Standard S12 Research Articles

Evaluation of ANSI low frequency measurement standard S12.9 part 7 in light of current research

ANSI S12.9 Part 7 (2016) Measurement of Low-frequency Noise and Infrasound Outdoors in the Presence of Wind and Indoors in Occupied Spaces was developed over 2-3 years and was a much needed guide to standardize the measurement of low frequency sound and infrasound. Since then, research has advanced what are now considered best practices, and technology has advanced to make instrumentation available to consultants and researchers to help solve several limiting issues in measurements. This paper provides a review of the standard and recommends improvements to the techniques used in the measurement of low frequency-infrasound outdoors. These improvements include better assessment and understanding of wind noise, the importance of sensor placement, and advances in transducers, wind screening, arrays and calibration. The information provided includes best practice with a conceptual understanding of the interaction with the environment in low frequency-infrasound measurement; references are provided for a deeper dive into each topic.

Classroom mock-up meeting Standard S12.60

The Acoustical Society of America (ASA) developed a standard entitled Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools (ASA/ANSI S12.60-2010) that provides a minimum set of requirements to help school planners and designers “provide good acoustical characteristics for classrooms and other learning spaces in which speech communication is an important part of the learning process.” In this revision, several details were revised for incorporation into building codes. Despite the obvious benefits of quieter classrooms, incorporating the standard into building codes met with resistance. A common perception was that in order to meet the standard’s requirements, specialized HVAC equipment and installation methods would be necessary, resulting in an installed cost beyond what most schools could afford. Acoustical prediction tools indicated that the requirements could be met using standard HVAC equipment and installation methods. To verify the predictions, a simulated classroom was built and several common types of equipment including a single-zone air handling unit, a high-efficiency water-source heat pump, and a packaged rooftop unit were tested. The selected products were standard catalog offerings, without any special attenuation features, that were operated at typical airflow and static pressures. This paper describes those tests, the conclusion, and the resulting recommendations.

Assessing impact of near-ground meteorology on spectral variability in static jet aircraft noise measurements

ANSI/ASA standard S12.75 (2012) provides guidance on allowable meteorological conditions for acoustical measurements of installed high-performance jet engines. This paper investigates meteorological effects on acoustic data acquisition by analyzing recent measurements of a T-7A-installed GE F404 engine. During this measurement, the aircraft was run up six times at engine powers from idle to full afterburner, with test conditions following those prescribed by S12.75. However, far-field spectra show variability between runs, despite relatively uniform test conditions. Measurements of the vertical temperature gradient show a correlation between the gradient and spectral characteristics. This analysis suggests that local temperature profiles must be considered more carefully in future full-scale measurements. [Work supported by ONR Grant No. N00014-21-1-2069.]

Declaration and verification of product noise emission levels and the new ANSI/ASA S12.61 standard

The primary goal of any product noise declaration (or “labeling”) initiative is to enable consumers and other purchasers to make informed buying decisions. It doesn't matter if the product is relatively low-noise and the concern is one of annoyance or if the product is very loud and the concern is one of noise hazard. The purchaser still needs to know the noise level in order to make a prudent choice. This should be easy, right? We bring the product into a test lab and measure its sound power level. Then we report that number, correct? Yes, that would be true for testing and reporting a single unit. The problem comes when we are attempting to declare (label) an entire production series ( “batch”). The 100 000 Model XYZ leaf blowers will each have slightly different levels. Suddenly we are talking about population parameters, sampling, and (because we also have to verify that the declared value is correct) statistical inference and probability of acceptance. It soon gets complicated. This paper will go over some of the basic concepts needed to understand product noise declarations and verifications and will describe the newly published ANSI/ASA standard S12.61 that sets forth the requirements for making these.

The evolution of standard S12.60 acoustical performance criteria, design requirements, and guidelines for schools

The committee on standards for the Acoustical Society of America was asked by the US Access board and others to develop standards for acceptable acoustics in classrooms. The effort resulted in a standard comprised of several parts. The first document was approved in 2002 and this later became part 1. The initial desire was to have a federal rulemaking and incorporate the standard into coverage for the Americans with Disabilities Act. Part 2 was approved in 2009 and provided guidance for relocatable learning spaces. The intent to have a federal rulemaking was thwarted by political factors so Part 1 was revised in 2010 with the intent to put the document into a format that would allow its incorporation or use in building codes. Part 3 is still being developed, but it is intended for Information Technology Equipment in Classrooms. Part 4 was approved in 2019 and gives guidance for education spaces such as gymnasia and other spaces used for physical education.

