National Plastics Quality Supervision and Inspection Center: PVC pipes belittle quality, which is equivalent to self-breaking

In the first quarter of this year, the State Administration of Quality Supervision, Inspection and Quarantine deployed and the National Plastic Products Quality Supervision and Inspection Center (Beijing) was responsible for conducting national supervision and spot checks on the product quality of rigid PVC pipes for water supply and drainage. The results of the spot check showed that among the 64 enterprises that were spot checked, 41 were qualified and 23 were unqualified, with a pass rate of 64.1%. Among them, the qualified rate of the drainage pipe products was only 65.0%, and the qualified rate of the water supply pipe products was 62.5%. Compared with the spot check before 2000, the quality of water supply pipe products basically maintained the original level, but the sampling qualification rate of drainage pipe products dropped by nearly 15%. The quality of PVC-U drainage pipe products is worrying. To this end, I invited Liu Shansheng, director of the National Plastic Products Quality Supervision and Inspection Center, to analyze the deep-seated reasons and solutions for the serious decline in the quality of PVC-U drainage pipe products.

Liu Shansheng introduced that this time not only spot-checked companies with a certain degree of popularity and production capacity, but also spot-checked the products of small and medium-sized enterprises that have a certain sales share in the market. The products of 47 small enterprises, 27 qualified products, and the product sampling pass rate of 57.4%; the products of 11 medium-sized enterprises, 8 qualified products, and the random inspection pass rate of 72.7%, the products of 6 large enterprises, and 6 qualified products. The qualified rate of spot check is 100%. This once again confirms the general rule that the product quality of large enterprises is better than that of medium and small enterprises, and the product quality of medium enterprises is better than that of small enterprises. Through the quality analysis of the unqualified products, the main quality problems of the drainage pipe products reflected in this spot check are reflected in the unqualified tensile yield strength, the unqualified drop-weight impact test, and the unqualified Vicat softening temperature; the main quality of the water supply pipe The problem is reflected in the failure of the hydraulic test and the failure of the drop-weight impact test. The results of the spot check also showed that the quality problems that occurred in the previous spot checks, such as the deviation of specifications and dimensions, have been greatly improved, but the “high filling” problem has a tendency to expand. Some small enterprises also have many problems in the production process, and there are many product quality problems. In particular, the quality of drainage pipes is showing a trend of rapid decline, which should cause the industry to pay enough attention. In addition, one of the 40 drainage pipe manufacturers in the spot check unexpectedly exchanged samples, and another did not send samples. These two enterprises were directly judged as unqualified enterprises in the spot check. This also shows that some companies are very aware of the quality of their products and have taken illegal measures to circumvent quality supervision. …

Liu Shansheng believes that there are several reasons for the sharp decline in the quality of polyvinyl chloride plastic pipe products for construction:

The price of raw materials is rising. In 2003, China implemented anti-dumping on polyvinyl chloride resin, which prevented the import of raw materials from major polyvinyl chloride resin producing countries such as the United States, Japan and other countries. However, some large domestic raw material manufacturers are not very normal in production, resulting in a serious shortage of supply capacity. Domestic resin prices have been rising all the way. Polyvinyl chloride resin rose from the original 5,000 yuan/ton to 8,000 yuan/ton, and the price of the product remained basically at the original price before the end of October, making the profit margin of the production enterprise reduced or no profit at all. Large-scale enterprises have a large stock of raw materials and large quantities when purchasing, and the prices of raw materials purchased are slightly lower, resulting in slightly lower production costs. At the same time, large enterprises pay more attention to corporate management, which guarantees product quality to a certain extent. Due to the price of raw materials, many small and medium-sized enterprises have reduced or stopped production. However, due to market demand, some companies began to use various recycled materials to process or add a large amount of calcium carbonate to produce in order to make product sales, resulting in a substantial decline in product quality. To

