Petition for Rulemaking; Request for Information on Acoustics

ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD

36 CFR Chapter XI

[Docket No. 98-4]

Petition for Rulemaking; Request for Information on Acoustics

AGENCY: Architectural and Transportation Barriers Compliance Board.

ACTION: Request for information.

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SUMMARY: The Architectural and Transportation Barriers Compliance Board

has received a petition for rulemaking from a parent of a child with a

hearing loss requesting that the ADA Accessibility Guidelines be

amended to include new provisions for acoustical accessibility in

schools for children who are hard of hearing. Several acoustics

professionals, parents of children with hearing impairments,

individuals who are hard of hearing, and a consortium of organizations

representing them have also urged the Board to consider research and

rulemaking on the acoustical performance of buildings and facilities,

in particular school classrooms and related student facilities. The

Board seeks comment on the issues outlined in this request for

information. After evaluating responses to this request for

information, the Board will determine a course of action. Alternatives

under consideration include research, rulemaking, and technical

assistance on acoustical issues.

DATES: Comments should be received by July 31, 1998. Late comments will

be considered to the extent practicable.

ADDRESSES: Comments should be sent to the Office of Technical and

Information Services, Architectural and Transportation Barriers

Compliance Board, 1331 F Street NW., suite 1000, Washington, DC 20004-

1111. E-mail comments should be sent to [email protected].

Comments sent by e-mail will be considered only if they include the

full name and address of the sender in the text. The petition and

comments are available for inspection at the above address from 9:00

a.m. to 5:00 p.m. on regular business days.

FOR FURTHER INFORMATION CONTACT: Lois Thibault, Office of Technical and

Information Services, Architectural and Transportation Barriers

Compliance Board, 1331 F Street NW., suite 1000, Washington, DC 20004-

1111. Telephone number (202) 272-5434 extension 32 (voice); (202) 272-

5449 (TTY). These are not toll-free numbers. Electronic mail address:

[email protected].

SUPPLEMENTARY INFORMATION:

Availability of Copies and Electronic Access

Single copies of this publication may be obtained at no cost by

calling the Access Board's automated publications order line (202) 272-

5434, by pressing 1 on the telephone keypad, then 1 again, and

requesting publication C-11. Persons using a TTY should call (202) 272-

5449. Please record a name, address, telephone number and request

publication C-11. This document is available in alternate formats upon

request. Persons who want a copy in an alternate format should specify

the type of format (cassette tape, Braille, large print, or computer

disk). The petition and this request for information are also posted on

the Board's Internet site at http://www.access-board.gov/rules/

acoustic.htm.

Background

The Architectural and Transportation Barriers Compliance Board

1 (Access Board) is responsible for developing accessibility

guidelines under the Americans with Disabilities Act of 1990 (ADA) to

ensure that new construction and alterations of facilities covered by

the law are readily accessible to and usable by individuals with

disabilities. The Access Board initially issued the Americans with

Disabilities Act Accessibility Guidelines (ADAAG) in 1991. The

guidelines contain scoping provisions and technical specifications for

designing elements and spaces that typically comprise a building and

its site so that individuals with disabilities will have ready access

to and use of a facility.

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\1\ The Access Board is an independent Federal agency

established by section 502 of the Rehabilitation Act (29 U.S.C. 792)

whose primary mission is to promote accessibility for individuals

with disabilities. The Access Board consists of 25 members. Thirteen

are appointed by the President from among the public, a majority of

who are required to be individuals with disabilities. The other

twelve are heads of the following Federal agencies or their

designees whose positions are Executive Level IV or above: The

departments of Health and Human Services, Education, Transportation,

Housing and Urban Development, Labor, Interior, Defense, Justice,

Veterans Affairs, and Commerce; General Services Administration; and

United States Postal Service.

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Although ADAAG contains a number of provisions for access to

communications, including requirements for text telephones, assistive

listening systems, and visible alarms, it does not include provisions

for the acoustical design or performance of spaces within buildings and

facilities.

[[Page 29680]]

The Department of Justice (DOJ) regulations implementing titles II and

III of the ADA contain additional requirements for communications with

individuals with disabilities and for auxiliary aids and devices to aid

in communication.2

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\2\ Under the ADA, the Departments of Justice and Transportation

are responsible for issuing regulations to implement titles II and

III of the Act. The regulations must include accessibility standards

for newly constructed and altered facilities. The standards must be

consistent with the accessibility guidelines issued by the Access

Board. The Department of Justice and the Department of

Transportation regulations currently include ADAAG 1-10.

