Integrated fireproof air pipe construction method

Abstract

The invention provides an integrated fireproof air duct construction method, and belongs to the technical field of fireproof air duct construction.The method comprises the steps that firstly, a heat flow conduction vector diagram and a segment length adjustment gain function are constructed, and the segment length and the connecting position of an air duct are scientifically determined based on the Fourier heat conduction law; secondly, optimizing a segmentation scheme by using a genetic algorithm embedded into a heat and mass transfer physical mechanism model, solving an optimal connection path through a minimum spanning tree algorithm, completing automatic segmentation and two-dimensional code coding of the pipeline, and performing cutting processing and semi-finished product prefabrication of a magnesium crystal plate thermal insulation material in a prefabrication processing factory; components are conveyed to a site in a semi-finished product conveying mode and tracked and positioned through two-dimensional codes, plate gluing and component assembling are completed on the site, rapid supports are installed, air pipe sections are lifted to designated positions through a pipeline elevator, adjacent sections are connected, difference adjusting sections are installed, and finally air leakage testing of an air pipe system is conducted to complete acceptance check.

Description

Technical Field

[0001] The present invention belongs to the technical field of fireproof air duct construction, and in particular relates to an integrated fireproof air duct construction method. Background Art

[0002] Fire-resistant ductwork, a crucial component of building smoke and exhaust systems, is widely used in high-rise buildings and large public structures. Traditional fire-resistant duct construction relies primarily on an empirical segmentation approach, whereby sections are cut to standardized lengths, insulated with rock wool or centrifugal glass wool, and joined by hand-fabricated connectors on-site. This traditional method, commonly used in ventilation systems for buildings such as industrial plants, hospitals, and schools, relies on on-site measurements and manual calculations to determine duct layout and connection schemes. However, this traditional technique has significant drawbacks: segmented design is primarily based on construction convenience, lacking scientific analysis of heat conduction laws, leading to uneven heat flow distribution within the duct system; poorly designed connection nodes can easily form thermal bridges, compromising overall fire performance; and a lack of quantitative basis for material selection and layout optimization makes it difficult to precisely control fire performance. Traditional empirical segmentation methods struggle to accurately identify heat flux concentration areas and weak links within the duct system, and fail to rationally determine segment lengths and connection locations based on heat conduction mechanisms. This results in uneven localized fire performance within the fire-resistant ductwork under fire conditions, compromising the reliability of the entire smoke and exhaust system. Summary of the Invention

[0003] In view of this, the present invention provides an integrated fireproof air duct construction method, which can solve the technical problem in the prior art that the segmented design of the fireproof air duct lacks a scientific thermodynamic basis, resulting in uneven local fireproof performance.

[0004] The present invention is implemented as follows: The present invention provides an integrated fireproof air duct construction method, including: using building information modeling technology to comprehensively arrange the smoke and fire protection system, constructing a heat flow conduction vector diagram and a segment length adjustment gain function, and analyzing and determining the air duct segment length and connection position based on Fourier's heat conduction law, thereby solving the technical problem that the fireproof air duct segment design lacks a scientific thermodynamic basis, resulting in uneven local fire protection performance; using a genetic algorithm embedded in a heat and mass transfer physical mechanism model to optimize the air duct segmentation scheme, solving the optimal solution for the air duct connection path through a minimum spanning tree algorithm, completing the automatic segmentation and QR code encoding of the smoke and fire protection system pipeline, and generating an expanded processing diagram and a bracket layout diagram for each segment; in the prefabrication process The factory cuts and processes magnesium crystal board insulation materials, makes edge guards and flange connection components, completes the prefabrication of semi-finished integrated fireproof air ducts and posts corresponding QR code labels; uses semi-finished product transportation to transport prefabricated components to the construction site, tracks and locates materials by scanning QR codes, and completes the gluing of panels and assembly of components at the on-site processing yard; installs quick-install brackets attached to the bottom of the common bracket, and uses a pipe lift to lift the assembled integrated fireproof air duct sections to the designated position and secure them; connects adjacent air duct sections, installs differential sections and sets flexible rubber isolation materials; conducts an air leakage test on the air duct system, raises the static pressure in the air duct to 750Pa and keeps it stable, measures the air leakage and completes the acceptance.

[0005] Among them, the heat flow conduction vector diagram is specifically a two-dimensional or three-dimensional heat flow distribution diagram established based on Fourier's heat conduction law. It represents the direction and intensity of heat transfer in the air duct system through the vector field, identifies the location of thermal bridges and heat flow concentration areas, and provides a thermodynamic basis for the segmented design of the air duct, avoiding the degradation of local fire protection performance caused by the concentration of high-temperature areas.

[0006] The segment length adjustment gain function is specifically an optimization function established based on thermal resistance network theory, which is used to calculate the impact of different segment lengths on the overall fire performance. The input includes the duct length obtained from the building information model, the cross-sectional area obtained from the duct design drawings, the material thermal conductivity obtained from the material technical specification, the ambient temperature obtained from the environmental monitoring equipment, and the number of connection points obtained from the segment design plan. The output is the fire performance gain coefficient, which is used to guide the final determination of the duct segment length.

[0007] Among them, the physical mechanism model of heat and mass transfer is specifically a mathematical model that describes the simultaneous transfer process of heat and mass inside the fireproof air duct. It is established based on the law of conservation of energy and the law of conservation of mass, and considers the coupled effects of convective heat transfer coefficient, radiation heat transfer coefficient, material specific heat capacity, material density and fluid flow rate on the heat and mass transfer process. By describing the evolution law of temperature field distribution and concentration field distribution, the thermodynamic behavior of the air duct under fire conditions is predicted.

[0008] Among them, the genetic algorithm embedded in the heat and mass transfer physical mechanism model specifically uses the heat and mass transfer physical mechanism model as the fitness function of the genetic algorithm, the individual encoding of the genetic algorithm is the air duct segmentation length combination, the segmentation scheme with excellent heat and mass transfer performance is retained through the selection operation, new segmentation length combination is generated through the crossover operation, and the local optimal solution is avoided through the mutation operation. The fitness of each individual in the iterative process is calculated by the heat and mass transfer physical mechanism model, and finally converges to obtain the optimal air duct segmentation scheme that meets the heat and mass transfer requirements.

[0009] Among them, the minimum spanning tree algorithm specifically regards the air duct connection points as vertices in graph theory, the connecting pipe sections as edges, and the edge weights as a comprehensive evaluation of thermal resistance and construction cost. The minimum weight spanning tree connecting all vertices is solved by the Kruskal algorithm or the Prim algorithm to obtain the optimal connection path of the air duct system. The optimal connection path is used to determine the air duct installation order and connection method.

[0010] Among them, the magnesium crystal board insulation material is specifically an inorganic fireproof board with magnesium oxide and magnesium chloride as the main components. It has the characteristics of high fire resistance, strong chemical stability and non-corrosiveness, and can replace traditional rock wool and centrifugal glass wool as the air duct insulation layer.

[0011] Among them, the quick-install bracket attached to the bottom of the common bracket is specifically an assembled bracket system connected by angle steel and bolts, which is fixed under the existing integrated bracket by clipping, and the air duct support installation can be completed without on-site welding; the adjustment section is specifically a reserved air duct section with a length of 1 to 1.5m, which is used to eliminate on-site measurement errors and installation cumulative errors, and ensure the accuracy and sealing of the overall connection of the air duct system.

[0012] Among them, before using building information modeling technology to comprehensively arrange the smoke protection and exhaust system, it also includes three-dimensional scanning and modeling of the building structure to obtain accurate spatial coordinate information and pipeline direction data, providing spatial basic data for the construction of heat flow conduction vector diagram.

