A summary of 41 issues encountered during fire safety inspections – see if you’ve made any of them!

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In recent years, the Beijing Fire Department has identified many practical problems during fire safety inspections of high-rise buildings under its jurisdiction. Some of them are due to poor architectural design ； Some continue to use old standard provisions that do not meet the requirements of new standards ； In some cases, the owners modify the design without permission ； Some are due to errors in construction and installation ； There are also cases where the construction progress is too fast, and so on. When discussing each issue, this article merely cites the relevant regulatory requirements and provides necessary explanations; these are not necessarily comprehensive and are provided for reference only. Issues that are clearly related to the commissioning of system equipment, such as the inability of smoke exhaust outlets and smoke exhaust fans to operate in conjunction with each other, the failure of the smoke exhaust valves to shut down automatically when manually operated, the inability of the smoke exhaust fans to stop running during end-point water discharge tests, the failure of the sprinkler pumps to start automatically, the inability of the fire dampers to descend after the fusible alloy is intentionally broken, and the failure of the safety exit evacuation indicator lights to light up, will not be discussed here for now. Fire safety inspections are divided into three types: inspections for concealed works, inspections for rough finishing, and inspections for final finishing. 1. The fire safety acceptance of concealed works is conducted after the building is put into use. Fire protection facilities and fire-resistant components for which fire inspection and acceptance cannot be carried out. Fire safety inspection conducted during the construction phase. For example, fire-resistant spraying for steel structures, fire protection pipelines and connections, etc. 2. The fire protection inspection for rough completion involves the functional inspection of the fire protection systems and facilities within the building. Primarily, the fire protection systems and facilities have been installed and commissioned. But it is a construction project that has not yet undergone interior decoration. Applicable after the main construction of the building is completed. Fire system inspection before a building is put up for rent or sale. Even after the rough-fit fire safety inspection is passed, the building is not yet ready for use; it is necessary to complete the fire safety inspection for the fine-fit work before it can be put into use. 3. The fire safety inspection for fully finished interior decoration is the fire safety inspection conducted before a building is completely completed and ready for use. The fire safety inspection of buildings focuses on verifying whether the following aspects meet the regulatory requirements: (1) the overall layout of the building and the internal layout, including the location of fire control rooms, fire pump rooms, etc.; (2) the division of the building into fire and smoke prevention zones; (3) the interior decoration materials used in the building; (4) safety evacuation routes and fire elevators; (5) fire water supply systems and outdoor fire hydrant systems; (6) indoor fire hydrant systems; (7) automatic sprinkler systems; (8) fire alarm and interconnection systems, including emergency fire broadcasting and fire telephone communication systems; (9) smoke prevention and exhaust systems, including the fire-related functions of air conditioning and ventilation systems; (10) gas extinguishing systems; (11) fire power supplies and their distribution, including emergency lighting and evacuation sign systems; (12) the placement of fire extinguishers, among others. I. The civil air defense door in the elevator lobby of the basement is used in place of a fire door; all high-rise buildings have basements. Some floors are equipped with civil air defense doors as part of the civil air defense system. Very thick cement doors are difficult to open and close. During inspection, it was found that the civil air defense doors in the underground level had been used in place of fire doors. The civil air defense door in the elevator lobby of the underground floor replaced the fire door, resulting in the absence of a lobby in the civil air defense floor. In the past, civil air defense doors could be used as a substitute for fire doors, but current regulations no longer permit this. These are traditional issues encountered in construction reviews and fire safety inspections. Civil air defense regulations require that civil air defense doors cannot replace fire doors. The corrective measure is to install a fire door in front of the civil air defense entrance. II. The opening direction of the fire doors and fire locks is reversed: the fire doors on the ground floor do not open outward, while the fire doors on the other floors do not open toward the ground floor. Fire doors