The windproof structural measures for metal roof photovoltaic support systems need to comprehensively consider multiple factors, as follows:

1. Material and structural design

Support material: Use weather-resistant steel (such as carbon structural steel, low-alloy high-strength structural steel) or aluminum alloy to ensure its stability and corrosion resistance under wind load. For example, materials such as stainless steel bolts and aluminum alloy rail purlins must meet the requirements of standards such as GB/T 3190 and GB/T 3077.

Structural stiffness: The support system must have sufficient stiffness and strength to resist wind loads. For example, the support span of a sloped roof photovoltaic module has an allowable deflection of L/250, and needs to be designed based on wind speed (0.3 kN/m²) and snow load (1.4 kN/m²).

2. Connection and fixing measures

Connection method: The connection between the bracket and the roof must be made with high-strength bolts (such as blind rivets, self-tapping screws) or welding, and ensure that the force transmission path of the connection node is clear to avoid additional load on the metal roof panel. For example, the aluminum alloy block is fixed to the guide groove purlin with stainless steel bolts, and anti-slip measures must be set.

Fixing density: In wind-sensitive areas, it is necessary to increase the density of fixed supports and screws, and use clamp connections or assemblies to enhance the bearing capacity when necessary. For example, when a single screw column is insufficient, you can increase the contact points or use a line contact clamp.

3. Ventilation and drainage design

Ventilation gap: A ventilation gap (recommended ≥100mm) must be reserved between the photovoltaic module and the roof to suppress temperature rise and prevent condensation and dripping. For example, when installing photovoltaic modules on a sloped roof, an independent ventilation channel must be set up.

Drainage function: The bracket layout must not affect roof drainage to avoid rainwater leakage. For example, when the photovoltaic bracket components and the roof are made of different materials, insulating gaskets or anti-corrosion measures must be used.

4. Waterproof and anti-corrosion treatment

Waterproof structure: The connection nodes between photovoltaic modules and metal roofs need to adopt flexible waterproof measures (such as neutral weather-resistant sealant) or additional waterproof layers to prevent rainwater penetration. For example, the overlap of metal roofs needs to be coated with base coating first, and then embedded with sewn polyester cloth.

Anti-corrosion measures: Except for stainless steel, other materials need to select surface treatment (such as hot-dip galvanizing, electrostatic powder spraying) according to the degree of environmental erosion, and ensure that impurities such as welding slag and oil stains are removed before installation.

5. Special design for wind resistance

Wind-resistant reinforcement: During the secondary reinforcement of metal roofs, wind-resistant clamps (such as foam strips and plastic saddle pads) can be used to enhance the fixing effect. For example, large metal roofs such as terminal buildings and high-speed rail stations need to be clamped to improve wind resistance.

Wind direction and layout optimization: Adjust the layout of the photovoltaic array according to the local wind direction and wind speed, and set up windproof vents to reduce the impact of wind. For example, the slope roof bracket system uses holes to install hook brackets and combines physical fixation to improve wind resistance.

6. Construction and acceptance

Construction safety: Construction is strictly prohibited in rainy, snowy and windy weather. Avoid collision when transporting components. Check and deal with leakage or hot spot problems in time after installation.

Acceptance requirements: PV components must be reliably connected to the main structure of the roof, and the bracket should be connected to the lightning protection grounding system at more than two points.