JACT
JACT, Inc.
University Park, PA
Project 2: STC & NC Design
IM Building Addition Phase One
University Park, PA
Andrew Aumiller / Kevin Clement / Sebastian Jongerius / Goli Razaghi / Luke Thompson
Group #5
JACT
Index
1.0 Introduction ….……………………………………………………………………………………….......
2-3
2.0 Room Acoustics Background .……………………………………………………………………….
3-4
3.0 Background Noise Level Recommendations ..……………………………………………….
4-5
4.0 STC Analysis & Recommendations .……………………………………………………….……..
7-14
4.1 STC of Original Partitions ..……………………………………………………….…………
7
4.2 Analysis of Original Partitions ..…………………………………………….…………….
8-10
4.3 Analysis of Moveable Partition …………………………………………….…………….
11-14
5.0 Summary ….……………………………………………………………………………….…………………
15
5.1 Report Highlights .………………………………………………………….…………………..
15
5.2 Recommendations ……………………………………………………………………………..
15
6.0 Appendix ……………………………………………………………………………………………………..
16
7.0 References……………………………………………………………………………………………………
17
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1. INTRODUCTION
Located on the corner of University Drive and Bigler Road across from Beaver Stadium lies the
Intramural Building, a facility used for recreational and educational purposes by faculty and staff at Penn
State. This is outlined in the buildings mission statement which explains, “We strive to satisfy all Penn State
students, faculty and staff with the friendliest service and the most diverse selection of sports activities, all in
one location [5].” The IM Building is home to a number of different types of spaces which require certain
acoustical characteristics specific to each task being done in each space.
When conducting an acoustical analysis of the spaces within the Intramural Building Addition in terms
of sound isolation and background noise, it is important to identify which spaces are likely to generate a lot of
noise and which spaces require low background noise levels requiring high amounts of isolation. For example,
the mechanical rooms (M004 and M202) are likely to generate a lot of noise due to the acoustical nature of
HVAC equipment and increased structure-borne noise from massive vibrating machines within these
rooms. Other rooms that are likely to generate a lot of noise include the fitness areas (103 and 203) as well as
the multipurpose rooms (007, 124, 125) due to the amount of people that occupy these spaces at one time as
well as the structure-borne noise generated from workout equipment hitting the floor. Multipurpose room
007 will be especially noisy since it will be used for group fitness classes that use amplified music causing a
prevalent amount of airborne noise. Rooms that require low background noise levels include classroom 008 in
the basement, all the offices on the first floor (101A-101K and fitness office 103A), the conference room 101L
and both workrooms (101M and 203A). Special attention should be placed on office 101J as well as workroom
101M. The zone approach was used to pick Office 101J to be used as an academic advisor’s office for athletes
due to the amount of privacy an academic advisor needs. This space was picked because it is next to a quiet
director’s room as well as very far away from the noisy multipurpose rooms. The workroom 101M, which will
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be used for physical therapy and first aid, should have high STC rated partitions due to the importance of clear
communication between an athlete and a physical therapist.
2. ROOM ACOUSTICS BACKGROUND
Before an acoustical analysis can be completed a foundation in how room acoustics work is needed. In
Project one the acoustical analysis was focused on how sound produced in a room affected that room. To do
that the absorptive properties of the room surfaces were studied to obtain and alter the reverberation times
associated with rooms in the Intramural Building. In this project our acoustical analysis focus has shifted to
how adjacent rooms affect each other’s background noise levels, Noise Control (NC) ratings, Sound
Transmission Class (STC) ratings, and the Transmission Loss (TL) of the partition separating the rooms.
Background noise levels refer to the sound pressure levels in a room at the different octave bands. It is
difficult to look at all of the background noise levels for every octave bands so a single number system was
developed called NC rating. To find the NC rating of a room its background noise levels must be plotted on the
NC curve graph. The nearest NC curve that is completely above all of the background noise levels is that NC
the room is rated. There are many standard target NC values for different types of rooms found in the notes
that were used for the acoustical analysis.