shall be swing doors that open in the direction of evacuation and shall be manually operable from either side when closed. Fire doors in evacuation corridors, stairwells, and anterooms should have a self-closing function. Double and multiple fire doors should have the function of closing in sequence. Fire doors that remain open at all times. It should have the function of automatically shutting down and providing signal feedback in case of a fire. III. Fire doors are equipped with door stoppers; some use latches while others use magnetic door retainers. Fire doors in corridors, stairwells, and anterooms used for evacuation should have the ability to close automatically. That is. Fire doors, except for those that remain open, must not have door stoppers. When using a magnet-type door catch on a fire door, it cannot close on its own; a latch is required. A fire door must not be manually opened from either side. IV. For shared stairwells, the stairs on the ground floor are not separated from those in the basement by fire doors; basements or semi-basements should not share stairwells with the upper floors. When shared stairwells are necessary, they should be located at the entrances to the ground floor and the basement or semi-basement levels. Separate it with partition walls having a fire resistance rating of not less than 2 hours and Class B fire doors. And there should be obvious markings. The original clause used “not appropriate”. In the 2001 version, it was changed to “shall not” as a mandatory provision that must be enforced. V. The hinged fire door located next to the fire curtain has been removed or locked; in the past, once the fire curtain was lowered. It cannot be used for evacuation. Add sliding fire doors. It ensures that evacuation is possible from both sides. This is a regulation formulated in light of the lessons learned from the Karamay fire in Xinjiang. VI. A louver has been added to the fire door of the pump room; the pump room is equipped with a regular door. A louver has also been added to the fire door of the pump room, which is otherwise a regular door, and the pump room has regular windows that lead to other areas. The equipment rooms for automatic fire suppression systems, as well as ventilation and air conditioning rooms located in high-rise buildings, should be separated from other areas by partition walls with a fire resistance rating of at least 2 hours, floors with a fire resistance rating of 15 hours, and Class A fire doors. The doors of the fire pump rooms in high-rise buildings should be Class A fire-resistant doors with a fire resistance rating of 12 hours. The pump room should be equipped with Class A fire doors; if the pump room has windows leading to other areas. Its windows should be of Class A fire-resistant type. Such practices are common in building renovations; the intention is to improve air convection and ventilation in the pump room, but they clearly violate regulatory requirements. VII. Rooms in office, commercial, or food service areas that are larger than 60 m2 shall have only one door; rooms in the basement that are larger than 50 m2 shall also have only one door. The area of rooms located between two safety exits shall not exceed 60 m². Time. It can be specified that the clear width of each door should not be less than 0.9 meters for rooms located at the end of a corridor. When the area does not exceed 75 m2, one door may be installed, with a clear width of no less than 14 meters. Basement rooms with an area of no more than 50 m2 and a maximum occupancy of 15 people may also be equipped with one door. Therefore. Rooms on the ground floor with an area of over 60 m2, and rooms underground with an area of over 50 m2, must be equipped with two doors. VIII. Failure to install fusible alloy in fire shutters: In light of the lessons learned from the fire that occurred in Karamay, Xinjiang. Beijing has issued a regulation requiring that all fire shutters be equipped with fusible alloys. Furthermore, the fusible alloy should be installed outside the ceiling. This is to prevent excessive control failure. Fire shutters can still descend due to their own weight, thereby serving to prevent the spread of fire. 9. When a fire elevator and service elevators share the same machine room, there is no separate machine room for the fire elevator; the fire elevator shaft and machine room shall be separated from adjacent elevator shafts and machine rooms by partition walls with a fire resistance rating of not less than 2 hours. When opening a door in a partition wall. Class A fire doors should be installed. The corrective measure is to build a partition wall to separate them. It can also be separated by fire doors, or both elevators can be used as fire elevators. 10. Flammable materials such as wood shall not be used for decoration inside fire elevators; the interior decoration of fire elevator carriages must be made of non-combustible materials. This practice must be corrected. 