Standards need to adapt to rapid changes
The increase in the variety of waterproof material products, the expansion of application fields, the advancement of test equipment, and the update of reference standards are the main reasons for the revision of the national standard of "Building Waterproof Aging Test Method".
The national standard "Aging Test Method for Waterproof Materials in Buildings" (GB/T 18244-2000) was issued on October 17, 2000, and implemented on May 1, 2001, and has a history of more than 20 years. During this period, the product types and application fields of building waterproofing materials have undergone tremendous changes.
For example, before 2000, the main products of building waterproofing membranes were only petroleum asphalt paper tire linoleum, and oil paper. SBS and APP waterproofing membranes had just entered the country, and the output was very small. Twenty years later, SBS, APP, PVC, TPO, self-adhesive coils, etc. have become mainstream products in the market. The national standard "Aging Test Method for Building Waterproof Materials" (GB/T 18244-2000) is no longer suitable for waterproof materials' current production and development. We need to build our country.
At the same time, the application field of waterproof materials is also expanding. In addition to being used in industrial and civil buildings, the use of waterproof materials is widely used in subways, tunnels, bridges, water conservancies, railways, aviation, and national defense projects. The performance and service life put forward higher requirements.
In addition, with the advancement of technology, the modernization level of artificial climate-accelerated aging equipment has increased. For example, in the test chamber used for accelerated aging by fake climate (xenon arc lamp), most of the test conditions such as temperature and humidity and xenon lamp need to be adjusted manually. There are many influencing factors during the test process, the test results fluctuate wildly, and the reproducibility is poor. The new generation of aging test instruments is automated and intelligent, which can improve the accuracy and repeatability of test results.
At the beginning of the 20th century, the 2000 edition of "Aging Test Methods for Waterproof Materials in Buildings" refers to the international standard ISO 4892:1994 "Plastics - Methods of Exposure to Laboratory Light Sources". The standard was later revised.
All of the above have contributed to the revision of the national standard "Aging Test Methods for Building Waterproof Materials".
The old and new "Aging Test Methods for Building Waterproof Materials" are very different
Zhu Zhiyuan said that now the types of waterproof products have increased and the application occasions have expanded. This revision of the standard has revised the scope of the standard. Safety warning clauses have been added to the general regulations, the standard conditions for laboratory maintenance and specimen preparation have been revised, and the requirements for specimen storage and pre-test specimen disposal conditions have also been added.
The new standard has made major revisions to the aging performance evaluation items. The appearance, tensile properties, and low-temperature performance of the test items evaluated after the aging test in the old standard have been revised. The new standard has increased the types of aging evaluation test items and changed It is divided into two categories: non-destructive items and destructive items, and the calculation formulas for the retention rate and change rate of tensile properties have also been modified. The hot air aging test also modifies the test temperature according to the product type and also modifies the test period. Artificial climate accelerated aging - xenon arc test has higher requirements on the light intensity, temperature, and humidity control, which reduces the error of test results between different instruments. Artificial climate accelerated aging - fluorescent UV lamp test adds an exposure cycle, 8h drying, 0.25h spray, 3.75h condensation.
In addition, the new standard removes ozone burn-in and carbon arc burn-in, which are now rarely used and relatively expensive.
The aging performance evaluation items of different waterproof materials are different
Talking about the difficulties encountered in the process of standard revision, Zhu Zhiyuan said that the types and application scope of waterproof products have changed, and the revised national standard "Aging Test Methods for Building Waterproof Materials" should try their best to accommodate this change and solve different types of changes. Feasibility of product preparation test pieces, reducing uncontrollable factors.
The artificial climate accelerated aging equipment is constantly improving. There are imported equipment and domestic equipment, and there are many types of equipment, including xenon arc lamps and fluorescent ultraviolet lamps. With different aging equipment, different laboratories, and different people using the same product to test, how much does the test value change? Is the difference in the final result within an acceptable range? In the process of standard revision, the drafting unit has done a lot of tests to verify whether the test method can accurately reflect the aging performance of building waterproof materials and to evaluate the repeatability and repeatability of the test method.
