Evaluate the regional fire risk per the following factors: the flammability, physical and chemical properties of materials, the release frequency and quantity of combustible substances, the characteristics and arrangement of equipment and pipelines, the terrain, climate and ventilation conditions of the area, the ignition source in the area (including spontaneous combustion, static sparks and high temperature surfaces), the ignition source outside the area (including lightning and combustible vapor cloud explosions), etc. Then determine the risk level according to the frequency and consequences of the fire.
The
valves that are used to transport hazardous media such as the combustible, toxic, strongly corrosive and radioactive media and are likely to be used under the high temperature or radioactive working conditions are supposed to be the fireproof
valves, which can prevent the subsequent severe accidents triggered by the leakage of media happening under the fire circumstances.
The fireproof
valves must have the standard tests such as API607, API6FA, ISO10497, etc. The valves which are used for the combustible media and the valves which adopt the electrical insulation valve seats should adopt the anti-static structures.
In the region which has the high level fire risk rating, in order to protect a great number of hazardous media from leaking, to prevent the conflagration area from enlarging and to reduce the destroy of the fire, the pipelines or facilities such as the large pumps, the main fuel pipes, the loading and unloading pipelines in the wharves and the containers for toxic media which are likely to give rise to the leakage of the hazardous media should be equipped with the fire emergency block
valve.
Explosion is a more devastating accident than fire, and preventing the explosion is an important factor which is needed to be considered in chemical safety design of valves. Controlling the ignition source is one of the measures to prevent the explosion. All electrical equipment essentially belongs to the ignition sources. Therefore, chemical safety design requires that all the electrical equipment including the
valve drive devices must adopt the explosion-proof structures in the places with the potential explosive danger.