Developing standard exposure-response relationships to inform protected area management

The Schultz Curve, which was embodied in ANSI Standard S12.9 Part 4, has been a central informative tool for urban planning and noise impact analyses. Numerous field studies have been conducted by the Volpe Transportation Center and others to develop the foundation for the same type of tool for national parks. I will review what these studies have revealed, and how they compare with the urban noise standard. Park settings vary more widely than urban environments, so one challenge for devising a standard is addressing the potential variety of receptors and the contexts in which effects could be analyzed. The complexity of this issue increases dramatically when considering the nonhuman receptors of noise in national parks, and the effects of noise on human-wildlife interactions.

Application of alternative synthetic kernel approximation to radiative transfer in regular and irregular two-dimensional media

Alternative synthetic kernel (ASKN) approximation, just as the standard SKN method, is derived from the radiative integral transfer equations in full 3D generality. The direct and diffuse terms of thermal radiation appear explicitly in the radiative integral transfer equations as surface and volume integrals, respectively. In standard SKN method, the approximation is employed to the diffuse terms while direct terms are evaluated analytically. The alternative formulation differs from the standard one in that the direct radiation wall contributions are also approximated with the same spirit of the synthetic kernel approximation. This alternative formulation also yields a set of coupled partial differential-the ASKN–equations which could be solved using finite volume methods. This approximation is applied to radiative transfer calculations in regular and irregular two-dimensional absorbing, emitting and isotropically scattering media. Four benchmark problems-one rectangular and three irregular media-are considered, and the net radiative flux and/or incident energy solutions along the boundaries are compared with available exact, standard discrete ordinates S4 and S12, modified discrete ordinates S4, Monte Carlo and collocation spectral method to assess the accuracy of the method. The ASKN approximation yields ray effect free incident energy and radiative flux distributions, and low order ASKN solutions are generally better than those of the high order standard discrete ordinates method.

Comparison of occupied and unoccupied noise levels in K-12 classrooms

Current research at the University of Nebraska—Lincoln aims to establish how indoor environmental conditions in K-12 school buildings impact student scholastic achievement. A large-scale in-situ survey is being undertaken to gather data on (1) indoor environmental conditions under different seasons or outdoor conditions (fall, winter, and spring), and (2) student’s standardized test outcomes and demographics, as classroom aggregates with no individually identifiable information. In this paper, acoustic data gathered to date from 110 classrooms are mined to determine how occupied and unoccupied noise levels correlate. The ANSI Classroom Acoustics Standard S12.60 (2010) specifies guidelines for unoccupied background noise levels, but students learn in occupied spaces. Logged acoustic data over multiple school days are analyzed to determine if designing for unoccupied noise levels is appropriate to achieve desired occupied acoustic conditions. [Work supported by the United States Environmental Protection Agency Grant Number R835633.]

A Influência do ruído na habilidade auditiva de ordenação temporal para sons verbais

OBJETIVO: apurar a relação entre o ruído presente em sala de aula e a habilidade auditiva de ordenação temporal para sons verbais. MÉTODOS: estudo descritivo transversal, com amostra de 209 estudantes com idade entre sete e dez anos. Foi realizada a avaliação do ruído em 13 salas de aula de oito escolas públicas municipais de Belo Horizonte, por meio da medição do parâmetro acústico nível de pressão sonora equivalente, com as salas de aula vazias e mobiliadas, de acordo com a norma American National Standards Institute (ANSI) S12.60. Para avaliar a habilidade auditiva de ordenação temporal para sons verbais nos estudantes, foi utilizado o teste de memória sequencial verbal. Para fins de análise estatística, o ruído foi categorizado pelo valor da mediana e relacionado aos resultados dos estudantes no teste. RESULTADOS: a maioria dos alunos apresentou resultado normal no teste e não houve diferença em relação ao gênero e à idade. Todas as salas de aula apresentaram valores de nível de pressão sonora equivalente acima do preconizado pelas normas regulamentadoras internacionais (ANSI S12.60 e Bulletin 93) e nacional (Associação Brasileira de Normas Técnicas -NBR10152). Ao relacionar o ruído com o desempenho dos alunos no teste, houve diferença, com maior ocorrência de alterações nos alunos pertencentes às salas mais ruidosas. CONCLUSÃO: os níveis de ruído mensurados nas salas de aula estão acima do permitido pelas normas e constatou-se relação entre ruído presente na sala de aula e maior dificuldade na habilidade auditiva de ordenação temporal.

