Theatre Design & Technology - Summer 1986 - 18

TECHNICAL REPORT

Fred M. Wolff

Sound Reduction Door at
Bagley
Wright
Theatre

.
J

by Frederick J erant

The Bagley Wright Theatre in the Sealtle Civic Center is the second building
for the Seattle Repertory Theatre. It
replaces a playhouse that was constructed for the 1962 World's Fair. Before the new theatre was built, many
support activities, including set construction, were scattered in shops
throughout the city. The new 10,000
square-foot scene shop is adjacent to
the stage and connected to it via an 18 '
by 24' doorway. Despite the noise generated by the shop machinery, including a 25-h.p. air compressor and a hydraulic pump, there is no noise leakage
onto the stage. The common walls are
built of 24" concrete block and the
doorway is sealed with a Jamisonic®
sound-reduction door 4" thick.
According to . Sue Alden, AlA,
project architect, the original design of
the new theatre called for two sound
reduction doors-one on each side of
a proposed corridor between the two
areas-as a means of reducing the anticipated sound level. For budgetary
rea ons, the corridor was eliminated
and a single door was speci fied to do
thejob.

a filling of sound absorbent, fire resistant materials between the front and
back metal panels.
Acoustical efficiency of the door is
measured in terms of its sound transmission class (STC). To arrive at a rating-this door is rated at STC 47-a
standard curve is used to describe transmission losses for various materials.
Thi curve is defined by ASTM procedure E413 for specimens tested in accordance with ASTM procedure E90.
A flush sill permits easy movement
of scenery and equipment through the
doorway. Providing a bottom sealing
surface under the door at the opening is
a 7', 9.8 lbs.-per-linear-ft. steel channel. This channel i anchored in the
concrete floor. An inflatable, pneumatic sealing system provides a tight
seal between the bottom of the door
and the sill.
eoprene gaskets at the top of the
door and the sides are compressed and

DOOR

ODOR PANEL

7C9·B
* STEEL

FLOOR CHANNEL
PNEUMA TIC SEAL
IN BonOM OF ODOR

Cross-section oj the pnel/maric seal
between the bOllom oj fhe door and the sill.

a seal achieved by a series of cam roller
mechanisms. As two tubular columns
at each side of the door are rotated, the
cam roller assemblies are driven against
the front face of the door to move it
toward the wall. In this manner, the
gaskets at the edges of the door are
compressed against the frame to create
a sound-tight seal.

It;-!

Sound Door Design
The sound reduction door installed
was engineered and fabricated by Jamison Door Co., Hagerstown, MD. It is a
9,000-lb., horizontal sliding, single leaf
door of all steel construction. Steel
sheeting for a door this massive is 14 gao
minimum. Sound reduction is achieved
by a steel noise dampening design, with
16

Th~:lIr~ 1)e,i~1l cl;; T~chnolo~~

"WHEN CAM ROTATES,
DOOR SEALS"

Cam roller sealing mechanism sql/ee::.es the sOl/nd door, lI'ifll dOl/ble roll' of holloll'
gasketing bonded to fhe sides and file head, againsf rhe mewl-clad casing.

SITT SlIIllIller 1986

Table of Contents for the Digital Edition of Theatre Design & Technology - Summer 1986