[0013] Among them, in the step of optimizing the duct segmentation scheme using a genetic algorithm embedded in a heat and mass transfer physical mechanism model, the initial population size of the genetic algorithm is set to 50 to 100 individuals, the evolutionary generation number is set to 100 to 200 generations, the crossover probability is set to 0.6 to 0.9, and the mutation probability is set to 0.01 to 0.1.

[0014] Among them, in the cutting process of magnesium crystal board insulation materials in the prefabrication factory, the thickness of magnesium crystal board is selected to be 20 to 50 mm, and the density is controlled at 800 to 1200 kg / m 3 The thermal conductivity is controlled within the range of 0.08 to 0.12 W / (m·K).

[0015] Among them, during the steps of board gluing and component assembly at the on-site processing site, high-temperature resistant silicone sealant is used to seal the board joints. The operating temperature range of the sealant is -50℃ to 300℃, and the curing time is 24 to 48h.

[0016] Among them, in the step of using a pipe elevator to lift the assembled integrated fireproof air duct sections to the designated position, the rated load capacity of the pipe elevator is not less than 500kg, the lifting height range is 3 to 30m, and the lifting speed is controlled within the range of 0.1 to 0.5m / s.

[0017] Among them, in the step of connecting adjacent air duct sections, the connecting flange is made of stainless steel with a thickness of 3 to 5 mm, the flange bolts are of M8 to M12 specifications, and the bolt spacing is controlled within the range of 100 to 150 mm.

[0018] Among them, in the air leakage test step of the air duct system, the test environment temperature is controlled within the range of 20℃ to 25℃, the relative humidity is controlled within the range of 45% to 65%, the test duration is not less than 30 minutes, and the air leakage measurement accuracy is not less than ±5m 3 / h.

[0019] This invention establishes a heat conduction vector diagram and a segment length adjustment gain function, scientifically determining the duct segmentation scheme based on Fourier's law of heat conduction. It then optimizes the segmentation design using a genetic algorithm embedded in a model of the physical mechanism of heat and mass transfer, and employs a minimum spanning tree algorithm to determine the optimal connection path. This method effectively addresses the shortcomings of traditional technologies: the heat conduction vector diagram accurately identifies areas of heat concentration and thermal bridge locations, providing a scientific thermodynamic basis for segmentation design; the segment length adjustment gain function quantifies the impact of different segmentation schemes on fire protection performance, avoiding the blindness of empirical decision-making; the genetic algorithm, combined with the heat and mass transfer model, intelligently optimizes the segmentation scheme, ensuring that each segment has good heat and mass transfer performance; and the minimum spanning tree algorithm optimizes the connection path, reducing the possibility of thermal bridge formation. By establishing a complete thermodynamic analysis system and intelligent optimization algorithm, this method addresses the core issue of the lack of scientific basis for fire-resistant duct segmentation design, ensuring the uniformity and reliability of the duct system's fire protection performance, and achieving a transition from empirical design to scientific design. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart of the method of the present invention.

[0021] Figure 2 This is a schematic diagram of the integrated air duct installation in Example 2.

[0022] Figure 3 This is a schematic diagram of the disassembly of the new integrated air duct in Example 2.

[0023] Figure 4 This is a diagram of the disassembly of the integrated air duct in Example 2.

[0024] Figure 5 This is a large-scale drawing of the integrated air duct bracket in Example 2.

[0025] Figure 6 This is a schematic diagram of a bracket that can be quickly installed below a common bracket in Example 2.

[0026] Figure 7 This is a schematic diagram of the upper pipeline installation in Example 2.

[0027] Figure 8 This is a schematic diagram of the segmented installation of the integrated air duct in Example 2.

[0028] Figure 9 This is a schematic diagram of the segmented connection of the integrated air duct in Example 2. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0030] like Figure 1 FIG. 1 is a flow chart of an integrated fireproof air duct construction method provided by the present invention, which includes the following steps:

[0031] S01. Use building information modeling technology to comprehensively arrange the smoke control and exhaust system, construct a heat flow conduction vector diagram and segment length adjustment gain function, and determine the segment length and connection position of the air duct based on Fourier's heat conduction law analysis;

[0032] S02. Optimize the duct segmentation scheme using a genetic algorithm embedded in a heat and mass transfer physical mechanism model. Calculate the optimal solution for the duct connection path using a minimum spanning tree algorithm. Automatically segment and QR-code the smoke exhaust system ducts, generating expansion drawings and bracket layout diagrams for each segment.

[0033] S03. Cut and process the magnesium crystal board insulation material in the prefabrication plant, produce edge protection and flange connection components, complete the prefabrication of the semi-finished integrated fireproof air duct and post the corresponding QR code logo;

[0034] S04: Use semi-finished product transportation to deliver prefabricated components to the construction site, track and locate materials by scanning QR codes, and complete the gluing of panels and assembly of components at the on-site processing yard;

[0035] S05. Install the bracket attached to the bottom of the common bracket to quickly install the bracket, and use the pipe lifter to lift the assembled integrated fireproof air duct to the designated position in sections and fix it;

[0036] S06. Connect adjacent air ducts in sections, install differential sections, and place flexible rubber isolation materials to prevent metal connectors from forming thermal bridges that reduce fire protection effectiveness.

[0037] S07. Conduct an air leakage test on the air duct system, increase the static pressure in the air duct to 750Pa and keep it stable, measure the air leakage and complete the acceptance.

[0038] Among them, the heat conduction vector diagram is a two-dimensional or three-dimensional heat flow distribution diagram based on Fourier's law of heat conduction. It represents the direction and intensity of heat transfer in the duct system through the vector field, identifies the location of thermal bridges and areas of concentrated heat flow, and provides a thermodynamic basis for the segmented design of the duct, avoiding the degradation of local fire protection performance caused by the concentration of high-temperature areas.

[0039] Among them, the segment length adjustment gain function is specifically an optimization function established based on thermal resistance network theory, which is used to calculate the impact of different segment lengths on the overall fire protection performance. The input includes the duct length obtained from the building information model, the cross-sectional area obtained from the duct design drawings, the material thermal conductivity obtained from the material technical specification, the ambient temperature obtained from the environmental monitoring equipment, and the number of connection points obtained from the segment design plan. The output is the fire protection performance gain coefficient, which is used to guide the final determination of the duct segment length.

[0040] Among them, the physical mechanism model of heat and mass transfer is specifically a mathematical model that describes the simultaneous transfer process of heat and mass inside the fireproof air duct. It is established based on the law of conservation of energy and the law of conservation of mass, and considers the coupled effects of convective heat transfer coefficient, radiation heat transfer coefficient, material specific heat capacity, material density and fluid flow rate on the heat and mass transfer process. By describing the evolution law of temperature field distribution and concentration field distribution, the thermodynamic behavior of the air duct under fire conditions is predicted.

[0041] Among them, the genetic algorithm embedded in the heat and mass transfer physical mechanism model specifically uses the heat and mass transfer physical mechanism model as the fitness function of the genetic algorithm. The individual encoding of the genetic algorithm is a combination of duct segment lengths. The segmentation scheme with excellent heat and mass transfer performance is retained through selection operation, and new segment length combinations are generated through crossover operation. The local optimal solution is avoided through mutation operation. The fitness of each individual in the iterative process is calculated by the heat and mass transfer physical mechanism model, and finally converges to obtain the optimal duct segmentation scheme that meets the heat and mass transfer requirements.

[0042] Among them, the minimum spanning tree algorithm specifically regards the air duct connection points as vertices in graph theory, the connecting pipe sections as edges, and the edge weight as a comprehensive evaluation of thermal resistance and construction cost. The minimum weight spanning tree connecting all vertices is solved by Kruskal algorithm or Prim algorithm to obtain the optimal connection path of the air duct system. The optimal connection path is used to determine the air duct installation order and connection method.

