What matters should be paid attention to when using the fire smoke exhaust fan after installation?

As the core equipment of fire emergency smoke exhaust, the operation stability of fire exhaust fan is directly related to the safety of evacuation and the efficiency of fire rescue. In the process of use after installation, it should be strictly controlled from four dimensions: daily inspection, operation specification, maintenance and emergency treatment. The specific precautions are as follows:

1. Daily inspection: Ensure that the equipment is "on standby at any time"

It is necessary to check the appearance and function of the fan and its supporting system regularly (once a week is recommended), focusing on the following contents to avoid failure in case of emergency due to minor faults:

Appearance and structure inspection

Check whether the casing, impeller and shaft of the fan are deformed, corroded and cracked, and whether the connecting bolts (such as the connection between the motor and the fan and the fan and the air duct) are loose, so as to prevent vibration or parts from falling off during operation.

Check whether the fire dampers (or smoke exhaust fire dampers) at the air inlet and air outlet of the fan are in the "normally closed" state (non-emergency), the valve body is clearly marked, and there is no foreign body blockage (such as dust and sundries), so as to ensure that it can be automatically opened according to the signal in case of fire.

Electrical system inspection

Check whether the terminals of the power line and control line are firm and whether the insulation layer of the cable is damaged, so as to avoid short circuit or poor contact.

Confirm that the dual power supply switching device of the fan (fire fighting equipment needs dual-circuit power supply) is functioning normally: manually switch the main and standby power supplies, and observe whether the fan can be started normally to prevent emergency failure caused by single power supply failure.

Check whether the cooling fan and protective cover of the motor are in good condition, and there is no dust on the surface of the motor (the dust will affect the heat dissipation and lead to overheating and burning of the motor).

Control and signal inspection

Test the "manual/automatic" control mode of the fan: manually press the "start/stop" button on the control cabinet, and the fan should be able to start and stop smoothly; Send the start signal remotely through the fire control room, and the fan should respond to start within 30 seconds (in line with the requirements of GB 51251 "Technical Standard for Smoke Prevention and Exhaust System in Buildings").

Check whether the signal feedback during fan operation is normal: after startup, the fire control room should be able to receive the feedback signal of "fan operation" and "fire valve opening", and trigger "fault alarm" when it fails.

Second, the operation specification: avoid misoperation or overload operation.

Fire-fighting smoke exhaust fans are divided into "emergency smoke exhaust" and "daily ventilation" (some two-speed fans have this function), so they must be operated strictly according to the scene specifications, and illegal use is prohibited:

Working condition distinction: it is forbidden to mix them up.

Emergency smoke exhaust condition: only when a fire occurs, it is automatically started (or manually started) by the fire linkage system, which is used to exhaust the thick smoke and toxic gas generated by the fire. At this time, it is necessary to ensure that the doors and windows in the smoke exhaust area are closed (to prevent the smoke from spreading) and that the smoke exhaust fire damper at the inlet of the fan is opened (it will automatically close when the temperature exceeds 280℃, so as to cut off the power supply of the fan and prevent the flame from spreading).

Daily ventilation condition (only two-speed fan): daily use of low speed operation, for general ventilation; Attention should be paid to: Do not switch to high-speed smoke exhaust mode during daily operation to avoid long-term overload operation of the motor, and switch to high-speed mode for testing at regular intervals (once a month, running for 5-10 minutes each time) to ensure normal emergency function.

In-service parameter monitoring

When the fan is running, it is necessary to observe whether the current and voltage are within the rated range of the motor (the instrument in the control cabinet shows normal). If the current rises abnormally, it may be that the impeller is stuck, the air duct is blocked or the motor is faulty, so it is necessary to stop the machine immediately for inspection.

Monitor the running sound of the fan: normally, it should be a steady "buzzing sound". In case of sharp rubbing sound and severe vibration sound, it is necessary to stop the machine immediately, and check whether the impeller rubs against the casing and whether the bearing is damaged (oil shortage or wear of the bearing is a common reason).

Prohibit illegal operation

It is forbidden to remove the casing and protective cover or touch the impeller with hands/tools when the fan is running (the impeller rotating at high speed has serious safety hazards).

It is forbidden to pile up sundries in the exhaust duct or close the exhaust outlet (it will lead to overpressure operation of the fan, burn the motor or damage the duct).

In non-fire scenarios, it is forbidden to start the emergency smoke exhaust mode at will (especially for single-speed fans, long-term high-speed operation will accelerate the aging of components).

