Item 7A Acoustical Reports MAS ffP
mO \/)L ACOUSTICS AUDIO-VIDEO ELV SYSTEMS NTERNATIONAL /
Consulting & Program Management
January 10, 2017
Mr. Truby McDougal
Corgan Associates, Inc.
401 North Houston Street
Dallas, TX 75202
Re: Ambulatory Surgery Center, Nolen Drive, Southlake—NLR Evaluation &Certification
Marsh/PMK Project# 16021-01
Dear Truby:
At your request, we have evaluated the Noise Level Reduction (NLR) provided by the building shell of the planned
Ambulatory Surgery Center in Southlake, TX. The project site on Nolen Drive in Southlake is within the Dallas/Fort
Worth International Airport Overlay Zone as defined by the Airport Compatible Land Use Zoning Ordinance 479.
Figures 1 and 2 verify that the project site is within the Ldr, 75 noise contour. This means that 35 dB of noise
reduction must be provided by the building shell.
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Project location within
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Figure 1—llrW International Airport Overlay'Map with L 75
Figure 2—Goo'gle Map with project site marked combined with
noise contours indicated in green and Lam,65 contours in purple. Airport Overlay Map shows location with Lam,75 noise contour.
Marsh / PMK International, LLC www.marshpmk.com
1130 E. Arapaho Road, Suite 580 Office: +1 .214.814.5940
Richardson, Texas 75081 USA Fax: +1 .877.521 .7071
Ambulatory Surgical Center, Southlake, TX—Acoustical Report
1/10/2017
Page 2
ACOUSTICAL DEFINITIONS OF TERMS USED IN THIS REPORT
Decibel (dB)
The decibel, abbreviated dB, is an indicator of relative loudness that ranges from the threshold of hearing, OdB, to
the threshold of pain, about 140dB. Human hearing perception is not linear, it is logarithmic, as is the decibel scale.
This is because the sound power of a 140 dB level at the top of human hearing range represents a change in sound
power of 100 trillion. The logarithmic decibel scale is the only way to reduce the level values to manageable
numbers. Following are some guidelines to understanding level changes in dB:
• 1 dB is a just noticeable change in the absence of any other noise.
• 3 dB is a barely noticeable change to the average person in a relatively quiet environment.
• 5 or 6 dB is plainly noticeable change. A 6 dB increase sounds about 1-1/2 times louder. -6 dB is 2/as loud.
• A 10 dB level increase sounds about twice as loud. -10 dB sound about half as loud.
Frequency in Hertz (Hz), Octave Bands and 1/3-Octave Bands
Sound waves are vibrations of the atmospheric pressure. A frequency is the number of vibration cycles per second
expressed in hertz (abbreviated Hz) after the German physicist Heinrich Hertz. One thousand Hz is 1 kHz. A
person with normal hearing can detect a range of 20 Hz to 20,000 Hertz. A note on a piano that is one octave
higher in pitch has a frequency that is twice that of the original note. So, note A4 vibrates at a frequency of 440 Hz
and A5 (one octave higher) vibrates at 880 Hz.
Noise measurement and analysis often uses one octave wide frequency bands, or octave bands. A range of 63 Hz
to 8 kHz is sufficient for most noise work. The industry standard octave band center frequencies of in this range
are 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz and 8 kHz. When possible, we prefer to use 1/3-octave
bands for measurements and analysis because of the additional amount of detail provided.
A-weighting (d BA)
Perceived loudness of a sound is frequency dependent. Human hearing is most sensitive to the midrange
frequencies from about 500 Hz to 4 kHz. Our hearing is far less sensitive at low frequencies and at very high
frequencies. When noise is measured and cited as an overall or broadband level, the frequency spectrum is
weighted in such a way that the low frequencies (especially) make less of a contribution to the overall result. There
are a number of weighting types. The one used in virtually all environmental standards is the "A"weighting. When
a broadband level has been A-weighted, it is most often indicated by adding an "A"to the dB unit (dBA).
Ld, and DNL
The average day-night level, Ld, (also called DNL), is a 24-hour average of the A-weighted noise that takes into
consideration the additional sensitivity to noise during nighttime hours by adding a 10 dB penalty to all noise
occurring between 10:00 PM and 7:00 AM.
STC and OITC
While the Sound Transmission Class (STC) design metric is widely used and understood, the more appropriate
metric for environmental noise is the Outdoor-Indoor Transmission Class (OITC). STC was initially developed as a
means of rating an assembly's ability to attenuate transmission of speech sounds from one room to another.