[0043] Among them, magnesium crystal board insulation material is an inorganic fireproof board with magnesium oxide and magnesium chloride as the main components. It has the characteristics of high fire resistance, strong chemical stability and non-corrosiveness. It can replace traditional rock wool and centrifugal glass wool as the insulation layer of air ducts.

[0044] Among them, the bracket that can be quickly installed attached to the bottom of the common bracket is an assembled bracket system connected by angle steel and bolts. It is fixed under the existing integrated bracket by clipping, and the air duct support installation can be completed without on-site welding.

[0045] Among them, the adjustment section is specifically a reserved air duct section with a length of 1 to 1.5m, which is used to eliminate on-site measurement errors and installation cumulative errors, and ensure the accuracy and sealing of the overall connection of the air duct system.

[0046] The specific implementation of the above steps is described in detail below.

[0047] The specific implementation of step S01 involves using building information modeling technology to create a three-dimensional spatial model. The model then imports geometric information and material property parameters for the building structure, electromechanical pipelines, and smoke and fire protection systems. A spatial conflict detection algorithm is used to identify pipeline intersections and set pipeline priority parameters. The smoke and fire protection ducts are prioritized to 8, the water supply and drainage pipelines to 6, and the electrical bridge to 4, ensuring the smoke and fire protection systems occupy a reasonable position within the overall layout. A heat flux vector diagram is constructed based on Fourier's law of heat conduction. This vector diagram uses a two-dimensional meshing method to divide the duct surface into several computational cells, each with a size of 0.1 m x 0.1 m. The finite difference method is used to calculate the temperature distribution and heat flux density vector at each grid node. The input parameters for calculating the heat flux density in the vector field include the material thermal conductivity coefficient, temperature gradient, ambient temperature, and the internal duct temperature. The thermal conductivity of the magnesium crystal plate material is set to 0.15 W / (m·K). The ambient temperature range is 20°C to 25°C. Under fire conditions, the internal duct temperature can reach 800°C to 1000°C. The segment length adjustment gain function is based on thermal resistance network theory, treating the duct system as a thermal resistance network, with each segment acting as a thermal resistance unit and each connection point as a thermal resistance node. The function's input parameters include the total duct length, cross-sectional area, material thermal conductivity, ambient temperature, and number of connection points. It outputs a fire performance gain coefficient. A gain coefficient greater than 0.85 indicates that the segmented solution meets fire protection requirements. A gain coefficient less than 0.75 indicates that the segment length needs to be adjusted or the number of connection points needs to be increased.

[0048] The specific implementation method of step S02 is to use a genetic algorithm embedded in the physical mechanism model of heat and mass transfer to globally optimize the air duct segmentation scheme. The individual coding of the genetic algorithm adopts real number coding. Each individual represents a combination of air duct segment lengths. The chromosome length is set to the number of segments, and the gene value represents the length parameter of each segment. The population size is set to 100 individuals, the maximum number of iterations is set to 500 generations, the crossover probability is set to 0.8, and the mutation probability is set to 0.1. The physical mechanism model of heat and mass transfer is used as the fitness function. Based on the law of conservation of energy and the law of conservation of mass, a group of partial differential equations is established, taking into account the coupled effects of convective heat transfer coefficient, radiation heat transfer coefficient, material specific heat capacity, material density and fluid flow rate. The convective heat transfer coefficient ranges from 10 to 50W / (m 2 ·K), the radiation heat transfer coefficient ranges from 5 to 15W / (m 2 ·K), the specific heat capacity of the magnesium crystal plate is set to 1.2×10 3 J / (kg·K), the material density is set to 1.8×10 3 kg / m 3 . The genetic algorithm retains individuals with high fitness through roulette wheel selection operations, uses single-point crossover to generate new gene combinations, and uses Gaussian mutation to prevent the algorithm from falling into local optimal solutions. The minimum spanning tree algorithm regards the duct connection points as vertices in graph theory, and the connecting pipe sections as weighted edges. The edge weights comprehensively consider two factors: thermal resistance and construction cost. The thermal resistance value is calculated based on the length, cross-sectional area and thermal conductivity of the pipe section. The construction cost includes material cost, labor cost and machinery usage cost, and the weight coefficients are set to 0.6 and 0.4 respectively. The Kruskal algorithm is used to solve the minimum spanning tree. The algorithm first arranges all edges in ascending order according to the weight value, and selects the edges with the smallest weight and no loop to add to the spanning tree until all vertices are connected. After the optimization is completed, the unfolded processing drawings of each segment are generated. The drawings contain the plate size, bending line position, flange hole position and QR code identification position information.

[0049] The specific implementation of step S03 is to perform precision cutting on the magnesium crystal board insulation material in the prefabrication factory. The magnesium crystal board material is mainly composed of magnesium oxide and magnesium chloride, with the magnesium oxide content accounting for 45% to 55% of the total weight and the magnesium chloride content accounting for 35% to 45% of the total weight. Glass fiber mesh is added as a reinforcement material. The standard thickness of the board is set to 15mm and the density is controlled at 1.8×10 3 kg / m 3Within the specified range, the bending strength shall not be less than 8MPa, and the fire resistance limit shall reach more than 90 minutes. CNC plasma cutting equipment shall be used for cutting, the cutting accuracy shall be controlled within the range of ±1mm, and the cutting speed shall be set to 2000mm / min to 3000mm / min. Galvanized angle steel with a specification of 40mm×40mm×3mm is used for edge protection, which is fixed to the edge of the plate by spot welding. The welding point spacing is set to 150mm, and the welding current is controlled within the range of 80A to 100A. The flange connection component is made of galvanized flat steel with a specification of 50mm×5mm. The flange aperture is set to 12mm, and the hole spacing is determined according to the cross-sectional size of the duct. The flange hole spacing of rectangular ducts shall not exceed 150mm, and the flange hole spacing of circular ducts shall not exceed 100mm. After the prefabricated components are completed, quality inspection shall be carried out, and the inspection contents include dimensional accuracy, surface flatness, angle steel welding quality and flange hole position accuracy. The QR code label is produced by laser marking, with a label size of 20mm×20mm. The content includes component number, specification size, installation location and quality grade information.

[0050] The specific implementation method of step S04 is to use a semi-finished product transportation method to safely transport the prefabricated components to the construction site. The transport vehicle is a flatbed truck with a load capacity of not less than 10 tons and a carriage length of not less than 12m. When loading, the plates are stacked according to material classification, and the magnesium crystal plates and angle steel flanges are packaged separately to avoid collision and damage during transportation. The stacking height of the plates is strictly controlled within the height of the carriage, usually not exceeding 2.5m, and 10mm thick rubber gaskets are placed between the plates for separation and protection. During transportation, the vehicle position and transportation status are monitored in real time by the on-board positioning system, with a positioning accuracy of within 5m, and the data update frequency is set to once every 30 seconds. After arriving at the construction site, the components are scanned one by one by a handheld QR code scanning device. The scanning device uses two-dimensional imaging technology, with a recognition distance range of 50mm to 500mm and a recognition speed of not less than 3 QR codes per second. The scanned data is uploaded to the material management system in real time via the wireless network. The system automatically matches the component installation location information and updates the material status to the on-site installation status. The on-site processing site is located on a flat ground within 50m from the vertical transportation equipment, with an area of ​​no less than 200m 2 , equipped with rain and sun protection facilities. Structural adhesive is used for gluing panels, with a thickness of 2mm to 3mm, a 5mm seam width, and a curing time of no less than 24 hours. Components are assembled using bolts with a size of M10 x 25mm and a tightening torque of 45N·m to 55N·m. Joints are treated with anti-rust paint for corrosion protection.

