A minor question regarding a standard (HG/T21514~21535)
Thread Content
I would like to ask everyone: The standards HG/T21514_21535 for steel manholes and handholes now include a series of manholes and handholes made entirely of stainless steel. Does this mean that HG/T21514_21535 also replaces standards such as HG/T21595_21604 for stainless steel manholes? This isn’t clearly stated in HG/T21514_21535. If it doesn’t replace those standards, then what is the difference between the stainless steel manholes specified in HG/T21514_21535 and those in HG/T21595_21604? The HG/T21595_21604 standard shouldn’t have been abolished, right? Please give me some guidance. I apologize for any mistakes in my question
In my opinion, the differences between the two are as follows: 1. HG21594 features stainless-steel manholes for normal pressure conditions, while HG21514 uses only carbon steel manholes for such conditions; 2. The flanges of the stainless-steel manholes in HG21594 are made of carbon steel lined with stainless steel (except that the flanges of the manholes for normal pressure conditions are entirely made of stainless steel), whereas all the flanges in HG21514 are made of stainless steel; 3. The pressure ratings for the manholes in HG21594 include six levels: normal pressure, 0.6, 1.0, 1.6, 2.5, and 4.0. The pressure ratings for the manholes in HG21514 include eight levels: normal pressure, 0.25, 0.6, 1.0, 1.6, 2.5, 4.0, and 6.3. Therefore, these two standards should be consistent with each other
Based on the above analysis, it can be concluded that HG21514 is simpler to manufacture than HG21594, has a wider range of applications, and is more cost-effective
This issue seems to have been discussed before; the 2005 standard explicitly states that it replaces the 95 standard, meaning only the carbon steel manholes have been updated. As for the addition of fully stainless-steel manholes in standard version 05, it is intended to facilitate applications that require a fully stainless-steel material; however, it cannot replace the standard for 99-grade stainless-steel manholes. Moreover, according to standard version 05, stainless steel is generally used in situations where the pressure is below 16 kilograms. Using fully stainless-steel materials in cases with higher pressures is not economical, so it is still necessary to consider using the 99-grade stainless-steel manholes.
The new standard simply replaces the carbon steel standard and adds stainless steel materials; it should operate in parallel with the 99th version of stainless steel standards.
Oh, I see. Thank you all for your help, haha
If it is a manhole at atmospheric pressure made of stainless steel, standard 05 can be used; can carbon steel be replaced with stainless steel in that case?
Why isn’t there anyone willing to give guidance? Is this question too simple, and do people think it’s not worth answering? If that’s the case, I would really appreciate it if someone could take the time to help out. Thank you very much.
The stainless steel manholes in the HG/T21514~21535 series are made entirely of stainless steel (with the exception of some structural components), whereas the stainless steel manhole flanges and cover plates in the HG/T21595～21604 series come with linings. It’s mainly this difference. I am aware of some aspects related to the formulation of the HG/T21514~21535 series of manholes.
The current standards for manholes are all based on chemical industry requirements. When I was translating materials related to gas stations, I remembered that the American Fire Association also has relevant guidelines