Medium classification and hazard level
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This post was last edited by Taizhou Newcomer on 2018-5-4 at 08:52. There is a device that uses liquid ammonia as its medium; its operating pressure is 1.55 MPa, while the design pressure is 1.72 MPa. The operating temperature is 50 degrees Celsius, and the design temperature is 70 degrees Celsius. The volume of this device is 3.1 cubic meters. Does it fall under the category of Medium Pressure Class II? Liquid ammonia is considered to have moderate hazard levels (according to the regulations, information regarding toxicity and explosivity must be specified for such media); so, is liquid ammonia flammable or explosive? Does the pipe flange need to be a strong butt-welded flange? A RF face PN25 flange will do
Category II: moderate hazard from liquid ammonia; it is not flammable or explosive. Welded steel pipe flanges with a neck can be used, and an RF sealing surface is sufficient
The material presents a moderate level of hazard; ammonia falls under the category of highly permeable substances with moderate hazard as specified in point (2) of regulation 3.2.5, and therefore the requirements of this point must be followed – an RF finish can be used for the flange sealing surfaces.
Where can I find information about high permeability?
Material properties: There is one item that must be specified in the regulations (toxicity and degree of explosion hazard?)
Material properties of liquid ammonia: moderate hazard. Another example is methanol: explosive; benzene: extremely hazardous and explosive.
The permeability of ammonia should be high; otherwise, there would be no ammonia leakage test in the density test