Transmission Loss and Sound Transmission Class have a similar relationship as that of background noise
level and NC. The key difference is that TL and STC deal with the partitions between different rooms. TL is the
amount of sound that can pass through a partition and is measured at different frequencies. This presented
the same problem we had with background noise levels the fact that no one wants to look through the values
for every octave band. This lead to the creation of the STC curves. The TL values are plotted onto the STC
diagram and then analyzed to determine which STC value the partition falls in. There are two criteria that the
partition has to meet to be classified for that STC curve. No TL value can be more than eight dB above the STC
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curve and the sum of all deficiencies cannot be greater than 32 dB. A deficiency is the amount that any TL
value is above the STC curve. To find STC values a spreadsheet using logic statements is used to make sure
that both criteria are met. So rooms that have similar NC values will need lower STC walls because nether
room will be bothered by the noise levels in the adjacent room. While adjacent rooms with drastically
different NC values will need a higher STC partition to prevent the louder room from affecting the quite room.
These factors are what were taken into account when the acoustical analysis was performed for this project.
3. BACKGROUND NOISE LEVEL RECOMMENDATIONS
The recommendation for the background noise level of each room in the IM Building addition were
found using Table 1, corresponding rooms to their appropriate tasks while taking into account the surrounding
rooms for additional assumptions. The noise criteria found for the desired rooms of the IM Building addition
are shown in table 2. The multi-purpose rooms on both the basement and the first floor were given a NC value
of 25 considering their various uses, mainly that of group fitness classes using amplified music and as a
classroom on occasion which can vary in loudness. The work room was given the role of physical therapy and
was attributed a NC value of 30. The office located next to the director’s office was chosen to be the advisors
room with an NC value of 30, this location was chosen because the director’s office having to be relatively
quiet. All of the other offices including the break room and the office lobby were given an NC value of 35 as
they do not require being as quiet and isolating as the directors or advisors office. Each of the rooms were
designed to meet the maximum specified noise criteria design target value.
Table 1: Recommended Noise Criteria (NC) Design Targets for various spaces:
Recommended NC (or RC) for rooms
Types of Room or Space
Recording or broadcast studios, concert halls, large auditoriums, large churches
Small auditoriums, movie theatres, music practice rooms, large meeting &
teleconferencing rooms, small churches, courtrooms, chapels
Bedrooms, hospitals, residences, hotels, classrooms (classrooms must be ≤ 35 dBA)
Private or semiprivate offices, libraries, small conference rooms
NC
15-20
20-30
25-30
30-35
4
Large offices, reception areas, retail stores, restaurants, gymnasiums
Lobbies, laboratories, drafting rooms, secretarial areas, maintenance shops
Kitchens, laundries, school & industrial shops, computer equipment rooms
JACT
35-40
40-50
45-55
Table 2: Summary of Noise Criteria targets for desired room:
Room #'s
7
8
101
101A
101B
101C
101D
101E
101F
101G
101H
101J
101K
101M
101L
103
124
125
Room
Multi-purpose
Classroom
Office Lobby
Office
Office
Break Room
Office
Office
Office
Office
Office
Advisors
Director’s Office
Physical therapy
Conference
Fitness
Multi-purpose
Multi-purpose
NC Target
25
30
35
35
35
35
35
35
35
35
35
30
30
30
30
25
25
25
The location of the rooms and their corresponding noise criteria values are show in color-coded layouts
of the basement and first floor. The color-coded layout for the first floor is shown in Figure 1. Both multipurpose rooms are coded in blue for an NC of 25, these two rooms as separated by a movable partition. The
fitness room also had an NC of 25, but this room is isolated on the right wing of the building. All the offices
were grouped together around the office lobby and next to the break room, each with an NC value of 35. The
conference room, physical therapy room, advisors office, and director’s office are also grouped together next
to the offices spaces, each with an NC value of 30. The color-coded layout for the basement is shown in Figure
2. The multi-purpose room, of NC value 25 is located adjacent to the classroom, of NC value 30 on lower left
corner of the plan.