With overcapacity, prices have become market competitors. Unfair competition among enterprises is an important factor restricting the improvement of the quality of the rigid PVC pipe industry. Because the production capacity far exceeds the market demand, market competition is becoming increasingly fierce, and this is especially true in the drainage pipe market, which requires relatively simple production technology and quality level. Market competition has made the price factor a trick, forming a vicious circle in which the lower the price, the better the sale. As a result, some large companies also produce products of different grades and prices in order to adapt to the market and seek living space. Some of their methods are to reduce pipes. Wall thickness, more is to increase the amount of calcium carbonate added. The price of a Ф75mm drainage pipe produced according to the standard is not less than 17 yuan/meter, but the price of products sold in some building materials markets in Beijing is only 17 yuan/piece (4 meters per pipe). Crush it or break it into pieces. In this spot check, the tensile yield strength of 12 unqualified drainage pipe products was unqualified, and the products of two companies even broke into several pieces in the flat test, which fully illustrates the reality of overfilling. This abnormal competition has seriously affected the technological progress and industry development of PVC pipes. …

The phenomenon of OEM has increased, and product quality has not been properly controlled. In the daily entrusted inspection and this spot check, many OEM manufacturers were found, that is, one party transfers its trademark to another company for production, or a company with a registered trademark does not produce its own products but entrusts another company to produce it. This kind of production method of paid transfer of trademarks, if well controlled, will undoubtedly increase the market share of high-quality products. But the actual situation is not completely like this. In this spot check, the quality of the transfer enterprise’s own product meets the standard requirements, but the product quality of the OEM manufacturer has a large gap with the standard requirements. This should arouse the attention of the transferring enterprise, and don’t lose the brand reputation of the enterprise because of small profits. …

The management of the enterprise is not strict. A small number of enterprises have chaotic management, and the enterprises do not control the production process and production process strictly, which leads to poor production stability. In the test, we found that there are big differences between different samples of the same batch of pipe products. For example, the measured wall thickness deviation of Φ40mm pipes is 2.0mm ~ 3.0mm, which is far beyond the deviation range specified by the standard. The wall thickness can be seen with the naked eye. The test results of longitudinal shrinkage rate of individual enterprise pipes are between 5% and 10%, the uniformity is extremely poor, and there are yellowing and warping phenomena. All these fully illustrate the unstable state of process control in enterprise production. …

Faced with increasingly severe quality conditions, Liu Shansheng believes that the government’s rectification actions alone cannot guarantee product quality for a long time. The most important thing is for everyone to take action. To this end, he made the following suggestions:

1. Improve laws and regulations. The root cause of the proliferation of inferior products lies in the unsound laws and regulations. Although there are construction laws and bidding laws, the existing laws and regulations for durable construction products are far from enough. According to the experience of advanced countries in the world, the quality guarantee period of general construction products is 30 years, while our country only has a one-year warranty. Due to the particularity of construction products, it provides some illegal builders with a way to evade legal obligations. For this reason, he suggested that the representatives of the industry’s National People’s Congress propose to the National People’s Congress to amend the relevant laws to extend the quality guarantee period of China’s construction products to 20-30 years. If quality problems occur during the warranty period, the construction developer should bear the responsibility for maintenance and compensation, and the serious ones should bear it. criminal responsibility. In this way, illegal behaviors of builders can be curbed, and they can be urged to pay more attention to quality and strengthen self-supervision. …

At the same time, the quality of construction materials is controlled by the implementation of the material delivery inspection system. The quality problems of the material quality are jointly responsible for the project supervision and inspection agencies, and the responsibility period is also 20-30 years. Such a long-term accountability system should increase the responsibilities of these institutions and restrain them from harming the long-term interests of customers for short-term interests. …

2. Vigorously develop industry self-discipline and support high-quality products. The market belongs to the entire industry, and the elimination of products from the market affects the interests of the entire industry. Therefore, only when everyone acts together can the product quality and technical level of the entire industry be effectively improved. Liu Shansheng believes that associations or professional committees should actively contact the government’s quality supervision department to carry out related quality inspections and standardize industry behavior. In the absence of corresponding laws and regulations, some industry quality inspections can be carried out, and products of good quality and high reputation can be recommended to customers.

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