We will explain the design space of pipe, which is the basic part of piping design.
If we fail here, the plumbing work at the chemical plant will fail in an instant.
It would be best to set it wide for now.
A factory that can think like this can be said to be a blessed environment where you don’t have to worry about costs and have plenty of space.
You want to make the spacing as narrow as possible to use the space as effectively as possible, but if you make the spacing too narrow, the pipes will interfere with each other and people will complain that it’s difficult to work with.
Many piping designers have this problem.
Therefore, we have put together a design philosophy to avoid mistakes when designing the spacing between pipes.
In order to design the spacing between pipes, it is necessary to collect a lot of information.
First, let’s consider a scene where multiple pipes are lined up in parallel.
It is often seen on piping stands.
For parallel piping, ensure the minimum space where the piping can be physically installed.
Close proximity of flanges
Flanges of adjacent pipes do not touch each other.
If this condition is ensured, there will be minimal interference.
How close can the two pipes be when they are lined up as shown in the diagram below?
For bare piping, the outermost part of the piping is the flange.
The minimum requirement is to arrange these flanges side by side so that they do not touch each other.
Secure the minimum working space between the flanges and decide where to install the pipes.
Flange outer diameter of piping ① + flange outer diameter of piping ② + work space
Let’s do some calculations using SGP piping + JIS10k flange as an example.
JIS10k flange-JIS10k flange distance.
It is the sum of the flange outer diameter/2 of 25A to 50A.
It would be a good idea to add an appropriate work space here and line up the pipes using rounded numbers.
Proximity of piping and flanges
The idea that the flanges do not touch each other is actually an idea that allows for some leeway.
If you want to narrow it down a little more, you can consider a staggered arrangement.
It looks like the image below.
By simply shifting the flanges slightly instead of placing them in the same position, it is possible to bring the pipes closer together.
Even if multiple pipes are lined up, there are only two patterns for the flange positions, as shown below, so it will not interfere with the design.
Flange outer diameter of pipe ① + pipe outer diameter of pipe ② + work space
For piping ① and piping ②, the large piping is ① and the small piping is ②.
Now, let’s calculate the approach distance in this case.
First, calculate the outer surface of the pipe and the outer surface of the flange.
JIS10k flange-piping distance
If you set the work space E to, for example, 30 mm (where you can fit your hand) and round the numbers, it will look like the following.
Staggered piping distance
This distance is determined by the piping designer.
In some cases, it may be set in 5mm increments, and in other cases, it may be set in larger increments.
In the case of bare piping, it was only necessary to consider the outside surface of the piping and the outside surface of the flange, but things change a bit when insulation is added.
Reduce the distance by the thickness of the insulation.
You must consider the outside diameter of the flange cover on the large piping side, and the piping outside surface and insulation thickness on the small piping side.
Especially the small piping side is often overlooked.
Flange outer diameter of pipe ① + flange cover thickness of pipe ① + pipe outer diameter of pipe ② + insulation thickness of pipe ② + work space
The calculations become a little complicated because there is a pattern that determines whether both piping ① and piping ② have insulation, or whether only one side has insulation.
It gets even bigger with the steam trace.
If using jacket piping , there is a possibility of making a mistake in the flange diameter, so be careful here.
Options are the source of mistakes.
Next, let’s think about the header.
I’ll use a pump header as an easy-to-understand example, but the same goes for a tank header.
The key is whether or not there is a valve.
A valve is usually attached to the header.
Considering the case where valves are connected by flanges, it seems to be a good idea to ensure the distance between the flanges.
With valves, you have to consider additional handle operations.
For example, the image of a ball valve is as follows. The same goes for butterfly valves.
The handle takes up more space than the ball valve body.
When I tried to install the handle, it hit the valve next to it …
Failures like this are quite common.
If we made a mistake like this, we would have to deal with it by modifying the handle at the field level.
Handles vary depending on the valve manufacturer, so you will need to find out which manufacturer’s handle you are using.
Now, I would like to introduce some points to keep in mind when considering staggered header piping to make the header piping as compact as possible.
If you use staggered piping and shift the valve positions, it certainly seems possible to narrow the rows.
Here we are assuming a ball valve, but next time we have to consider the rotation of the ball valve’s handle.
I staggered the valves so they wouldn’t interfere with each other and stuffed the headers, so when I tried to turn the handle, it hit the valve next to it. . .
This is also a development that is very easy to fall into.
Personally, I do not recommend using a staggered arrangement for the header, as the conditions become complicated at this point.
It’s difficult when you make a mistake in piping design and have to correct it during on-site construction.
For valves other than ball valves and butterfly valves, there is no need to consider turning the handle.
Generally, the larger the diameter of a gate valve or globe valve, the larger the handle.
There is a possibility that the handles may interfere with each other, but what is more important is work safety.
As mentioned in the staggered arrangement, it is not just a matter of “minimally requiring hands”, but also consideration must be given to tasks such as changing the handle, changing posture, and putting weight on the handle.
You will probably decide while imagining the work at your desk.
I think you need to look at the safety factor.
Proximity of piping is a fundamental consideration in piping design.
In order to create a piping layout that will not cause any problems in the future, collect a variety of information and make a comprehensive decision.
I recommend the following books.
We introduced the concept of setting the close spacing between pipes in a chemical plant.
For parallel installations, consider the distance between flanges, the benefits of staggered arrangement, and options for insulation, tracing, and jacketing.
For the header, you also have to consider the area around the handle.
There are many factors to consider, and you want to set it up with some leeway.
Please feel free to post any concerns, questions, or concerns you may have regarding the design, maintenance, and operation of chemical plants in the comments section. (The comment section is at the bottom of this article.)
*We will read all comments received and respond seriously.