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On April 6, 1997, the Access Board received a petition for

rulemaking from a parent of a child with a severe to profound hearing

loss requesting that the Board address ``architectural acoustics in

schools'' and develop ``new rules'' for children who are hard-of-

hearing. The petition argues that children who have hearing and other

disabilities, including learning, auditory processing, speech and

language, and developmental disabilities, face numerous communications

barriers in schools because of poor acoustics and that these barriers

may prevent them from receiving a meaningful education. The petition

requests that the Board develop ``acoustical guidelines * * * [to]

ensure adequately low noise and reverberation so that the speech-to-

noise ratio and speech-to-reverberation ratio allow satisfactory

communication and learning.''

A consortium of organizations representing persons with

disabilities (Alexander Graham Bell Association for the Deaf, Inc., the

American Speech-Language-Hearing Association (ASHA), Auditory-Verbal

International, Inc., the National Center for Law and Deafness, the

National Cued Speech Association, and Self Help for Hard of Hearing

People (SHHH)) submitted comments to the Board in previous rulemakings

asserting that a poor acoustical environment is as significant a

barrier to individuals with hearing, speech, and language impairments

as stairs are to persons who use wheelchairs.

The consortium's comments included a position paper on acoustics in

educational settings developed by ASHA in 1994. The paper cited data on

the increasing prevalence of hearing loss, particularly among children

and young adults, and reported on research that identified children

with mild hearing losses as more at risk for general psychosocial

dysfunction and lags in academic progress than were children with

normal hearing. Other cited studies showed the relationship between

poor room acoustics and low speech comprehension in children with

hearing, learning, and developmental disabilities. Reverberant

classrooms with high ambient noise levels were identified as

significant contributors to communications difficulties. The position

paper included a number of recommendations for the acoustical

performance of classrooms to improve conditions for listening, hearing,

and understanding speech.

Other commenters to ADAAG rulemakings noted that the acoustics of

many restaurants adversely affected the ability of individuals who are

hard of hearing to communicate with companions and with service staff.

In response, the Access Board contracted with Batelle, a research

organization in Columbus, OH, to study improved speech communication

for persons with hearing impairments in dining areas. A literature

study, post-occupancy evaluations of several facilities, and

recommendations were developed by Batelle engineers and reviewed by an

eight-member advisory panel. The authors identified background noise

levels and reverberation as the acoustical characteristics most subject

to design and construction manipulation and most significant for

adequate speech communication. Several panel members suggested that

other facility types, particularly schools, could benefit from the

application of such acoustical requirements.

Hearing Loss and Other Disabilities

Government health statistics document that more Americans report a

hearing loss than any other disability, and the incidence of hearing

loss has increased significantly in the last 25 years. A recent

assessment by the Centers for Disease Control and Prevention (CDC)

found that 13% of a representative sample of children between the ages

of 6 and 19 had a high frequency hearing loss and 7% a low frequency

hearing loss of 16 dB or more, a level at which perceiving and

understanding words would be affected.

Increasing numbers of young children experience mild temporary and

recurring hearing loss caused by otitis media, an inflammation of the

middle ear that is the most frequent medical diagnosis for children.

Research also shows that children with learning, speech, and

developmental disabilities have a higher incidence of abnormal hearing

and of repeated instances of ear problems. ``Hearing Loss: The Journal

of Self Help for Hard of Hearing People'' reported in 1997 that one-

fourth to one-third of the students in typical kindergarten and first-

grade classrooms will not hear normally on a given day.

Speech Communication

Effective speech reception--understanding, not just hearing--is the

primary educational issue for people with auditory disabilities. A

Cornell University study published in the journal ``Environment and

Behavior'' indicates that excessive classroom noise impedes the

acquisition of language and cognitive skills by all children. The

acquisition of language is necessary for brain and intellectual

development. Research with children who are deaf has shown that the

mastery of a system of communication is essential to future learning

and that failure to acquire effective language skills by the age of six

cannot be fully remediated.

Language acquisition is dependent in large part upon exposure to an

organized system of communication, such as a signed, voiced, or tactile

language. For children who will use voice communication, the

intelligibility of the spoken language is a critical factor. Speech

intelligibility is a measure of the proportion of the spoken message

that gets through to the listener, and is affected by signal volume,

the distance between the speaker and listener, and the acoustic

characteristics of the room, including background noise levels and

reverberation time.

