Code for fire protection design of high-rise civil buildings (referred to as "High-rise Code") (GB50045-95). Since its implementation in 1995, it has been partially revised three times in 1997, 1999 and 2001. The fire protection design of civil buildings has played a very good role in regulating and guiding. However, there are also some questionable issues that arise during the implementation of the "High Regulations". This article discusses the issues encountered in the practice of high-rise civil building design and the implementation of "Mandatory Provisions for Engineering Construction Standards" in the past few years, and provides an analysis of the "High Regulations" on the prevention and control of emissions. Some opinions and suggestions are put forward on several items such as smoke, ventilation and air conditioning.
1 Building Classification
Article 3.0.1 of the "High-rise Building Regulations" divides high-rise buildings into one based on their nature of use, fire risk, evacuation and fire-fighting difficulty, etc. Category, Category II. However, with the in-depth development of my country's socialist reform and opening-up and the introduction of wholly foreign-owned Taiwanese capital, some developers, in order to save investment in fire protection equipment for high-rise buildings, require designers to classify high-rise buildings into Category II buildings as much as possible. Especially for high-rise buildings not listed in this article, it is more difficult for designers to convince developers that they must follow the fire protection work policy of "prevention first, combined with fire protection".
For example, a company’s office building in the city has a building height of more than 24m, high building decoration standards, a VRV air-conditioning system, a product showroom on the ground floor, and a conference room on the top floor (which can be changed to a multi-functional conference room in the future) room), the developer requires it to be designed as a Category II high-rise building for ordinary office buildings. Another example is a commercial and residential building with a building height of 50m. Each floor of the three-story shopping mall below has a construction area of more than 1500m2 and is equipped with a centralized air-conditioning system. In the residential part, each household has three (or four) rooms, one living room, one kitchen, two toilets and two balconies, and the building decoration standards are High, and reserved locations and holes for installing air-conditioning equipment. The developer requires that the building be designed as a Class II commercial and residential building. It is obvious that the former should be an important office building due to its high construction standards, multiple building functions and high fire risk, and should be designed as a Class I high-rise building for fire protection. In the latter, because the building area of each floor of the shopping mall exceeds 1500m2, and the area of each floor of the residential building does not exceed 1500m2, but the building decoration standard is high and has its own air-conditioning equipment, it should be designed as a first-class commercial and residential building for fire protection. However, because the "High-level Regulations" do not have stricter, clearer and quantitative definitions of important office buildings, ordinary office buildings, high-end residential buildings, ordinary residential buildings, etc., it is difficult to persuade developers to classify the above-mentioned office buildings and commercial residential buildings as Class I high-rise buildings shall be designed for fire protection.
With my country's accession to the WTO and the introduction of wholly foreign-owned Taiwanese capital, more high-end office buildings, residential buildings and other high-rise buildings will be constructed. It is urgent to require the "High-end Regulations" to regulate high-end residential buildings and ordinary residential buildings. High-end hotels, ordinary hotels, high-end office buildings, scientific research buildings, archives buildings and ordinary office buildings, scientific research buildings, archives buildings, etc. have stricter, clearer, more detailed and quantitative provisions to better judge high-rise buildings Category, fire protection design of high-rise buildings.
2 General layout and layout
Article 4.1.2 of the "High-level Regulations" "Except for boilers using liquefied petroleum gas as fuel, when the above equipment is subject to conditional restrictions, it must When arranged in a high-rise building or podium, the total evaporation capacity of the boiler should not exceed 6. 000t/h, and the output of a single boiler should not exceed 2. 000t/h. "Evaporation capacity is used twice in this article ", so the boiler in the article should be a steam boiler. This article states that "evaporation capacity" is used three times, so the boiler in the article description should also be a steam boiler. However, the description of this article does state that "according to the requirements of the "Hot Water Boiler Safety and Technical Supervision Regulations" newly issued by the Ministry of Labor", why should the editor use the "Hot Water Boiler Safety and Technical Supervision Regulations" to stipulate the design parts of the steam boiler room? .
