Understanding Vibration – #4 Vibration Isolation

As we’ve suggested, one of the most important things a good architect can do is to prevent vibration from travelling throughout a structure. It may be simple to think of isolation as a matter of throwing some spring mounts under a weight and letting it be. But not all scenarios are equal, and not all isolation techniques are equal. Vibration isolation is a complex field, but the principles are generally the same across the architectural and design worlds. It comes down to understanding the nature of the vibration you’re dealing with, and how that’s going to affect the environment.

The demands created by vibration on a roof are going to be different to those in a basement, or in a hospital wing. A fan will have different demands to a motor.

Choose a support system that’s too rigid, and you risk rapid fatigue and cracking; too soft, and you’ll end up with the vibration amplifying and shaking even more.

That’s more stress, more risk, and more clients coming back asking why it wasn’t done properly the first time.

The goal is to achieve the most appropriate isolation efficiency for the application. The isolation efficiency is the measure of what percentage of total vibratory force is absorbed by isolators at a certain compression or deflection, and at a certain disturbing frequency. That means that the efficiency of any one isolator can vary wildly depending on the application, so it’s important to understand the situation before selecting an isolator from a catalogue.

Determining the isolator depends on a few major and related points, which we’ll need a visual aid for.

Ideally, if you’re designing a walkway that’s perpendicular to the roof pitch, you’ll be aiming for a walkway as close to level as possible.

For the same reason that slopes need to become steps if they have a gradient of greater than 7°, when a walkway is running perpendicular to the roof pitch and that roof pitch exceeds 7°, the walkway must be levelled.

This is another situation where minimising the difficulty for people also increases the safety.

Given that most new roofs are 5° or less, it’s become very easy to design walkways that are not only under that 7° limit but, with some extra consideration, can be made level.

Unfortunately, vibration is often overlooked or oversimplified, even by some of the greatest architects and engineers. Download the ebook to make sure you’re prepared for vibrations in any form they come.

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