Fire-resistant board for ventilation ducts This new type of inorganic fire-resistant board is made primarily from natural mineral powders such as magnesium oxide and silica, reinforced with polymer-modified materials, and filled with lightweight additives. To minimize the likelihood of fires occurring in ventilation ducts as much as possible, we typically choose fire-resistant boards for auxiliary installation. During the manufacturing process, we carefully incorporate certain concrete materials to reduce the board’s thermal conductivity, ensuring that even under high-temperature conditions, it remains difficult to ignite and does not produce harmful gases. Below, we’ll introduce the key installation precautions and construction guidelines for fire-resistant boards used in ventilation ducts:

　　I. Precautions for Installing Fire-Resistant Boards in Ventilation Ducts

　　1. For more complex civil buildings, during the design phase, all types of work—including HVAC, plumbing and drainage, power supply and lighting, as well as architectural design—should first involve coordinated discussions on space partitioning and the determination of elevation ranges for each type of piping system. Generally, you should not exceed the limits set for your own scope; if a pipe segment crosses boundaries, you should consult with other relevant parties.

　　2. The general principle for resolving collisions and ensuring coordination among various ventilation ducts is: “Let smaller ducts yield to larger ones, and pressurized ducts yield to non-pressurized ones.” For example, if a water pipe collides with an air duct, the water pipe should be repositioned. If hot and cold water pipes collide with sewer pipes, the hot and cold water pipes should be rerouted.

　　3. Before construction begins, the engineer responsible for equipment should draw the piping and single-line diagrams for each trade on the floor plan. Use a different colored pen for each type of pipe. Consolidate the elevations at each intersection to identify any conflicts and resolve them before installation.

　　4. To reduce investment, save space, and lower the floor height, some pipelines that do not have slope requirements can be routed through beams (such as water supply pipes and fire sprinkler main pipes).

　　II. Fire-resistant board for ventilation ducts Key points of construction technology

　　1. Board material inspection upon arrival

　　First, perform a visual inspection. The surface should be smooth and free of chipped edges or corners. Second, the boards must come with a manufacturer’s certificate and test report, and all performance indicators of the boards must meet the requirements specified in the design and JT6-00 standards.

　　2. Duct fabrication

　　a. Based on the design requirements, combined with the on-site layout and measured data, prepare duct fabrication drawings and compile a material-cutting schedule. The inner side length of the duct specifications shall be used as the reference. Before cutting the板材, the cutting dimensions must be rechecked.

　　b. The four inner corners of the rectangular duct are reinforced with equal-leg angle steel as internal corner keels and secured using hexagonal flange self-tapping screws. The duct flanges are welded from four-corner steel sections. When marking and cutting materials, ensure that the inner length of the welded flanges does not exceed the inner length of the duct.

　　When assembling the four side panels of the duct, use the angle steel flanges at both ends of the duct as the primary supporting keel. Depending on the duct dimensions, weld the end-angle steel flanges together with the corner angle steel keels and the angle steel keels to form the internal keel framework of the duct.

　　The side panels are fixed to the flanges using hexagonal flange-face self-drilling and self-tapping screws, with a screw spacing no greater than 150 mm. The side panels are also fixed to the inner angle steel studs using hexagonal flange-face self-tapping screws, with a screw spacing no greater than 230 mm.

　　e When fabricating ductwork, minimize the number of butt joints as much as possible. Longitudinal butt joints on sheet materials should avoid the centerlines of the longer sides; butt joints between opposite surfaces should be staggered. The cross-sections of spliced joints should be coated with a waterproof sealant.