Hot water boilers are better than steam boilers in terms of use, management, safety, energy saving, etc. When boilers must be arranged in high-rise buildings or podiums, hot water boilers should be recommended first. It is recommended to add provisions for the use of hot water boilers in the "High-Level Regulations".
3 Fire zoning and fire separation
In the design of high-rise buildings, the division of fire and smoke zoning is extremely important. The division of fire protection zones should not only limit the spread of fire and reduce losses, but also facilitate daily use and management to save investment. Article 5.1.1 of the "High-rise Regulations" stipulates that "firewalls used in high-rise buildings shall be divided into fire protection zones". Article 5.1.3 of the "High-Level Regulations" stipulates that "when a firewall and other fire separation facilities are installed between a high-rise building and its podium,?". From the above two items, it can be seen that firewalls are used to divide fire zones and perform fire separation. However, the "High-level Regulations" do not clearly define fire separation and do not stipulate under what circumstances fire separation should be set up. Articles 5.1.1 to 5.1.4 of the "High-Level Regulations" point out that foreign regulations stipulate that high-rise buildings should be equipped with firewalls at certain distances. Fire protection partitions and fire protection partitions are two different concepts. There can be several fire protection partitions in a fire protection partition, but a fire protection partition is not necessarily a fire protection partition. Firewalls and partition walls are two different concepts. In high-rise buildings, the former requires a non-combustible body with a fire resistance limit of no less than 3.00h, while the latter requires a non-combustible body with a fire resistance limit not that high.
Since the "High-Level Regulations" do not clearly stipulate fire protection separation, different understandings of fire protection zoning and fire separation have emerged during the review of fire protection design and construction drawings of high-rise buildings.
This involves the layout, selection and investment of fire protection equipment. Some designers believe that a firewall is a fire protection zone. For example, the partition wall between equipment rooms in the basement of a high-rise building (generator room, oil storage room, high-low power distribution room, water pump room, refrigerator room, etc.) is a firewall and is a fire protection zone. Separate. If each zone is equipped with an independent air supply and exhaust system, the design will become very complicated. It is recommended that the "High-Level Regulations" add provisions regarding fire separation.
4 Smoke-proof partitions and smoke-proof vertical walls
Article 5.1.6 of the "High Regulations" "Aisles with smoke exhaust facilities and clear heights not exceeding 6.00m Rooms should be divided into smoke-proof zones by using smoke-proof hanging walls, partition walls or beams protruding no less than 0.50m from the ceiling. The building area of each smoke-proof zone should not exceed 500m2, and the smoke-proof zone should not cross the fire zone. "Article 8.4.5 of the "High Regulations" for mechanical smoke exhaust: "The horizontal distance between the smoke exhaust outlet in the smoke prevention zone and the farthest point should not exceed 30m." As mentioned in the literature [2][3], when implementing these two When smoke is vented, especially in large-area rooms, the following problems will be encountered: ① Beams with a beam height greater than 0.50m are regarded as smoke-proof vertical walls, and the room is naturally divided into many small smoke-proof zones. The results are as follows: A maximum smoke-proof zone shall not be less than 120m3h per square meter. The calculated smoke exhaust volume is very small, but the system has many smoke exhaust outlets, making the control system complicated; ② When the beam heights are the same, the boundaries between smoke-proof zones are blurred; ③ Due to the " Article 8.4.5 of the "High-level Regulations" stipulates that the horizontal distance between the smoke exhaust outlet and the farthest point of mechanical smoke exhaust should not exceed 30m. When natural smoke exhaust is performed, what should be the horizontal distance between the smoke exhaust outlet and the farthest point? The author believes that Article 5.1.6 of the "High-Level Regulations" only applies to aisles and rooms with a clear height not exceeding 6.00m, and does not apply to large-area shopping malls and exhibition halls. It is recommended that the "High-level Regulations" add provisions regarding smoke-proof partitions in large-area rooms, and limit the minimum area of smoke-proof partitions that match the minimum smoke exhaust volume of a single smoke exhaust machine.
