How should membrane structure buildings be maintained? A guide.
Membrane structures are increasingly used in stadiums, commercial centers, and urban landscapes, favored for their unique shapes, lightweight texture, and self-cleaning properties. However, while membrane structures possess a degree of self-cleaning capability, this function is inherently limited. Therefore, regular maintenance can enhance their aesthetics and durability. Below is a maintenance guide summarizing the formation of dirt, potential shortened lifespan, and causes of damage to membrane structures.
The main causes of dirt buildup on membrane structures include air pollution, bird droppings, fallen leaves and pollen, and poor drainage due to a shallow slope. If there is no rain for an extended period, the dirt accumulated on the membrane structure's surface is unlikely to be easily cleaned by rainwater, affecting not only the building's aesthetics but also potentially corroding the membrane coating due to adhering chemicals or organic matter.
Different cleaning strategies are needed for different situations.
In ordinary environments, such as parks or residential areas with little greenery, it is recommended to clean every 6 to 12 months. In heavily polluted areas near roads, factories, or coastal areas with frequent sandstorms and bird droppings, the frequency should be increased to once every 3 to 6 months.
In rainy or high-humidity environments, it is recommended to check and actively drain water approximately every 3 months to prevent mold growth on materials without anti-mold properties, which can seep into the membrane material.
Use a soft-bristled brush or sponge with low-pressure water (≤0.2MPa) to rinse from top to bottom, avoiding scratches from mud and sand. For stubborn stains, apply a neutral detergent and let it sit for 2 to 3 minutes to soften before gently wiping; vigorous rubbing is strictly prohibited.
Do not use gasoline, alcohol, chlorine, or strong acids and alkalis as cleaning aids. These substances can directly damage the PVDF or PTFE protective coating on the membrane surface, causing the membrane to lose some of its functions and accelerating aging.
Membrane structures under normal use and maintenance have a relatively long lifespan, generally exceeding 25 years. However, improper usage habits or extreme external stimuli can significantly shorten its actual lifespan or even cause it to be damaged directly.
The applicable temperature range for membrane structures is typically between -40℃ and 60℃. Therefore, when installing lighting or heating equipment on-site, sufficient safety distance must be maintained from the membrane surface to prevent the high temperatures generated by the equipment from directly burning the membrane coating.
In membrane structures, air-supported membranes, tensile membranes, and steel membrane structures all rely on the tension of the membrane material to maintain their structural shape.
Insufficient tension will cause the membrane surface to shake violently in wind and rain, accelerating membrane fatigue; excessive tension may exceed the elastic limit of the membrane material, leading to tearing.
Therefore, it is recommended to conduct membrane material stress value testing at least once a year. If it is lower than 80% of the design value, it needs to be re-tensioned.
If a membrane structure is exposed to a humid environment or water accumulation for a long period, moisture will seep into the membrane material, damaging its properties. Even with chemically stable PTFE coatings, tensile strength can decrease by 5% to 16% after prolonged immersion in water. Therefore, it is recommended to regularly check for any substances remaining in the drainage gaps and ensure that the drainage system designed in the original specifications remains unobstructed.
Damage to membrane structure buildings often comes from external mechanical forces, chemical corrosion, and extreme weather.
To ensure the safety of membrane structure buildings, maintenance needs to be carried out according to the following comprehensive prevention mechanism.
The membrane surface must not come into contact with sharp objects such as knives and nails. During routine maintenance, if workers need to step on the membrane, they must change into clean, soft-soled shoes to prevent sand and dirt from abrading the surface. Hard metal objects should not be piled on the membrane surface for extended periods to avoid accidental impacts or scratches that could damage the membrane.
Steel structures are prone to rusting after prolonged use or contact with acidic or alkaline solvents, weakening the overall structural strength of the building. Furthermore, rust-inducing water from rainwater can contaminate and corrode the membrane. Therefore, it is recommended to perform a complete rust prevention maintenance (rust removal and application of specific rust inhibitors) on the entire steel structure approximately every year, or to select steel structures with rust prevention functions during the design and spare parts phase, and to regularly lubricate and maintain key connection parts such as steel cables and anchor points.
Membrane structure building systems are generally equipped with a pressure relief program. This program senses the pressure level and intelligently releases pressure during snowfall and rain, and intelligently controls pressure to stabilize the structure during typhoons or strong winds. Therefore, this program should not be turned off unless absolutely necessary.
If it must be turned off: In heavy snow, excessive snow accumulation may exceed the membrane material's load-bearing limit, leading to structural deformation or even cracking. Manual snow removal must be carried out immediately. Before a typhoon or strong wind arrives, the windproof cables should be checked for tightness. However, the overall risk will be higher than not turning off the pressure relief program.
Finally, if a crack appears on the membrane surface, if it is less than 20cm, it can be repaired using the provided membrane material of the same type and a heat sealing machine. For medium to large cracks within 50cm to 2m, there is no need to worry about sudden tearing safety. Aluminum clamps can be used to firmly clamp the patch membrane material at the top and bottom of the damaged area, and after-sales maintenance should be requested.