New Features of Flexible Waterproofing of Light Steel Roof in Guangben Second Factory

Outstanding performance, especially suitable for hot areas and asphalt concrete deck projects. In Western Europe, modified bitumen membranes have become the dominant waterproof material (eg Italy 95%, France 85%); in the United States, modified bitumen membranes have grown in recent years: the fastest products.

Since the mid-1970s of the 20th century, polymer waterproof sheets have been widely used in Europe, the United States, Japan, and other developed countries, and have become a new force for roofing materials. Polymer waterproof sheets include EPDM (ethylene propylene diene monomer rubber), butyl rubber, CSPE (chlorosulfonated polyethylene), polyisobutylene, and other rubber products; PVC, CPE (chlorinated polyethylene), PE (polyethylene) Resins such as ECB (ethylene copolymer asphalt) are most commonly used with EPDM and PVC. In the United States and Japan, EPDM has been used most successfully. The annual usage in the United States is as high as 120 million square meters. In recent years, TPO (thermoplastic polyolefin) waterproof sheets have been favored by countries. It not only has the superior properties of ethylene-propylene rubber, but also hot welding seams, indicating a good development prospects in this field.

Zhu Dongqing said that at present, China's waterproofing is still based on modified SBS, supplemented by polymer-polymeric waterproof sheets or coils, such as PVC and EPDM. However, although the TPO with the relatively best performance has been used abroad, there is no precedent for application in our country. The waterproof material of the light steel roofing flexible waterproofing system applied in the Guangzhou Honda No.2 Plant is the reinforced PVC coiled material in the 1.2 mm polyester fabric in the polymer waterproof material.

Reinforced PVC webs in polyester fabrics have high tear strength and low elongation at break. Their tensile strength is above 1 000 N/50 mm, and their elongation at break is about 12*%. They can be used under greater stress. Only a small amount of deformation occurs; and this type of coil has excellent impact resistance; these properties are particularly suitable for mechanically fixed roof systems. The special surface coating treatment of this type of coil material does not attract dust, is easy to clean, bright in color and has a certain metallic texture. In addition, the special anti-ultraviolet auxiliaries in reinforced PVC webs in polyester fabrics, as well as the use of stiffeners, greatly enhance the anti-aging properties of the web.

Infiltrated Company's reinforced PVC web in 1.2 mm polyester fabric used in Guangben Project can pass the artificial weathering test for more than 3,500 hours (the national standard requires 1000 hours). The surface of this type of coil is silver-gray, with strong sunlight reflection ability, which can reject a large amount of light heat outside the roof system, reduce the temperature of the surface of the coiled material in summer, and greatly reduce the indoor air-using cost. It is therefore an environmentally friendly material.

In view of the current national standards for PVC materials, there is a certain lag, a few days ago, Guangzhou Honda was officially established in the second factory area in Zengcheng, Xintang, Guangzhou. The plant uses a lightweight steel structure system that is highly earthquake-resistant, recyclable, environmentally friendly, energy-saving, and convenient to construct, and has successfully applied a flexible steel roof waterproofing system.

Zhu Dongqing, secretary-general of the China Building Waterproof Materials Association, told reporters that people usually only pay attention to the fireproofing and corrosion protection of steel structures. In fact, waterproofing should also be highly regarded.

He said that many people will mistakenly believe that steel structures and light steel structures are carefully designed and calculated, and that they are closely embedded in the joints, and they are considered as seamless and there is no leakage of water. This is a misunderstanding. Because the steel structure and the light steel structure are inevitably subject to the thermal expansion and contraction under the influence of natural temperature, this thermal expansion and contraction effect brings about potential leakage problems at the node.

