122 Chapter 5
as an acoustical treatment is typically tested in accor-
dance with the ASTM E84 standard to measure flamma-
bility.^38 The results of the ASTM E84 test are a flame
spread index and a smoke developed index. Building
codes further classify materials according to the test
results. International Building Code (IBC) classifications
are as follows:^39
- Class A: Flame spread index = 0–25,
smoke developed index = 0–450. - Class B: Flame spread index = 26–75,
smoke developed index = 0–450. - Class C: Flame spread index = 76–200,
smoke developed index = 0–450.
Materials to be used as interior finishes, such as
acoustical treatments, are often tested in accordance with
ASTM E84, with test results provided in manufacturer
literature. The ASTM E84 test results and corresponding
IBC classifications for some typical acoustical materials
are summarized in Table 5-4.
In general, most acoustical materials are Class A
materials. Some acoustical foam treatments, as well as
some acoustical treatments made of wood, are Class B.
Care should be taken that any acoustical treatments
made of foam or wood have been tested and that the
manufacturer can provide proof of testing. It should also
be noted that some jurisdictions require that acoustical
foam materials be subjected to more stringent flamma-
bility requirements, such as the NFPA 286 test method.^40
With regards to breathability, precautions should be
taken if the acoustical treatment material contains fibers
that could be respiratory or skin irritants. The fibers of
many common acoustical treatments, such as glass fiber
and mineral wool panels, are respiratory and skin irri-
tants, but are harmless once the treatments have been
installed in their final configuration, usually with a fabric
or other material encasing the fibrous board. Nonethe-
less, precautions such as wearing gloves and breathing
masks should be taken when handling the raw materials
or when installing the panels. Additionally, damaged
panels should be repaired or replaced in order to mini-
mize the possibility of fibers becoming airborne.
Some facilities may have additional safety require-
ments. Some health care facilities may disallow porous
materials of any kind to minimize the possibility of, for
example, mold or bacterial growth. Clean room facili-
ties may also prohibit the use of porous materials on the
grounds of minimizing the introduction of airborne parti-
cles. Correctional facilities will often prohibit any mate-
rials that can be burned (including some fire-resistant
materials) and securing acoustical treatment panels to
walls or ceilings without any removable mechanical
fasteners, such as screwed, rivets, bolts, etc. Still other
facilities may have safety requirements based on, for
example, the heat produced by a piece of machinery, the
chemicals involved in a manufacturing process, and so
on. The applicable laws, codes, and regula-
tions—including rules imposed by the end user— should
always be consulted prior to the purchase, construction,
and installation of acoustical treatments.5.7 Acoustical Treatments and the EnvironmentAcoustical treatments should be selected with an appro-
priate level of environmental awareness. Depending on
the application, selection could include not only what the
material itself is made of, but also how it is made, how it
is transported to the facility, and how it will be disposed
of should it be replaced sometime in the future. Many
acoustical treatments, such as those consisting of natural
wood or cotton fibers, can contribute to Leadership in
Energy and Environmental Design (LEED) certification.
Unlike audio electronics where overseas manufacturing
has become the norm, acoustical treatments are often
manufactured and fabricated locally, thus saving on the
financial and environmental costs of transportation.
Even acoustical treatments such as polyurethane
foam panels, which are a byproduct of the petroleum
refining process and can involve the use of carbon
dioxide (a greenhouse gas) in the manufacturing process,
are becoming more environmentally friendly. For
example, one manufacturer of acoustical foam products,
Auralex Acoustics, Inc., has begun using soy compo-
nents in their polyurethane products, thereby reducing
the use of carbon-rich petroleum components by as
much as 60%.
The best possible environmentally friendly approach
to the use of acoustical treatments is to limit their use.
The better a facility can be designed from the beginning,
the fewer specialty acoustical treatment materials will be
required. Rooms from recording studios to cathedrals
that are designed with acoustics in mind from the begin-
ning generally require relatively fewer specialty acous-
tical treatments. Acoustical treatments are difficult to
avoid completely; almost every space where the produc-
tion or reproduction of sound takes place, or where the
ability to communicate is tantamount, will require some
acoustical treatment. Nonetheless, the most conserva-
tive approach to facility design should ensure that only
those acoustical treatments that are absolutely necessary
are implemented in the final construction.