Therefore, the lowest frequency considered is 125 Hz. OITC was developed as a means of rating the ability of a
building fagade component to attenuate transportation-related noise down to 80 Hz. STC is a curve-fitting method
that does not yield a number that can simply be subtracted from the source side noise level to estimate the receiver
side level. OITC is a calculation method specifically designed to provide this feature. Subtracting an OITC rating
from the outdoor A-weighted noise level provides a close estimate of the indoor A-weighted level.
OBJECTIVES
Airport noise contours are developed based on predicted long-term (annual) average day-night levels. Because
the Ambulatory Surgery Center is within the Ld, 75 noise contour, Ordinance 471 requires that the building shell
reduce outdoor-to-indoor noise transmission by 35 dB. Our two objectives were to determine if the current design
meets this requirement and if not, to develop and recommend improvements to achieve 35 dB of NLR.
Marsh / PMK International, LLC www.marshpmk.com
1130 E. Arapaho Road, Suite 580 T Office: +1 .214.814.5940
Richardson, Texas 75081 USA r Fax: +1 .877.521 .7071
Ambulatory Surgical Center, Southlake, TX—Acoustical Report
1/10/2017
Page 3
ANALYSIS
Approach
We evaluated the building "from the inside out," considering the outdoor-to-indoor noise transmission paths from
the perspective of a person in each space with a unique mix of exterior fagade components including roof/ceiling,
walls, windows and doors. We determined the 1/3-octave sound transmission loss (TL) characteristics of each
component either from available laboratory test reports or by acoustical modeling (if test reports were not available).
For each space, we determined the total area of exterior building components and the percentage of that area
applicable to each component. We then combined the TL data to arrive at a "composite TL curve"for each space.
From the composite TL curve, we calculated the STC and OITC ratings.
Overall Results
Figures 3 and 4 compare the overall TL curves and ratings of each space, first as designed and then with some
improvements that we will describe going forward. The shape of each curve reveals strengths and weaknesses of
the NLR at specific 1/3-octave frequency bands. The key piece of information is the composite OITC rating of each
space,which is provided in the legend of each chart. Note that in Figure 3 (as designed),the range of OITC ratings
is from 28 to 30. This means that at least 5 to 7 dB of additional noise reduction is required. To account for possible
calculation inaccuracies (especially where we relied on acoustical modeling), we prefer to have a 3 dB minimum
margin of safety. Therefore, we'd like for all OITC ratings to be at least 38. Notice on the chart of Figure 4 (with
recommended NLR improvements) that the range of OITC ratings is 38 to 41.
Composite TL&Ratings:As Designed Composite TL&Ratings:With Improvements
85 85
80 8o
75 75 ---
70 70 - -
65 - 65 --- - -
60 60 -
55 55
m m
:a v
50 vi s0 ---- - ---
0 0
0 45 0 45
E 40 E 40
v 35 v 35
00 0
i 30 vi 30 ....
25 25
20 —Reception 109&Waiting 100(STC 38,OITC 28) 20 —Reception 109&Waiting 100(STC 47,OITC 38)
—Business Office 110(STC 41,OITC 30) —Business Office 110(STC 46,01TC 39)
15 —Office 111(STC 41,OITC 30) 15 —Office 111(STC48,0ITC40)
10 —Pre-Op 115(STC 39,DIX 28) 10 —Pre-Op 115(STC 48,OITC 39)
—Endo 120(STC 41,OITC 29) —Endo 120(STC 51,OITC 41)
5 —Dictation 133(STC 39,OITC 28) - 5 - - Dictation 133(STC 50,01TC 39)
0 0
ti ry ry m a n .y ry ry m a .n
1/3-Octave Center Frequency(Hz) 1/3-Octave Center Frequency(Hz)
Figure 3—Predicted composite'I'L curves by space along with Figure 4—Predicted composite TL curves and ratings based on
composite STC and OITC ratings based on the current design. the recommended NLR improvements.
Marsh / PMK International, LLC www.marshpmk.com
1130 E. Arapaho Road, Suite 580 Office: +1 .214.814.5940
Richardson, Texas 75081 USA r Fax: +1 .877.521 .7071
Ambulatory Surgical Center, Southlake, TX—Acoustical Report
1/10/2017
Page 4
Recommended Roof-Ceiling Improvements
Effect of Recommended Roof-Ceiling Improvements
The currently designed roof-ceiling assembly is the 85
most important weakness in the NLR capabilities of the
building shell. We recommend sandwiching the 80
polyisocyanurate roofing insulation between two 75 ;
Georgia-Pacific DensDeck roof boards. In our 0
acoustical model, we added a '/2" DensDeck board on
top of the polyisocyanu rate (under the TPO roofing 65
membrane) and a V DensDeck board under the 60
polyisocyanurate (on top of the metal roof deck).
