Acoustical and Environmental Noise Impact Evaluation Stateside New Orleans, Louisiana

Transcription

1 Acoustical and Environmental Noise Impact Evaluation New Orleans, Louisiana For Richard Kelso II Pelican Operations, LLC By, LLC May 13, 2016 Project No.

2 356 CR 102 Oxford, MS May 13, 2016 Richard E. Kelso II Pelican Operations, LLC 200 Carondelet St. Apt New Orleans, LA Report: Acoustical and Environmental Noise Impact Evaluation New Orleans, Louisiana Richard Kelso: This report covers the acoustics/noise investigation made of the site and schematic drawings for the proposed project on 600 block of Mazant St in New Orleans, Louisiana. The work was performed in accordance with our Proposal dated May 3, Thank you for the opportunity of working with you on this project. Please call me if we can help you further. Very truly yours, David S. Woolworth Principal

3 EXECUTIVE SUMMARY Sound monitoring was performed on the property to determine the ambient background sound levels along Chartres, Royal, and in the middle of the site (property line) during the day and night. The sound levels recorded on site were used to determine the design criteria for the project. The design criteria is to produce sound levels below the existing background sound, as to minimize the impact on the local soundscape. This is considerably below the legal limit. The lowest sound level on site in the middle of the night with little to no activity is 46dBA Leq (equivalent sound level), and 48dBA LAS10 as compared to the residential legal limit of 55dBA LAS10. The acoustical design of the hostel has undergone multiple iterations, with an increasing massing and height to block courtyard sound from traveling toward the immediate property line of the neighbors on the same block. The more active and public side of the hostel is adjacent to Chartres St. and the train tracks/waterfront. The less active and private hostel side (quieter side) faces Royal St. The hostel designs have been computer modeled for noise propagation, and verified with hand calculations. The most recent design iteration meets our design criteria of 40dBA (LAeq) at the property line with a fully populated courtyard and bar with exaggerated sound levels. This is significantly below the 46dBA LAeq recorded during the quietest monitoring period. This sound level can be assumed roughly equivalent to 42-43dBA LAS10, which is below the lowest ambient 48dBA LAS10 measured on site. It should be noted that courtyard loudspeakers are considered as part of the design impact. The owner understands that such an arrangement requires appropriate controls on the loudspeaker system, and that methods of best practice will be employed (i.e. localized distributed loudspeakers, operational sound level limits and low frequency limits). It should also be noted that this is not scheduled as a live music venue, and was not evaluated as such. We have additionally provided: A preliminary analysis of sound that leaves the top of the building to answer questions posed by the neighborhood. See VERTICAL SOUND PROPAGATION below. A graphical representation of impact over a 3 day period. Figure 3 in the report shows the design criteria for sound footprint of the project. This has been met at the property line and facades of buildings for the exceptional case modeled. 1 of 14

4 Note that we have reviewed the report submitted to the city by Michael Bolan, Major problem: unwanted sound invading our homes late into the evenings ; we would like to provide the following comments for consideration: Mr. Bolan's report is a good effort to raise issues on sound related to the project and has aided in driving improvements in the design since its submission, as well as this environmental impact study. We believe the report has served a positive purpose in this process. Mr. Bolan's report is not an objective analysis of the proposed project, it is incomplete, and in places is inaccurate or out of context. Mr. Bolan is not a noise control or acoustical engineer, and his report should not be considered an expert's report. Mr. Bolan's expertise lies in electrical engineering. This environmental sound study addresses numerous concerns expressed in Mr. Bolan's report and we hope any other neighborhood concerns regarding soundscape impact of the proposed project. We encourage the neighborhood folks to educate themselves further by reading New Orleans sound ordinance and soundscape resources available through the City Council website: 2 of 14