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Figure 1: Color-coded layout of Noise Criteria targets for the First Floor
Figure 2: Color-coded layout of Noise Criteria targets for the Basement
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4. STC ANALYSIS & RECOMMENDATIONS
4.1 STC of Original Partitions
The partitions for each of the rooms analyzed are important in determining whether the proper noise
control value is suitable in each room. In order to find the type of partitions used, it was determined by using
the schedule in the IM Building addition construction drawings. From the description in the drawings, it was
then compared to partition types in the NRC-CNRC for the transmission loss data in gypsum board walls. The
actual walls in the IM Building were not exactly the same in the NRC-CNRC document because of the
conversion from imperial units to the metric system. Jact, Inc. found the most similar type of wall to obtain the
transmission loss data.
The data provided by the document was then double-checked in a spreadsheet to make sure the
correct sound transmission class (STC) was provided to properly adjust the design. Every partition STC class
was the same except for partition D which was one value smaller. The STC value obtained through the
spreadsheet was used throughout the rest of the proposal rather than the STC value from the NRC-CNRC.
There were three different STC values found for the wall partitions. The lowest was a value of forty
between the offices and the office lobby. This wall partition was also used between the corridor and the multipurpose room along with the classroom. A larger STC value for forty-seven was used to divide office spaces,
which was an acceptable in most cases. The last type of partition was used to divide the classroom and the
multi-purpose room in the basement. It has a value of fifty-one.
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4.2 Analysis of Original Partitions
JACT
When recommending the STC value for partitions between spaces it was very essential to understand
what each space was going to be used for. A general office was important to have fairly quiet so the faculty
members would be able to work efficiently without being distracted. However, the conversations held in these
offices most likely not being very important that no sound can leave the room. Therefore, it was decided the
STC target should be a value of about fifty between two offices. The office lobby was a place for mostly faculty
to walk to their individual offices and sometimes have visitors wait outside for a particular meeting. For this
reason the STC target value between a general office and the office lobby was determined to be slightly lower
at 45. The advisors and directors offices were decided to need higher STC values based upon their important
and private conversations that the faculty would not want others to hear outside of the room. The conference
and physical therapy room were also found to need higher STC values because of the potential private
conversation, but also partially loud conversations, especially in the conference room. The classroom was
another room that required high STC values on its partitions so the professor and students would not be
distracted by sounds outside of the room. The multi-purpose partitions main goal was to isolate the sound
from important rooms that did not want any loud noise. A complete list of the STC target values developed by
JACT, Inc., original partition information, and new recommendations can be found in Table 3. Further details of
the original partitions can be found in Table 4.
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Table 3: Summary of the Original Partitions with STC Targets and new Recommendations
Room #'s
007 & Q002
007 & 008
008 & Q002
101A & 101
101A & 101B
101B & 101
101C & 101
101C & 101D
101D & 101
101D & 101E
101E & 101
101E & 101F
101F & 101
101F & 101G
101G & 101
101G & 101H
101H & 101
101H & 101J
101J & 101
101J & 101K
101K & 101
101L & 101
101L & 101M
101M & 101
124 & 125
103 & Q101
Room 1
Room 2
STC Target
Multi-purpose
Corridor
Multi-purpose
Classroom
Classroom
Corridor
Office
Office Lobby
Office
Office
Office
Office Lobby
Breakroom
Office Lobby
Breakroom
Office
Office
Office Lobby
Office
Office
Office
Office Lobby
Office
Office
Office
Office Lobby
Office
Office
Office
Office Lobby
Office
Office
Office
Office Lobby
Office
Advisors
Advisors
Office Lobby
Advisors
Directors
Directors
Office Lobby
Office
Office Lobby
Conference
Physical Therapy
Physical Therapy
Office Lobby
Multi-purpose
Multi-purpose
Fitness
Main Level Hall
50
60
60
45
50
45
40
60
45
50
45
50
45
50
45
50
45
55
50
60
55
45
60
50
41
40
Original Partition
Type
STC
B
40
D
51
B
40
B
40
A
47
B
40
B
40
A
47
B
40
A
47
B
40
A
47
B
40
A
47
B
40
A
47
B
40
A
47
B
40
C
47
B
40
B
40
B
40
B
40
E
32.8
B
40
Suitable
No
No
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
Yes
No
No
No
Yes
Recommended
Partition (STC)
II
I
I
I
II
II
I
I
I
II
Refer to Note (1)
-
Note (1): due to the small opening in the wall connecting the two rooms,
we are unable to increase the STC value and make the wall and partition
more absorptive.