Additionally, we added R-15 (3-1/2" thick) fiberglass m 55
insulation on top of the lay-in ceiling to providea 50
damping in the air cavity between the roof deck and s �%
the ceiling. These changes increased the roof-ceiling s 45
STC from 37 to 48 and the OITC from 26 to 38. The 40
change in roof-ceiling TL values are seen by the blue
curves in Figure 5 where the dashed line is "as = 35
designed" and the solid line is "with improvements." 30
The best example we have of how improving the roof 25
improves the building NLR is in Endo (120) because 20
this room has no exterior windows or doors. The
composite TL values and resulting composite ratings 15 `fir' ---Roof Model,As Designed(STC 37,OITC 26)
are entirely made up of one exterior wall in 10 ____ -Roof Model w/changes(STC48,°ITC 38)
combination with the roof-ceiling assembly. The red ---Endo12°,As Designed(STC41,OITC29)
curves in Figure 5 show the 1/3-octave composite TL 5 -Endo 120,Improved Roof-Celliog(STC51,°'TC'1`
improvements to Endo (120) with the composite STC °
rating going from 41 to 51 and the composite OITC
from 29 to 41. While this is more than is needed for 1/3-Octave Center Frequency(Hzi
this particular room, the degree of improvement in the Figure 5 —Results of recommended improvements to the roof-
roof-ceiling assembly is required in order to achieve ceiling assembly using Endo 120 as an example.
the needed NLR in rooms that have windows.
Windows
Even in Pre-Op (115) where there are many punched windows, the improved roof-ceiling assembly is enough to
achieve the required NLR. However, the Reception/Waiting (109/100) space has so much glass area that this
becomes the limiting factor. In the current design, the storefront and punched windows are 1" insulating glass
comprised of two 1/" glass panels separated by a '/2" air space. We looked at making one of the glass panels
laminated, but this fell short. Even laminating both panels with the typical polyvinyl butyral (PVB) interlayer material
fell short. However, using a newer and superior interlayer material called ESCL (enhanced sound control laminate)
from Northwestern Industries achieved the goal. Please note that we are recommending use of insulating double
laminated glass with ESCL not only for the storefront, but also for the four punched windows in the west side of the
Reception/Waiting area. Comparing the dark blue curves on Figures 3 and 4 shows that this improves the OITC
rating from 28 to 38, which fulfills our desire for a 3 dB margin of safety above the required NLR of 35 dB.
Exterior Door at Dictation (133)
Assuming a hollow metal exterior door in Dictation (133), the NLR falls well short of the 35 dB requirement. We've
determined that an STC 45 acoustical door is needed. We recommend Model 459573 Metal Door from Overly
Doors Company. Using this door will raise the composite OITC rating for Dictation (133) from 28 to 39. Product
literature for the recommended door can be downloaded at the following link: http://door.overly.com/product/459573
Marsh / PMK International, LLC www.marshpmk.com
1130 E. Arapaho Road, Suite 580 Office: +1 .214.814.5940
Richardson, Texas 75081 USA r Fax: +1 .877.521 .7071
Ambulatory Surgical Center, Southlake, TX—Acoustical Report
1/10/2017
Page 5
SUMMARY AND CONCLUSION
The Ambulatory Surgical Center in Southlake as designed does not meet the 35 dB NLR requirement of Airport
Compatible Land Use Zoning Ordinance 479. We have recommended the sandwiching the roofing insulation
between two roofing boards and adding R-15 insulation on top of the lay-in ceiling to improve the overall roof-ceiling
assembly. We have recommended upgrading the storefront glass and the glass in punched windows within the
Waiting/Reception area to insulating double laminated glass with a specific type of interlayer material. Finally, we
have recommended using an STC 45 acoustical door in the exterior wall of Dictation (133).
We hereby certify that the building shell evaluation for Noise Level Reduction (NLR)was carried out in accordance
with the standards of the acoustical design industry. Our calculations and results indicate that incorporation of the
recommended additional sound attenuating features described above, with proper attention to any penetrations of
the shell, should produce an overall NLR of at least 35 dB.
