When purchasing a tee, are specifications required, and is wall thickness also necessary? Are the wall thicknesses of the three ports of a standard tee the same?

It may vary depending on the caliber. The wall thickness needs to be provided.

The standard version does not need to be provided; specifications alone are sufficient

It’s usually standard; it depends on how high the pressure needs to be

First, it is necessary to determine the standard – whether it is a national standard, a US standard, or some other standard – and such standards specify the nominal dimensions and wall thickness grades. When purchasing tees, the wall thickness is not usually specified directly; instead, the wall thickness grade is indicated, such as Sch40, etc. Tees with the same diameter have the same wall thickness, and tees with different diameters also have the same wall thickness grade, but their actual wall thicknesses vary. Go take a look at the standards and you’ll understand. American standard: ASME B16.9; Chinese standard: GB/T 12459

The question is simple: describe clearly what you need. The simplest answer is to order the tee based on the specific dimensions and thickness of its three ports according to your requirements. No matter how detailed or well-written the description is, it’s just superficial; ultimately, it’s necessary to stick to something simple and practical. The manufacturer will understand this, and the product produced will meet the specified requirements and function as intended. That’s a brief explanation; now let’s talk about the actual notation. The three ports of a tee consist of two ports connected to the main pipe, which are referred to as the main pipes, while the middle port is called the branch pipe. Generally, the branch pipe is thinner than or the same thickness as the main pipes, though there are also special cases where the branch pipe is thicker than the main pipes—these are less common. In actual production, except for forged tees, steel tees are made through cold drawing processes, resulting in main pipes that are thicker and branch pipes that are thinner. The same applies to tees with equal diameters, as the branch pipes are formed by cold or hot drawing from the main pipes, making them thinner than the main pipes. The notation follows the formula of outer diameter + wall thickness, such as Φ630x426/12x10 and Φ630x10. In the first example, it’s a tee with unequal diameters: the outer diameter of the main pipe is 630 mm, with a wall thickness of 12 mm, while the outer diameter of the branch pipe is 426 mm, with a wall thickness of 10 mm. The second example refers to a tee with equal diameters. This notation is the most straightforward and least prone to errors. According to standard notation, it’s written as Tee T(S) STD DN600-I and Tee T(R) DN100x80-II SCH40. Both represent tees with equal or unequal diameters, with specifications and wall thicknesses indicated. Here, “I” and “II” are used to denote series—“I” refers to tees with equal diameters and a wall thickness of 10 mm, with an outer diameter of Φ609.6 mm (DN600-I refers to this diameter). The second type is a tee with unequal diameters, with outer diameters of Φ108x89, and wall thicknesses of 6.02 mm and 5.49 mm respectively

Is there a tee in which the main pipe directly splits into two smaller branches? ?

The standards are generally the same; the wall thickness varies with pressure. The answer on the 2nd floor is very detailed; you can refer to it: D

For this item, simply tell them the diameter and the pressure, and then, based on the actual conditions of one’s project, decide whether to use standard specifications or non-standard ones.

There are standards for all of these; what’s listed above covers most of them. I’d like to add one more: SH/T 3408