Table 4: Description of Original Partitions in the IM Building Addition
Code from
Drawings
NRC TL #
(Page)
A
3T
TL-92-413
(Page 50)
B
3D
TL-93-365
(Page 44)
C
3C
TL-92-413
(Page 50)
D
4D
Tl-93-299
(Page 27)
Partition
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
Decription
single layer of 13 mm type gypsum board
90 mm steel studs at 610 mm on centre
90 mm of glass fibre insulation in cavity
single layer of 13 mm type gypsum board
single layer of 13 mm type gypsum board
90 mm steel studs at 406 mm on centre
90 mm of glass fibre insulation in cavity
single layer of 13 mm type gypsum board
single layer of 13 mm type gypsum board
90 mm steel studs at 610 mm on centre
90 mm of glass fibre insulation in cavity
single layer of 13 mm type gypsum board
single layer of 13 mm type X gypsum board
150 mm steel studs at 610 mm on centre
150 mm of glass fibre insulation in cavity
single layer of 13 mm type X gypsum board
NRC
STC
Spreadsheet
STC
47
47
40
40
47
47
52
51
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The recommendations provided in this report were needed because the original partition STC values
were found to be not adequate. The spaces that lacked proper STC rated walls were rooms that generate
particularly loud noise and ones that needed to be quiet inside to allow for important and private
conversations. The most notable recommendation change was dealing with the physical therapy room and
conference room. The new partitions being recommended were found using the Architectural Acoustics
Principles and Design [2]. After the recommendations are put into place it will greatly improve the spaces in
the IM Building Addition to not only isolate sound from other spaces, but also to allow the private
conversations held by faculty and students to be kept private when necessary. Table 5, provides detailed
descriptions on the recommended wall partitions.
Table 5: Summary of the Descriptions of the Recommended Partitions
Partition
I
II
Reference
Architectural Acoustics
Principles and Design
(Appendix J - Page 414)
Architectural Acoustics
Principles and Design
(Appendix J - Page 414)
Description
Reported STC Spreadsheet STC
5/8" gypsum (3+3 layers) on 3-5/8"
metal studs 24" o.c., 3" fiberglass
61
61
5/8" gypsum (2+1 layers) on 3 5/8"
studs 24" o.c., and 2" fiberglass
51
51
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4.3 Analysis of Moveable Partition
Table I: Summary of Transmission Loss data and STC Contour
Levels for the Dorma Moveo alternate movable partition
STC
50
1/3
OctaveAdjustment Contour
Band
for Contour
Level
Frequency Level (dB)
(dB)
(Hz)
125
-16
34
160
-13
37
200
-10
40
250
-7
43
315
-4
46
400
-1
49
500
0
50
630
1
51
800
2
52
1000
3
53
1250
4
54
1600
4
54
2000
4
54
2500
4
54
3150
4
54
4000
4
54
TL
(dB)
33
33
36
40
42
46
48
52
52
52
53
53
52
53
53
54
Total
Max
Deficiency
Deficiency
(dB)
≤ X dB?
1
4
4
3
4
3
2
0
0
1
1
1
2
1
1
0
28
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Pass
60
Transmission Loss (dB)
50
40
30
TL values
STC contour
20
10
0
125
1250
1/3 Octave Bands (Hz)
Figure 1: The transmission loss values from 125 to 4,000 Hz ⅓ octave
bands and information required to solve the STC value of Dorma
Moveo alternative moveable partition
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Table II: Summary of Transmission Loss data and STC Contour Levels for the
Panelfold Moduflex® Model 640 Gypsum Face Panel alternate movable partition
STC
JACT
52
1/3
OctaveAdjustment Contour
Band
for Contour
Level
Frequency Level (dB)
(dB)
(Hz)
125
160
200
250
315
400
500
630
800
1000
1250
1600
2000
2500
3150
4000
-16
-13
-10
-7
-4
-1
0
1
2
3
4
4
4
4
4
4
TL (dB)
36
39
42
45
48
51
52
53
54
55
56
56
56
56
56
56
36
35
39
42
44
46
47
52
54
56
56
58
60
61
61
63
Total
Max
Deficiency
Deficiency
(dB)
≤ X dB?