5 Smoke prevention, smoke exhaust and ventilation, air conditioning
5. 1 Natural smoke exhaust can open the horizontal distance from the farthest point of the outer window
《 The "High Regulation" does not stipulate the horizontal distance between the natural smoke exhaust outlet in the smoke prevention zone and the farthest point during natural smoke exhaust. Since the horizontal distance from the farthest point of the openable exterior window for natural smoke exhaust is not defined, designers have the following questions when implementing the "High-Tech Regulations": ①Article 8. 2. 2. 3 of the "High-Level Regulations" The window area for natural smoke exhaust shall comply with the following regulations: the area of openable external windows of an inner walkway not exceeding 60m in length shall not be less than 2% of the walkway area" and Article 8.4.1.1 of the "High Regulations" "1. Mechanical smoke exhaust facilities should be installed in high-rise buildings and high-rise buildings with a height of more than 32m that do not have direct natural ventilation and are more than 20m in length, or have direct natural ventilation but are more than 60m in length. What is the reason for the upper limit of 60m for walkways? ②The reason why the length of the inner walkway is limited to 20m in Article 8.1.3.1 of the "High-Level Regulations" "Inner walkways with a length of more than 20m in Class I high-rise buildings and Class II high-rise buildings with a building height exceeding 32m shall be equipped with smoke exhaust facilities" is because What? ③In high-rise buildings, there are above-ground rooms with openable exterior windows, large areas, and large depths. When the depth exceeds how much, do mechanical smoke exhaust facilities need to be installed? ④In special circumstances, such as using a long inner walkway that can open the outer window to naturally exhaust smoke, is it feasible when only one end can open the window?
Article 8. 1. 3 of the "High-level Regulations" explains that "according to on-site fire observations, the maximum walking distance for people with their heads down and nose covered in thick smoke is 20 to 30 meters." Obviously, the "High-Level Regulations" use the lower limit of 20m for the maximum walking distance for people who lower their heads and cover their noses in thick smoke to determine whether smoke exhaust facilities are installed in the inner walkways of high-rise buildings; Twice of 30m: 30m × 2 = 60m Determine whether mechanical smoke exhaust facilities are installed in the inner walkways of high-rise buildings with openable exterior windows. In this way, it is unreasonable to use different upper and lower limits to determine whether to install smoke exhaust facilities and mechanical smoke exhaust facilities for the same inner walkway issue.
In high-rise buildings, there are above-ground rooms with openable exterior windows, large areas, and large depths. When the depth exceeds what level, mechanical smoke exhaust facilities are required? Different depth values are recommended in various literatures. Literature [4] recommends 30m and 20m, Literature [5][6] recommends 30m, and Literature [3] recommends 60m. Why are there these different depth values that make readers confused? This is because: ① Different authors have adopted different upper and lower limits for the maximum walking distance for people in dense smoke; ② Different authors have different concepts of depth. Some are for openable windows on one long side of a large above-ground room, and some are For rooms with large depths, windows can be opened on both long sides.
It is not difficult to see that all the above problems involve a key value: the horizontal distance from the farthest point of the outer window that can be opened for natural smoke exhaust. As long as this value is determined, then the reasons for the upper limit of the length of the inner walkway, the need for mechanical smoke exhaust facilities in large-depth above-ground rooms when the depth exceeds the certain limit, and the reason why there is only one end of the long inner walkway that can open the exterior windows to naturally exhaust smoke. The question of whether it is possible to open the window will be solved.
