本标准涉及存在爆炸性粉尘环境和可燃性粉尘层的区域的识别和分类，以便对此类区域的火源进行适当评估。在本标准中，爆炸性粉尘环境和可燃性粉尘层是分开处理的。在第4条中，描述了爆炸性粉尘云的区域分类，粉尘层是可能的释放源之一。第7条描述了粉尘层着火的危险。本标准中的示例基于工厂实施的有效内务管理系统，以防止粉尘层积聚。如果不存在有效的内务管理，区域分类包括粉尘层可能形成爆炸性尘云。当可燃纤维或飞灰可能造成危险时，也可遵循本标准的原则。 本标准适用于在正常大气条件下，由于存在爆炸性粉尘环境或可燃粉尘层而存在风险的情况。它不适用于地下采矿区，该区域可能因混合混合物、炸药粉尘、自燃或烟火物质或其他不需要大气氧气燃烧的粉尘、超出本标准所述异常概念的灾难性故障（见注1）而产生风险，因粉尘排放易燃或有毒气体而产生的任何风险。本标准未考虑火灾或爆炸后间接损害的影响。注1:这种情况下的灾难性故障适用于储存筒仓或气动输送机的破裂。注2:在任何工艺装置中，无论大小，除了与设备相关的火源外，可能有许多火源。 在这种情况下，需要采取适当的预防措施以确保安全，但这些措施不在本标准的范围内。

This standard is concerned with the identification and classification of areas where explosive dust atmospheres and combustible dust layers are present, in order to permit the proper assessment of ignition sources in such areas.In this standard, explosive dust atmospheres and combustible dust layers are treated separately. In Clause 4, area classification for explosive dusts clouds is described, with dust l ayers acting as one of the possible sources of release. In Clause 7, the hazard of dust layer ignition is described.The examples in this standard are based on a system of effective housekeeping being implemented in the plant to prevent dust layers from accumulating. Where effective housekeeping is not present, the area classification includes the possible formation of explosive dust clouds from dust layers.The principles of this standard can also be followed when combustible fibres or flyings may cause a hazard.This standard is intended to be applied where there can be a risk due to the presence of explosive dust atmospheres or combustible dust layers under normal atmospheric conditions.It does not apply tounderground mining areas,areas where a risk can arise due to the presence of hybrid mixtures,dusts of explosives, pyrophoric or pyrotechnic substances, or other dusts that do not require atmospheric oxygen for combustion,catastrophic failures which are beyond the concept of abnormality dealt with in this standard (see Note 1),any risk arising from an emission of flammable or toxic gas from the dust.This standard does not take into account the effects of consequential damage following a fire or an explosion.NOTE 1 Catastrophic failure in this context is applied, for example, to the rupture of a storage silo or a pneumatic conveyor.NOTE 2 In any process plant, irrespective of size, there can be numerous sources of ignition apart fr om those associated with equipment. Appropriate precautions will be necessary to ensure safety in this context, but these are outside the scope of this standard.