Zhu Dongqing said that the application of the flexible water-proof waterproofing system for the roof of this Honda No. 2 Plant was particularly focused on the following three characteristics: First, it applied a flexible waterproof system for light steel roofs, and secondly, it used a mechanical fixing method to waterproof the roof. Layers, insulation layers, and roofing are effectively combined. Third, in the construction of the roof, the project has for the first time chosen a waterproof and thermal insulation integrated contracting construction method, effectively reducing the mutual wrangling between the waterproof and thermal insulation construction units. More clearly defined responsibilities.

Waterproof classification According to Zhu Dongqing, the modified asphalt coil felt is basically a SBS and APP modified bituminous coil material. The carcass is glass fiber felt and polyester felt. SBS modified bitumen membrane has excellent overall performance, especially low temperature performance. According to the analysis of roofing test results of SBS modified bitumen roll used under different climatic conditions for 20 years, the technology is relatively stable, and there is no large-scale performance change in long-term use. APP Modified Asphalt Coil has good anti-aging properties. High-temperature-resistant domestically-enhanced PVC coils, which are absolutely dominant in the European and American markets, have not been covered by the current national standard.

The material standards for reinforced PVC coils in polyester fabrics can only refer to and quote DN German Industrial Standards and EN European Standards.

Construction methods According to the characteristics of new types of waterproof materials, China has developed some new processes, technologies and equipment, and some have formed work methods. Such as hot melt method, cold paste method, high frequency heat welding method, as well as empty shop, sticky, sticky, mechanical fixing and other new construction methods.

In the Guangzhou Honda project, the reinforced PVC sheet in the polyester fabric was laid with a mechanical fixing system. The mechanical fixing system fixes the coil on the base layer by means of a fixing member fixed on the structural layer of the crucible/steel plate, etc., with a metal gasket or a U-shaped pressing bar, and a metal gasket is used on the large surface to match the self-tapping self-drilling screw. Fixed, metal washers and fixtures are usually located at the overlapping edges of the web and are covered under a closed integrated web waterproof layer.

The mechanical fixing system model is based on the European UEAtc (system critical test) and EOTA inspection procedures, and conducts a dynamic simulation test of wind load damage, so as to determine the effect of the fixed part on the system (the effect between the coil and the gasket, the fixing and the holding force). The allowable load value Wadm under the action of the role between the layers, the gasket and the fixture, etc.) is used as the basis for the calculation of the spacing between the fixtures of the specific project.

In the mechanical fixing system, the overlap between the coils is completed by hot air welding of the PVC coils. During the construction, the large surface of the roof is welded by an automatic welder, and the details and nodes are manually operated by manual welding guns. The tightness of the impervious PVC weld seam welded by hot air is high and comparable to that of the base metal. Its long-term hot-air solderability makes the maintenance of the roof system exceptionally easy.

The mechanical fixing method has the advantages of reliability, economy, and convenience in the construction of waterproof projects. Compared with the traditional full-stick method, it has the characteristics of relatively low requirements on the grass roots and the construction is affected by the weather. It has been widely used in some developed countries. According to the survey, in 1997, 36% of the roofs of single-layered synthetic polymer coils were mechanically fixed in the United States. In 1998, 70% of the roofs of single-layer synthetic polymer coils laid in Europe were mechanically fixed.

Zhu Dongqing said that the basic principle of the mechanical fixing method is to use the gripping force between the screw and the hard base to resist the floating force of the roof wind load on the waterproofing membrane. There are specific requirements for the use of waterproofing membranes, construction fittings and roofing. For example, it is required that the coil material should generally be a thermoplastic polymer waterproofing material for reinforcing ribs, and has good tensile strength, tear resistance, wear resistance, UV resistance, and good joint strength...

Waterproofing problem The infiltration resistance technology expert introduced in detail the standard construction level of the single-layer waterproofing of the flexible waterproofing system for light steel roofs and related system accessories and requirements. He said that this technology is in line with the latest international products and is suitable for mechanical fixing. This kind of superior performance reinforced polyester fiber fabric has excellent performance considering the factors of wind resistance design and wind load. Compared with the traditional steel structure, the flexible waterproof system of light steel roof, especially PVC single layer waterproof, has obvious advantages in anti-condensation, roof waterproof maintenance, handling of outlet components, sunroof and gutter solutions and so on.

