Pipe dimension marking

Our institute uses the second method; however, the length of the valves is generally not standard

The second method is also used, without indicating the valve length. They are simply 2D and line diagrams generated directly in 3D, without the need for manual annotation

We use the first marking method; the single-line diagrams generated in 3D all indicate the flange surfaces and valves!

Two-dimensional piping usually takes the center of the valve as the starting or ending point, without indicating the valve length.

Piping is labeled in two ways: based on the installation point and based on the turning point. Traditional manual methods and those that rely solely on CAD drawing typically use a marking system based on the turning points; this way, there is no need to calculate the lengths of pipes and valves, as these are already included in the dimensions. It is not necessary to consider the length of the pipes in between, which reduces the workload for designers. For 3D modeling software, design is carried out in a \"building-block\" manner, which makes it complicated to calculate the length of pipes; since the length of the pipes must be taken into account to determine their precise position, a marking system based on the installation points is usually used. Currently, abroad, a marking method based on the installation point is commonly used, which makes construction easier and saves materials. For example, suppose a pipe is connected to one end of a elbow, and then a valve is attached. Using the marking method based on the turning point, a value of 1000 can be assigned from the elbow to the center of the valve; this makes the diagram easier to read. However, the plumber carrying out the installation does not know the length of the pipe in between, and thus needs to measure it on site. Moreover, the pipe segment in question is not made up of whole lengths of material, resulting in plenty of waste ； According to the marking method at the installation points, regardless of the length of the elbows or valves, only the middle section of the pipe is marked as 1000. As a result, the distance from the elbow to the center of the valve is not 1000; it might be a value like 1123. This may not look ideal, but it makes construction much easier – the plumber simply needs to cut a 1-meter-long pipe for installation. This results in very little waste material, thus saving materials. Of course, there aren’t many rules in China; we just use things however is most convenient. To be honest, it’s still a matter of mindset. Sometimes I wonder too: Americans are so wealthy yet they pay great attention to thrift, being particularly careful in design, construction, and even in the details of daily life. Meanwhile, we, as developing poor countries, waste astonishing amounts of resources; it seems that the gap isn’t just technical in nature. This post was last edited by Boring Pavilion Grand Scholar on 2009-4-15 at 15:29.]

I think what was said on the sixth floor was great. Are there any materials showing the markings on the pipes, like what those symbols mean?

We all use the second method. The key point is that for some projects, it’s not necessary to use 3D; using CAD in those cases can be quite troublesome

From a construction perspective, it is necessary to indicate the length of the valve using the second method. Because when installing and cutting the pipes, the construction party must determine the required length of the pipes by taking into account the length of the pipe sections, and subtracting the lengths of fittings, flanges, valves, and other accessories. Without the length dimension of the valve, it is impossible to determine the length of pipe that needs to be cut, which causes significant inconvenience in pipeline installation. Therefore, it is generally necessary to specify the length of the valve, and this specification must be as accurate as possible.

It is best to indicate the length of the valve, as this will provide guidance for on-site installation! ! !

Friend upstairs, let me tell you a joke: A man went to buy shoes. He measured his foot size at home, but when he arrived at the market he realized he had forgotten the piece of paper with the measurement in his pocket, so he couldn’t buy the shoes and had to go back home. To be honest, few people mark the dimensions of standard components on the drawings; at most they indicate the specifications. Of course, each design agency has its own ways of being lazy, and it’s possible to spot those tricks, but it’s hard to point them out: lol. During on-site construction, plumbers don’t pay attention to the length of valves; they don’t even use a ruler to measure it. They just hold the pipe against the valve and that’s it!

Hehe, even valves of the same model can have different lengths; valves produced by different manufacturers are not identical. The diagrams from Jiaonai Institute do not indicate the valve length.

From a construction perspective, it is necessary to indicate the length of the valve using the second method. Because when installing and cutting the pipes, the construction party must determine the required length of the pipes by taking into account the length of the pipe sections, and subtracting the lengths of fittings, flanges, valves, and other accessories. Without the length dimension of the valve, it is impossible to determine the length of pipe that needs to be cut, which causes significant inconvenience in pipeline installation. Therefore, it is generally necessary to specify the length of the valve, and this specification must be as accurate as possible.

For valve markings, for socket-welded valves the marking is done at the center of the valve, while for butt-weld flanged valves it is marked at the flange surface

You’re right! ...Except in special cases, these tasks are generally not done, as they require effort with little return. :( Of course, I’m referring to 2D mapping.)

The second marking method is generally used to indicate the length and model of valves. It should be easy to construct; construction-related factors must also be taken into account during the design phase! Save resources.

Just as someone mentioned above, specifying a special length – one that only some manufacturers can supply – wouldn’t that be even more troublesome?