Natural smoke exhaust can open the horizontal distance from the outer window to the farthest point. It involves whether the maximum passing distance for people who lower their heads and cover their noses in thick smoke is 20m or 30m. The author believes that this value should be based on the density of people during a fire. , The degree of perfection of the automatic fire alarm system and fire extinguishing system, and the use of non-combustible and refractory materials in building materials. Due to the following reasons: ① Most fire cases show that most of the deaths are due to suffocation due to inhalation of toxic smoke; ② Shopping malls, auditoriums, multi-functional halls, restaurants, conference rooms, singing and dancing entertainment screenings in high-rise buildings The density of people in public places such as public places is high, and the natural smoke exhaust conditions after decoration in these places are very poor; ③ According to the policy of "prevention first, combining prevention and fire prevention", and at the same time, our country's economic strength now allows for high-rise building design Enforce stricter measures. Therefore, the maximum passing distance for people who lower their heads and cover their noses in heavy smoke should be 20m. The author recommends adding a line in the natural smoke exhaust section of the "High-level Regulations" that "the horizontal distance from the farthest point of the openable external window for natural smoke exhaust should not exceed 20m." . In this way, Article 8.2.2.3 of the "High Regulations" is changed to "The window area using natural smoke exhaust shall comply with the following regulations: the area of the openable external window of the inner walkway not exceeding 40m in length shall not be less than 2% of the walkway area." Article 8.4.1.1 of the "High-Level Regulations" is changed to "In the first-class high-rise buildings and the second-class high-rise buildings with a building height exceeding 32m, there is no direct natural ventilation, and the inner walkway with a length of more than 20m or although there is direct natural ventilation, However, mechanical smoke exhaust facilities should be installed for inner walkways with a length exceeding 40m."
It should also be pointed out that the safe evacuation distance in Article 6.1.5 of the "High-Level Regulations" is based on the allowed evacuation time of personnel. Within the building, evacuate quickly through the walkways at a distance where the safety exit or evacuation sign can be seen through the smoke; the evacuation distance in Article 6.1.7 is the straight-line distance from any point in the room to the nearest evacuation exit. These distances ensure rapid evacuation of personnel in the event of a fire. These distances are different from when a person walks a distance of 20 meters with his head lowered and his nose covered in thick smoke, and then opens or breaks the external window in front of the external window to naturally exhaust the smoke. In the former, people evacuated through the safety exit during the fire, while in the latter, after walking 20m in the thick smoke, they had to open or break the outer windows to naturally vent the smoke. Stricter measures should be adopted for the latter.
5. 2 Ventilation and air-conditioning room
Article 5. 2. 7 of the "High-Level Regulations" "Equipment rooms, ventilation and air-conditioning rooms of automatic fire extinguishing systems located in high-rise buildings , partition walls with a fire resistance rating of not less than 2.00h, floor slabs of 1.50h and Class A fire doors should be used to separate them from other parts." Do all ventilators and air conditioners need to be located in the machine room? During construction drawing review and construction review, some reviewers require a special air-conditioning room in addition to a fire damper at the exit for thin air-conditioning cabinets hoisted in the ceiling. Some reviewers even talk about fans with air ducts in the ceiling. The coil unit must also have a dedicated air-conditioning room. Such misunderstood and excessive requirements for the provisions of the "High-Level Regulations" are not only economically wasteful but also bring great difficulties to the professional design of air-conditioning and architecture.
Similarly, whether the special axial flow smoke exhaust fan must be located in the machine room, especially when the equipment room with a single room area in the basement is less than 50m2 is equipped with a special axial flow smoke fan without an air duct. At this time, the author thinks that there is no need to set up a dedicated computer room.
Article 5. 2. 7 of the "High-level Regulations" explains: "When this partial revision was made, it was considered that the ventilation and air-conditioning machine room is a room where ventilation and smoke exhaust pipes gather, and it is also an important part of the spread of fire. In order to prevent fires from spreading and expanding inside and outside the ventilation and air-conditioning machine rooms." The special axial flow smoke exhaust fan can work continuously for 30mm at 280 ℃. The motor and blade rotating parts are inside the fan casing. When the axial flow smoke exhaust fan does not have an air duct, there is no problem of internal and external fire phase spread. . A possible problem is that the axial flow smoke exhaust fan shell deforms in high-temperature smoke above 280 ℃ during a fire. Therefore, a dedicated axial flow smoke exhaust fan with a fire protection shell with a fire resistance limit of not less than 1.50h does not need to have a dedicated machine room.