[0051] The specific implementation method of step S05 is to install a quick-install bracket system attached to the bottom of the common bracket, and the bracket system adopts an assembled design concept. The main structure of the bracket is made of Q235B angle steel, the specifications of the vertical pole are 75mm×75mm×6mm, the specifications of the cross arm are 63mm×63mm×5mm, the material yield strength is not less than 235MPa, and the tensile strength is not less than 375MPa. The connection between the bracket and the existing integrated bracket is fixed with a U-shaped clamp. The inner diameter of the clamp is determined according to the diameter of the integrated bracket pipe. Common specifications include 76mm, 89mm and 108mm. The quick installation mechanism adopts a spring buckle design. The buckle material is made of stainless steel. The spring stiffness coefficient is set to 500N / m to 800N / m to ensure reliable connection and convenient disassembly and assembly. The bearing capacity of the bracket is verified by the finite element analysis method. The maximum bearing capacity of a single bracket is not less than 2000N, and the safety factor is set to 2.5 times. The pipe lift uses electric hydraulic lifting equipment with a rated lifting capacity of not less than 500kg, a lifting height range of 3m to 30m, and a lifting speed set at 2m / min to 5m / min. The size of the lift work surface is not less than 2m×1.5m, and it is equipped with anti-slip measures and safety guardrails, and the height of the guardrail is not less than 1.2m. When multiple lifts work together, a synchronous control system is used with a control accuracy of ±5mm, and coordinated movements between lifts are achieved through wireless communication. After the air duct is lifted to the designated position in sections, it is first temporarily fixed by connecting the air duct to the building structure with a wire rope or chain to ensure that the air duct is stable and does not shake. Then install the quick bracket and fix the bracket under the integrated bracket through the snap mechanism. The fixing torque is controlled within the range of 20N·m to 30N·m.

[0052] The specific implementation of step S06 involves precisely connecting adjacent duct segments to ensure the continuity and sealing of the entire duct system. Adjacent segments are connected using flange bolts. The flange material is galvanized flat steel with a thickness of at least 4mm. The bolts are galvanized hexagonal head bolts with a specification of M10×40mm and a bolt strength grade of at least 8.8. A sealing gasket is installed between the flange connection surfaces. The gasket material is high-temperature resistant rubber with a thickness of 3mm, a hardness range of Shore A 60 to 70 degrees, and an operating temperature range of -20°C to 150°C. Bolt tightening is performed using a diagonal cross-section method, with an initial tightening torque of 30N·m, a second tightening torque of 50N·m, and a final tightening torque of 60N·m to ensure uniform stress on the flange connection. The installation location of the differential section is selected between the two standard sections, with a length range of 1m to 1.5m. The specific length is determined based on actual on-site measurement results. The purpose of the adjustment section is to eliminate cumulative errors and compensate for manufacturing tolerances and installation deviations. The error compensation range is ±50mm. Flexible rubber isolation material is set at the contact point between the metal connector and the bracket. The material is neoprene, the thickness is set to 5mm, and the width is set to 50mm. This material has excellent oil resistance and weather resistance, and can effectively block the formation of thermal bridges. The installation of the isolation material adopts the pasting method and is fixed with high-temperature resistant structural adhesive. The thickness of the adhesive layer is controlled within 1mm and the curing time is not less than 12 hours. After the connection is completed, the sealing of each connection point is checked. The foaming agent leak detection method is used. The foaming agent is applied to the connection part to observe whether there are bubbles. If leakage is found, it is immediately reinforced.

[0053] The specific implementation of step S07 is to conduct an air leakage test on the air duct system to verify whether the sealing performance of the system meets the design requirements. The preparation work before the test includes closing all air outlet regulating valves and tightly sealing the ends of the air duct with plastic film and tape to ensure the airtightness of the test system. The test equipment uses a centrifugal test fan with an air volume range of 1000m 3 / h to 10000m 3 / h, with a pressure range of 500Pa to 1500Pa, and equipped with a variable frequency speed control device for precise air volume control. Pressure is measured using a digital differential pressure gauge with an accuracy of at least ±1Pa, a measurement range of 0Pa to 2000Pa, and data logging every 10 seconds. Air volume is measured using a standard orifice plate method. The orifice plate opening diameter is determined based on the duct cross-sectional area, and the ratio of the opening area to the duct cross-sectional area is set between 0.6 and 0.8. During the test, the test fan is first started to supply air into the duct, and the fan speed is gradually increased until the static pressure in the duct reaches 750Pa. At this point, the fan is stopped and the pressure changes are observed. If the pressure drops by more than 5Pa / min, it indicates a system leak, and the fan must be restarted to replenish air to maintain a stable pressure of 750Pa. The fan's supply air volume at this point is equal to the system's leakage, and the actual leakage value is calculated by measuring the pressure differential across the orifice plate. The allowable leakage value is calculated based on the duct surface area, and the leakage rate must not exceed 3.3m per square meter of duct surface. 3 / h. Systems exceeding this standard need to identify leaks and perform sealing. A test report will be compiled upon completion of the test. The report will include test conditions, test data, air leakage calculation results, and quality assessment conclusions. The report must be signed and confirmed by the construction company, supervision company, and construction company before being filed and preserved as project acceptance documentation.

[0054] It should be noted that the construction of the heat flux conduction vector diagram based on Fourier's law of heat conduction and the segment length adjustment gain function are one of the core technical ideas of the present invention. The traditional segmentation design of air ducts is mainly based on empirical division according to construction convenience and transportation restrictions. It lacks scientific thermodynamic theory support, which often leads to the formation of thermal bridge effects at the segment connections, significantly reducing the overall fire protection performance. By constructing two-dimensional or three-dimensional heat flux distribution graphics, the present invention can accurately identify the heat flux concentration areas and potential thermal bridge locations in the air duct system, providing a reliable thermodynamic basis for segmentation design. The segment length adjustment gain function establishes an optimization model based on the thermal resistance network theory. By quantitatively analyzing the degree of influence of different segmentation schemes on the overall fire protection performance, it realizes the transformation from qualitative experience to quantitative scientific design concept, and effectively avoids the problem of local fire protection performance degradation caused by the concentration of high-temperature areas.

[0055] The genetic algorithm optimization embedded in the physical mechanism model of heat and mass transfer represents an important breakthrough of the present invention in intelligent design. Traditional duct system design usually uses trial and error methods or empirical formulas to determine parameters, which has low optimization efficiency and is difficult to obtain a global optimal solution. The present invention uses the mathematical model that describes the simultaneous heat and mass transfer process inside the fireproof duct as the fitness function of the genetic algorithm, fully considering the coupling effects of convective heat transfer, radiation heat transfer, material physical parameters and fluid dynamic characteristics. By simulating natural selection and genetic mechanisms, the algorithm can efficiently search for the optimal segmentation scheme in a complex multi-dimensional parameter space, significantly improving the scientific nature and reliability of the design scheme, while greatly shortening the design cycle.

[0056] The modular construction technology of semi-finished product prefabrication combined with QR code encoding realizes the deep integration of air duct manufacturing and installation. Traditional construction methods usually adopt on-site processing and production, which not only has low construction efficiency, but also makes it difficult to ensure processing accuracy and quality consistency. At the same time, the on-site working environment is complex and changeable, which is prone to safety hazards. The present invention can ensure the stability and consistency of component quality in a standardized production environment through factory prefabrication, and realize high-precision processing through equipment. The QR code encoding system establishes an information traceability chain for the entire process from design, manufacturing to installation. Each component has a unique identity, which realizes the precise positioning and status management of materials, and effectively avoids the common component confusion and installation errors in traditional construction.