Meeting the classroom acoustics standard on a historical room

The Department of Speech-Language-Hearing Sciences at University of Minnesota occupies Shevlin Hall built in 1906. We were called in 2013 to help with the acoustic and sound system redesign of room 110 to be used as a classroom, as the room had very poor speech intelligibility due to the very high ceiling and hard walls, resulting in a very reverberant environment. Our goal was to meet the current classroom acoustics standard ANSI S12.60. Reverberation time and noise measurements were performed, and the room was modeled using EASE for the prediction of results. The model was compared with measurements, and several alternatives were explored. After the changes were implemented, measurements confirmed the improvement to the room's intelligibility was acquired and the historic character of the room was preserved.

Development of1H-31P Animal RF Coil for pH Measurement Using a Clinical MR Scanner

H and the 31 P surface coils were designed to acquire signals from mouse tumors. Two coils were positioned orthogonally for geometric decoupling. The pH values of various pH phantoms were calculated using the 1 H decoupled 31 P MR spectrum with the Henderson-Hasselbalch equation. The calculated pH value was compared to that of a pH meter. Results: The mutual coil coupling was shown in a standard S12. Coil coupling (S12) were -73.0 and -62.3 ㏈ respectively. The signal-to-noise ratio (SNR) obtained from the homogeneous phantom 1

Hot topics in architectural acoustics: Classroom acoustics and archaeoacoustics

When ASA members discovered that typical American classrooms were too noisy or reverberant for serious learning in 1988 they began a successful grassroots movement to fix them. By 2002, ASA volunteers produced the first-ever ANSI standard for classroom acoustics. The effort was led by ASA’s TCAA and supported by three other TCs, the S12 Standards Committee, courageous ASA staffers, and elected officers. ANSI Standard S12.60 was adopted fully or partly by school districts, states, and architectural authorities including the Green Building Council. Classroom acoustics research reporting remains active at ASA meetings. We show how this standard helps to make a better world. The new fields of archaeoacoustics and historical acoustics are “hot”. They employ scientific acoustics to study the past. Their novel hypotheses and discoveries attract young investigators to acoustical careers. Sound was more important in the quiet ancient world. Many are fascinated by the 1988 discovery of strong correlation between the locations of Paleolithic cave paintings and cave resonance. Why? A pyramid at Chichen Itza, Mexico, chirps like a bird revered in Mesoamerican cultures. The chirp is explained by applying the convolution theorem to pyramid architecture. Was it intentionally designed? Other archaeoacoustic and historical acoustic examples are addressed.

Estimating occupant satisfaction of HVAC system noise using quality assessment index

Noise may be defined as any unwanted sound. Sound becomes noise when it is too loud, unexpected, uncontrolled, happens at the wrong time, contains unwanted pure tones or unpleasant. In addition to being annoying, loud noise can cause hearing loss, and, depending on other factors, can affect stress level, sleep patterns and heart rate. The primary object for determining subjective estimations of loudness is to present sounds to a sample of listeners under controlled conditions. In heating, ventilation and air conditioning (HVAC) systems only the ventilation fan industry (e.g., bathroom exhaust and sidewall propeller fans) uses loudness ratings. In order to find satisfaction, percent of exposure to noise is the valuable issue for the personnel who are working in these areas. The room criterion (RC) method has been defined by ANSI standard S12.2, which is based on measured levels of in HVAC systems noise in spaces and is used primarily as a diagnostic tool. The RC method consists of a family of criteria curves and a rating procedure. RC measures background noise in the building over the frequency range of 16-4000 Hz. This rating system requires determination of the mid-frequency average level and determining the perceived balance between high-frequency (HF) sound and low-frequency (LF) sound. The arithmetic average of the sound levels in the 500, 1000 and 2000 Hz octave bands is 44.6 dB; therefore, the RC 45 curve is selected as the reference for spectrum quality evaluation. The spectral deviation factors in the LF, medium-frequency sound and HF regions are 2.9, 7.5 and -2.3, respectively, giving a Quality Assessment Index (QAI) of 9.8. This concludes the QAI is useful in estimating an occupant's probable reaction when the system design does not produce optimum sound quality. Thus, a QAI between 5 and 10 dB represents a marginal situation in which acceptance by an occupant is questionable. However, when sound pressure levels in the 16 or 31.5 Hz octave bands exceed 65 dB, vibration in lightweight office construction is possible.

