In the HVAC industry, most sound or noise is generated via rotating equipment and air and fluid movement through ducts and pipes. This movement creates vibration, sound, or noise. Vibration in its simplest form can be considered an oscillation or repetitive motion of an object around an equilibrium position. In the HVAC industry, sound is usually generated by some form of vibration from equipment. Although sound is not present without vibration, there can be vibration without sound noticeable to the human ear. Therefore, the best way to reduce sound is to limit the vibration produced by mechanical equipment. Examples are rotating shafts or gears, thermal processes such as combustion, or fluid dynamic means such as airflow through a duct or fan interactions with air.

What are the effects of vibration?

Unresolved vibration can cause problems affecting both the equipment itself, the building and its users. Recurring vibrations can cause:

• Damage to the equipment
• Transmitted noise
• Discomfort for people
• Safety issues for those near the vibrating equipment
• Damage to the structure of the building
• Increased maintenance requirements for the equipment
• Decreased lifespan of the equipment
• Malfunctioning equipment
• Violation of regulatory requirements

These issues are why vibration isolation is so important.

Common Sources of Vibration

In HVAC installations, vibration often originates from rotating machinery or from bulk air movements. Vibration tends to increase with time as system components wear down, but it can also be present in new installations as a consequence of poor design decisions:

• Oversized compressor or chiller.
• Oversized fans and blowers.
• Use of inadequate supports.
• Poorly designed air ducts
• General Lack of maintenance.

How to resolve vibration?

Vibration isolation is the key to solving the problem. Isolating the source of vibration from the supporting structure is typically the most efficient approach to eliminate vibration. Carefully selected vibroacoustic isolators need to be placed, where possible, directly in between the mounting structure and the equipment that produces unwanted vibration. The isolators can then effectively absorb up to 99% of excess vibration produced by the equipment.