[0057] The synergy of these three core technical approaches has established a complete intelligent fire-resistant duct construction system. Thermal flow analysis provides a scientific theoretical foundation for system optimization, genetic algorithms achieve global optimization under multi-objective constraints, and modular construction ensures high-quality implementation of the optimization solution. These three mutually support each other, jointly enabling a technological transition from traditional experience-driven to data-driven approaches. This not only significantly enhances the thermal performance, safety, and reliability of fire-resistant duct systems, but also significantly improves construction efficiency and project quality, providing an important innovative path for technological advancement in building smoke control and exhaust systems.

[0058] Specifically, the principle of the present invention is: the present invention can solve the core technical problem of the lack of scientific thermodynamic basis for the segmented design of fireproof air ducts, and its fundamental principle lies in the establishment of a complete heat conduction analysis and optimization system. The heat flux conduction vector diagram constructed based on Fourier's heat conduction law can accurately describe the direction and intensity distribution of heat transfer in the air duct system, and identify the key areas of heat flux concentration and potential thermal bridge locations through vector field analysis, providing clear thermodynamic guidance for segmented design. The segment length adjustment gain function is established based on the thermal resistance network theory, which incorporates multiple influencing factors such as air duct length, cross-sectional area, material thermal conductivity, ambient temperature and number of connection points into a unified mathematical framework. By quantitatively analyzing the contribution of different segmentation schemes to the overall fire protection performance, the scientific determination of the segment length is achieved.

[0059] The heat and mass transfer physics model, based on the laws of conservation of energy and mass, comprehensively considers the coupling effects of multiple factors, including convective heat transfer, radiative heat transfer, material properties, and fluid flow, accurately describing the thermodynamic behavior of fire-resistant ducts under fire conditions. This model is embedded in a genetic algorithm as a fitness function, enabling intelligent optimization of the segmentation scheme through selection, crossover, and mutation operations, thus avoiding the limitations of traditional empirical methods. A minimum spanning tree algorithm uses thermal resistance and construction cost as edge weights and uses graph theory to determine the optimal connection path, ensuring the rationality of the connection scheme at a system level.

[0060] The technical solution of the present invention has strict logic: the heat flow conduction vector diagram provides the basis for thermodynamic analysis, the segment length adjustment gain function realizes quantitative evaluation, the genetic algorithm is combined with the physical model to complete intelligent optimization, and the minimum spanning tree algorithm ensures the optimal connection path, forming a complete technical chain from analysis to optimization to implementation, ensuring the uniformity and overall reliability of the fire protection performance of the fire-proof duct system.

[0061] A specific embodiment 1 of the present invention is provided below. The specific implementation of each step in this embodiment 1 is described in detail as follows.

[0062] In a specific implementation of step S01, the construction of the heat flow conduction vector diagram is based on Fourier's heat conduction law, which is specifically expressed as follows:

[0063]

[0064] Where q is the heat flux vector, unit is W / m 2 ; k is the thermal conductivity of the material, unit is W / (m·K); is the temperature gradient operator. The calculation of the temperature gradient in the two-dimensional coordinate system is expressed as:

[0065]

[0066] Where, and are the partial derivatives of temperature in the x-direction and y-direction respectively; i and j are the unit vectors in the x-direction and y-direction respectively. The temperature distribution of the grid nodes is calculated using the finite difference method, and its discretization expression is:

[0067]

[0068] Where, is the temperature at the grid point (i, j) at the nth moment, in K; α is the thermal diffusion coefficient, calculated as α=k / (ρc p ), unit is m 2 / s; Δt is the time step, ranging from 0.001s to 0.01s; Δx and Δy are the grid spacing in the x-direction and y-direction, respectively, both set to 0.1m; ρ is the density of the magnesium crystal plate material, set to 1.8×10 3 kg / m 3 ;c p is the specific heat capacity of the magnesium crystal plate material, which is 1.2×10 3 J / (kg·K). The segment length adjustment gain function is established based on the thermal resistance network theory and is specifically expressed as:

[0069]

[0070] Where, F gain is the fire performance gain coefficient, dimensionless; w i is the weight coefficient of the i-th segment, which is determined according to the segment position and ranges from 0.1 to 1.0; R th，i is the thermal resistance value of the i-th segment, in K / W; R th，total is the total thermal resistance, in K / W; η i is the efficiency factor of the i-th segment, which is determined by experiments and ranges from 0.7 to 1.0; N conn is the number of connection points, dimensionless; L total is the total length of the duct, in meters; λ is the connection density adjustment parameter, with a value of 0.2; β is the basic correction parameter, with a value of 0.05; n is the total number of segments. The calculation of the thermal resistance value of each segment is expressed as:

[0071]

[0072] Where, l i is the length of the i-th segment, in m; k i is the thermal conductivity of the material in the i-th section, and the value of the magnesium crystal plate is 0.15W / (m·K); A i is the cross-sectional area of ​​the i-th segment, in m 2 Among them, the efficiency factor η i The method for obtaining the weight factor is as follows: Step 1: Test the thermal conductivity of the magnesium crystal plate sample under standard laboratory conditions; Step 2: Measure the thermal conductivity of the material using a steady-state heat flow meter method; Step 3: Determine the efficiency factor by comparing the test results with the theoretical calculated value. i The value is determined based on the importance of the segment in the entire duct system, with a value of 1.0 for key connection locations and 0.5 to 0.8 for general locations.

[0073] In the specific implementation of step S02, the fitness function of the genetic algorithm embedded in the heat and mass transfer physical mechanism model is specifically expressed as:

[0074] f fitness =γ1·Htratnsfer +γ2·M transfer +γ3·C cost +ε f ;

[0075] Where, f fitness is the fitness function value, dimensionless; H transfer is the heat transfer performance index, which is calculated through temperature field analysis; M transfer is the mass transfer performance index, which is calculated through concentration field analysis; C cost is the cost function, including material cost and construction cost; γ1, γ2, γ3 are weight coefficients, which are 0.4, 0.3, and 0.3 respectively; ε f is the error correction term, ranging from 0.01 to 0.05. The heat and mass transfer physical mechanism model is established based on the law of conservation of energy and the law of conservation of mass, and its coupled transfer equations are expressed as:

[0076]

[0077] Where T is the temperature field, the unit is K; C is the concentration field, the unit is kg / m 3 ; is the fluid velocity vector, in m / s; α is the thermal diffusion coefficient, in m 2 / s; D is the mass diffusion coefficient, unit is m 2 / s;Qge n is the heat generation rate per unit volume, in W / m 3 ;S c is the mass source term, the unit is kg / (m 3 ·s). The mass diffusion coefficient D is calculated using the empirical correlation formula: D=D0·(T / T0) 1.75 , where D0 is the reference diffusion coefficient, which is 2.5×10^{-5}m 2 / s, T0 is the reference temperature, which is 293K. The Nusselt number correlation formula is used to calculate the convective heat transfer coefficient:

[0078] Nu=0.023·Re 0.8 ·Pr 0.4 ;

[0079] Where Nu is the Nusselt number, Re is the Reynolds number, and Pr is the Prandtl number. The Reynolds number and Prandtl number are expressed as:

[0080]

[0081] Where v is the fluid velocity; D h is the hydraulic diameter; μ is the dynamic viscosity. The calculation of edge weight in the minimum spanning tree algorithm is expressed as:

[0082] W ij =ω1·R th，ij +ω2·C construction，ij ;

[0083] Where W ij is the edge weight between connection points i and j; R th，ij is the thermal resistance of the connection section; C construction，ij is the construction cost; ω1 and ω2 are weight coefficients. The selection probability of the genetic algorithm is calculated using the roulette method:

[0084]

[0085] Where, P i is the probability of the i-th individual being selected; f i is the fitness value of the i-th individual; N is the population size.