11. There are no drainage facilities at the bottom of the fire elevator shaft; a water barrier should be installed at the entrance to the fire elevator vestibule. Drainage facilities should be provided at the bottom of the shaft of fire elevators. The capacity of the drainage well shall not be less than 2 cubic meters. The discharge capacity of the drainage pump should not be less than 10 L/s. In the past, there were water collection pits at the bottom of building fire elevators, but no drainage system was in place; nowadays, most construction projects are equipped with drainage facilities at the bottom of fire elevator shafts. 12. Fire elevators cannot reach the basement; only service elevators can access it. In residential buildings, the first basement floor is often used as a bicycle garage, while another floor is used for civil defense purposes. Therefore, if a fire elevator cannot reach the basement, it is still possible to have service facilities and offices for staff in the basements of public buildings; hence, a fire elevator must be able to reach the basement. In addition, the fire elevator should be able to reach all floors above ground. It’s only during acceptance that it’s discovered some things are not like this, which is quite problematic; some can be changed, but others cannot.   13. Doors such as those to elevator shafts and fan rooms that are located in stairwells shall not have any other doors, windows, or openings other than those providing access to public corridors. This is a problem present in many buildings. The solution is to install an elevator and fan room door on another wall in the machine room, so that it does not open directly into the stairwell. 14. The top-floor fire elevator lacks a vestibule; this is a structural modification made arbitrarily by the property owners during building renovations and must be corrected. 15. There should be steps in the vestibule of the fire elevator; no steps shall be present within 1.4 meters inside and outside the door of the evacuation exit, and the door must open outward without any threshold. This issue relates to structural changes made arbitrarily by the property owner during building renovations, which must be corrected. 16. Low exhaust air volume and low positive pressure supply air volume: During construction, blockages or obstructions in the air ducts due to waste disposal, as well as low airflow from the fans, are the reasons for the low exhaust air volume and low positive pressure supply air volume. The mechanically pressurized supply fans shall ensure that the air pressure in smoke-proof stairwells is 40Pa–50Pa, while the air pressure in vestibules, shared vestibules, vestibules of fire elevators, and enclosed refuge floors is 25Pa–30Pa. In the areas where mechanical smoke exhaust systems are installed, the air volume of the smoke exhaust fans must be sufficient to handle the smoke extraction from one smoke control zone; this volume should be calculated at no less than 60 m³/h per square meter. The minimum air extraction capacity of a single fan should be 7200 m³/h when dealing with the smoke extraction from two or more smoke control zones. It shall be calculated at not less than 120 mVh per square meter of the maximum smoke control zone area. 17. For air ducts with a width of 1.2 meters, there is no sprinkler protection; when the width of the ventilation duct exceeds 1.2 meters, sprinklers should be installed below its underside. That is, in areas where the duct width is 1.2 meters or more, the ducts should be protected by sprinklers. 18. A large conference hall has an area of 375 m2 and lacks smoke extraction facilities. Another large banquet hall on the second floor has an area of 1200 m2, has no windows and no smoke extraction facilities; its corridors are 40 meters long and also lack smoke extraction facilities. Natural smoke exhaust is available in the basement level. This applies to the following areas in category I high-rise buildings and category II high-rise buildings with a height of over 32 meters. Mechanical smoke exhaust systems should be installed in: (1) interior corridors that have no direct natural ventilation and are longer than 20 meters, or those that do have direct natural ventilation but are longer than 60 meters; (2) ground-level rooms without windows or rooms with fixed windows that cover an area of more than 100 m2 and are frequently occupied or contain large amounts of combustible materials; (3) atriums that do not have conditions for natural smoke exhaust or whose clear height exceeds 12 meters; (4) basements and other areas where the total area of all rooms exceeds 20 m2, or where a single room has an area of more than 50 m2 and is frequently occupied or contains large amounts of combustible materials, unless natural smoke exhaust is achieved through windows such as window wells. Undoubtedly, smoke exhaust facilities should be installed in the aforementioned locations.   