Commercial Architecture June 2018 - 36

acoustics

PROJECT

Addressing
Noise
Issues
Poor acoustics
in existing
spaces have
a variety of
solutions.
Baffles provide double-sided absorption, but with a smaller overall system depth than clouds.

well-informed architect or interior designer

source has stopped emitting a sound. It is expressed in

Acoustically absorbent materials, such as high-density

involved in new construction has an infinite

seconds. RT can be calculated mathematically based on

fiberglass clouds, baffles, and direct-to-deck ceiling and

variety of products available to create an

the volume of the room and the square footage of sound-

wall panels are extremely effective at reducing reverbera-

acoustically optimized space from the ground up. Un-

absorbing surfaces within it, or it can be measured with a

tion time.

fortunately, not every new space is built according to

sound-level meter.

When speech privacy is a specific concern, such as in

acoustically enlightened principles, leaving thousands

Background noise is the noise level in a space mea-

an open-office setting, acoustic masking can be added

of offices, classrooms, restaurants, and other spaces with

sured when the specific noise being studied is absent. Ma-

alongside absorbent installations. This involves introduc-

poor acoustics and sound control, giving occupants and

jor sources of background noise are HVAC noises, out-

ing finely tuned volume and frequency signatures that fall

owners a headache.

door noises, reflected speech sounds (echo), and noise

within the acoustical range of human speech. It doesn't

It can be difficult to fundamentally change the way a

from adjacent spaces. Background noise is usually ex-

eliminate speech sounds, but rather it reduces the physical

built space behaves acoustically. HVAC systems aren't eas-

pressed as dBA, a measure that reflects the response of the

zone of speech intelligibility by blending in with them.

ily replaced or rerouted. Trendy finish materials won't be

human ear, which is less sensitive to low and high

abandoned, even if they turn a café into an echo chamber.

frequencies.

The addition of a wall-to-wall suspended ceiling is rarely

Calculating the precise amount of sound absorption
in a space using the sound-absorption coefficient for each
material multiplied by the surface area of that material,

practical. However, there are steps that can be taken to

REVERBERATION VS. ABSORPTION

then finding the sum of all absorptive materials in the

address noise issues in existing spaces with limited disrup-

Sound reflects readily off of hard surfaces, as relatively

space, is more math than anyone but professional acousti-

tion to the occupants and the operating budget.

little energy carried in the sound wave is absorbed into

cians care to do on the subject. Fortunately, there are

A number of tests can be performed to determine

the surface material. As reflection builds throughout a

some general rules of thumb that can be followed to deter-

whether a space meets the requirements of acoustic com-

room, a web of competing sound waves gradually decays

mine how much sound absorption is needed in a given

fort. These can be performed by professional acousticians,

as it is absorbed, bit by bit, into the exposed surfaces in

space, based on the form the acoustic material takes. Each

but technical support teams for acoustic ceiling and wall

the space.

form has its advantages, depending on the design con-

Reverberation is an increasing problem due in part to

manufacturers also have the appropriate expertise and

some current interior-design trends. Hard-surface floors,

equipment to test a facility.
The two most practical measurements are reverberation time and background noise.
Reverberation time (RT) is time required for an average sound in a room to decrease by 60 decibels, once the
36

COMMERCI A L A RCHI T EC T URE

JUNE 2018

cerns and structural realities of the space requiring
remediation.

the move away from fabric-covered cubicles, glass walls
and partitions, open plenums, and exposed structures all

DIRECT-TO-DECK PANELS

add to the reflective surfaces, increasing reverberation

Direct-to-deck acoustic panels, which can be glued or

times.

screwed directly to the ceiling structure without wires or

commercialarchitecturemagazine.com

http://www.commercialarchitecturemagazine.com

Table of Contents for the Digital Edition of Commercial Architecture June 2018