A large body of clinical and scientific research supports the

particular need for good acoustics in teaching environments. The

Acoustical Society of America (ASA) has established a Classroom

Acoustics Subcommittee of its Architectural Acoustics Committee that

has held four symposia on classroom acoustics issues. At an ASA

conference held in June 1997, researchers presented evidence that

excessive noise levels impair a young child's speech perception,

reading and spelling ability, behavior, attention, and overall academic

performance.

Because the ability to understand speech does not mature in

children before the age of 15, children are less effective listeners

generally than are adults. Additionally, children have less experience

in deriving meaning from context. A representative sample of children

without hearing loss or other audiological disability, even when tested

in above-average listening environments, could make out only 71% of a

teacher's words. Those in the worst environments ``got'' only 30% of

the message directed at them.

The listening abilities of children with hearing impairments,

particularly those with mild to moderate hearing loss, are even more

affected by poor acoustics than are those of children whose hearing

falls within normal

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ranges. A 1997 study of children with minimal sensorineural hearing

loss showed lower scores for basic skills and communications testing

and a high rate--37%--of retention in grade. In addition, these

students functioned below normally hearing children in evaluations of

behavior, energy, stress, social support, and self-esteem. Other

studies have shown that children with learning and developmental

disabilities perform less effectively in noisy spaces.

In their chapter on ``Speech Perception in Specific Populations''

(from the book ``Sound-Field FM Amplification''), Drs. Carl Crandell,

Joseph Smaldino, and Carol Flexer have identified at-risk populations

as young students generally (less than 13-15 years of age); children

who have a history of otitis media, children for whom English is a

second language, and children with auditory disabilities, including

those with hearing loss, central auditory processing deficits, learning

disabilities, developmental delay, and attention, speech, and language

disorders.

Acoustical Performance of Rooms and Spaces

In analyzing how effectively an individual can hear and understand

in a given space, an acoustician or audiologist will consider three

criteria: Distance from the sound source (the `signal'), the level of

background sound (noise), and the effects of reverberation. By

controlling background noise levels and room reverberation time,

designers can provide good speech intelligibility, measured by the

signal-to-noise ratio. The signal-to-noise ratio is the relationship

between the loudness of the message and the background sound it must

overcome to be heard and understood. A significantly positive signal-

to-noise ratio is necessary for maximum performance where room sound

levels are high; children with hearing impairments require a higher

signal-to-noise ratio than do children with normal hearing.

Distance from the source has a significant effect on signal-to-

noise ratio, since the loudness of a direct sound falls off in

proportion to the distance between the speaker and listener. Children

with hearing impairments and other disabilities affecting listening

need to maintain a consistent and close relationship with the sound

source. Speech intelligibility can be enhanced by delivery and

performance styles, by the use of reflective surfaces at the speaking

location, and by amplification.

Background noise--whether from heating, ventilating, and air

conditioning (HVAC) systems, other noise generated within the space, or

outside noise--also interferes with effective listening because it

competes with the spoken message. High background noise values across

the frequencies of speech (500 to 2000 Hz) require louder speech

signals to overcome. Background noise (or ambient sound) design

criteria are typically expressed as a range between two noise criteria

(NC) curves, which plot sound levels across 8 standard frequencies.

Sound levels in existing spaces can be tested at these frequencies

using a sound meter. The NC rating for a room is typically between 5 to

10 points below the dBA reading. Design engineers can specify HVAC

equipment with low noise ratings and limit sound generated by system

operation in a variety of ways. Rooms and spaces can be protected from

unwanted exterior sound by mass, insulation, and isolation in wall and

slab construction and by minimizing (or sound protecting) openings.

Reverberation--reflected sound that persists within a room or

space--also masks the sound of the spoken message and increases

background sound levels. The longer the reverberation time, the greater

the effect. Reverberation is expressed in seconds (R60), measured as

the time it takes for sound to decay 60 dB after the source has stopped

producing it. Reverberation is a function of the physical properties of

the room and can be calculated if the volume, surface area, and surface

absorbencies of a space are known. Reverberation can be controlled by a

manipulation of the absorbency of surfaces within a space and the

proportions and volume of the space.

When reverberation time and background noise are controlled, speech

effort and sound levels decline, leading to a reduction in room noise.

