Introduction to fire-resistant silicate board covering for ventilation ducts
Release time:
2025-07-29 11:00
Source:
We often see project requirements where the fire-resistant wrap of ductwork consists of a metal duct + rock wool + calcium silicate board. This structure is common in some fire ducts assembled on-site. Of course, there is no problem assembling it into a finished product in the factory. A general illustration is as follows: 
Let's look at its cross-sectional view:
Using calcium silicate board as a fire-resistant board has its own advantages compared to other board materials, such as thin board thickness, high flexural strength, and low board density. Because many fire ducts are located in basement spaces and the environment is in a high-humidity state for a long time, the fact that calcium silicate board is not afraid of moisture or efflorescence is quite important. After all, no one wants to see the safety hazard of metal connectors being corroded over the years.
In some basements with longer installation times, we have found that ducts with magnesium oxychloride cement board as fire-resistant wrapping boards all show signs of rust on bolts and other metal connectors. In the current downturn in the construction industry, everyone is desperately trying to lower prices and win bids at low prices. The safety hazards caused by the use of inferior building materials may not be apparent in the short term, but over a longer period, it will be a major safety hazard.
The density of current low-density calcium silicate board can reach below 1.0g/cm³, close to the density of water. Used as a fire-resistant board for fire ducts, it can greatly reduce the weight of the structure.
The common fire resistance limits of using calcium silicate board for duct wrapping fire-resistant boards are shown in the table below :
Fire-resistant wrapping of ducts has gradually received attention in recent years with the implementation of new fire protection regulations. Calcium silicate board, as one of the options for fire-resistant wrapping boards, has its own advantages and disadvantages. For example, the price is higher than magnesium oxychloride cement board and other magnesium-based materials. Because it is a hard board material, its construction convenience is somewhat lacking compared to soft wrapping materials. There is never an ideal material that can do everything. As long as its advantages meet our requirements, it is suitable.
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