Is galvanized fireproof iron sheet suitable for outdoor or high-humidity fireproof partition applications?
Publish Time: 2025-11-11
In modern building fire protection systems, fireproof partition materials not only need to meet stringent fire resistance requirements but also adapt to diverse usage environments. Especially in high-humidity and highly corrosive environments such as outdoors, underground garages, coastal areas, or industrial plants, traditional fireproof boards are prone to moisture damage, deformation, strength reduction, and even loss of fire resistance. Galvanized fireproof iron sheet, with its unique "metal substrate + fireproof composite layer" structure, exhibits excellent weather resistance and corrosion resistance while maintaining superior fire resistance, making it an ideal choice for high-humidity and outdoor fireproof partition applications.1. Galvanized Layer: The First Barrier Against Moisture and CorrosionGalvanized fireproof iron sheet uses cold-rolled steel sheet as the base material, with a surface treated by hot-dip galvanizing or electro-galvanizing to form a dense zinc alloy protective layer. Zinc is chemically reactive and can form a stable basic zinc carbonate film in the air, effectively blocking moisture, oxygen, and salt spray from corroding the internal steel substrate. In environments with relative humidity consistently above 70% or in the presence of acid rain, sea breezes, or salt spray, the galvanized coating significantly slows down the corrosion process of steel plates. Depending on the amount of zinc plating, its outdoor service life can reach 10–20 years, far superior to unprotected steel. This characteristic allows galvanized fireproof iron sheets to be used directly for fireproofing or partitioning in damp areas such as semi-outdoor awnings, equipment room exterior walls, and subway entrances without the need for additional anti-corrosion coatings.2. Fireproof Core Material: Stable Fire Resistance Unaffected by HumidityThe fireproof function of galvanized fireproof iron sheets primarily relies on the inorganic fire-resistant materials in the core layer or surface composite, such as intumescent fire-retardant coatings, calcium silicate boards, rock wool, or vermiculite boards. These materials are inorganic, do not absorb water, and do not mold; even when exposed to high humidity environments for extended periods, their physical structure and fire resistance remain stable. For example, in the event of a fire, the intumescent coating rapidly foams upon heating to form an insulating char layer, effectively blocking heat transfer to the unexposed side; while the rock wool core material, with its low thermal conductivity and high melting point, maintains the integrity of the partition for 90–120 minutes. Unlike wood or fiber-based fireproof boards, galvanized fireproof iron sheet does not expand, delaminate, or deteriorate in strength due to moisture absorption, ensuring consistently reliable fire resistance.3. Structural Stability: Addressing the Challenges of Temperature and Humidity DeformationIn environments with large diurnal temperature variations or drastic seasonal humidity changes, the thermal expansion and contraction of materials, along with moisture expansion and contraction, can easily lead to problems such as joint cracking and loosening of fasteners, compromising the continuity of the fireproof partition. Galvanized fireproof iron sheet, with its metal frame, has a low coefficient of linear expansion and excellent dimensional stability. Combined with a dedicated keel system and elastic sealant for joint treatment, it can effectively absorb minor displacements, preventing structural failure due to environmental stress. Furthermore, its high compressive and impact resistance allows it to withstand wind loads and minor collisions, making it suitable for complex locations such as ventilation shafts and pipe shafts where both protection and fireproofing are required.Galvanized fireproof iron sheet, through the dual advantages of "metallic weather resistance + inorganic fireproofing," successfully overcomes the limitations of traditional fireproof materials in humid and outdoor environments. It not only provides robust protection during fires but also maintains long-term serviceability in harsh everyday climates. For modern building projects that prioritize safety, durability, and optimized life-cycle costs, galvanized fireproof iron sheet is undoubtedly the preferred solution for high-humidity and outdoor fireproof partition applications, offering both reliability and economy.
