Instrument flange specification standards

Ministry of Chemical Industry: HG/T20615-2009 (American standard)； HG/T20592-2009 (European standard) ； Petrochemical industry: SH/T3406-2013

Standards such as HG/T20593-20615 are also available; it is possible to consult the manufacturer as well, and select the appropriate flange (in accordance with the relevant standards) based on the table. When selecting, factors such as the temperature and pressure curve of the flange and the applicable temperature range of the material should be taken into account.

I’m asking about your company’s expertise in process engineering and piping; we work in automatic control, so we use whatever others use.

For the process connections of instruments, there are usually multiple options available (including various flange types)； If given a choice, select the most universal standard for the device ； If the options are limited, choose the standard that is most convenient to use in combination, or one that can be matched ； If there is no alternative, the manufacturer is required to provide flanges, or the customer must find a way to fabricate them themselves. .

The problem now is that we have old equipment, and there are many modifications required; basically, model 20592 is used throughout the equipment area. My previous workplace mainly used B16.5, and the difference between the two standards is quite large. Ugh, I really don’t understand why so many standards were created

This issue can only be attributed to shortcomings in your management. Most of the chemical enterprises we have today use HGT20592 and HGT20615; the former is in line with European standards, while the latter is in line with American standards. There are also a small number of products that comply with Japanese standards (JIS), among others. The main reason is that when we establish standards, we refer to the stronger ones (in terms of breadth). Currently, most chemical processing units use HGT20615 (note LG and LT/LG); only a few fields such as water supply and drainage use HGT20592. My previous notes: 1Q012 – Why are ASME A standards chosen for instruments? It’s all about quality; high-end instruments and equipment are designed to work in conjunction with top-tier systems, or they are manufactured by such companies, and therefore they adhere to ASME standards rather than HGT20615. 1Q013: Why are both ASME and HGT20615 A used in design? Generally, the requirements for pipes are not as stringent as those for instruments or equipment; therefore, in China pipes are primarily governed by HGT20615 (which corresponds to the American standards, with HG20592 corresponding to European standards). To ensure consistency with these instruments, the flange standards are specified as ASME, which means that the pipe connections associated with such instruments are also typically designated as ASME. For equipment, it is certainly inappropriate for the nozzles of the same piece of equipment to sometimes conform to ASME standards and at other times to HGT20615 standards. Moreover, sometimes imported equipment also follows ASME standards; therefore, it makes sense to make the equipment interfaces comply with ASME as well. As for your company’s use of HGT20592 and HG20615, for some flanges with different pressure ratings and diameters, the bolt spacing is the same, allowing them to be interchanged. So as long as the management between them is streamlined and the direction and boundaries are clearly defined, it’s actually quite easy.

Excellent, right?: victory:

The standards for flanges are generally determined by the materials team during the design of a facility, with specifications being established by taking into account factors such as the properties of the material, pressure, and corrosion. The first thing we do in the design process is to obtain the material specifications in order to select the flange.

It’s a company that has been around for 20 years; I’ve been here for less than a year, and there are many things that need to be changed. In my previous workplace, since we used more foreign-made equipment, it was mainly ASME or 3406 standards; there were also cases where the Ministry of Chemical Industry’s 20592 standard was used.