Attenuation performance of active noise reduction headsets using American National Standard s12.42 and the proposed U.S. Environmental Protection Agency Hearing Protector Labeling Regulation

The attenuation performance and noise reduction rating (NRR) of six commercially available active noise reduction (ANR) headsets was assessed using the proposed environmental protection agency (EPA) regulation. The passive attenuation results were collected using American National Standard Institute (ANSI) S12.6 method for measuring real-ear attenuation at threshold (REAT) of hearing protectors while the active attenuations results were collected using ANSI S12.42 methods for the measurement of insertion loss of hearing protection devices in continuous or impulsive noise using microphone-in-real-ear (MIRE) or acoustic test fixture procedures. ANSI/ASA S12.68 methods of estimating effective A-weighted sound pressure levels when hearing protectors are worn was used to compute noise reduction metrics including the noise reduction statistic A-weighted (NRSA) and the graphical noise reduction statistic (NRSG). The proposed NRR labels for the ANR headsets were computer per the guidance in the draft U.S. EPA regulation. The presentation will include the baseline passive, active, and total attenuation, the NRSA and the Graphical NRSG, and the proposed EPA labels for passive attenuation and total attenuation while in an active mode.

Acoustic test fixture for insertion loss measurements of hearing protector devices.

According to ANSI standard S12.42 new aspects have to be considered when measuring the Insertion Loss of Hearing Protectors at an Acoustic Test Fixture. First, the ear simulator has to be able to measure up to 170 dB SPL, so a 1/4 in. microphone is needed. The ear canal extension is also longer than the standard extension known from KEMAR and is fitted with flesh simulation. The circumaural pinna has a larger diameter to ensure a perfect seal for all kinds of hearing protection devices (HPD). Furthermore, the total system consisting of ear simulator, ear canal extension, and pinna is heated to body temperature. All the effects of these new aspects have been measured to assess their influence compared to previous ATF types like the ISO 4869-3.

The rest of the school: An investigation into good acoustical design of non-classroom spaces in primary and secondary schools.

The focus on acoustics in recent standards and guidelines such as the ANSI Standard S12.60, the Leadership in Energy and Environmental Design (LEED) for Schools system, and the Collaborative for High Performance Schools (CHPS) has rightly been on classrooms. Each of them does address other school environments also, although sometimes without particular specificity. After reviewing relevant American standards and guidelines for gymnasiums, libraries, lobbies, corridors, auditoriums, and other spaces that do not fit neatly into the classroom designation, this paper addresses good practices in the acoustical design of such critical environments through the use of a series of case studies. Specifically, the authors suggest room acoustics design parameters and appropriate background noise and sound isolation criteria for non-classroom spaces in primary and secondary schools.

Ambient noise levels and reverberation times in Mississippi school rooms.

Nine elementary school classrooms at three Mississippi public schools were selected at random for noise and reverberation time measures to monitor voluntary compliance with ANSI standard S12.60‐2002 (Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools). 1‐h equivalent dBA noise levels and reverberation times (T60) were measured with SPECTRAPLUS Version 5.0 software. Measures were taken on separate days at each school in unoccupied classrooms with the HVAC system operating. For ambient noise measures, an Audix TR40 omnidirectional microphone was placed in a 12 in. stand on a student’s desk near the middle of the room and oriented toward the teacher’s desk at a 45 deg angle. For the reverberation time measure a 400 W loudspeaker (Yamaha BR15M) was placed on the teacher’s desk about 3 m from the microphone. Results showed that noise levels varied from 28 to 51 dBA with broad spectra containing peaks at 120 Hz and harmonics. Five of nine classrooms had noise levels that exceeded the ANSI recommended level of 35 dBA. Reverberation times varied from 0.21 to 0.62 s; only one classroom exceeded the recommended minimal reverberation time of 0.6 s. Acoustical modifications to reduce noise levels and reverberation times will be addressed.

Low background noise is needed for good student‐to‐student classroom communication.

ANSI standard S12.60 requires that background noise not exceed 35 dBA in unoccupied lecture classrooms. Despite the strong and broad research basis for ANSI’s 35‐dBA requirement, some classroom noise guidelines permit 45 dBA (notably California Collaborative for High Performance Schools and Leadership in Energy and Environmental Design). How did this come about? The 45‐dBA limit was a compromise between the 50‐dBA guidelines then prevailing and ANSI’s 35‐dBA limits. There is no audiological basis for a 45‐dBA BNL limit. With 45‐dBA BNLs, the speech to noise ratio (SNR) in the rear of small classrooms is well below the 15‐dB minimum required for sustained learning. With 35‐dBA BNLs, the SNR approaches ANSI’s 15‐dB minimum. It is underappreciated that BNLs of 35 dBA or less also promote better student‐to‐student (STS) communication. For every 10 dB of background noise reduction, the physical range of STS communication increases by a factor of about 3.16, and the floor area encompassed increases by a factor of 10. As BNL is reduced, eventually all classroom occupants are within communication range.