Domestic single-layer waterproofing and national standard specifications exist in the practical use of the waterproof layer of reasonable use of the time when there is no standard for judgment, difficult to judge and other issues, designers were forced to use more quantifiable waterproof layer as the basis. As a result, the new high-quality, long-life single-layer new type waterproof material has not been popularized, and the low-quality and low-quality materials are still popular because they meet the requirements of the waterproof layer number, and the waterproof industry as a whole is slowly improving. Happened.

According to experts, flexible waterproof technology and mechanical fixing systems can be applied not only to light steel roofs such as Guangzhou Honda, but also to other ground layers such as concrete structures, wooden boards, and precast concrete panels.

As for the single-layer waterproofing system, we can fully learn from the mature experience of Europe and the United States, boldly introduce new materials and new technologies, and promote the use of new materials and technologies and promote national standards as soon as possible by formulating enterprise engineering methods, special technologies, participation standards, and optimization atlas methods. Associated with the relevant standards of developed countries to improve the overall level of the waterproof industry. dS-T Guangzhou Honda's second plant is located in Xintang, Zengcheng, Guangzhou, about 30 kilometers from the existing plant, and the first phase of investment is 2.2 billion yuan. It is planned to be put into production in the second half of 2006. The area of ​​the currently completed five workshops is approximately 150,000 square meters. Assembly shop (66000m2), painting press workshop (16000m2). The second phase of the project currently under construction is a 10,000m2 stamping and welding shop (200,000m2) and a parts warehouse (200,000m2) with a total of 30000m2. The architectural design unit of the project is Wuhan Dongfeng Design and Research Institute Co., Ltd., and its waterproof material production and construction unit is waterproof. System (Shanghai) Co., Ltd. The structural layer of the light steel roofing flexible waterproofing system is from the bottom to the top: 0.8 mm galvanized profiled steel plate, 0.3 mm PE membrane insulation layer, 40 mm extruded polystyrene insulation board and 1.2 mm polyester fiber fabric inner reinforcement PVC sheet. The thermal insulation board and the waterproof membrane are mechanically fixed on the base laminated steel plate by special screws and gaskets.

The project not only has a large project area, but also includes a large number of detailed nodes on the roof, such as 1240 skylights (10mX0.8m in size and 350mm in height) and more than 160 fan-seats. The infiltration resistance method of secondary closing basically guarantees the waterproof seal at the node. In addition, the old and difficult problems of high and low cross-connect processing are also coordinated with the steel structure company. The method of low-span waterproof at the top of the high-span facade is used first, and then the method of fixing the high-rise facade wall panel can be satisfactorily solved. Permeation resistance is fixedly connected between the lightning protection zone and the roofing waterproof material, and the sealing and closing solution of the small penetration part attracts the attention of experts. The most challenging node is that the paint shop has about 35 high-temperature outlet pipes, and the pipe surface temperature is around 200C. It is difficult to solve the watertight problem of the waterproof material or system in general. To this end, osmotic resistance between the PVC membrane and the heat pipe is provided with a certain thickness of the rock panel insulation layer, and a special water treatment method, the PVC membrane and the pipe is sealed between the closure, completely solved the high temperature The influence of the coil (after treatment, the surface temperature of the coil outside the heat pipe and the outdoor temperature difference is kept below 5C), and achieves a perfect waterproof effect.

The Guangzhou Honda No. 2 Plant Project achieved integrated design and construction of waterproof and thermal insulation, eliminating problems that may arise in construction coordination, material matching, and system assurance among different sub-contracting units. The owner only needs to be waterproof with the waterproof package. System companies deal directly with them, greatly simplifying the operation process of the project, and infiltration resistance provides the owner with the assurance of the entire project waterproof insulation system. This method of overall operation is worth promoting in the field of waterproofing.