Can high-pressure threaded flanges be used for GC1 pipes?
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According to Article 53, Paragraph (3) of TSGD0001-2009 \"Regulations on Safety Supervision of Pressure Piping – Industrial Piping\", threaded flanges shall not be used for GC1-class piping, and there are no exemption provisions. In plants for producing synthetic ammonia and urea, lens gaskets and high-pressure threaded flanges are commonly used. Will it not be usable in the future?
This threaded flange is not that threaded flange. High-pressure threaded flanges equipped with lens gaskets have been in use for a long time; the original standard was H67. Nowadays, the enterprise standards of Zhejiang Industrial University and Yueyang Zhusheng are generally adopted, and these standards have been approved through formal procedures, so they can be used with confidence.
High-pressure threaded flanges are in accordance with JB/T450-2008; this standard was originally introduced from the former Soviet Union. It is still usable in China at present, but some experts suggest that it should be abolished. The recommended approach is to use flanges that comply with the German standard DIN EN1092, with lens gaskets according to DIN2696 being used for the sealing surfaces. Of course, this is something for the future.
Thank you! ““This threaded flange is not that threaded flange” – which clauses can illustrate this? The existing oversight agencies have raised this, and we have no provisions to respond with.
This post was last edited by xxj19810407 on 2016-5-26 at 15:27. Try saying it this way and see if it works. Threaded flanges cannot be used for GC1 grade pipelines; they refer to threaded flanges for low pressures, and are applicable to clause 5.2.5 of GB/T20801.3, which deals with pipe thread connections with threaded sealing. The high-pressure threaded flange JB/T450 falls under the category of straight-threaded connections as specified in clause 5.2.6; it is a short-pipe connection flange that is sealed using lens gaskets. It is stated in 5.2.6b that it can be used for GC1 grade pipelines. To add, as I mentioned above, such standards should be phased out; using high-pressure flanges in accordance with the national standard GB/T9115, along with lens gaskets for sealing, meets the regulatory requirements.
The threaded flange as mentioned in the regulations refers to pipe fittings with threaded connections in low-pressure systems, which are sealed solely by threads. It’s not the same as threaded flanges for high-pressure systems.