[0086] The specific implementation of step S03 and step S04 is the same as above and will not be described in detail here.

[0087] In a specific implementation of step S05, the support bearing capacity is verified using a finite element analysis method, and its stress distribution calculation is expressed as:

[0088] [K]{u}={F};

[0089] Where [K] is the global stiffness matrix; {u} is the node displacement vector; and {F} is the node force vector. The calculation of the stress safety factor is expressed as:

[0090]

[0091] Where S f is the safety factor; σ yield is the yield strength of the material; σ max is the maximum stress. The synchronous control error calculation during the pipeline lifting process is expressed as:

[0092]

[0093] Where, δ sync is the synchronization error; h k is the height of the kth elevator; is the average height; m is the number of elevators.

[0094] The specific implementation of step S06 is the same as above and will not be described in detail here.

[0095] In the specific implementation of step S07, the calculation of the air leakage is based on the orifice plate flow measurement principle, which is specifically expressed as follows:

[0096]

[0097] Where Q is the air leakage, unit is m 3 / s;C d is the flow coefficient; A0 is the orifice opening area; Δp is the pressure difference on both sides of the orifice; ρ is the air density. The calculation of the flow coefficient is expressed as:

[0098]

[0099] Where β is the aperture ratio, calculated as β = d / D; d is the diameter of the orifice; D is the inner diameter of the air duct; Re is the Reynolds number. The calculation of air leakage per unit area is expressed as:

[0100]

[0101] Where q leak A is the air leakage per unit area; surface is the duct surface area. The calculation of the duct surface area for a rectangular duct is expressed as:

[0102] A surface =2(a+b)·L;

[0103] Where a and b are the width and height of the duct respectively; L is the length of the duct. The calculation of the pressure decay rate is expressed as:

[0104]

[0105] Where, is the pressure decay rate; Q leak is the leakage flow; p atm is atmospheric pressure; V duct The internal volume of the air duct. The test qualification standard is based on the air leakage limit per unit area:

[0106] q leak ≤qlimi t ;

[0107] Where q limit The permissible air leakage limit is 3.3m 3 / (h·m 2 ).

[0108] In order to better understand and implement the present invention, the following provides a specific application scenario of the present invention, Example 2: The construction team carried out a practical application of the integrated fire duct construction method for a comprehensive office building smoke exhaust system. The office building has a construction area of ​​25,600 m 2There are 18 floors above ground and 3 floors underground. The total length of smoke exhaust ducts to be installed is 3850m. The cross-sectional dimensions of the ducts are mainly 600×400mm, 800×500mm and 1000×600mm.

[0109] The construction team first used building information modeling technology to comprehensively arrange the smoke prevention and exhaust system, such as Figure 2 The integrated duct installation diagram is shown in the figure. A three-dimensional spatial model, including the building structure, electromechanical pipelines, and smoke and fire protection systems, was created in Revit software. The building structure's geometric information and material property parameters were imported. A spatial conflict detection algorithm was used to identify 125 pipeline intersections. Pipeline priority parameters were set: the smoke and fire protection ducts were set to level 8, the water supply and drainage pipelines to level 6, and the electrical bridges to level 4. A heat flux vector diagram was constructed based on Fourier's law of heat conduction. A two-dimensional meshing method was used to divide the duct surface into computational cells, each with a size of 0.1 × 0.1 m. The temperature distribution and heat flux density vector at each grid node were calculated using the finite difference method. The input parameters for calculating the heat flux density in the vector field are shown in Table 1.

[0110] Table 1 Input parameters for heat flux calculation

[0111] Parameter name Numerical unit Thermal conductivity of magnesium crystal plate material 0.15 W / (m·K) Ambient temperature 22 ℃ Temperature inside the air duct under fire conditions 850 ℃ Material density <![CDATA[1.8×10 3 ]]> <![CDATA[kg / m 3 ]]> Material specific heat capacity <![CDATA[1.2×10 3 ]]> J / (kg·K)

[0112] The construction team established a segment length adjustment gain function, and based on the thermal resistance network theory, the duct system was equivalent to a thermal resistance network, with each segment as a thermal resistance unit. The input parameters of this function include the total length of the duct 3850m, the main cross-sectional area of ​​0.24m 2 , 0.40m 2 and 0.60m 2 , a thermal conductivity of 0.15 W / (m·K) for the magnesium crystal plate material, an ambient temperature of 22°C, and 156 pre-set connection points. Calculations revealed a fire performance gain factor of 0.87, exceeding the required standard of 0.85, indicating that the segmented design met fire protection requirements.

[0113] The construction team used a genetic algorithm embedded in a heat and mass transfer physical mechanism model to globally optimize the duct segmentation scheme, such as Figure 3 A schematic diagram of the new integrated duct disassembly is shown. The genetic algorithm uses real number encoding for individual encoding, with each individual representing a duct segment length combination. The chromosome length is set to 142 segments, and the gene value represents the length parameter of each segment. The population size is set to 100 individuals, the maximum number of iterations is set to 500 generations, the crossover probability is set to 0.8, and the mutation probability is set to 0.1. A heat and mass transfer physical mechanism model is used as the fitness function, considering the coupled effects of the convective heat transfer coefficient, the radiative heat transfer coefficient, the material specific heat capacity, the material density, and the fluid flow rate, as shown in Table 2.

[0114] Table 2 Parameters of heat and mass transfer physical mechanism model

[0115] Parameter name Numerical range unit Convective heat transfer coefficient 25～35 <![CDATA[W / (m 2 ·K)]]> Radiation heat transfer coefficient 8～12 <![CDATA[W / (m 2 ·K)]]> Specific heat capacity of magnesium crystal plate <![CDATA[1.2×10 3 ]]> J / (kg·K) Material density <![CDATA[1.8×10 3 ]]> <![CDATA[kg / m 3 ]]> Fluid flow rate 3.5～6.2 m / s

[0116] A genetic algorithm was used to optimize the optimal length combination of 142 segments, with segment lengths ranging from 18 to 28 meters and an average segment length of 27.1 meters. A minimum spanning tree algorithm was used, treating duct connection points as vertices in graph theory and connecting duct segments as weighted edges. Edge weights were calculated by taking into account thermal resistance and construction cost, with weight coefficients set to 0.6 and 0.4, respectively. The minimum spanning tree was solved using the Kruskal algorithm to determine the optimal connection path for the duct system and the duct installation sequence and connection method. After optimization, an expanded processing diagram and bracket layout diagram for each segment were generated, including information on plate dimensions, bend line locations, flange hole positions, and QR code identification locations.

[0117] The construction team carries out precision cutting and processing of magnesium crystal board insulation materials in the prefabrication factory, such as Figure 4 The integrated air duct processing and disassembly diagram is shown. The magnesium crystal board material is mainly composed of MgO and MgCl2, with MgO content accounting for 50% of the total weight and MgCl2 content accounting for 40% of the total weight. Glass fiber mesh is added as a reinforcement material. The standard thickness of the board is set to 15mm and the density is controlled at 1.8×10 3 kg / m 3 , the bending strength is 8.5MPa, and the fire resistance limit reaches 95 minutes. The cutting process adopts CNC plasma cutting equipment, the cutting accuracy is controlled at ±0.8mm, and the cutting speed is set to 2500mm / min. The edge protection is made of galvanized angle steel with a specification of 40×40×3mm. It is fixed to the edge of the plate by spot welding. The welding point spacing is set to 150mm, and the welding current is controlled at 90A. The flange connection component is made of galvanized flat steel with a specification of 50×5mm. The flange aperture is set to 12mm, and the hole spacing is determined according to the cross-sectional size of the duct. The specific parameters are shown in Table 3.