0
4
3
3
4
5
5
1
0
0
0
0
0
0
0
0
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
25 Pass
70
Transmission Loss (dB)
60
50
40
TL values
30
STC contour
20
10
0
125
1250
1/3 Octave Bands (Hz)
Figure 2: The transmission loss values from 125 to 4,000 Hz ⅓ octave bands and
information required to solve the STC value of Panelfold Moduflex® Model 640
Gypsum Face Panel alternative moveable partition
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Before beginning the analysis of the alternative moveable partitions, first an STC rating of the current
moveable partition was found as a baseline comparison for the alternative partitions. Online research found
that the Modernfold Acousti-Seal Model 933E partition that is installed in the multipurpose room has an STC
rating of 41 dB [4].
The two alternative movable partitions analyzed came from Panelfold Incorporated and Dorma. The
Dorma partition is the Moveo model which helps add flexibility and convenience within a space. It’s sealed
composite lightweight construction with acoustic core helps increase transmission loss and isolates sound
within the room the sound is meant for. The Dorma Moveo is designed for spaces which include conference
rooms, exhibition and studio spaces, and gymnasiums. This movable partition offers multifunctional and
open-plan spatial configurations and has an STC rating of 50 [1]
The second partition analyzed was the Panelfod Moduflex Model 640. This movable partition is made
of Gypsum face panels and is ideal for high, expansive areas where remote operation is required. This
partition is made specifically for gymnasium and folds in accordion style just like the partition currently
installed in the multipurpose room. The STC rating of this partition is 52, which is greater than both the
Dorma Moveo model and the current Modernfold model [3].
A TL analysis of the composite wall was done to find what STC rating the entire wall was, which consists
of the permanent wall above the moveable partition, the moveable partition itself, as well as an opening at
the top, end section of the permanent wall. The first step to find the composite wall TL value was to find the
transmission coefficient of each material in the wall. Working backward from the Transmission Loss (TL)
equation an equation for transmission coefficient can be found as
TL = 10log⁡(1⁄τ)
(1)
−TL
τ = 10 10
(2)
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Where TL is the rated STC of the partition (dB) and τ is the transmission coefficient. The permanent
wall has a rated STC of 40dB and the moveable partition, as stated previously, was found to have a rated STC
of 41dB. The rated STC of an opening is known to be zero because there is no material to stop the sound.
The next equation needed is the equation for the TL of a composite wall. This equation is dependent
on the areas and transmission coefficients of each material. The area of each section of the composite wall
includes 450 ft2 for the moveable partition, 369.5 ft2 for the permanent wall, and 0.5 ft2 for the opening in
the wall. This comes to a total of 820 ft2.
The equation used to find TL of the composite wall is
∑n
S
TLcomp = 10log [⁡∑ni=1τ Si ]⁡⁡⁡⁡⁡⁡⁡⁡(3)
i=1 i i
Where TLcomp is the TL of the composite wall, Si is the surface area of each individual section, and τi is
the individual transmission coefficient of each section.
The TL of the composite wall, TLcomp, is calculated as
820
TLcomp = 10log [(10−4.1 ⁡x⁡450)+(10−4 ⁡x⁡369.5)+(100 ⁡x⁡0.5)] = 32⁡dB
(4)
This shows the rated STC for the current composite wall is 32 dB. Replacing the current movable
partition with a Panelfold Moduflex Model 640 STC 52 Gypsum Face Panel system which has a much higher
STC than the original partition only increases the STC of the composite wall by 0.2dB. This change is negligible
so we elected to keep the original partition type therefore not adding costs from uninstalling and reinstalling a
new moveable partition. The reason it is impossible to make a big impact on the composite walls STC is that
the opening in the wall makes such a huge impact in the walls STC value.