5 PROJECT DESCRIPTION The proposed construction will consist of a 2 floor guestroom structure that includes a swimming pool/courtyard, basic services, and at least three enclosed food/drink areas on an existing empty lot, with a 3rd floor bar/lounge. Our investigation will evaluate the current schematic design in regard to layout, and evaluate potential environmental impact of the facility occupants, programming and supporting mechanical systems. PROJECT LOCATION The proposed project located as facing Mazant Street between Chartres and Royal Streets in New Orleans, Louisiana. The address is 4109 Chartres St. See Figure 1. PURPOSE AND SCOPE The purposes of this investigation are to explore the acoustical conditions at the project site, examine the proposed construction to determine the resulting environmental sound impact, and to provide engineering analysis leading to recommendations for design criteria and design and construction of appropriate acoustical treatments. As this investigation is preliminary, the conclusions and recommendations reached will be based on the available information; additional analysis and detailed recommendations will be required when development and construction plans are firmly established. Figure 1: Site Zoning map location. From Zoning Docket City Planning Commission Staff Report on Mazant St. 3 of 14

6 SOUND LEVEL MONITORING The property was monitored for three days ( to ) to determine the sound levels using 5 minute intervals and logging LAeq and LAmax (See Figure 2). Figure 2: Location of field monitors. Long term monitors were at locations 1 and 2. Short term comparative measures were taken at location 3 and directly across from location 3 at the middle of the block on Mazant. (Image from Google Earth). Inset shows sound level meter at location 3 at night. Summary of Findings (see Figures 3 to 5): The sound levels are higher on the Chartres side of the site compared to Royal, except for events (such as automobiles) on Royal St. This is due to the proximity to the river/waterfront activity and the higher level of vehicle traffic on Chartres. It can be seen that the levels of typical activity almost continuously exceeds the Sound Ordinance Sec for residential LASmax in both locations, and LAS10 on Chartres. The LAS10 on Royal falls below the legal limit except for periodic events. Sound samples taken in the middle of the site/property line between Chartres and Royal are found to be lower than at the roads: At 1:30-2:00am on Thursday with minimal activity: 48 db LA10 (legal limit 55dB) 46 db LAeq (used to evaluate our modeled source) These numbers correlate to a brief measurement made Monday, March 21 st around midnight. The predominant sounds include vehicles, people, insect, birds, trains, and river traffic/river sounds. 4 of 14

7 Figure 3: Field monitors at Chartres and Royal, LAeq (A-weighted equivalent sound level). Note that LAS10 legal limit is shown for comparison; for this case it is typical to add 2-3dB to the LAeq shown to estimate the LA10 at the same location. LA10 is the sound level exceeded 10% of the time. 5 of 14

8 Figure 4: Field monitors at Chartres and Royal, LAmax (A-weighted maximum sound level). Note that LASmax legal limit is shown for comparison. What can be seen here is that Chartres exceeds the limit almost continuously, and Royal St. fluctuates continuously due to activity and events (events are usually vehicles). 6 of 14

9 Figure 5: Field Monitor Middle of Lot Near Property Line, :40am - 2:06am. All samples are 1 minute intervals. Events are usually vehicles. Note parallel monitor samples at Chartres and Royal for reference, which clearly shows the middle of the lot is insulated from the thoroughfares. LAS10 at the property line for this period is 48dBA, and LAeq for this period is 46dBA. The site had occasional vehicles and some river activity. This sample correlates with a sample taken at midnight on a Monday March 21, No residential air conditioners or compressors were active during these measurements. 7 of 14

