Anchors & Bolts for HVAC Construction in Georgia

Where are nuts and bolts used in a ventilation system?

Nuts and bolts are used wherever two or more components have to be fixed mechanically and reliably.

They may be needed:

• when joining mounting profiles;
• when assembling duct support structures;
• when fixing ventilation equipment;
• when connecting flange profiles;
• for securing flanges;
• when installing fixings and hangers;
• when assembling metal frames.

Different sizes and types of nut and bolt can be used within one system.

What is the difference between a nut and a bolt?

A bolt is a threaded fastening element, while a nut is screwed onto its threaded part and secures the connection. The simple principle is: the bolt passes through the corresponding hole in the parts being joined, the nut is placed on the other side, and when tightened both elements fix the components to each other. In a specific joint a washer, a lock nut or another protective or auxiliary element may also be used.

How to select the bolt size

The bolt size has to match the hole, the thickness and the load of the components being joined. During selection the diameter, length, thread type, the size of the corresponding nut and the total thickness of the parts being fixed all matter.

A bolt that is too short may not provide a reliable connection with the nut, while an excessively long bolt takes up unnecessary space in some installations.

Why does thread size matter?

A nut and a bolt have to match each other in thread size and type. Using an incorrect pair can cause thread damage, incomplete tightening, weakening of the connection, deformation of the part and difficulty in installation. A nut forced into place is not a correct fastening solution.

Why does load matter?

Not every nut and bolt is intended for the same mechanical load. In an HVAC system the fixing may carry the weight of the duct, the insulation, the fan or unit, the load of the profile structure and vibration. The higher the load, the more important it is to use fasteners of the appropriate class and size.

Is a washer required?

A washer is used under the head of a nut or bolt and can help distribute the load over a wider surface. Depending on the specific use, a washer can protect the surface, reduce local deformation and improve the stability of the tightening. Whether a washer is necessary depends on the specific joint and installation requirements.

What is a lock nut?

In some structures it is important that a nut does not loosen easily under vibration or long term operation. In such cases a special lock nut, an additional nut or another mechanical securing method can be used. This can be particularly important close to fans and other equipment that generates vibration during operation.

Why does the material matter?

The material of nuts and bolts affects their strength, corrosion resistance, service life and compatibility with the environment. The requirements of a dry indoor technical space and of an outdoor or high humidity environment can differ. If a fastener is constantly exposed to moisture or another aggressive environment, a material with suitable protection has to be selected.

Where are nuts and bolts used together with profiles?

In a mounting profile system nuts and bolts can be used to connect two profiles to each other, to secure a corner fixing, to fix another component to the profile, to assemble a support frame and to fix equipment to a profile.

For example, an HVAC mounting joint may consist of profile plus fixing plus bolt plus washer plus nut, although the exact configuration always depends on the specific system.

Nuts and bolts in a flange profile system

When making flanged connections between rectangular ventilation ducts, fasteners are used to secure the sections firmly to each other. In such a joint the correct bolt size, a matching nut, even tightening of the flange, a gasket where required and a sealed connection are particularly important. Over tightening is not always correct either, since it can deform the profile or another part.

How tight should a bolt be?

A fastener should be tightened enough for the joint to be stable, but excessive tightening can damage the component. Too much force can cause thread damage, stretching of the nut, deformation of the profile, over compression of the gasket and damage to the mounting joint. For critical structures the tightening force should be determined according to the technical requirements.

How does vibration affect fasteners?

Fans and other moving HVAC equipment generate vibration while running. Under long term vibration an incorrectly selected or insufficiently secured fastener can loosen over time. It is therefore necessary to use the correct fixing system, apply appropriate tightening, add vibration isolation where required and carry out periodic technical inspection.

What are the most common mistakes when selecting nuts and bolts?

Choosing the wrong diameter

The bolt may not fit the hole in the profile or the fixing.

Incorrect length

A bolt that is too short cannot be secured properly, while one that is too long complicates the installation.

Using an incompatible nut

The thread of the nut and the bolt have to match.

Ignoring the load

A small fastener may not be sufficient for heavy equipment.

Over tightening

This does not always increase safety and can damage the fastener or the profile.

How to select nuts and bolts in practice

Before selection it helps to know:

• which components have to be joined;
• the size of the fixing holes;
• the thickness of the parts being joined;
• what bolt diameter is required;
• what length is needed;
• what type of nut should be used;
• whether a washer is required;
• what load the joint carries;
• whether vibration is present;
• what the working environment is.

With this data fasteners of the correct size and type can be selected.

Which products may be needed together with nuts and bolts?

When choosing a product it is therefore advisable to consider not only a single nut or bolt, but the whole mounting joint.

Nuts and bolts at NB Group

NB Group supplies nuts and bolts for the installation of ventilation, HVAC and other engineering systems. They can be used in profile systems, in duct installation, in assembling fixing structures, when securing ventilation equipment and when connecting various metal elements.

When choosing a suitable product the size, length, thread type, load and compatibility with other mounting components all matter. NB Group branches are located in Tbilisi and Batumi.