Can’t see the forest for the trees

A recent project survey highlights a few issues that we often find when we’re called in to provide solutions for elevator equipment sound disturbances.

This projects dry to submersible mod project generated noise disturbance complaints from the adjacent residential master suite. Finding a solution to mitigate the disruptive sounds had the property management and elevator contractor spending countless hours in discussion, research, and time needed to see it through to the final product installations.

The first treatment attempt at sound reduction was in wrapping the power unit with a “soundproofing” material. When this didn’t provide acceptable results the efforts turned to a sound treatment of the motor room with a “soundproofing” sound absorption material applied to the machine room walls.

Each product each product had been recommended and sourced from a couple of the many internet-only based “soundproofing” companies. The results of the combined products provided a barely perceptible reduction for the residents.

On recommendation of an elevator consultant, C.E. Electronics – Acoustics Group was contacted to perform a project sound survey to determine best available treatment options to meet desired sound reduction levels. The operational equipment sound levels were under the performance guidelines established by National Elevator Industry, Inc. (N.E.I.I.) of 85 dBA within the machine room.

The “soundproofing” products in this project are also often used within the industry in attempt to mitigate equipment sound disturbances; unfortunately as is the case with most installations of these products they do not provide desired levels of sound reduction.

  • How important is it for you to have fire rated materials in your machine room?

Commonly suggested tank wraps from the internet based sound companies; often a black rubber or plastic based material, do not have a proper fire ratings for this type of application or even worse – not fire tested at all.

This project used a black, plastic-based wrap material that actually has a UL classification marking; however, a further look into the actual UL classification shows it is only applicable for use within wall and floor/ceiling construction assemblies, not for use as a surface facing material as it’s installed in this application!

  • How important is it that you maintain temperatures of the oil and in the machine room?

Wrapping hydraulic units may create higher oil temperatures, possibly affecting car leveling and life expectancy of the equipment. Adding an oil cooler would help with the increased oil temperatures; however, you’ve created an additional noise source, increased heat into the machine room, and increased the overall treatment cost.

  • The disruptive frequencies generated by hydraulic power units are low, why would you install a material that is only effective in absorbing high frequencies?

 While the machine room’s wall treatment material did provide a Class A Fire Rating, its sound absorption rating is extremely low for the disruptive frequency ranges generated from hydraulic elevator equipment.

  • How do you contain equipment sounds within a machine room when you have holes in the wall?

The original disconnect was installed directly on the wall studs, having the drywall cut tightly against its edges. This box was replaced with a smaller box leaving a 2” gap around three sides of the box, exposing the master suite side wall board and thin cavity insulation.

A fundamental rule for sound control is that any area where air may pass sound will also pass. The machine room must be constructed as airtight as possible to contain the sounds within the room. Worse than letting sound pass into the residential space, the open area in the wall negates any fire rating of the wall!

This wall opening is the root of this projects noise disturbance that would render any sound reduction treatment virtually ineffective.

We have two treatment options available 1) Seal the machine room hole with gypsum board. Unfortunately this would involve running new conduit to the disconnect box so that the box could be mounted on the surface of the drywall 2) Remodel of the wall on the residential side to provide a high sound rating.

Last I heard it was still in the who is going to pay discussion phase. Sound familiar?

Our industry experience has shown more often than not the internet-only based companies do not have enough knowledge of elevator systems and their environments to recommend effective sound control treatments. As the only sound control company with Q.E.I. on staff and a market focus on elevator equipment sound control solutions we are uniquely qualified to provide you effective sound control solutions.

If you have an existing installation with noise issues or wish to be proactive on a new installation give us a call to discuss specifics of your project.

CQuiet Sound Control Product Solutions

CQuiet |ˈsē ˈkwī-ət | verb: to have the ability to see quiet



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