10 DESIGN DEVELOPMENT The design criteria of 40dBA (LAeq) at the property line is below the Sec Noise Ordinance sound level limit LAS10 55dBA for residential areas at nighttime (40dBA LAeq correlates to 42-43dBA LAS10 for this application, based on our field observations) Table 1: Excerpt of from Section 66 on Environment of the New Orleans City Code. The reason for setting the design criteria below the ambient sound levels is: To minimize the impact on the existing soundscape: Blending into the sound scape requires that new sounds are below the existing ambient levels, or they will be clearly perceivable as well as raise the sound level. To build in a factor of safety to the design by modeling an exaggerated sound source; this puts normal operation below our design criteria. The new design creates a taller and wider barrier on the side of the property line, and includes a set of walkways around the perimeter of the courtyard that reflect incident sound downward. The spread of reflected sound leaving the courtyard upward is reduced (See Figure 6) The model uses source level for continuous sound: 88dBA at 1 meter from source* to represent groupings of people communicating loudly. Multiple sound sources are distributed around the project. This is to estimate worst case, which is very high levels of activity. This level of activity is difficult to maintain, and we do not expect this to be the sound levels encountered at the premises; this sound level is used to build in a factor of safety to the estimated impact. *Note that ANSI S3.5 American National Standard Methods for Calculation of the Speech Intelligibility Index provides Average Male Peak Speech Spectra: the loudest shown is a shout which is 82dBA at 1 meter from source. 88dBA is the equivalent of 4 of these sources closely grouped. The sound spectra used in the models is from the VCE Sound Ordinance Investigation and Recommendations, April 10, 2014, Appendix A6, p17, data set CY2 88/90, %20Appendix.pdf 88dBA at 1 meter is similar to applause in an auditorium, or a lawnmower at 5' (Egan, Architectural Acoustics, 1988). The results of the modeling of the structure and surrounding area are shown in Figures 7 and 8 It is noted that the current model uses only hard surfaces with negligible sound absorption (concrete). The inclusion and addition of sound absorptive surfaces which are normal for the project will reduce the reflected sound energy inside the courtyards and further reduce the sonic footprint from activity at the hostel. 8 of 14

11 This project and the model does include consideration for ambient pre-recorded music, with distributed (small) local loudspeakers. The control afforded by such a system includes (a) sound level, (b) low frequency reduction. Our conceptual discussions at this time have met with the approval of the developer. Assumptions are based on existing designs in use. ** **This project and our model does not include live music, as that is not part of the hostel programming. It should be noted here that to expect to never hear any sounds would be unreasonable. With the presence of people comes activity, and with activity comes sound in the neighborhood. The analysis is focused on activity inside the courtyard, and is intended to show that we have observed best practice and the impact on the soundscape has been minimized. Figure 6: 1 st Order Reflection Study of Previous and Current Design. Top: earlier design, Middle and Lower: Current Design iteration, public and private area respectively. Green- 1 st reflections, Red- direct sound. The current design is a distinct improvement, creating a more robust barrier between the hostel and the immediate neighbors. 9 of 14

12 Figure 7: Sound level mapping of yards adjacent to property with all public areas active. Sound levels shown in dba. This model includes 18 sound sources distributed around the project, representing 72 people shouting. All of the building surfaces are modeled as concrete (sound reflective). Figure 8: Distribution of sound levels over areas mapped in Figure 7. A small percentage of area slightly exceeds 40dBA in our worst case model. 10 of 14

13 VERTICAL SOUND PROPAGATION Some members of the neighborhood association* expressed concern for sound that travels upward. They asked where will it go? First, sound that is directed upward will continue to travel upward, and will lose intensity over distance with spreading. On certain occasions, there is the potential for wind or temperature inversion to redirect sound downward. Such an effect can be experienced as you walk away from an outdoor concert, or during a sporting event near a neighborhood, when you can hear the event clearly at some distance. A local example is folks listening to Jazzfest on their back porch at some distance away. Atmospheric effects such as these can be ignored up to 300' (about a block in each direction), but may not manifest themselves for much greater distances. At 300', our worst modeled case (4 men shouting as a single source, 88dBA at 1 meter) drops 40dB to 48dB, which is the ambient LA10 in the quietest area we measured in the dead of night. The farther the sound travels from there, the lower level it will be. Remember that a single man shouting we are setting at 82dBA at 1 meter; this becomes 42dBA, below typical ambient sound. Several other factors minimize this concern: Change in db level = 20log(R2/R1) =20log(300'/3') =40dB where R2=distance 2, R1=distance 1 There is no direct sound or ground reflections to reinforce the refracted sound. Sound traveling along a trajectory closer to the ground that is likely to be focused closer to the source has already been reflected off of a surface, reducing its energy. It also traveled an additional distance to reach the wall. The sound from the courtyard will generally be a set of incoherent, diffuse reflections, so there will not be distracting information (intelligible conversation); the sound will blend with the ambient background noise. Based on our knowledge of the planned programming, our model is of an extreme situation that is not likely, which builds in a factor of safety. Also keep in mind that shouting is difficult to maintain over time. Our worst case for ambient sound is the middle of the night. If a person is indoors, their home will provide a further level of isolation. (See New Orleans Sound Ordinance and Soundscape Investigation and Recommendations, Appendix E p92-97, %20Appendicies%20OA% pdf) There may be a desire to compare this to outdoor music venues or any venue without noise abatement, but this is not an appropriate comparison. Keep in mind that the sound levels and focusing of sound is of a much greater level/degree at the outdoor concerts and sporting events, and this is not the programming for the hostel. *Neighbors First of Bywater 11 of 14