It has been estimated that over 90% of those who have a hearing loss

have usable residual hearing and would benefit from an enhanced speech

environment. Where classrooms and child care centers do not provide

acceptable listening conditions, even amplification will not achieve

maximum effect in improving speech communication. Poor acoustics can

also compromise the effectiveness of personal hearing aids and devices

and limit the usefulness of auxiliary aids and services. Good acoustics

can enhance the usefulness of such aids and improve listener reception

of unamplified speech, as may occur in group interchange. Because most

mild hearing losses in children are not diagnosed, children with such

losses (15-25 dB), including those with temporary hearing loss due to

otitis media, will not generally be using amplification devices.

Many groups concerned with the acoustics of educational

environments recommended that new implementing regulations for the

Individuals with Disabilities Education Act (IDEA), currently being

developed by the U.S. Department of Education, require that services

for covered students be delivered in an acoustically appropriate

environment. Two cases have been reported to the Board in which IDEA or

Rehabilitation Act decisions directed that the room acoustics in

existing school classrooms be improved to accommodate children with

hearing loss. Requirements that students with disabilities be educated

in the least restrictive environment mean that every classroom is

likely to have a youngster with a diagnosed auditory disability in

attendance; additionally, during the course of a school year, many

children will be temporarily affected by mild and possibly recurring

hearing loss associated with otitis media and other illnesses.

Classroom Acoustics

Studies of classrooms around the country and test data submitted by

parents and acoustical consultants indicate that classrooms and day

care facilities are not being designed to provide adequate speech

intelligibility even for children without auditory impairments.

Research on seven child-care facilities in Canada documented noise

conditions in four centers that exceeded the 75 dB limit considered

safe for day-long exposure for adults by the World Health Organization.

Open plan centers had particularly excessive noise levels and were

reported to have more health problems among children and staff as well

as other disadvantages. Acoustical treatment that reduced reverberation

time in the noisiest setting from 1.6 seconds to .6 seconds resulted in

a 5 dB decrease in sound level and staff assessments of substantial

improvement in comfort. A 1994 survey of school facility conditions

conducted by the General Accounting Office (GAO) reported that poor

acoustics were ranked by administrators as the most significant problem

affecting the learning environment. Twenty-eight percent of responding

schools identified acoustics for noise control as being unsatisfactory

or very unsatisfactory. Eleven million children were estimated to be

affected. Of these, CDC estimates suggest, more than a million and a

half children may have a temporary or permanent hearing loss.

[[Page 29682]]

Acoustical Design Standards and Guidelines

Reverberation and background noise limits are common elements in

existing acoustical standards, recommendations, and good-practice

guidelines for classroom design and construction. Audiometry rooms and

educational classrooms designed specifically for persons with auditory

impairments have short reverberation times and very low background

noise levels. Similar requirements are applied to rooms such as

broadcast and recording studios, including teleconferencing facilities,

where speech communication is the primary function, and in sound

testing facilities such as anechoic chambers. Low background noise and

short reverberation times contribute to positive sound-to-noise ratios,

maximal sound transmission indices, and high speech intelligibility

values.

Achievements in the design of concert hall acoustics and

specialized environments for materials testing and measurement

demonstrate that good hearing environments can be accomplished with

current design, modeling, construction, and testing procedures. It

appears that a consensus on the general scope and content of acoustical

performance criteria for classrooms is developing among audiologists,

acousticians, and consumers and that existing acoustical guidelines for

educational and other facilities may be adaptable for incorporation

into ADAAG.

While some factors--for instance, a rise in exterior noise levels

due to a change in nearby noise sources--are beyond the control of the

design professional, `bad' acoustics are largely architectural

problems, solvable by architectural means. Architects and other design

professionals routinely practice simple acoustical design procedures in

specifying floor, wall, and ceiling finishes. Acousticians are

regularly retained for the more demanding design and engineering of

music and performance facilities. Several software programs are

available to model the acoustical performance of spaces that have been

designed but not built. Criteria for the acoustical design of spaces

are widely available in textbooks and technical publications.

