Fire exhaust fans are no stranger to us; they are widely used in our daily lives. Fire exhaust fans are categorized into axial flow fire exhaust, centrifugal fire exhaust, roof-mounted fire exhaust, and pipe-mounted fire exhaust fans. These are the common types of fire exhaust fans. How much do you know about fire exhaust fan products? Today, let's take a look at the commonly used axial flow fire exhaust fans, including product details, selection, maintenance, and precautions. Please see the introduction provided by Dezhou Shituo Air Conditioning Equipment Co., Ltd., the manufacturer of axial flow fire exhaust fans. If you have any questions, feel free to call us at any time.。
Axial Flow Fire and Smoke Extraction Fan Detailed Introduction:
The axial flow fire exhaust fans meet the requirements of GA211-1999 standard. Our company has established an internal quality assurance system exceeding this standard, enabling continuous operation for 100 minutes at 400℃ high temperatures and 20 hours per cycle at 100℃ without damage. They are widely used in high-end residential buildings, ovens, underground garages, tunnels, and other applications. Additionally, we have developed six series of axial flow fans: Type I, Type II, Type III, Type D, Type IG, and Type IIG, tailored for different environments.
Fire exhaust fans can be configured with variable or multi-speed drives to meet the diverse requirements of advanced residential buildings, achieving dual functionality for both normal ventilation and high-temperature smoke exhaust during fire usage. This fan incorporates advanced CAD system software and is a newly developed product with multi-objective optimized design, boasting an efficiency greater than 80% and a flat efficiency curve, which is beneficial for energy conservation. This fire exhaust fan occupies less space than centrifugal fans; it is primarily an axial flow fan, which can be directly mounted on walls and comes in vertical, horizontal, or suspended installation options, significantly reducing the footprint. Moreover, it is not affected by large motor sizes or high air volume requirements, featuring a direct motor connection for reliable operation.
Section Two:Axial Flow Fire Smoke Exhaust FanSelection Instructions
Fan Selection:
Select the required air volume of the fan based on the size of the kitchen space and the arrangement of the exhaust hoods.
The calculation method is as follows:
1. Total air exhaust capacity, based on kitchen space, 40-60 air changes per hour.
For instance, if the total kitchen area is 160 square meters with a height of 3 meters, the required ventilation volume would be 160 x 3 x 60 = 28,800 m³/h.
2. Locally, based on the windward surface of the kitchen exhaust hood (subtracting the length against the wall from the circumference of the exhaust hood), the wind speed is approximately 0.5 meters per second.
For a kitchen exhaust hood with a circumference of 25 meters, where the wall-adjacent length is 10 meters, the required ventilation volume is 3600 x (25 - 10) x 0.5 = 27,000 m³/h.
Section 3: Calculate the static pressure required for the fan based on the pipeline conditions.
1. Determine the duct cross-sectional area based on air volume and velocity (approximately 10-15 m/s). The width-to-height ratio of the duct should not exceed 2:1 (to save materials and reduce air resistance).
2. Calculate the air resistance (i.e., the static pressure required by the fan) based on the wind speed, wind duct cross-sectional area, elbows, and changes in diameter.
III. Select an appropriate fan based on the calculated air volume and static pressure.
1. Selection Key Points:
The main control parameters for selecting exhaust fans are operating temperature, air volume, total pressure, efficiency, noise, motor power, speed, and shaft power.
The exhaust ventilation fan should operate normally for a long period under conditions where the medium temperature does not exceed 85°C.
The exhaust ventilation fan should ensure: continuous operation for 30 minutes at a medium temperature of 280°C, and continue to operate normally after the medium temperature cools down to the ambient temperature.
At the rated speed, within the working area, the actual pressure curve of the fan should conform to the specifications outlined in the instruction manual.
Axial flow exhaust fans will have a pressure deviation of ±5% corresponding to the specified flow rate.
Centrifugal exhaust fans will have a pressure deviation of ±5% at the specified flow rate.
