The difference between the two types of pipes in Series I under standard HG20553
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I have a question for the experts: In standard HG20553, the I-series pipes are divided into two types. Ib is the rounded version of Ia, with similar outer diameters; one is an imperial pipe while the other is a pipe according to petrochemical standards. Can these two types of pipes be used together in welding? If so, does it require that they be of the same type, or can they be used together within a certain DN range? After all, the I-series and II-series pipes cannot be welded directly to each other; even if used together, special fittings are needed
Using them interchangeably is too confusing; it’s recommended not to do that
I don’t understand what the purpose of the original poster’s cross-use is. In many projects I’ve worked on in China, there was frequent switching between different materials, and the reason for that was to save costs and to make it easier to obtain the materials needed. Moreover, they are all designed directly by the user’s own units. For example, for a DN150 specification, the valves or pumps are originally designed to use piping with a diameter of 168; they change this to 159, which makes it easier to purchase such components and saves costs. In this case, a transition flange can be installed at the outlet of the valve, pump, or equipment to achieve the same result
Of course, the purpose is not for cross-use; if someone asks me, I wouldn’t know how to answer. In cases where, for example, it’s a pipeline project related to the petrochemical industry that needs improvement, and accidentally British-standard pipes are purchased, or vice versa – British-standard pipes are used in a project that requires petrochemical-standard pipes – I would just ask whether they can be used interchangeably Or put it this way: is there really a difference between Ia and Ib?
Use a imperial-to-metric conversion adapter to connect them, or use a pair of flanges as an intermediate connection~
I’m asking about Ia and Ib, not metric and imperial