Acoustical testing protocols are developed and maintained by

several private sector organizations. The American Society of Heating,

Refrigeration, and Air Conditioning Engineers (ASHRAE) issues standards

that include the acoustical performance of equipment installed in

buildings and facilities. The American National Standards Institute

(ANSI), in conjunction with the ASA, has established several protocols

for the measurement of room sound levels, including ANSI S12.2 Criteria

for Room Noise Measurement. ANSI has recently established a committee

to develop a classroom acoustics standard. Foreign and international

standards also exist. Model codes contain both standards and

requirements for sound-rated construction components in multi-family

housing and other occupancy types. The developers and operators of

hotel, medical, and housing facilities typically establish similar

acoustical standards for sound transmission through floors, walls,

structure, and HVAC systems.

``Architectural Acoustics'', by M. David Egan (McGraw-Hill, Inc.,

1988), a standard reference work for design professionals, recommends a

background noise level of less than 20 dB (NC-20) for critical music

performance (including broadcast and recording studios) and

audiological spaces; a range of NC-20 to NC-30 for less demanding,

speech-focused halls and rooms, and NC-30 to NC-35 for classrooms.

Recommended reverberation limits range between .6 and .8 seconds. The

author notes, however, that NC curves to provide satisfactory listening

environments for persons with hearing impairments need to be lower by 5

(resulting in a recommendation of NC-25 to NC-30 for classrooms serving

adults with hearing loss). Egan recommends that reverberation time in

such rooms should not exceed .5 seconds.

The ASA recommends an average reverberation time in classrooms

between .6 seconds minimum and .8 seconds maximum; ambient room noise,

when measured without occupants, between 30 dBA minimum and 35 dBA

maximum; room criteria (RC) curve--used to measure HVAC and equipment-

generated noise--should not exceed RC-25, and the signal-to-noise ratio

should be able to achieve +15 dB. The ASA has recently established a

multi-committee initiative to work on the development of guidelines for

acoustics. A workshop seminar was held in Los Angeles in December 1997

to begin the process of developing consensus recommendations.

The ASHA recommends that noise levels in unoccupied classrooms not

exceed 30 dBA (or a NC-20 curve) and that reverberation time not exceed

.4 seconds across speech frequencies. Signal-to-noise ratios (measured

at the student's ear) should exceed +15 dB.

Dr. Crandell et al. recommend that elementary and secondary school

classrooms for `at-risk' students should have unoccupied ambient noise

levels that do not exceed NC-25 or a sound pressure level of 35 dBA and

a reverberation time that does not exceed .4 seconds in the speech

frequency range.

Portugal's classroom noise standards, adopted in 1988, limit

reverberation time in general classrooms to .6-.8 seconds and in

special classrooms to .6 seconds; equipment background noise may not

exceed 35 dBA. Wall construction between classrooms must have a sound

transmission class (STC) rating of at least 50 dB. The Swedish Board of

Housing, Building and Planning has adopted Building Regulations BBR 94,

with amendments, that include detailed guidelines for protection

against noise for several building types, including schools, by means

of specified areas of sound absorbent surfaces within classrooms,

acoustical isolation between classrooms, and limits on background noise

from building systems and equipment.

The State of Washington Department of Health rules, WAC 248-64-320

Sound Control, include a limit (NC-35) on background noise in

classrooms. The Los Angeles County Unified School District--the largest

in the world in numbers of students enrolled--has recently adopted a

similar standard for the noise output of classroom HVAC equipment. ANSI

S12.2-1995 suggests an NC range of 25-30 for classrooms and an RC in

the same range. A tabular comparison of values for acoustical criteria

in classrooms is presented in Table 1.

Other bases for prescribing and testing acoustical characteristics,

including values for speech-to-noise ratio and the speech transmission

index (STI), may be applied to diagnose existing acoustical conditions

in classrooms, but do not appear useful in a new construction standard.

The STI takes into account the effects of noise and reverberation and

can be adjusted to obtain values for listeners with hearing

impairments. Both rely on in-use measurements.

Cost

High-performing acoustical environments are achieved at some

premium in construction cost. Knowledgeable design, construction, and

materials specification, an investment in high-quality HVAC equipment,

and careful installation and workmanship are required to ensure that

design values are reflected in performance. Special consideration of

room configuration, proportion, and location may also be necessary.

Furthermore, the measures necessary to

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control sound in classrooms may raise other issues affecting cost. For

instance, carpeting is recommended to add absorbency for reverberation

control and to minimize the self-noise of student movement. However,

carpeting may require a change in maintenance procedures. Controlling

ambient noise in many urban schools may require that windows be kept

closed even in pleasant weather, when HVAC systems might operate at

lesser capacities. Students with moderate to severe hearing impairments

may also require the use of amplification systems to increase speech

intelligibility to effective values.

