I will explain the piping support used in chemical plants.
Piping support is one of the key points in piping design.
This knowledge is essential not only for plumbing engineers but also for mechanical engineers.
You may have installed it somehow, but just one support can greatly change the workability at the site.
Read this article to understand the key points of support design.
Even if you plan to use the piping for a long time, let’s be conscious of it properly at the design stage and drop it into the drawing.
An engineer who knows the field!
Type of Piping support
A collection of major supports used for piping in chemical plants.
Details are explained below.
Place floor
The image of the floor-standing type support is as follows.
The basic form of support is to place it on the floor.
It consists of a support section and a horizontal section, and the horizontal section receives the piping.
It is basic to use angles for both posts and horizontals. It’s easy to connect.
Use channels to increase intensity. There are times when you use a channel only for the struts.
If the height of the floor installation is high, the strength will decrease, so try hanging it from the ceiling.
If you can’t even hang it from the ceiling, use a pipe support instead of an angle or channel support.
Even if pipe supports are made, they cannot be expanded, so the use of pipe supports is limited in chemical plants where there are many extensions and alterations to the pipes.
Expandability is OK in the image of adding to the horizontal part.
In the above figure, the branch is attached to the left side of the support and the piping is attached, and later the branch is extended to the right side.
suspended from the ceiling
Ceiling suspension is also frequently seen in chemical plants.
Since piping becomes an obstacle in the factory, it is common to construct it in a high place where people and equipment cannot pass.
Weld the supports from the ceiling beams and attach the piping to them.
Although it is basic to align the height of the piping, it may not be possible to adjust depending on the diameter of the piping.
In such a case, support is added to raise the height of the horizontal part.
This shape is called a “horse”.
Dakimakura
Hugging supports are also common in chemical plants.
The hug support is the image below.
It is not fixed to the floor or ceiling, but a bundle of pipes.
It is often used when one pipe is thick and strong and the other is thin and bends easily.
The position and number of pipe supports are decided on-site to a certain extent and then installed, but there will always be missing parts.
Check for lack of support by moving it by hand.
If the pipes sway here, it will be judged that it is better to add support.
When the field welding of the support is completed and the final check shows that it needs to be manually reinforced, I don’t bother to weld additional supports. Tedious.
Therefore, it is common to reinforce with a hugging support.
It can be installed without on-site welding, so it is useful as an emergency construction.
I was doing a test run and needed to add piping, but I can’t weld.
In such a case, connect the pipes to the surrounding pipes by connecting them with a support. It’s a skill.
bracket
The bracket type has the following shape.
It has a structure in which a bracket is attached to the piping.
Commonly used for pipes that pass through the floor.
This is the most reliable method for receiving the vertical load of piping.
Since it penetrates the floor, it is also possible to take a ceiling support from the underfloor (ceiling of the lower floor).
The ceiling support increases the play allowance of the piping, so it is easy to use, but there is still some danger.
dummy
A dummy support looks like this: Right side.
A dummy support welds a support to the pipe.
In general, pipes are connected to elbow pipes.
It looks like cheese and has a dummy cheese shape, so I guess it’s called a dummy support…
It is often used when the dimensions of the support such as piping racks are fixed.
If the rise position of the piping is fixed and it cannot be extended from the rack support, a dummy support is attached to the piping side to support the load.
Actually, the ceiling-mounted type shown on the left is good, but if you can’t secure the span of the support, consider using a dummy support.
However, it is difficult to weld and prone to corrosion, so trend monitoring is necessary.
Be aware of vertical piping
Remember that pipe supports carry vertical loads.
General values are defined for pipe support intervals for each diameter.
However, it is unlikely that the support will be calculated and installed according to this spacing.
Attach the support to a position that is easy to attach and move it by hand to check.
Textbooks tend to focus only on supporting horizontal piping, but what is more important is vertical piping.
I really want to get support for this.
In the figure above, it is basic to receive the load of the vertical pipe directly with the support as shown on the right side.
As shown on the left side, vertical piping with floor support + U bolts is weaker in terms of strength.
The vertical load of the pipe must be supported only by the frictional force of the U-bolt.
If the pipe is directly supported by the floor support, the support is effective against bending stress and compressive stress, so it is sturdy.
Ceiling supports are similar, but are a little weaker as they are supported by tensile stress rather than compressive stress.
Piping support member
The support member uses the material of steel.
Several patterns are conceivable for the shape.
Angles are fundamental in chemical plants.
It is easy to obtain, strong, and easy to process. Super convenient.
Since the flat plate is weak, it is not used as the main support member, but it is used in a secondary role.
The channel is strong and has a sense of security, but it feels a little excessive and is used less frequently.
There are cases where pipes are used instead of struts.
However, it is a bit difficult to process into complex shaped supports, so I don’t use it much.
Members such as roller tubes and spring hangers may be used to fix pipes in general buildings.