III. Maintenance: prolong the service life of the equipment and ensure the emergency performance.

Regular maintenance (small maintenance once every three months and major maintenance once a year is recommended) is the key to ensure the long-term and reliable operation of the fan. The specific contents are as follows:

Cleaning and maintenance

After shutdown, use compressed air or soft brush to clean the dust on the fan casing and motor surface (dust accumulation will affect heat dissipation and lead to overheating of the motor); If oil stains are attached to the impeller (such as kitchen exhaust fan), it should be wiped with neutral cleaner to avoid vibration caused by imbalance of the impeller.

Check the valve plate and actuator of the smoke exhaust fire valve, remove the dust and sundries in the valve body, and ensure that the valve plate can be opened/closed flexibly (valve plate jamming will lead to smoke exhaust failure).

Lubrication maintenance

The fan bearing needs to be filled with grease regularly (choose the model according to the equipment manual, such as No.3 lithium-based grease): when it is in minor maintenance, replace it with new grease when it is in major maintenance (the old grease will harden, leading to bearing wear), and the filling amount should be 1/2-2/3 of the inner space of the bearing (too much will lead to bearing overheating).

Check the wear of the motor bearing: If there is a "stuck" or abnormal sound during rotation, the bearing should be replaced in time (bearing damage will lead to eccentricity of the motor shaft and wear the impeller).

Component maintenance and replacement

Check the impeller: if the impeller is deformed and the blades are broken, it needs to be corrected or replaced in time (the imbalance of the impeller will cause the fan to vibrate violently and damage the casing and motor); Check whether the connecting key between the impeller and the shaft is loose, and if it is loose, it needs to be tightened again.

Check the fire damper: test the "temperature fuse" function of the fire damper (the temperature sensing element of the valve body can be baked with a hot air blower, and the power supply of the fan should be automatically turned off and cut off when the temperature reaches 280℃). If the fuse is aging or the actuator fails, it is necessary to replace it with a new component.

Check the electrical components: replace the aging power cord and control cord (the insulation layer needs to be replaced immediately if it is damaged), and fasten the loose terminal; Test the pull-in function of contactors and relays. If the contacts are ablated, they need to be polished or replaced (contact failure will cause the fan to fail to start).

Record archiving

Establish a fan maintenance file, and record in detail the time, content, problems found and treatment results (such as replacement parts model, grease type, etc.) of each inspection and maintenance, so as to trace the equipment status and predict the failure in advance.

Fourth, emergency treatment: standardize the operation in case of fire, and deal with it in time in case of failure.

Fire emergency start-up and operation

In case of fire, if the fire-fighting linkage system does not automatically start the fan, it needs to be started manually through the field control cabinet or fire control room immediately: first confirm that the fire damper in the smoke exhaust area is opened, and then start the fan to avoid "idling" or overpressure of the fan.

After the fan is started, it is necessary to monitor the smoke exhaust effect through the fire control room (for example, whether there is smoke exhaust at the smoke exhaust port). If it is found that the smoke exhaust port is not open, the air duct is blocked or the fan is reversed (the motor wiring error will lead to reversal, so it is necessary to cut off the power and adjust the phase line).

When the smoke exhaust fire damper automatically closes due to the temperature reaching 280℃, the fan should be powered off synchronously to stop running (to prevent the flame from spreading through the air duct). At this time, it is not allowed to forcibly open the fire damper or restart the fan.

Sudden fault handling

If the fan stops suddenly during operation, it is necessary to cut off the power supply first and check the cause of the failure: if it is overload protection (thermal relay tripping), after the motor cools down (about 15-30 minutes), check whether there is air duct blockage and impeller blockage, and then restart after troubleshooting; If the motor is burnt out (with burnt smell), it needs to be replaced before use.

If the fan fails to start in case of fire, standby smoke exhaust facilities (such as standby fan and natural smoke exhaust port) should be activated immediately, and fire rescue personnel should be informed to avoid delay in smoke exhaust and evacuation.

V. Supplementary precautions for special scenes

High-temperature environment (such as kitchen and boiler room): It is necessary to shorten the maintenance cycle (minor maintenance once every two months), and focus on checking the oil pollution of the impeller and the heat dissipation of the motor to avoid the accelerated aging of components caused by high temperature.

Damp environment (such as underground garage and basement): it is necessary to strengthen anti-corrosion treatment (regularly brush anti-rust paint), check the waterproof seal of electrical system (to prevent short circuit), and waterproof grease can be used for motor bearings.

Two-speed fan: It is necessary to test the high-speed and low-speed switching function regularly (once a month) to ensure the smooth operation of the motor during switching and avoid the failure of high-speed smoke exhaust in case of emergency due to switching failure.

In short, the use of fire smoke exhaust fans should follow the principle of "regular inspection, standardized operation, scientific maintenance and emergency priority", which should not only avoid equipment damage caused by daily misoperation, but also ensure that they can "come at the call and fight when they come" in case of fire, so as to truly play the role of emergency smoke exhaust security.