is installed in the ceiling, the fire - resistance limit should be ≥0.5 hours; if it is directly exposed indoors, it should be ≥1 hour.

     - For ducts passing through fire - resistant partitions or in the corridor ceiling, the fire - resistance limit should be ≥1 hour (it can be relaxed to 0.5 hours for equipment rooms and garages).

     - Vertical ducts must be placed in independent shafts, with a fire - resistance limit of ≥0.5 hours.

 

3.Layout and Zoning Design

   - Smoke exhaust ducts shall not pass through building settlement joints or deformation joints to avoid leakage caused by structural deformation.

   - The horizontal distance between the air supply opening and the smoke exhaust opening should be ≥5 meters. If they are in the same smoke - proof zone, the air supply opening should be set below the lower edge of the smoke storage warehouse.

 

II. Installation Specifications for Fire Smoke Exhaust Ducts

1.Material and Connection Requirements

   - Other water - using facilities are strictly prohibited from being connected to the pipeline after the alarm valve. Galvanized steel pipes or galvanized seamless steel pipes are preferred to prevent corrosion and leakage.

   - Pipe connections must be tightly sealed. Flange gaskets should be made of high - temperature - resistant rubber or asbestos materials to prevent smoke leakage.

 

2.Slope and Drainage Settings

   - The pipes of the automatic sprinkler system should be set with a slope towards the drain pipe or auxiliary drain pipe. The slope is preferably 0.002 - 0.005 to ensure timely drainage of accumulated water.

   - The diameter of all water distribution pipes or branch pipes should be ≥25mm to ensure stable water flow pressure.

 

3.Key Points for Installation in the Ceiling

   - Smoke exhaust ducts in the ceiling should be treated with fire - proof and heat - insulation measures, such as being wrapped with rock wool, calcium silicate boards, etc., to prevent high - temperature from igniting combustibles.

   - When passing through partition walls or floors, steel sleeves should be installed and sealed with fire - proof mud to ensure the integrity of the fire - proof partition.

 

4.Sprinkler Configuration and Hazard Levels

   - The number of sprinklers needs to be determined according to the building's hazard level: in buildings with light and medium hazard levels, the number of sprinklers on each water distribution branch pipe should be ≤8.

   - Kitchen fume exhaust ducts should be set up separately, and a fire damper with an operating temperature of 150°C should be installed to prevent fires caused by oil accumulation.

 

III. Key Precautions

-Inspection and Testing: After installation, air - tightness testing and linkage commissioning are required to ensure that equipment such as smoke exhaust fans and fire dampers respond normally.

-Regular Maintenance: Inspect the cleanliness of the inner wall of the duct, the flexibility of the valve, and the integrity of the fire - resistant layer every six months, and replace aging components in a timely manner.

 

Following the above specifications can significantly improve the reliability of the fire smoke exhaust system and gain valuable time for personnel evacuation and fire fighting. In actual projects, the latest documents such as the "Technical Standards for Building Smoke Control and Exhaust Systems" should be combined to ensure that the design and construction meet the dynamically updated technical requirements.