ADAAG Criteria

To be useful, acoustical recommendations and standards should

employ design techniques, data, and sound measurement protocols

available and familiar to architecture, engineering, and construction

practitioners and applicable during design phases. Like a building

code, ADAAG is intended for use in new construction and alterations of

buildings and facilities. It contains provisions for construction

elements, items, and finishes that are fixed to the building structure.

Furniture and equipment, including portable communications devices, are

covered by the DOJ regulation, not ADAAG.

The Board recognizes that amplification technologies may be

required for effective communications in some rooms and spaces and for

some individuals. Such solutions, including those that use portable

assistive listening systems and sound field technology, are beyond the

scope of the building and facility provisions in ADAAG. However, such

technologies cannot be fully effective in noisy environments;

amplification in highly reverberant environments will exacerbate

listening and hearing problems. Furthermore, the effectiveness of

personal devices, particularly hearing aids, is also compromised in

noisy environments. And, because the learning environment includes

interaction with peers and other individuals in classrooms and other

settings, instructor amplification only may not fully remove barriers

to hearing, listening, and learning where acoustical design is flawed.

Based upon public comments to this notice and on information

already available and outlined in this notice, the Board will consider

whether it is appropriate for ADAAG to include criteria for such

acoustical performance characteristics as reverberation time and

background noise. Several non-rulemaking options will also be

considered, including additional research, the development of advisory

materials, and guidance and technical assistance for design

professionals.

In response to the petition, the Board wishes to focus this request

for information on the acoustical performance of classrooms and related

spaces used by children, including day care settings for pre-primary

ages. However, the Board will consider comments and recommendations on

the scope and technical provisions of acoustical criteria appropriate

for buildings and facilities and other occupancies, as well.

The Board seeks relevant research, standards, data, test reports,

analyses, and recommendations from acoustical engineers and

consultants, design professionals, educators and educational

administrators and counselors, audiologists, specialists in hearing

impairments, parents of children with disabilities and persons with

hearing, speech, and language disabilities, including learning and

developmental disorders, and the organizations that represent them.

Commenters are encouraged to address their responses to the issues

outlined below.

Question 1: Implementing acoustical guidelines in educational

facilities for children may be necessary for youngsters with auditory

and related disabilities to function effectively in school. (a) Should

all rooms and spaces within a school setting be included in coverage?

Some comment has identified gymnasiums, pools, and cafeterias as

particularly problematic for students with hyperacusis, a heightened

sensitivity to noise, and for those with learning and auditory

processing disabilities. Such facilities are often highly reverberant

due to their large areas of hard, sound-reflective surfaces. (b) Should

acoustic guidelines include coverage of these spaces? Would a less

stringent standard be appropriate in non-classroom school facilities?

What acoustical properties are appropriate in multi-purpose spaces that

accommodate recreation, performance, and food service activities at

different times during a school day? (c) In view of the importance of

early language acquisition, how should child care settings be covered?

Are there acoustical criteria in current health and safety standards

for child care facilities? (d) Should the Board consider the

development of guidelines for a wider range of facility types for a

more universal range of users? If so, what facilities might be

included?

Question 2: The Board has received information on several cases in

which the acoustical environment was an issue in an Individualized

Education Plan prepared by a school system for a child with a hearing

impairment. Would a common standard for the acoustical design of

educational facilities be helpful to design professionals seeking to

provide acoustically satisfactory environments and to school systems

seeking to comply with educational mandates for children with

disabilities? Are current design manuals, recommendations, and other

technical assistance on acoustical design sufficient?

Question 3: There is considerable research that shows that

controlling classroom noise and reverberation will benefit student

learning. However, it is not clear at what levels effective listening

by children with mild, moderate, severe, or profound hearing losses and

other disabilities is compromised and whether such conditions can be

achieved in some classroom environments, where ``self-noise'' and

student activity also contribute to a poor listening environment. (a)

Is there research that identifies the specific acoustic requirements

necessary for effective listening by children with various hearing,

speaking, and learning disabilities? What acoustical performance and

testing standards are appropriate for classrooms in which children with

auditory disabilities are integrated? Are there data that relate

specific acoustical criteria to the usability of buildings and

facilities by children with learning disabilities, developmental

disabilities, and other disabilities that affect speech reception,

learning, and communication? (b) What are the relative contributions of

low reverberation values and low background noise values to effective

communication for people with hearing loss? (c) Can the acoustical

environment be improved sufficiently through design and construction

measures for children with hearing and other impairments to receive

significant communications benefit?