19. Dual-power supply for fire control rooms, fire pumps, smoke prevention and exhaust fans, etc. shall not allow mutual switching at the end points. For high-rise buildings, an automatic transfer switch shall be installed at the final distribution box to supply power to fire control rooms, fire pumps, fire elevators, smoke prevention and exhaust fans, etc. These are the provisions newly revised in the 2001 edition of the High-Rise Building Code; they represent the technical safeguards that ensure important fire-fighting equipment can function effectively during a fire. Most buildings from the past did not do this. However, during building renovations, such measures should be implemented as much as possible, especially in important buildings; for example, Beijing West Railway Station underwent such renovations. 20. Ducts passing through firewalls: Ducts that pass through firewalls. There are no fire dampers installed; the air ducts passing through walls in garages lack fire dampers; the positive pressure ventilation ducts in the basement also lack fire dampers; no fire dampers are installed for ventilation systems that cross gas protection zones; there are no fire dampers in the air ducts used for power distribution and smoke exhaust; and no fire dampers are present in the ventilation ducts that pass through fire compartments, among other issues. The insufficient installation of fire dampers in certain areas is a common issue in construction projects. Smoke exhaust ducts must be made of non-combustible materials. Smoke exhaust ducts installed in the ceiling. Its insulation layer shall be made of non-combustible materials and shall maintain a distance of not less than 150 mm from combustible materials.   Fire dampers should be installed in the air ducts of ventilation and air conditioning systems in any of the following situations: (1) where the ducts pass through fire compartments; (2) where they pass through the partitions and floors of ventilation and air conditioning rooms, as well as important rooms or rooms with a high fire risk; (3) on the horizontal sections where vertical ducts meet horizontal ducts on each floor; (4) on both sides of areas where the ducts pass through expansion joints. The first three cases can be arranged on one side. The latter case should be provided on both sides. 21. Fire dampers not being secured with separate hangers is a common problem in construction projects. In the explanation of the provisions regarding the installation of fire dampers in high-rise buildings. The installation requirements for fire dampers include measures such as separate supports and hangers. To prevent duct deformation from affecting the closure of the fire damper, while ensuring that the fire damper can close tightly on its own in the direction of the airflow. 22. Emergency lighting shall not be provided in areas such as fan rooms, pump rooms, elevator lobbies, and public corridors. Emergency lighting shall be installed in the power distribution room, fire control room, fire pump room, smoke control room, standby generator room, main telephone room, and other rooms that need to remain operational in the event of a fire. And the illuminance for normal lighting should be ensured. Emergency lighting shall be provided in stairwells, antechambers of smoke-proof stairwells, fire elevator shafts and their antechambers, shared antechambers, and refuge floors. Emergency lighting shall be provided in evacuation corridors in public buildings, as well as in interior corridors in residential buildings whose length exceeds 20 meters. 23. The horizontal openings in the strong-current electrical shafts on a certain floor are not sealed; the vertical openings in the strong and weak-current electrical shafts of that building are also not sealed. There are openings in the strong-current electrical shafts on a certain floor, and the vertical openings in the strong and weak-current electrical shafts of that building remain unsealed as well. There are holes through fire compartments, and the water pipe shafts lack enclosing walls, among other issues. In high-rise buildings with a height not exceeding 103 meters, cable shafts and pipe shafts should be located at the floor levels every 2 to 3 floors. Non-combustible materials with a fire resistance rating equivalent to that of the floor slabs should be used as fire barriers; in high-rise buildings with a height of over 100 meters, these barriers should be installed at each floor slab. Use non-combustible materials with a fire resistance rating equivalent to that of the floor slab for fire separation. Holes that connect cable shafts, pipe shafts to rooms, corridors, etc. Its gaps should be filled tightly with non-combustible materials. The basic method of actual sealing involves using fireproof putty and fireproof pads to seal the strong and weak current shafts on each floor. In construction projects, water pipes are generally sealed, and the sealing of high-voltage electrical compartments is relatively good. There are many problems with the low-voltage shafts. This is one of the most common problems during acceptance: the large number of openings in fire compartments is a difficult issue to resolve. Some projects are done to meet fire safety inspection requirements. The night before the acceptance. Organize workers to work overtime to carry out all the sealing. During the fire safety inspection. The main reason for this issue is that the construction work has not yet been completely completed. 