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5.0 SUMMARY
5.1 Report Highlights
The IM Building Addition has many spaces with multiple uses. This varies from offices, multi-purpose
rooms, to classrooms that all require and make different noise levels. In this report JACT, Inc. analyzed some
of the existing rooms within the new addition. It was found that the offices and classrooms needed to have
relatively low noise criteria because of the tasks in these rooms. STC ratings for all of the partitions between
the rooms analyzed were found. Some of the partitions were found to be acceptable to the STC targets
determined. While other partitions were not suitable for the intended purposes, therefor recommended
partitions had to be provided.
5.2 Recommendations
Based on the calculations done on the different partitions in the building, not all of the partitions meet
the criteria and are 5-10% of the targeted STC. The original partitions used in the building have a lower sound
isolating system and make it possible for sound to travel to other rooms easier, creating more background
noise in the adjacent rooms. Therefore, two partitions were recommended as a replacement for the partitions
that did not meet the criteria. The difference between the original partitions and the recommended partitions
is about a 10 dB increase in STC value. This increase is made by adding to the number of layers of gypsum
board and increasing the thickness of the fiberglass used in the partition to increase the sound isolation.
The recommendation for the moveable partition was to keep the existing partition even though it has a
low STC. This is because the composite wall it is part of has an opening to the other multipurpose room. This
opening is so influential in the composite wall transmission loss calculation that the changing of the moveable
partition to a higher STC is negligible. The recommendations provided in the advisors office and other
confidential areas required a partition with a high STC, while having a low a transmission loss. This allows for
the privacy of conversations and other activities to be mostly kept within the room.
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6.0 APPENDIX
Partition A Spreadsheet
STC
47
1/3 Octave-Band
Frequency (Hz)
Adjustment for
Contour level (dB)
Partition A
Contour Level
(dB)
TL (dB)
Deficiency
(dB)
125
160
200
250
315
400
500
630
800
1000
1250
1600
2000
2500
3150
4000
3
3
3
3
3
1
0
1
1
1
1
0
0
0
0
0
31
34
37
40
43
46
47
48
49
50
51
51
51
51
51
51
25.3
29.3
31
35
40.2
45.2
50.6
55.1
58.5
60.9
63.7
65.5
65.2
54.2
47.7
48.7
5.7
4.7
6
5
2.8
0.8
0
0
0
0
0
0
0
0
3.3
2.3
Max Deficiency
≤ 8 dB?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Total
Pass
Pass
Wall is STC:
47
80
70
60
Transmission Loss, TL (dB)
50
40
STC 47
30
20
10
0
125
500
2000
One-Third Octave Band Frequency (Hz)
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7.0 REFERENCES
1) "DORMA MOVEO." MOVEO – operable sound-insulating partitions. N.p., n.d. Web. 14 Apr. 2014.
<http://www.dorma.com/ae/en/products/dividing/operable_partitions/moveo_en/index-3723-389913425.html>.
2) Mehta, Madan, James Johnson, and Jorge Rocafort. Architectural Acoustics: Principles and Design.
Upper Saddle River, pp 27, 44, and 50 NJ: Prentice Hall, 1999. Print.
3) "Moduflex® Model 640." Panelfold®. N.p., n.d. Web. 14 Apr. 2014.
<http://www.panelfold.com/productsub.asp?categoryID=3&productID=24>.
4) "Operable Partitions: ACOUSTI-SEAL® CONTINUOUSLY HINGED ELECTRIC WALL." Modernfold Operable
Partitions. N.p., n.d. Web. 14 Apr. 2014.
<http://www.modernfold.com/operable_partitions_con_hinged.aspx>.
5) "The Official Site of the IM Building." Recreation Facilities. Athletics Penn State University. Web. 14
Apr. 2014. <http://www.athletics.psu.edu/rec/imbldg/>.
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