Why can’t plate flat welding flanges be used?
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This post was last edited by security on 2011-8-1 at 10:01. Plate flat welding flanges shall not be used for process materials and pipelines carrying flammable media. Our company produces lubricants, which are classified as Category CB flammable liquids that are non-toxic, harmless, and non-corrosive. So why cannot plate flat welding flanges be used? If not, what type of flange would be more suitable? The operating temperature of this liquid is 60°C, with PN1.6MPA pressure rating
Personally, I think it is an acceptable option; I recommend using an external metal-wound gasket as the shim. If flanges are used instead, male and female flanges with an internal ring gasket can be selected.
Generally, plate-type flat welding flanges have poor sealing performance; depending on your working medium as well as pressure and temperature conditions, it is sufficient to use raised-face flanges. They cost roughly the same and offer better sealing performance.
Flat welding flanges have poor welding safety, with significant planar deformation during welding; therefore, they cannot be used for hazardous media. It is recommended to use butt weld flanges; as for the sealing surface, any type will do.
A raised flange with a neck can be used, WN, RF
It is recommended to use butt-welded flanges with a specific diameter for better sealing performance
Lubricating oils are classified as Class C flammable liquids that are non-toxic, harmless, and non-corrosive; then why can’t plate butt weld flanges be used? Butt weld flanges can be employed when the pressure is low.
Personally, I recommend using WN-RF flanges (with neck welding and a convex surface); they offer good sealing performance and are relatively inexpensive:lol
In fact, every product has specified limits for its usage; as long as those limits are not exceeded and safety is carefully observed, it’s fine.
Hehe, first of all, I am not in favor of using plate-type butt weld flanges; at least, butt weld flanges with a neck should be used. Additionally, flat welding flanges paired with wound gaskets are also not suitable, as clearly stated in GB/T20801!
This post was last edited by yyxn on 2018-5-24 at 11:46. The standard \"SH/T3059-2012 Specifications for the Selection of Materials for Petrochemical Piping\" specifies as follows: 7 Pipe Components 7.3 Flanges 7.3.1 The selection of flanges shall comply with the following requirements: c) Plate-type flat flanges shall not be used for pipes carrying toxic or flammable media. ““Prohibited” is a negative term meaning it is not allowed; lubricants belong to Class B flammable liquids, and the use of plate flat flanges is not permitted.