24. Some evacuation indicator lights were installed in the wrong direction, and the safety exit signs in stairwells were placed incorrectly; the installers did not understand the professional requirements, so people could not reach the evacuation routes following the directions indicated. 25. The underground garage lacks emergency lighting, and there are insufficient evacuation signs in it. Emergency lighting should provide a lighting intensity of no less than 0.5 Lx in the event of a fire. Additionally, it is generally required that evacuation signs be visible from any point in the underground garage to facilitate the evacuation of people. 26. Safety exit lights should not be installed next to fire shutters or at garage doors that open outward and lack evacuation signs. Sliding fire doors are installed. Here, the emergency exit lights should not be installed at the fire shutters. It should be adjusted to the swing fire door. Egress signs should be installed on the swing fire doors on the garage partition walls. And it should be added on both sides of the door. 27. Overpressure at the top-level fire hydrants: The static water pressure at the outlet of the fire hydrants should not exceed 0.8 Mpa. A zoned water supply system should be adopted when the pressure is greater than 0.8 MPa. When the water outlet pressure at the fire hydrant nozzle is greater than 0.5 MPa. A pressure-reducing device should be installed at the fire hydrant. The water discharge pressure at the fire hydrant outlet should be greater than 0.5 MPa. During fire extinguishing. It’s difficult for people to hold a water gun. Overpressure is divided into static overpressure and dynamic overpressure. Often, the most favorable point of the system is where static pressure overload occurs, while the most unfavorable point is where dynamic pressure tends to exceed the limit after the large pump starts up. Install pressure-reducing orifice plates at the fire hydrants, use pressure-stabilizing valves, or install variable-flow pressure control pumps, and so on. If 3 to 4 fire hydrants are installed in other floors while there is only one fire hydrant on the top floor and no pressure reduction measures are taken, overpressure issues may occur at that top-floor fire hydrant. The solution is to implement pressure reduction measures at the test fire hydrant as well. 28. The light on the fire hydrant button does not shine, or there is no light indicator on the fire hydrant button. There are two types of buttons that can be used as fire hydrant buttons: one type is those controlled by high-voltage electricity, where all the buttons on the fire hydrant pipes are connected in series or parallel and then linked to the electrical control panel of the pump. Each button has an indicator light that remains off under normal conditions and turns on when fire suppression is activated, or stays on under normal conditions and turns off when fire suppression is activated. This type of button is simple to connect and control. It is the switch for the electrical control cabinet that remotely controls the pump. But it is difficult to maintain. Especially in large buildings. In cases with a large number of fire hydrants, if a failure occurs in one of the parallel connections. It is necessary to check each item individually; otherwise, the pump system, or more precisely the electrical control cabinet of the pump, will operate frequently in automatic mode, and a fault will occur if there is a problem in one of the components connected in series. It is also necessary to check each item individually, otherwise all the pump start buttons may become ineffective. Second, the manual alarm button also serves as the pump start button. It has an independent address that allows for the display of the locations where fire hydrants are enabled one by one; the system operates stably and reliably, and is easy to maintain. Pump start control is transmitted through the alarm controller. Given the increasing reliability of alarm systems in recent years, the author believes that the latter approach is better – it is simpler, more reliable, and easier to maintain. Some manual alarm buttons that also serve as fire hydrant buttons lack indicator lights; a signal module is used instead as the button. The fire hydrant buttons in domestic alarm systems can have indicator lights, while some foreign products do not come equipped with such lights. 29. The pump-start signal is a false signal. Not many buildings use this approach; the control and signal wires running from the pump room to the control room lack one feedback wire for the pump-start signal.   