Bracket and Pipe Support

To stabilize the location of piping installations, specific connections and tools are required, and it is better to obtain specialized information for ordering them. These connections are known by various terms. For example, in industries, they are referred to as pipe supports.

A correct and logical selection of brackets and pipe supports is vital for the success of a project. For proper execution of installation operations, it is necessary to have supports in certain sections of the pipes at the installation site. Choosing the right bracket or support is considered in all design and construction phases during the execution phase.

Important Points in Designing or Selecting Supports

The design of supports, like other aspects of plumbing, requires study and experience and must be considered from the beginning of the project in the preliminary phase. Required technical specifications should be provided to the plumbing designer according to each project's requirements. In any case, the following points should be considered in the design of supports:

Studying the technical specifications provided for supports at the beginning of the project (if available) for the suitable selection of supports during design.

Considering the design temperature of pipes to determine the strength and type of material for the support and necessary arrangements for insulation, etc.

Having adequate information about the materials of the plumbing system and the supporting accessories to reduce galvanic reactions at the connection points of the supports to the pipes.

Maximizing the use of existing structures, especially main structures, to reduce the number of supports and eliminate complex supports.

Standardizing types of supports (Standard Support Drawing) to reduce the number of support drawings required.

Examining the feasibility of the designed supports and simplifying the design, for example, making it easier to support pipes and avoiding connections of supports to plumbing accessories such as fittings.

Bringing supports as close as possible to components that act like concentrated forces in the system, such as valves and flanges, vertical pipes, points of connection between two pipes, and pipe direction changes in horizontal position.

The possibility of repairing the plumbing system.

Considering the displacements of pipes and equipment and avoiding rigidifying the plumbing system.

Considering external forces such as wind, earthquake, and internal forces like the discharge from safety valves.

Paying attention to foundation conflicts and overlaps.

Different Types of Supports

Supports can generally be divided into four main categories:

Weight Supports like ..., Sleeper, Saddle, Rod Hanger, Shoe

Rigid Restraints like Guide, Stop, U-Bolt, etc.

Dynamic Supports (Snubber) like Shock Absorber, Spring, ...

Sway Brace for controlling vibration.

To complement the above content, it is essential to consider the following point. As we know, every element in three-dimensional space has six degrees of freedom: three translational degrees along the X, Y, Z axes, and three rotational degrees around the X, Y, Z axes. It is crucial to understand that the purpose of supporting is not to completely restrain translational and internal movements but to control those movements in the desired direction, accomplished with consideration of geometric conditions such as line, temperature, length, diameter, etc., to provide appropriate flexibility for the plumbing system.

Next, we will further examine the mentioned classifications.

Weight Supports

Vertical forces are controlled in two ways: from the bottom of the pipe and above the pipe. If the vertical force is controlled from the bottom of the pipe, it is referred to as Rest; if that force is controlled from the top of the pipe, it is referred to as Hanger.

Some supports used as Rest include Shoe, Saddle, Dummy, Trunnion.

Shoe: Typically made of plate or channel, and sometimes Plate in various sizes.

Saddle: Used to spread the force applied to the pipe when the weight is high.

Dummy: Made from pipe (usually one size smaller than the pipe) and used in horizontal pipes or the elbow to control vertical force.

Trunnion: Also made from pipe and is welded to vertical pipes to control the weight of the pipe. Trunnion is also used as an intermediary to guide the pipe in vertical lines.

Support without intermediary parts: Often, a pipe sits directly on a beam or structure without any intermediary.

The weight support that is in the form of a Hanger is a rod. This support is only resistant to tension, and its connection point is from the top of the pipe. An important point about these supports is that they are not suitable for compressive force, and pipe displacements should not cause an angle change of more than ±4 degrees in the rod's vertical axis.

Pipe Clip: One of the components observed in Rod Hanger supports. The Pipe Clip is selected based on the size of the pipe and the load it must bear. The two main types are clips with two screws or three screws, with the latter used for pipes with insulation thickness of over 1 inch (25 mm).

Rigid Restraints

The function of these restraints is to resist weight forces, displacements caused by heat, external forces like wind and earthquakes, etc. These restraints can be made from simple shapes of structural steel like channels, angles, or beams, or complex shapes like Rigid struts. The selection of each one is based on the forces or moments and constraints needed to control displacement.

One of the most common supports is U-Bolts, made by bending a rod. This support resists pipe displacements in two directions and generally has a much lower shear capacity than its tensile capacity. U-Bolts are usually used when the lateral force is low (as Guides), but depending on the arrangement of the U-Bolt nuts, they can also be used as Anchors for low forces and smaller sizes.

If lateral forces exceed the allowable U-Bolt values, strap supports can be used, and if they greatly exceed the mentioned range, construction steels can be employed.

Rigid Restraints without intermediary components: Rigid restraints are sometimes applied directly with structural steel, but an intermediary connection may also be used to contain the forces.

Through the use of intermediate connections, necessary constraints in all directions of the coordinate axes can be provided. Bearings Lugs, Shear Lugs, Trunnion, and Dummy are types of these intermediate connections.

As previously mentioned, Bearing Lugs are for transferring lateral forces to main restraints, and Shear Lugs are used to prevent axial movements of the pipe. Intermediate connections Trunnion and Dummy, which are made from pipe, are used to restrain lateral or axial loads to the main pipe. If such intermediate connections are used to limit translational and rotational movements of the pipe in all directions of the coordinate axes, they are called Anchors.

Rigid Strut is also one of the supports that control force in one direction. This support includes an adjustable middle pipe during installation, whereby increasing the length reduces the allowable load. This support has a limitation on the angle change around the support axis, which is approximately ±4 degrees.

Dynamic Supports

Dynamic supports include (Snubber) Shock Absorber and Springs.

(Snubber) Shock Absorber is one of the supports that change length during slow displacements but acts as a rigid restraint during sudden forces and loads; it should never be used to support the weight of the piping system.

Springs are also one of the dynamic supports that have elastic behavior and are used in slow displacements.

Sway Brace

This support is used to control vibration and absorb impact force, or sometimes to resist displacements caused by heat. This support is very suitable for cases where precise control of impact force is not desired. These supports increase the natural frequency of the system, thereby reducing the dynamic force.

Final Words

Unique design problem-solving is used in every structure. Clause 321.1.1 of the ASME B 31.3 piping standard suggests the use of specialized support elements to prevent possible hazards and accidents in design. Likewise, special supports can be used to address challenges in executing designs and creatively implementing projects; however, consulting experts is essential when using any of these special components. Who would you prefer to consult for advice?

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