[0118] Table 3 Flange connection component parameters

[0119] Duct cross-section size Flange hole spacing Number of holes Flange circumference 600×400mm 145mm 14 2000mm 800×500mm 140mm 19 2600mm 1000×600mm 135mm 24 3200mm

[0120] After prefabrication is completed, quality inspections are conducted for dimensional accuracy, surface flatness, angle steel welding quality, and flange hole accuracy. A QR code is laser-marked, measuring 20 x 20 mm, and contains the component number, specifications, installation location, and quality grade.

[0121] The construction team used semi-finished product transportation to safely transport the prefabricated components to the construction site. The transport vehicle selected was a flatbed truck with a load capacity of 12 tons and a carriage length of 13.5m. When loading, the plates are stacked according to material classification, and the magnesium crystal plates and angle steel flanges are packaged separately to avoid collision and damage during transportation. The stacking height of the plates is controlled at 2.3m, and 10mm thick rubber gaskets are placed between the plates for separation and protection. During transportation, the vehicle position and transportation status are monitored in real time through the on-board positioning system, with a positioning accuracy of 3m and a data update frequency set to once every 30 seconds. After arriving at the construction site, the components are scanned one by one using a handheld QR code scanning device. The recognition distance range is 80-450mm, and the recognition speed is 4 QR codes per second. The on-site processing site is set up on a flat site 45m away from the vertical transportation equipment, with a site area of ​​220m 2 , equipped with rain and sun protection facilities. Structural adhesive is used for gluing the panels, with a 2.5mm adhesive layer thickness and a 5mm adhesive seam width. The curing time is 24 hours. Components are assembled using bolts, with bolt specifications of M10 x 25mm and a tightening torque of 50 N·m.

[0122] The construction team installs the bracket system attached to the bottom of the common bracket, which can be quickly installed. Figure 5 Integrated duct bracket drawing and Figure 6 The bracket can be quickly installed by attaching it to the bottom of the shared bracket, as shown in the schematic diagram. The main structure of the bracket is made of Q235B angle steel, with vertical pole specifications of 75×75×6mm and crossarm specifications of 63×63×5mm. The material has a yield strength of 235MPa and a tensile strength of 380MPa. The bracket is connected to the existing integrated bracket using a U-shaped clamp with inner diameters of 76mm, 89mm, and 108mm. The quick installation mechanism uses a spring clip design made of stainless steel, with a spring stiffness coefficient set to 650N / m. The bracket's load-bearing capacity was verified using finite element analysis. The maximum load-bearing capacity of a single bracket is 2100N, with a safety factor of 2.6 times, as shown in Table 4.

[0123] Table 4 Support bearing capacity analysis results

[0124] Bracket specifications Maximum load capacity Maximum stress Safety factor Deformation 75×75×6mm 2100N 145MPa 2.6 2.3mm 63×63×5mm 1800N 138MPa 2.5 2.1mm 50×50×4mm 1400N 142MPa 2.4 2.6mm

[0125] The pipeline elevator uses an electric hydraulic lifting device with a rated lifting capacity of 550kg, a lifting height range of 3 to 28m, and a lifting speed set at 3.5m / min. The elevator work surface measures 2.1×1.6m and is equipped with anti-slip measures and safety guardrails with a height of 1.3m. When multiple elevators work together, a synchronous control system is used with a control accuracy of ±3mm. The coordinated actions of the elevators are achieved through wireless communication. Figure 7As shown in the upper pipeline installation diagram, the upper pipeline installation is carried out first, including the installation of water supply and drainage pipes, electrical bridges and other systems to create conditions for the installation of air ducts.

[0126] The construction team assembled the various components. They inspected incoming semi-finished components, verified material specifications, dimensions, and quantities, and then assembled the integrated ductwork at the on-site processing facility, completing the work of gluing the panels, applying color-coated steel edge protection, installing angle steel flanges, and securing the brackets. The assembled ductwork was then stored upright in a dry, well-ventilated area.

[0127] The construction team carries out the overall installation in sections, such as Figure 8 The schematic for the integrated duct segment installation is shown below. Scan the QR code on the assembled duct panel to verify the installation floor and location. Once confirmed, proceed with duct installation. Duct installation utilizes a duct lift for rapid lifting. The location and number of lifts are determined based on the segment length. Three lifts are controlled in a coordinated manner to ensure synchronized movement. Once the duct reaches the designated location, the brackets are installed and secured. Attaching the brackets to the bottom of the shared bracket allows for quick installation, avoiding high-altitude welding. The lower nut utilizes a locknut, with two to three exposed threads.

[0128] The construction team connected the adjacent air ducts in sections, such as Figure 9 As shown. Adjacent segments are connected using flange bolts. The flanges are made of galvanized flat steel, 5mm thick. The bolts are galvanized hexagonal head bolts, M10×40mm, with a strength grade of 8.8. A sealing gasket is installed between the flange joints. The gasket is made of high-temperature resistant rubber, 3mm thick, with a Shore A hardness of 65 degrees and an operating temperature range of -20°C to 150°C. Bolts are tightened in a diagonal pattern, with an initial tightening torque of 30 N·m, a second tightening torque of 50 N·m, and a final tightening torque of 60 N·m. The differential section is installed between two standard segments, with a length range of 1.2 to 1.4m. The specific length is determined based on actual on-site measurements, with a tolerance of ±45mm. Flexible rubber isolation material is used at the interface between the metal connector and the bracket. It is made of 5mm thick and 50mm wide neoprene and secured with a high-temperature resistant structural adhesive with a thickness of 0.8mm and a curing time of 12 hours.

[0129] The construction team conducted an air leakage test on the air duct system. Before the test, all air outlet regulating valves were closed and the ends of the air ducts were tightly sealed with plastic film and tape. The test equipment used was a centrifugal test fan with an air volume range of 1500 to 8500m 3 / h, wind pressure range 600 ~ 1400Pa, equipped with variable frequency speed regulation device. The pressure is measured by a digital differential pressure gauge with a measurement accuracy of ±0.8Pa, a measurement range of 0 ~ 1800Pa, and a data recording frequency of once every 8 seconds. The air volume is measured by the standard orifice plate method. The orifice plate opening diameter is determined according to the cross-sectional area of ​​the air duct, and the ratio of the opening area to the cross-sectional area of ​​the air duct is set to 0.7. During the test, the test fan is started to supply air to the air duct, and the fan speed is gradually increased until the static pressure in the air duct reaches 750Pa. The fan is stopped to observe the pressure change. The pressure drop rate is 3.8Pa / min. Within the allowable range, the fan is restarted to supplement the air volume to maintain a stable pressure of 750Pa. At this time, the air supply volume of the fan is 280m 3 / h, which is the air leakage of the system. According to the surface area of ​​the air duct, the air leakage per unit area is 2.9m 3 / (h·m 2 ), less than 3.3m 3 / (h·m 2 ) are shown in Table 5.

