China's standards of door locks were issued in June, 2000 and implemented in October, 2000. There are four original national standards for door locks, including GB8385-97 exterior door locks, GB8386-87 billiard core door locks, GB8387 blade core door locks and GB8388-87 spherical door locks, which were transformed into QB/T3837-1999, QB/T3838-1999, QB/T3839-1999 and QB/T3840-1999 in March, 1999. They were released and implemented in 1988. However, with the continuous development of the market economy, great changes have taken place in door locks products.
 

The product varieties are constantly enriched and the quality level is constantly improved. The cam lock is especially used in more and more applications. The original national standards and professional standards are far from meeting the quality and technical requirements of door locks under the new situation. Economic globalization is imperative, and the grade and quality of our door locks products must be improved. In order to be in line with international standards and narrow the gap with the developed countries in the world, it is conducive to eliminating trade barriers and increasing export earnings. The aim is to promote the development of China's lock industry and participate in international competition. Therefore, the original door locks standards must be revised. The State Light Industry Bureau and the National Daily Hardware Standardization Center respectively issued a notice to revise the original four door locks standards. The original bullet locks (SG205-80) and exterior double tongue locks (GB8385-87) are combined, and double button (Tiger) locks are added to be the exterior locks standards. The current light industry standard QB is the revised new standard.

The revision principle of the standard is as follows: on the basis of the original standard, it can only be improved, but not reduced.
 

It is necessary to fundamentally reverse the backward situation of low-grade products, low prices and poor technical level in China. We should adopt the policy of serious research and differential treatment, and revise it in combination with China's actual situation. In the process of revision, some foreign advanced standards such as American ANSI, British BS and Japanese industrial standard are adopted as the basis. At the same time, according to the requirements of national laws and regulations, we combined with the actual situation of the locks product. In the process of revising the standard, the classification provisions are made according to different needs. The exterior door locks and spherical door locks are divided into two categories: A-level and B-level. Basically, the differences between high-grade villas, apartments, commercial houses and unit houses are clearly distinguished.
 

The requirements of the newly revised standards are higher than those of the original standards. The main index of class a exterior door locks reaches the level of class B in British BS5872, which is higher than the original standard of our country, but lower than the level of class B in British BS5872 (Note: the level of class B in British BS standard is higher than that of class A). The main index of class a spherical door locks is close to the level of class II in American A ANSI/BAMA.A156.2-1996. The main indexes of class B products are close to the level of class III locks in ANSI/BA, A.A156.2-1996, and it is much higher than the original standards of our country. Therefore, the new standards including QB/T2473-2000, QB/T2475-2000, QB/T2474-2000 and QB/T2476-2000 are higher than the original standards.