Isolation of Floor Vibrations

Common Causes

• Placing a system operation in the wrong location can cause serious floor vibrations. Pumps, blower fans, cooling towers and boilers all make some vibration or noise when they operate. But if they are installed next to key support beams in the building and have the right noise pattern, the vibrations can become magnified and travel to other parts of the building, radiating outward. The solution involves finding the source of the vibrations and containing the problem. Rooftop HVAC units, compressors and motors are all common culprits.

Isolators

• Isolators -- which look like giant, durable springs -- are installed in floors underneath the units creating the vibrations. When the unit radiates vibrations into the floor, these giant springs absorb the vibration instead of allowing it to be carried on. The vibration is essentially isolated, affecting only the immediate floor.

Materials

• Isolators come in two main types: free standing and restrained. Free-standing versions have a base and single large bolt on the top of the spring for attachment. Restrained versions are fitted with a framework that allows for bracketing, clamping and other more complex installation procedures. Metal is a frequent composition material, but fiberglass and neoprene are also used. The springs are coated to help them resist corrosion and long-term damage.

Placement

• The most important step in the floor vibration isolation process is placement. Contractors with the proper measuring devices and experience in isolator set-up can pinpoint areas where vibration is being transferred and install the isolators correctly. For example, installing isolators at the bottom of a brace or beam may be more effective than trying to install the springs on the floor directly below an air conditioner.