The reason why these materials are not used in chemical plants is that the piping is often modified.
Once the piping route is decided , it will be replaced immediately if it corrodes, unlike in buildings where the piping is not remodeled for 10 or 20 years. Extensions and renovations are frequent.
In that case, you have to change the support each time.
In this case, an angle that is easy to modify is advantageous.
Piping support method
There are also several methods of securing pipes and support members.
U-bolt
Chemical plants often use U-bolts.
Since U-bolts are in line contact with the pipe, they can be tightened with a weak force.
Since the contact area is narrow, there are few areas where rainwater collects, which is also advantageous for crevice corrosion.
U band
In addition to U-bolts, U-bands may also be used.
The reason for using the U-band is to prevent it from being over-tightened.
Specifically, it is used for glass lining and fluorine resin lining piping.
If you tighten it too much, it may break.
others
There are many other ways to fix pipes, but they are rarely used.
- Spring hangers, turnbuckles, etc.
- rollers with brackets, etc.
Convenient materials are available in the market, but they are not suitable for chemical plants.
It is important not to adopt it simply because it is convenient or common in the world.
The same idea applies to chemical anchors.
Temporary fixing of piping
Introduces a method for temporarily fixing pipes in a chemical plant.
The procedure for installing pipes on-site in plumbing work is as follows.
- Prefab
- Temporary fixing
- Dimension matching
- permanent support
Even if you prefabricate based on the piping diagram, it is 100% impossible to install the piping without any errors.
On-site adjustment piping is always required.
In order to do that, we have to make a certain amount of prefabricated piping and pump it all at once on site.
Then, measure the remaining adjustment parts and make the piping,
We can finally set up support.
The timing of welding the supports on-site is quite late in the plumbing work, isn’t it?
There are several types of temporary fixing methods, as well as permanent fixing methods.
track number
The iron plate for temporary fixing of piping is a wire.
It’s not temporarily fixed with an iron plate, it’s temporarily fixed with a wire (laughs).
A wire is a wire.
It is a soft iron wire that can be deformed by hand.
Scenes of using ratchet wrenches with spikes to tighten wires are often seen in plumbing work at chemical plants.
It can be easily processed and can be fixed with a fairly strong force, so it is useful as a temporary fixing.
More than 90% of temporary fixings in chemical plants use wire.
It is used not only for construction work, but also for irregular work during production. Very convenient.
Takigi
Tsubaki is a wooden stick. It’s timber.
It is also called a flap angle.
Since the wood is a tree, it can be supported with a stronger force than the grid wire.
If it is only fixed with a number wire, the pipe will sway with the wind.
Iron or stainless steel pipes are fine, but glass lined pipes and FRP pipes can crack. I’m scared.
At times like this, it’s Rinki’s turn.
I have a strong impression that Kashiki is used to fix pipes in high positions.
Ukigi is also used to support aerial pipes that cannot be reached by wire.
Takigi is not only useful for piping, but also for temporary installation of equipment on the ground and temporary scaffolding inside tanks.
There is no problem because it is easy to obtain the number line, but it is surprisingly difficult to obtain the wood.
In many cases, Takigi is permanently installed in the factory as a management material.
It is the same idea as the scaffolding pipe.
jack
A jack is also used as a temporary stop for the pipes.
Jacks are used when you want to firmly receive the load and determine the height and slope of the piping.
Most of them can be handled with wood, but if you don’t have a wood of the right size, a jack will come into play.
Sometimes jacks are used on the headers of pumps and reactors.
Position adjustment is easy because it is a jack.
Height adjustment and purchase adjustment are easy, so I would like to use a lot of jacks,
There are also disadvantages such as being heavy, taking up space, and being expensive.
It’s case by case.
Support notation on piping diagram
Clearly mark the support on the piping diagram.
Currently, there are many modifications to existing facilities, so it is desirable that the existing piping support and the newly installed piping support are properly indicated.
In general, pipe supports have a recommended support interval for each diameter.
| 25A | 2.5m |
| 50A | 4.0m |
| 80A | 5.0m |
There are these recommended values, but in practice, I think it’s okay to handle them more roughly.
In my opinion, one fixed support every 5m is a must.
It is quite troublesome to judge for each caliber.
There are few opportunities to lay only one pipe, and when laying multiple pipes, a hugging support is also possible.
If the fixed supports are properly indicated on the piping plan, and one is attached every 5m, it will not be such a big problem.
As the plumbing work progresses and supports are added, if you shake the plumbing by hand and it shakes a lot, you should add supports.
reference
Plumbing supports are just as important as the plumbing itself, yet they are often neglected.
A general understanding of plumbing will help you understand the importance of support.
I recommend the books listed below.
related article
lastly
Introduced piping support for chemical plants.
We introduced the floor, ceiling suspension, hugging, dummy, etc. as support methods, angles as members, and U-bolts and U-bands as fixing methods. Temporary fixing is also described.
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