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Sound
Proofing Another Feature of All-In-One
Expansion Joint Sealant from EMSEAL
STC 62; OITC 52
These are the independent lab confimed sound
transmission class values of EMSEAL's
EMSHIELD expansion joints when tested in a
STC 68 wall.
For the uninitiated, these values are
excellent.
Consider also that
EMSHIELD WFR2
(for walls) and
DFR2
(for floors and decks) are additionally:
- watertight;
- airtight;
- fit joints from 1 - 6 inches;
- handle 50% joint movement;
- are 2-hour fire-rated per UL 2079;
- and thermally insulate.
When the goals of building design are to
control the indoor/outdoor exchange of
air to maximize energy efficiency, while
ensuring a watertight exterior, and a
livable interior, there is no longer a
reason to compromise any aspect of
design intent at expansion joints to
simultaneously achieve all three.
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Nor does
this "all in one" performance require special
accommodation in substrate design. WFR2
installs non-invasively and requires just 4
1/2-inches of available substrate depth to
achieve all of these performance attributes.
But back to sound...
To put into perspective the claim of
"excellent":
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"Using ASTM E-90 in
independent testing, the STC of a solid wall
when divided by a 2-inch wide, unsealed
expansion joint dropped from 68 to 17!"
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- the STC (Sound Transmission
Class) of a 2-foot thick
concrete wall is around 58.
- to achieve an STC 68 wall
requires two rows of studs on
staggered centers and separated
by a one-inch air gap, with
fiberglass batt insulation
between the studs, and two
layers of 5/8-inch gypsum
sheetrock on each face.
- The Uniform Building Code (UBC)
requires an STC in partitions in
Group -R occumpancies (including
hotels, motels, apartments,
condos, etc.) of 50 when tested
to ASTM E-90 in a lab or 45 if
tested in the field.
- LEED 3 allows points for
schools built with materials
that impart STC's of at least
35.
Even at STC 50 however, loud
speech is still audible, if not
understandable, across a
partition. A minimum STC 60 is
needed to block loud sounds such
as musical instruments and 60 is
generally considered necessary
in luxury accommodations.[1]
OITC is another matter
altogether and is relevant to
any structure attempting to keep
the indoor environment free from
objectionable outdoor noise from
airplanes, traffic, trains,
etc. Because outdoor noise is
characterized by deeper
frequencies, OITC (outdoor
indoor transmission class)
ratings are lower than STC
ratings.
In their paper, "Using Outside
to Inside Transmission Class
Measurements (OITC) in the
Design of a New School Near an
Airport,"[2]
John LoRang and Gary
Siebein measured worst case
noise from jet aircraft at a
proposed school site to be 107
decibels. Their conclusion is
that STC 51 door and window
systems, and STC 45-70 wall and
roof assemblies would be
required to meet the interior
design criteria.
So, what role would the
expansion joint play in this
scenario and if they are such a
tiny percentage of the wall
surface -- why do the STC and
OITC ratings of expansion joint
sealants even matter?
Using ASTM E-90 in independent
testing, the STC of a solid wall
when divided by a 2-inch wide,
unsealed expansion joint dropped
from 68 to 17! This means that
the sound blocking ability of
the wall is for all practical
purposes eliminated.
For each 10 decibel
deterioration in sound
transmission loss, the human ear
perceives a doubling of
loudness. So the 51
decibel increase through the
expansion joint in the test wall
yields a 5-times doubling of
perceived 'loudness ' to an
occupant of the adjacent room.
Clearly then, just like with
fire, water, and energy it is
essential to demand that your
expansion joint selection has
independently tested STC and
OITC values and that they do
not degrade the sound
attenuation of the wall, floor,
roof, window, and curtainwall
assemblies you are specifying.
Other EMSEAL Precompressed
Sealants Are Impressive Sound
Blockers As Well:
If you are specifying a joint
sealant and don't require the
fire rating, any of EMSEAL's
other benchmark precompressed
sealants will do the job of
waterproofing and handling
movement while still imparting
impressive sound proofing.
In fact, tests yielded STC's as
high as 72 and OITC's as high as
60 for our
COLORSEAL product when
installed into both sides of the
wall.
For a complete listing of STC
and OITC values, and for the
independent test reports, for
EMSEAL precompressed sealants
see our newly expanded
Sound Attenuation page in our
Knowledge Base at www.emseal.com
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[2]"Using
Outside to Inside
Transmission Class,
Measurements (OITC) in the
Design of a New School
Near an Airport"; Mark
LoRang, Siebein Associates,
Inc., 625 NW 60th St., Suite
C, Gainesville, Florida
32607,
Gary W. Siebein, Courtney
McGinnes, School of
Architecture, P.O. Box
115702, University of
Florida, Gainesville,
Florida 32611-5702; Hyun
Paek, Siebein Associates,
Inc.
________________________________________________________________________________
Coming Soon:
Hurricane Force Wind and
Water No Problem for
EMSEAL's
SEISMIC COLORSEAL--Independent
Lab Tests confirm the ability of
joint sealant to withstand
forces required of curtain wall
assemblies.
_________________________________________________________________________________
EMSEAL, established in 1959 and
located in the U.S. since 1979,
has provided sealant systems and
technical support to many
prominent structures including
stadiums, arenas, hospitals,
parking structures, airports,
malls and other commercial and
public sector projects.
EMSEAL products are used
worldwide, including in the new
Meadowlands, Yankee Stadium and
Citi Field in New York,
Westfield Malls, American
Airlines Arena in Miami, The
Empire State Building, Lincoln
Center, The CN Tower Toronto,
Watergate Hotel, Greensboro,
N.C. Coliseum, Houston
Intercontinental Airport, the
Pentagon, Nordstrom's Stores,
FedEx Field Washington Redskins
Stadium, Citizens Bank
Philadelphia Phillies Ballpark,
California Polytechnic and the
Atlantic Station in Atlanta.
EMSEAL operates out of two large
factories - its recently
relocated headquarters and
engineered products plant in
Westborough, MA and its
precompressed sealant
manufacturing plant in Toronto,
Canada.
For more information please
visit
www.emseal.com or contact
our Tech Team at 1-800-526-8365,
508-836-0280 or at:
techinfo@emseal.com.
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