The exhaust ventilation fan's A-weighted noise level at the operating conditions specified in the manual should comply with the requirements of JB/T8690-1998.
The smoke exhaust fan can be a standard steel centrifugal ventilation fan or a smoke axial flow ventilation fan. The specifications for the smoke exhaust fan are in accordance with the regulations of the "Code for Fire Prevention Design of High-Rise Civil Buildings." The minimum air volume of the smoke exhaust fan is 7200 m³/h, and the maximum air volume should not exceed 60,000 m³/h (referring to the maximum air volume of a single smoke exhaust zone).
The exhaust fan air volume should be increased by an excess of at least 10% to 20% of the required volume.
The pressure values of smoke control and pressurization fans should be calculated based on the不利 loop of the smoke exhaust system, ensuring a residual pressure of 40~50Pa within the smoke control staircases. For the antechambers, combined antechambers, fire elevator antechambers, and refuge floors, the residual pressure should be 25~30Pa.
Axial Flow Fire Exhaust FanShould comply with the current standard JB/T10281-2001 "Technical Conditions for Fire Smoke Exhaust Ventilation Fans."
The exhaust fan for the smoke extraction system should be separately installed. The location of the exhaust fan should be on the same level or above the smoke extraction area.
2. Test Method:
The impeller balancing and correction is performed according to the 7BIT9101 specifications on a dynamic balancing machine.
The impeller's overspeed test is conducted in accordance with the 7BIT6445 specifications.
Axial Flow Fire Smoke Exhaust FanThe mechanical operation test was conducted under normal operating speed, and after the bearing temperature stabilized for 20 minutes, the bearing's rise in temperature and vibration were measured. The rise in temperature should not exceed 4nC, and the vibration level and its corresponding values should comply with the relevant provisions of 7Bfr96V.
The aerodynamic performance test of the fire smoke exhaust fan is conducted in accordance with the provisions of GB/T 1236.
The noise measurement method for sound tests is conducted in accordance with the requirements of CB/r2888. The noise limits should comply with the provisions of 7BIT8690.
The high-temperature test is conducted in accordance with GA211 specifications. The high-field crystal performance requirements must reach the specified value of 4.42.
Axial Flow Fire and Smoke Extraction FanInstallation and Maintenance:
Kitchen exhaust fans are an indispensable key equipment for the kitchen. It is recommended not to install them inside the ceiling, but rather in the machine room, rooftop, or on the exterior wall, where maintenance is more convenient.
Kitchen exhaust fans, due to their long-term operation in high temperatures, humidity, and oil smoke gases, regular maintenance is indispensable.
3. Fault Point:
1. The impeller is covered in oil污, causing deformation of the blade curvature and angle, resulting in a significant drop in airflow and total pressure parameters, failing to meet the exhaust requirements.
2. Oil污 on the impeller leads to unbalanced impeller, increased vibration, and bearing damage.
3. Components are prone to rust and damage the fan in harsh environments.
Four, Special Note on Axial Flow Fire Extinguishing and Smoke Exhaust Fans: Generally, these require personal inspection and installation as they are core functional components. When selecting such exhaust fans, we must pay close attention to their functional characteristics and choose products that meet our usage requirements for a more suitable stable performance.
If centrifugal fire protection or axial fire protection operations are required, it is crucial to ensure that the terminal processing function is functioning properly; otherwise, it may affect the use standards of the components. Choosing the appropriate mechanical materials for such smoke extraction systems is the more normal processing technique, and it also offers better safety protection.
Axial high-temperature fire exhaust fans have functional requirements related to temperature. Generally, during operation, we maintain the temperature around 30℃. However, since the duration of operation affects temperature changes, it is particularly important to note that during prolonged use, a shutdown of about 10 minutes is necessary to ensure the normal functioning of the equipment.
Axial flow fire exhaust fans may exhibit abnormal sounds, severe motor overheating, live casing, circuit breaker tripping, and inability to start during operation. Immediate shutdown and inspection are required.