The control system sends a signal to start the pump in the control room, regardless of whether the pump actually starts or not. This activates the pump start indication signal. If the pump’s electrical control cabinet is set to manual mode. Although the control room shows an indication that the pump has started, the pump does not actually start and the water pressure does not increase. The pump’s electrical control cabinet is set to automatic mode, but in the event of a fault, the pump still does not start despite the indication in the control room. Only when the pump’s electrical control cabinet is in automatic mode and there are no faults will the control room show an indication that the pump has started. The pump was just started and the water pressure increased. The feedback signals in the first two aforementioned cases can both be regarded as false feedback; only when the pump actually starts can its feedback signal be considered true feedback. It is recommended to use a true feedback signal in the project. 30. The actually installed fire pumps and spray pumps are lower than the specifications specified in the building design; for example, the design specifications are 30LS and 21LS respectively. In practice, 25LS and 15LS are used. This issue must be corrected. There are two ways: one is to replace the pump, and the other is to adjust the parameters of the pump. Reducing the pump’s head height can increase the pump’s flow rate. Some products can be done this way. However, this solution is not recommended for fire pumps. 31. The water spray pump shall be started directly by a pressure switch, and a wet alarm valve shall be installed on the main outlet pipe of the spray pump. On the wet alarm valve, connect in sequence a filter, a ball with a volume of 20–30 cm3 as a delay element, a pressure switch, a hydraulic alarm bell that reaches 90 dB within 3 meters, and a drain pipe. When there is water flow in the main outlet pipe of the spray pump. As it passes through the aforementioned device, the pressure switch generates a passive contact switch signal. The feedback module sends an alarm signal, which in turn controls the pump to start. Now in fire protection engineering. Theoretically, it is the \"AND\" logic of the water flow indicator signal and the pressure switch signal of the wet alarm valve that serves as the start signal to activate the sprinkler pump; in practice, however, the pressure switch signal of the wet alarm valve alone is sufficient to activate the sprinkler pump. Because the pressure switch signal is stable and reliable. Old systems either have a spray pump that starts based solely on the signal from the water flow indicator, or they have a mechanism in which the spray pump starts after both signals undergo an \"AND\" operation. At the time of acceptance. Sometimes, cheating on-site to pass fire safety inspections can be detected from the printed records. Normal test and printing results, such as water discharge at the end of a three-layer spray system causing the flow indicator to trigger an alarm. After water is released from the fourth layer, causing the flow indicator to give an alarm, etc., the pressure switch also gives an alarm. Then, the spray water pump starts. And the cheating tests and printed results. For example, when water is released in three stages and the flow indicators do not give an alarm, in this case a person is instructed via walkie-talkie or mobile phone to start the pump; the order of events is reversed – first the sprinkler pump is started, then the pressure switch gives an alarm, and finally all the flow indicators give alarms. 32. The distance between the upward-facing water spray heads and the ceiling is too large. Older standards required that the distance between the splash plate of such spray heads and the ceiling be between 150 mm and 300 mm ； The specification in the 2001 version was changed to 75mm to 150mm. This problem arises when a new system is designed using data from the old specifications. 33. Incorrect selection of sprinkler heads leads to two problems: one is installing sprinklers on the walls. Side spraying should be used. While some are equipped with ordinary nozzles, which can spray both upward and downward. But it cannot be used for side spraying. Second, the wrong type is used: the upper spraying type is installed as a lower spraying type, and the lower spraying type is installed as an upper spraying type. 34. The outlet pipe at the end of the nozzle is a 20mm pipe; since the outlet pipe of the water spray system specified is also a 20mm pipe, problems arose as a result of designing based on this specification. **The standard requires a 25mm tube for this. 35. The end water testing device does not have a drainage mechanism; the older version of the standards did not require such a mechanism to be present. Therefore, in the past, when conducting a water discharge test on automatic sprinkler systems, hoses had to be temporarily connected to discharge the water nearby. In the 2001 edition of the new standards, the water discharged from the end test device should be released into the drainage pipe through an orifice flow. 36. The garage uses a wet-system but has no heating; new designs should not adopt this approach. It should be designed as a pre-action system. Currently, areas 50-60 in the underground garage are equipped with a pre-action sprinkler system. It can prevent freezing in winter. It also has a faster fire response time. Or. Designed as a dry system. But it’s used less now. For systems that do not take winter anti-freezing into account, electric heating is also used as a solution. The principle is to wrap the water pipeline with a resistive wire and insulating material. The electric heating is controlled at around 5°C. This method is power-consuming and is a remedial measure. 