This concludes our report. Please feel free to call me on my mobile phone at 469-964-9584 if you have questions.
Sincerely,
Marsh/PMK International, LLC
t4'1 q, qn.),
David E. Marsh, FASA
Principal
cc: Cleve Doyen—Marsh/PMK
Marsh / PMK International, LLC www.marshpmk.com
1130 E. Arapaho Road, Suite 580 Office: +1 .214.814.5940
Richardson, Texas 75081 USA r Fax: +1 .877.521 .7071
MARSmkt ACOUSTICS AUDIO-VIDEO ELV SYSTEMS
�t 1 INTERNATIONAL .�
Consulting & Program Management
IF I
March 24, 2017
Mr. Danny Rodriguez
Corgan Associates, Inc.
401 North Houston Street
Dallas, TX 75202
Re: Ambulatory Surgery Center, Nolen Drive, Southlake—Lobby/Waiting Area Glass Re-evaluation
Marsh/PMK Project# 16021-01
Dear Danny:
In the Reception/Waiting area of the referenced project, Corgan expressed a preference to use standard PVB
interlayer within the insulating laminated glass make-up rather than the ESCL interlayer we recommended. We
have re-evaluated the glass sound attenuation requirements based on standard PVB interlayer and based on the
drawing mark-ups you provided. For the record, our calculations were limited to the Reception/Waiting area as we
believe this the Business Office should be treated separately. Our 1/17/17 report concluded that the recommended
roof improvement will provide adequate sound attenuation for the Business Office (i.e., the 1" insulating glass does
not need to be upgraded).
Your mark-ups clarified that a portion of the storefront is
essentially spandrel glass. You suggested that this could be
backed up by a "1-sided wall" above the ceiling. 0�
On the right is the top portion of a sketch you sent to illustrate
your idea of using a wall behind the spandrel portion of the
storefront. Your wall (in blue) abuts to an I-beam at the top.
Instead, we recommend a continuous layer of 5/8" Type X
gypsum board, a "single-sided wall" from the ceiling up to the W
deck, to completely seal off the spandrel glass section from BAIT IM]oo�
the ceiling plenum. This approach is represented by a double
red line that was added to your sketch. The entire perimeter
of the wall should be sealed to adjoining surfaces with a non-
hardening acoustical caulk. 3"thick insulation should be used
as you have shown. I��
Our analysis showed that the "spandrel wall" improved the 1
sound attenuation marginally, but the overall OITC rating (the
composite OITC) still fell short. Recall that we are looking for j
a composite OITC rating somewhat above 35, preferably at
least 37 or 38.
We found that a 1-3/4" insulating laminated glass provides the needed additional sound attenuation. The
recommended make-up generally consists of two 3/8" glass panels with a 1" airspace between them. The inside
panel is comprised of two 1/" panels laminated together with a 0.03" PVB interlayer. Our analysis yielded a
composite OITC 37 based on this glass make-up for the storefront (including the spandrel portion) and the four
punched windows in the Reception/Waiting area along with the recommended wall behind the spandrel glass.
i
Marsh / PMK International, LLC www.marshpmk.com
1130 E. Arapaho Road, Suite 580 Office: +1 .214.814.5940
Richardson, Texas 75081 USA Fax: +1 .877.521 .7071
Ambulatory Surgical Center, Southlake, TX—Acoustical Report
3/24/2017
Page 2
The chart below plots the calculated 1/3-octave transmission loss (TL) values for the current design and with the
recommended changes. These changes provide significantly improved TL values, especially in the speech
frequency range where the improvement is nominally 6 dB.
Composite TL&Ratings: Reception/Waiting Area
75
70
65
60
55
50
m
a
M 45
0
0 40
E
M 35
r�o
a 30
c
0
0
Ln
25
20
15
10
5
0
1/3-Octave Center Frequency (Hz)
—Current Design(STC42,0ITC35)
With InsLarnGlass&Spandrel Wall(STC47,0ITC37)
This concludes our report. We hope the information provided with keep the project moving forward. Feel free to
call me if you have any questions.
Sincerely,
Marsh/PMK International, LLC
4, qr).A
David E. Marsh, FASA
Principal
cc: Truby McDougal&Wesley Johnston—Corgan
Cleve Doyen—Marsh/PMK
I
Marsh / PMK International, LLC www.marshpmk.com
1130 E. Arapaho Road, Suite 580 Office: +1 .214.814.5940
Richardson, Texas 75081 USA Fax: +1 .877.521 .7071