At present, the international standards for information technology equipment and audio and video equipment are IEC60950, IEC60065, their application scope is 2000m above sea level below the area, mainly in dry areas and temperate or tropical climate conditions to use the equipment, and the high altitude of the corresponding low pressure environment on the equipment safety performance should be reflected on standard.

The world has about 19.8 million square kilometers of land above 2000m above sea level, twice the size of China. These high-altitude areas are mainly distributed in Asia and South America, among which many countries and regions in South America are more than 2000m above sea level and inhabited. However, due to the relatively backward economy and low living standard in these countries and regions, the penetration rate of information equipment is also relatively low，As a result, the level of standardization falls far short of international standards and does not take into account additional safety requirements above 2,000 meters. Although the United States and Canada, located in North America, have developed economies and are widely used in information and electronic equipment, there are almost no people living above 2000m, so the UL standard of the United States does not have additional requirements for low pressure.In addition, most IEC member countries are in Europe, where the terrain is mainly plain. Only a few countries, such as Austria and Slovenia, have parts above 2000m above sea level, many mountainous areas, harsh climate conditions and sparse population. Therefore, the European standard EN60950 and the international standard IEC60950 do not consider the impact of the environment above 2000m on the security of information equipment and audio and video equipment。Only this year in the instrument standard IEC61010:2001 (Measurement, control and laboratory electrical equipment safety) has given a partial elevation of the electrical clearance correction. The effect of high altitude on insulation is given in IEC664A, but the effect of high altitude on temperature rise is not being considered.

Due to the geographical environment of most IEC member countries, general information technology equipment and audio and video equipment are mainly used at home and office, and will not be used in the environment above 2000m, so they are not considered. Electrical equipment, such as motors, transformers and other power facilities will be used in harsh environments such as mountains, so they are considered in the standards of electrical products and measuring instruments.

With the development of Chinese economy and the deepening of reform and opening-up policy, the electronic products of our country have been developed rapidly, the application field of electronic products is also more extensive, and play an important role in more occasions. At the same time, more and more attention is paid to the safety of electronic products.

1.  Research status and development trend of safety standards of electronic products.

Since the reform and opening up, predecessors in the domestic electronic product safety standards research, safety test and certification has carried out a lot of work, in the basic theory of safety research has made certain progress, at the same time constantly tracking the international standards and technical information of developed countries，National standards such as GB4943 (safety of information technology equipment), GB8898 (safety requirements of audio and video equipment) and GB4793 (safety of electrical equipment used in measurement, control and laboratory) have been developed, but most of these standards are adapted to the environmental conditions below 2000m above sea level, and China has a vast area. The geographical conditions and climatic conditions are very complex. The northwest region is mostly plateau, with a large number of people living there。Areas above 1000m account for 60% of China’s total land area, those above 2000m account for 33%, and those above 3000m account for 16%. Among them, the areas above 2000m are mainly concentrated in Tibet, Qinghai, Yunnan, Sichuan, Qinling Mountains and the western mountains of Xinjiang，Including Kunming, Xining, Lhasa and other densely populated provincial capital cities, these areas have rich natural resources in urgent need of development, with the implementation of the national western development policy, there will be a large number of talents and investment into these areas, information technology equipment and audio and video equipment will also be used in large numbers.

In addition, at the time of our joining the WTO, it is particularly important to safeguard the rights and interests of Chinese consumers by technical means rather than administrative means. Many developed countries all put forward special requirements in accordance with their own interests when importing electronic products according to the concrete situationIn this way, you protect your own economy as well as your own consumers. To sum up, it is of vital practical significance to understand the impact of environmental conditions in high altitude areas on electronic products, especially on safety performance.

2. Influence of low pressure on safety performance of electronic products.

The low pressure range discussed in this paper only covers land pressure conditions, not aviation, aerospace, airborne and environmental conditions above 6000m. As there are few people living in areas above 6000m, the impact of environmental conditions below 6000m on the safety of electronic products is defined as the scope of discussion，To compare the influence of different atmospheres above and below 2000m on the safety performance of electronic products. According to international authorities and current research results, the impact of air pressure reduction on the safety performance of electronic products is mainly reflected in the following points：

(1) Gas or liquid leaks out of the sealed shell
(2) The sealing container is broken or exploded
(3) The influence of low pressure on air insulation (electrical gap)
(4) The influence of low pressure on heat transfer efficiency (temperature rise)

In this paper, the effect of low pressure on air insulation and heat transfer efficiency is discussed. Because low pressure environmental conditions have no effect on solid insulation, so it is not being considered.

3 Effect of low pressure on breakdown voltage of electrical gap.

The conductors used to isolate dangerous voltages or different potentials mainly rely on insulating materials. Insulating materials are dielectric used for insulation. They have low conductivity, but they are not absolutely non-conductive. Insulation resistivity is the electric field strength of the insulation material divided by the current density passing through the insulation material. The conductivity is the reciprocal of the resistivity。For safety reasons, it is generally hoped that the insulation resistance of insulating materials is as large as possible. Insulating materials mainly include gas insulating materials, liquid insulating materials and solid insulating materials, and gas medium and solid medium are widely used in electronic information products and audio and video products to achieve the purpose of insulation, so the quality of insulating medium directly affects the safety performance of products.