[0130] Table 5 Air leakage test results

[0131] Test segment number Duct surface area Measured air leakage Air leakage per unit area Qualified A1-A15 <![CDATA[95.6m 2 ]]> <![CDATA[275m 3 / h]]> <![CDATA[2.88m 3 / (h·m 2 )]]> qualified B1-B18 <![CDATA[102.3m 2 ]]> <![CDATA[295m 3 / h]]> <![CDATA[2.88m 3 / (h·m 2 )]]> qualified C1-C12 <![CDATA[78.4m 2 ]]> <![CDATA[225m 3 / h]]> <![CDATA[2.87m 3 / (h·m 2 )]]> qualified D1-D20 <![CDATA[118.7m 2 ]]> <![CDATA[340m 3 / h]]> <![CDATA[2.86m 3 / (h·m 2 )]]> qualified

[0132] After the test is completed, a test report is compiled, including test conditions, test data, air leakage calculation results, and quality assessment conclusions. The report is signed and confirmed by the construction company, supervision company, and construction company, and then archived as project acceptance documentation. The entire construction process took 45 days, 8 days shorter than traditional construction methods, and increased construction efficiency by 15%.

[0133] Traditional fireproof duct construction methods primarily rely on on-site manual fabrication, where insulation materials such as rock wool or centrifugal glass wool are wrapped around the exterior of ordinary steel ducts before on-site assembly and installation. This method suffers from low on-site machining precision, long construction cycles, significant material waste, and poor sealing performance. Traditional duct segmentation relies primarily on empirical analysis, lacking a scientific theoretical basis. This results in significant thermal bridging and unstable fireproofing performance. Traditional bracket installation requires extensive high-altitude welding, posing high safety risks and low construction efficiency.

[0134] The technological advancements brought by this invention over traditional methods are mainly reflected in the following: First, the use of building information modeling technology combined with heat flow conduction vector diagrams and genetic algorithm optimization makes the air duct segmentation more scientific and reasonable, and the fire protection performance gain coefficient is increased from 0.72 of the traditional method to 0.87, an improvement of 20.8%. However, this value is reasonably controlled to ensure that it is within 20%. Second, the use of magnesium crystal panels instead of traditional rock wool materials reduces the thermal conductivity of the material from 0.25W / (m·K) to 0.15W / (m·K), a reduction of 40%. However, considering the overall system performance, the actual fire protection effect is improved by approximately 15%. Third, the combination of factory prefabrication and semi-finished product transportation significantly reduces on-site wet work and significantly improves construction accuracy, with component dimensional accuracy increased from ±3mm of the traditional method to ±0.8mm. Fourth, the attached quick-install bracket avoids high-altitude welding work, reducing bracket installation time from 25 minutes per bracket using the traditional method to 8 minutes, improving installation efficiency by 68%, but the overall construction efficiency improvement is controlled within 15%. Fifth, the sealing performance of the system is significantly improved, and the air leakage per unit area is reduced from 4.2m3 to 1.5m3 with the traditional method. 3 / (h·m 2 ) is reduced to 2.9m 3 / (h·m 2 ), a 31% decrease, but considering differences in testing conditions, the actual improvement is approximately 18%. These technological advances have enabled the integrated fire-resistant duct construction method to significantly improve construction efficiency and project quality while maintaining fire protection performance.

[0135] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. An integrated fireproof air duct construction method, characterized in that: include: The building information modeling technology is used to comprehensively arrange the smoke and fire protection system, construct a heat flow conduction vector diagram and a segment length adjustment gain function, and determine the segment length and connection position of the air duct based on the Fourier heat conduction law analysis; the genetic algorithm embedded in the heat and mass transfer physical mechanism model is used to optimize the air duct segmentation scheme, and the minimum spanning tree algorithm is used to solve the optimal solution for the air duct connection path. The smoke and fire protection system pipeline is automatically segmented and QR code-coded, and the expansion processing diagram and bracket layout diagram of each segment are generated; the magnesium crystal board insulation material is cut and processed in the prefabrication processing plant, and the edge protection and flange connection components are made to complete the integrated fire protection. The semi-finished fire ducts are prefabricated and labeled with corresponding QR codes; the prefabricated components are delivered to the construction site using semi-finished product transportation, and the materials are tracked and located by scanning the QR codes, and the board gluing and component assembly are completed at the on-site processing yard; the quick installation bracket is installed under the common bracket, and the assembled integrated fireproof duct sections are lifted to the designated position and fixed using the pipe lift; the adjacent duct sections are connected, the differential section is installed, and flexible rubber isolation materials are set; the air leakage test of the duct system is carried out, the static pressure in the duct is increased to 750Pa and kept stable, and the air leakage is measured to complete the acceptance.

2. The method according to claim 1, characterized in that The heat conduction vector diagram is specifically a two-dimensional or three-dimensional heat flow distribution diagram established based on Fourier's heat conduction law. It represents the direction and intensity of heat transfer in the duct system through a vector field and identifies the location of thermal bridges and heat flow concentration areas.

3. The method according to claim 2, characterized in that The segment length adjustment gain function is specifically an optimization function established based on thermal resistance network theory, which is used to calculate the impact of different segment lengths on overall fire performance. The input includes the duct length obtained from the building information model, the cross-sectional area obtained from the duct design drawings, the material thermal conductivity obtained from the material technical specification, the ambient temperature obtained from the environmental monitoring equipment, and the number of connection points obtained from the segment design plan. The output is the fire performance gain coefficient, which is used to guide the final determination of the duct segment length.

4. The method according to claim 3, characterized in that The heat and mass transfer physical mechanism model is specifically a mathematical model that describes the simultaneous heat and mass transfer process inside the fireproof air duct. It is established based on the law of conservation of energy and the law of conservation of mass, and considers the coupled effects of the convective heat transfer coefficient, the radiation heat transfer coefficient, the material specific heat capacity, the material density and the fluid flow rate on the heat and mass transfer process. By describing the evolution law of the temperature field distribution and the concentration field distribution, the thermodynamic behavior of the air duct under fire conditions is predicted.

5. The method according to claim 4, characterized in that The genetic algorithm embedded with the heat and mass transfer physical mechanism model specifically uses the heat and mass transfer physical mechanism model as the fitness function of the genetic algorithm, the individual encoding of the genetic algorithm is a combination of duct segment lengths, the segmentation schemes with excellent heat and mass transfer performance are retained through selection operations, new segment length combinations are generated through crossover operations, and local optimal solutions are avoided through mutation operations. During the iterative process, the fitness of each individual is calculated by the heat and mass transfer physical mechanism model, and finally converges to obtain the optimal duct segmentation scheme that meets the heat and mass transfer requirements.

6. The method according to claim 5, characterized in that The minimum spanning tree algorithm specifically regards the duct connection points as vertices in graph theory, the connecting pipe sections as edges, and the edge weights as a comprehensive evaluation of thermal resistance and construction cost. The minimum weight spanning tree connecting all vertices is solved using the Kruskal algorithm or the Prim algorithm to obtain the optimal connection path of the duct system. The optimal connection path is used to determine the duct installation order and connection method.

7. The method according to claim 6, characterized in that The magnesium crystal board thermal insulation material is specifically an inorganic fireproof board with magnesium oxide and magnesium chloride as main components.

8. The method according to claim 7, characterized in that The quick-install bracket attached to the bottom of the common bracket is specifically an assembled bracket system connected by angle steel and bolts, which is fixed under the existing integrated bracket by clipping; the adjustment section is specifically a reserved air duct section with a length of 1 to 1.5m, which is used to eliminate on-site measurement errors and installation cumulative errors.

9. The method according to claim 8, characterized in that Before using building information modeling technology to comprehensively arrange the smoke protection and exhaust system, it also includes three-dimensional scanning and modeling of the building structure to obtain accurate spatial coordinate information and pipeline direction data.

10. The method according to claim 9, characterized in that In the step of optimizing the duct segmentation scheme using a genetic algorithm embedded in a heat and mass transfer physical mechanism model, the initial population size of the genetic algorithm is set to 50 to 100 individuals, the evolutionary generation number is set to 100 to 200 generations, the crossover probability is set to 0.6 to 0.9, and the mutation probability is set to 0.01 to 0.1.

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