Question 4: The Board also seeks information on the acoustical

environment necessary for effective use of assistive technology,

including hearing aids and assistive listening devices, by children

with hearing loss. Because assistive technologies will be part of many

student accommodations, the Board is interested in the extent to which

poor acoustics compromise the effectiveness of technologies such as

sound field enhancement (in which the amplified voice of a teacher

fitted with

[[Page 29684]]

a microphone can be distributed to speakers placed around the perimeter

of a classroom) and direct broadcast to children with hearing loss

through personal assistive listening devices. At what thresholds of

background sound and reverberation will children with various degrees

of hearing loss be able to participate in meaningful classroom

listening if aided by amplification technology?

Question 5: The GAO report on school conditions highlighted the

multimedia classroom as the educational facility of the future. The

Board is interested in understanding the nature and characteristics of

such a classroom, particularly the extent to which it may be

interactive, with small group listening and discussion, multiple inputs

from speakers and media devices, frequent changes in speaker-listener

relationships, and other audio source conditions that may not be fully

adaptable to amplification technologies.

Question 6: The Board recognizes that decisions made by building

design professionals during the design phases of a project affect the

ultimate acoustical performance of a room or space. Determinations of

building siting, overall facility planning, and individual room volume

and proportion, floor, wall and ceiling assembly construction and

finishes, equipment specification, and HVAC system design all

contribute to the acoustic functioning of a room or space. However,

most recommendations for acoustical performance measure the results of

such design decisions, setting limits on reverberation and background

noise. (a) Can good speech listening conditions be achieved by setting

standards for reverberation time and background noise only? (b) Should

other design variables, for example, room configuration or proportion,

ceiling height, or size, be considered? The Swedish guidelines specify

wall and ceiling construction types and values in addition to limiting

background noise. Are these a useful model for possible guidelines? (c)

How might considerations of speech intelligibility, speech transmission

indices, and other measures that rely on in-use testing be incorporated

in acoustical design? What are the margins of error in acoustical

equipment, testing, simulation, and construction? (d) What are

effective means of acoustically retrofitting an existing classroom or

other space that performs poorly for speech perception? How successful

can such corrective action be in correcting perceived hearing and

listening problems?

Question 7: What is the square foot cost for new classroom

construction today? What additional square foot cost would be necessary

to meet average industry recommendations for reverberation time (R

.6--.8 seconds) and background noise (NC 35-40) for classrooms? What

would be the added cost, per square foot, of achieving values within

the ranges suggested by ASA (R .4--.6 seconds; NC 25-30)? What are the

relative costs of meeting reverberation limits as opposed to background

sound limits? What data are available on the costs of alterations to

existing environments to improve acoustical conditions?

Question 8: The Board also seeks information on the non-capital

costs and savings associated with constructing and maintaining

acoustically-appropriate classrooms and related educational facilities.

What are the cost implications of such design and finishes decisions

and operating procedures as room location and configuration, window

operability, and carpeting? What savings might accrue from the

elimination of some special education environments?

Question 9: How can compliance with acoustical design criteria be

assessed prior to facility occupancy and use? How can time and physical

variations in equipment manufacture, construction, and outside noise

conditions be accommodated in a guideline? What testing and compliance

practices have been used where standards are already in place?

Question 10: Many teachers and administrators have had experience

with open classrooms, in which several teaching groups may work

concurrently in a single large space, and with enclosed classrooms of

smaller size. (a) The Board is particularly interested in comments

offering a comparison of the effects on students and teachers, in

particular those with disabilities, of classroom acoustics in such

situations. (b) Do noisy classrooms exacerbate teacher stress? Are

there data available on the effects of classroom noise on teacher

health, comfort, or performance? (c) Do schools and systems have

information on student behavior and performance after acoustical

improvements, including the partitioning of open classrooms into more

discrete units, have been made?

Question 11: What approaches other than regulation under the ADA

might be successful in achieving good acoustical design? What

organizations and interests should be consulted in the Board's

consideration of acoustical issues?

Dated: May 26, 1998.

Thurman M. Davis, Sr.,

Chair, Architectural and Transportation Barriers Compliance Board.

Table 1 on recommended/required acoustical criteria for classrooms

follows:

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