14 RECOMMENDED SERVICES It is recommended that we be retained to review a final design and specifications in order that acoustic and vibration recommendations may be properly interpreted and implemented in the design and specifications. If we are not given the opportunity to make this recommended review, we can assume no responsibility for misinterpretation of our recommendations. LIMITATIONS This report has been prepared in accordance with generally accepted acoustic engineering practices for the exclusive use of Pelican Operations for specific application to the project. No other warranty, express or limited, is made. 12 of 14

15 EXPERT QUALIFICATIONS 13 of 14

16 David S Woolworth Principal dwoolworth@rwaconsultants.net David Woolworth has been performing consulting, education, and research in acoustics and noise control since He is an instructor for continuing education for professional architects in the field of acoustics and noise control in the Southeast, and is active in the ASA-TCAA and TCN on classroom acoustics standards and acoustics research. Annually he is a guest lecturer and mentor at Mississippi State University and Louisiana State University School of Architecture for the topics of architectural acoustics and noise control, and annually at the University of Mississippi in audiology and is an advisor for physics graduate students' independent study topics in architectural acoustics. Mr. Woolworth has been working in design and research of performance halls and musical instruments for over 25 years, and has been performing on the double bass for over 35 years in many genres, including playing 10 years professionally. His approach to design and analysis of music halls utilizes a combination of experience as a scientist and musician, and he specializes in historical architecture renovation, restoration, and re-purposing. Mr. Woolworth has worked as principal in the design or restoration of over 60 music halls and historical buildings. Mr. Woolworth has also served as a professor of physics at the University of Mississippi and conducted government research at the National Center for Physical Acoustics from 1994 to 2006 in the following areas: High Intensity Focused Ultrasound transducer development and testing for medical applications, Schlieren imaging and Particle Image Velocimetry for sound fields, Resonant Ultrasound Spectroscopy, sound isolation and transmission for naval vessels, and non-linear resonant cavities. His current research involves low frequency noise in communities, soundscape methods, and education in acoustics. He has produced over 35 publications, seminars, and presentations to technical societies. Education: University of Mississippi, M.A. Physics, 2000 Specialization in acoustics Rensselear Polytechnic Institute, BSME 1991 Specialization in architectural and musical acoustics and vibrations University of Hartford/Hartt School of Music, 1988 Acoustic Engineering and Classical Music Performance Affiliations: National Council of Acoustical Consultants Acoustical Society of America (ASA) ASA Technical Committee on Architectural Acoustics ASA Technical Committee on Noise Public Policy for Wind Turbines Acoustical Society of America Mid-South Chapter Institute of Noise Control Engineering Community Noise Working Group WG41 (ANSI S12.9) Outdoor Sound Measurement Working Group WG27 (ANSI S12.18) Robert Newman Foundation Co-chair of annual Student Design Competition New Orleans Musicians' Assistance Foundation National Advisory Board for NOMAF Safe Sounds Roland, Woolworth & Associates 356 CR 102 Oxford, MS of 14