Therefore, it is recommended to add to Article 5.2.7 of the "High-Level Regulations" the circumstances in which dedicated ventilation and air-conditioning rooms may not be required, such as: "Thin-type air-conditioning cabinets and fans mounted in a fire-proof zone" Coils do not need to be equipped with a dedicated air-conditioning machine room." "Specialized axial flow smoke exhausters with fire protection shells with a fire resistance rating of not less than 1.50h do not need to be equipped with a dedicated machine room."
5.3 The smoke-proof stairwells in basements and semi-basements should be equipped with independent smoke-proof facilities. "High-level Regulations" Article 6. 2. 8 "Stairwells in basements and semi-basements should be fire-resistant on the first floor. The partition wall with a limit of not less than 2.00h is separated from other parts and should lead directly to the outside. When the door must be opened on the partition wall, a fire door of not less than Class B should be used. The basement or semi-basement and the above-ground floor should not be *. **Same as stairwells, when stairwells must be used, a partition wall with a fire resistance rating of not less than 2.00h and a Class B fire door should be set up at the entrance and exit between the first floor and the underground floor, and there should be obvious logo".
According to this article and its description, the stairwells in basements and semi-basements are separated from other parts, so the smoke-proof stairwells in basements and semi-basements should be equipped with independent smoke-proof facilities. At present, there are no independent smoke prevention facilities in the basement and semi-basement stairwells of many high-rise buildings.
It is recommended to add a clause in the mechanical smoke prevention section of the "High-level Regulations": "Smoke-proof stairwells in basements and semi-basements should be equipped with independent smoke-proof facilities."
5. 4 Natural Smoke Exhaust Window
Article 8. 2. 4 of the "High-Level Regulations" "Smoke exhaust windows should be installed at the top and should be easily opened." Because it is "suitable to install", there are currently no dedicated smoke exhaust windows in many high-rise buildings with densely populated public places. In the event of a fire, people still open or break the outer windows to naturally exhaust smoke. The density of people in public places such as shopping malls, auditoriums, multi-functional halls, restaurants, conference rooms, song and dance entertainment venues, and entertainment venues in high-rise buildings is high, and the natural smoke exhaust conditions after decoration in these places are very poor, and some shelves and decorations are even The exterior windows are blocked by objects, making it difficult not only for smoke to pass through but also for people to reach the windows in the event of a fire. Therefore, it is recommended to add a paragraph to Article 8.2.4 of the "High-level Regulations": "The smoke exhaust window should be clearly marked and there should be no obstruction within 0. 8m in front of the window."
6 Some Suggestions
Many technical specifications in China are now longer than the text, and the "Advanced Regulations" are no exception. In order to better understand, implement and enforce the provisions of the "High-level Regulations", the editor compiled the research, discussion, and domestic and foreign materials during the revision process of the regulations into a "Revision Note" and published it as a "Provision Note". Strictly speaking, the description of the provisions has the same effect as the provisions. However, after three partial revisions in the "High-level Regulations" (GB50045-95), the description of the provisions is obviously very lengthy, and some parts of the descriptions of the provisions have also caused misunderstandings. The author suggests: ① Increase the length of the main body of the "High Regulations", incorporate part of the description of the provisions into the main body of the "High Regulations", and introduce many opinions and suggestions since the implementation of the "High Regulations" into the main body of the "High Regulations" to make the "High Regulations" Regulations are more operable.
For example, the document [7] suggested “merging Table 8. 3. 2. 1 to 4 in the main body of the specification and Table 17 of the clause description into one” and so on. ②In order to improve the seriousness of the "High-Level Regulations", it is recommended to cancel the current "Explanation of Articles" and put the research, discussions, domestic and foreign materials in the process of revising the standards, etc. in the form of literature or comprehensive articles as attachments to the "High-Level Regulations" behind. ③Only when disputes or major difficult issues are encountered during the implementation of the "High-Level Regulations", the editor shall publish a "Provisional Explanation (or Provisional Interpretation)" that has the same effect as the provisions through the authoritative organization. ④ Based on the above reasons, it is recommended to revise the "High-rise Regulations" to meet the development of high-rise building industry after my country's accession to the WTO.
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