House Committee Passes Student Loan Bill

You have accessThe ASHA LeaderPolicy Analysis1 Sep 2009House Committee Passes Student Loan Bill Neil Snyder Neil Snyder Google Scholar More articles by this author https://doi.org/10.1044/leader.PA1.14112009.1 SectionsAbout ToolsAdd to favorites ShareFacebookTwitterLinked In The Education and Labor Committee of the U.S. House of Representatives considered and passed H.R. 3221, the Student Aid and Fiscal Responsibility Act of 2009, which reorganizes the entire student loan industry. The legislation states that all student borrowers must get direct loans from the U.S. Department of Education rather than from other private industry lenders, such as Sallie Mae, Wachovia, or local banks. The bill would eliminate federally subsidized and guaranteed private-sector loans—about 60% of all student loans—at a savings estimated at $100 billion over 10 years. These savings would be redirected to other programs, including Pell Grants for students meeting income eligibility requirements. Lawmakers are at odds over whether or not the bill will benefit students seeking college loans and grants. According to a statement from George Miller (D-Calif.), Education and Labor chair, “The legislation…will generate almost $100 billion in savings over the next 10 years that will be used to boost Pell Grant scholarships, keep interest rates on federal loans affordable, create a more reliable and effective financial aid system for families, and enact President Obama’s key education priorities.” However, a press statement from Rep. John Kline (R-Minn.), ranking minority member of the committee, maintains that “The Democrats’ legislation, H.R. 3221, abolishes the Federal Family Education Loan (FFEL) program and redirects tens of billions in government savings and earnings toward new entitlement programs that do not directly benefit low-income students’ pursuit of higher education.” Noise Reduction Of particular interest to ASHA members is a provision in the bill that would direct $5 billion in estimated loan program savings to fund the 21st Century Green High-Performing Public School Facilities Act (Section 345). This act has already been passed—but not funded—by the Education and Labor Committee and the House of Representatives. This “green schools” act would allow states and school districts to use federal funds to reduce or eliminate exposure to classroom and environmental noise and would also encourage the use and compliance with the American National Standards Institute (ANSI)-approved Standard S12.6–2002, Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools. The legislation passed the committee along party lines by a vote of 30–17, with two Republicans voting in favor of the bill. It will now go to the full House, which will not consider it until after its August recess. It will not be considered by the Senate until later in the fall. In a separate but related issue, Rep. John Tierney (D-Mass.) offered—but withdrew—an amendment that would have provided automatic funding for a federal student loan forgiveness program that includes school-based speech-language pathologists and audiologists. This program has been authorized, but not funded. Rep. Tierney agreed to work with Rep. Miller to request funding for the program through the regular appropriations process. Author Notes Neil Snyder, director of federal advocacy, can be reached at [email protected] or 800-498-2071 ext. 5614. Advertising Disclaimer | Advertise With Us Advertising Disclaimer | Advertise With Us Additional Resources FiguresSourcesRelatedDetails Volume 14Issue 11September 2009 Get Permissions Add to your Mendeley library History Published in print: Sep 1, 2009 Metrics Downloaded 75 times Topicsleader_do_tagleader-topicsasha-article-typesCopyright & Permissions© 2009 American Speech-Language-Hearing AssociationLoading ...

Issues in the sound absorption treatment in classrooms.

Classrooms require adequate sound absorption to establish appropriate environments for listening and learning. Sound absorbing materials improve the classroom learning environment by reducing reverberation time and by reducing background noise levels. ANSI standard S12.60‐2002 provides simple methods for determining the amount of sound absorption needed to limit reverberation time. One of those methods is briefly reviewed. Throughout his career, Nixon’s forte was the sound absorption treatment of rooms. He and his colleague, the late Robin (Buzz) Towne, were pioneers—sounding the alarm that, with hardly anyones notice, poor classroom acoustics had become a widespread problem adversely impacting scholastic achievement. The two were also instrumental in motivating the Acoustical Society of America to lead the change toward a solution. The Society is indebted to Nixon both for his pioneering effort to awaken acousticians and others to the need for good classroom acoustics and for his diligent participation in the subsequent effort to develop an ANSI standard for that purpose.