37. It is not possible to force-shut down non-fire-related electrical systems on a certain floor; the entire building does not have the capability to force-shut down such systems. Non-fire-related electrical systems refer mainly to lighting power, power for non-fire-related equipment, and power used for air conditioning and ventilation. How to forcibly cut off non-firefighting power during a fire. The specifications do not specify any particular locations. The common practice nowadays is to cut off the non-fire-related power supply in the affected floor as well as in the two adjacent floors above and below in most cases when a fire breaks out on that floor; in a few cases, only the non-fire-related power supply in the affected floor is cut off. In some residential buildings, non-fire electrical circuits are forcibly cut off in a staged manner. Such as one section from floor 1 to 4, and one section from floor 5 to 8. The control room no longer has a function for manual direct control. Many models are equipped with a semi-automatic control function, that is, special switch buttons are provided to send commands to the on-site control module via the controller in order to control power shutdown. For old buildings, many non-fire power cuts can only be carried out in the substation room and cannot be controlled in a coordinated manner. 38. The fire control room is equipped with network devices and used as a network server room as well; it contains only fire protection equipment and security monitoring devices to serve as a disaster prevention center. It is the practice for the vast majority of buildings. To attach other types of devices, the required conditions must be met. Areas with strong electromagnetic field interference and other equipment that may affect the operation of fire control devices should not be located around the fire control room. For example, wireless communication devices may cause interference issues. It cannot be installed inside or around the control room. 39. Gas alarms should be powered by two separate power sources; this applies to boiler rooms as well. The gas company requires the installation of a small gas alarm controller for gas detection. The boiler room is also equipped with automatic fire alarm systems; when the smoke detectors or temperature sensors in that room give an alarm, it should trigger the disconnection of power supply to non-fire-related equipment in that area, thereby cutting off electricity to that room. If a gas alarm controller lacks battery backup and is not powered by a dual power supply, nor by a fire protection power source, it will result in the failure of the gas alarm system. This has raised the issue of the need for a gas alarm system to have dual power supplies. 40. Explosion-proof electrical appliances are not installed in full in direct combustion rooms or gas boiler rooms. It is required that all electrical equipment in such rooms use explosion-proof appliances. A common problem is that certain types of electrical appliances are non-explosion-proof. For example, all the others are explosion-proof, but the lights are not; all the others are explosion-proof, but the detectors are not; all the others are explosion-proof, but the distribution boxes and control panels are not, and so on. 41. The ceilings are made of aluminum-plastic panels; the third basement floor also has aluminum-plastic panel ceilings, and so on. The ceiling in the lounge area of the basement is covered with wooden decorations, while the ceilings in the lobby and multi-functional rooms are made of aluminum-plastic panels. The ceiling in the area in front of the elevators is also made of aluminum-plastic panels, and the third basement floor again has aluminum-plastic panel ceilings, and so on. The general principle of the codes for interior decoration of buildings is to require that ceilings be made of Class A non-combustible materials. High-rise buildings must be strictly controlled, while multi-story buildings should reach B1 level. The ceiling is made of Class A materials; there are currently two types: gypsum boards with light steel studs, and mineral wool sound-absorbing panels with light steel studs. Or use pure metal sheet ceilings such as aluminum sheets or aluminum Lexan sheets. The best fire resistance of aluminum-plastic panels reaches B1 level, while those of average quality reach B2 level. During acceptance, the materials used in high-rise buildings as mentioned in the aforementioned issue must be removed and their use is prohibited. Note: Some parameters or provisions in the text are no longer part of current standards, but they can still be used as a reference. Compiled from: Zhongzhi Building Resources zzguifan.com