Classroom noise and its effects on classroom learning

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SNAG Members. Murray Hodgson, Professor of Acoustics and Noise Control, UBCJanet Jamieson, Professor, Faculty of Education, UBCTom Tylka, Teacher of the Deaf and Hard of Hearing, Vancouver School DistrictMaureen Clarke, Teacher of the Deaf and Hard of Hearing, North Van School DistrictBev McKenna, Teacher of the Deaf and Hard of Hearing, Burnaby School DistrictLes King, Director of Facilities, Vancouver School BoardMark Keelan, Health and Safety Officer, BCTFKarin Bernauer, Teacher, Vanco30099

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Classroom noise and its effects on classroom learning

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1. Classroom noise and its effects on classroom learning School Noise Action Group (SNAG)

2. SNAG Members Murray Hodgson, Professor of Acoustics and Noise Control, UBC Janet Jamieson, Professor, Faculty of Education, UBC Tom Tylka, Teacher of the Deaf and Hard of Hearing, Vancouver School District Maureen Clarke, Teacher of the Deaf and Hard of Hearing, North Van School District Bev McKenna, Teacher of the Deaf and Hard of Hearing, Burnaby School District Les King, Director of Facilities, Vancouver School Board Mark Keelan, Health and Safety Officer, BCTF Karin Bernauer, Teacher, Vancouver School District Linda Rammage, Director, Provincial Voice Care Resource Program Glynnis Tidball, Audiologist, St. Paul’s Hospital Greg Johnson, Architect, Marceau Evans Johnson Architects Kathy Pickford, Principal, University Hill Elementary

3. Goals of SNAG Examine research that outlines the effects of noise in learning environments Increase awareness of acoustic issues in educational settings Inform school personnel, government officials, and the public of the benefits of quality classroom acoustics Develop local research projects to demonstrate the benefits of improved classroom acoustics Lobby the provincial government to adopt classroom acoustic standards

4. Current Issues: What is classroom noise? Why classroom noise is a concern? What can be done to improve classroom acoustics?

5. Noise Noise defined as unwanted sound Extremely high levels of noise can cause hearing damage (Occupational Health and Safety) Moderate levels of noise interfere with effectiveness and ease of communication

6. How noise is measured Sound levels measured in decibels (dB) 3 dB increase represents a doubling of intensity E.g., 35 dBA + 35 dBA = 38 dBA Does not correlate to what we perceive 3 dB increase is just barely noticeable 10 dB increase will sound 2 x as loud 20 dB increase will sound 4 x as loud Cannot estimate sound intensity by what we hear!

7. Decibel level of common sounds

8. Sources of noise in the classroom Outside noise sources Vehicles Voices Inside sources: Student activity Equipment: computers, projectors Reverberation (echo) of sound within the room Neighbouring classrooms Ventilation and heating systems

9. Signal-to-noise ratio (SNR) Signal-to-noise ratio (SNR): difference in dB between the speech (signal) and the noise Example: Teacher’s voice (signal) = 60 dBA Background noise = 45 dBA SNR = 60-45 = +15 dB

10. What might good SNR sound like? 1. Microphone placed on body of listener, 12 feet from the sound source 2. Microphone placed on lapel of talker - Linda Thibodeau, http://ahrc.utdallas.edu/online/ Thibodeau estimates SNR is +30 dB in quiet and 0 or -5 dB in noiseThibodeau estimates SNR is +30 dB in quiet and 0 or -5 dB in noise

11. “I am a dynamic figure, often seen scaling walls and crushing ice.” - Essay by Hugh Gallagher

12. What SNR’s do children need? Depends on age of child SNR (dB) required to achieve 95% speech intelligibility Grade 1: +15.5 Grade 3: +12.5 Grade 6: +8.5 Young adults (lab): +1 SNR of +10 dB 1 in 10 words not understood by Grade 1’s on average - Bradley, 2005

13. Speech understanding in younger children Auditory system still developing Children’s auditory system not fully developed until late teens (+ 15 yrs) Children do not process sound as well as older children/adults Knowledge base of language not fully developed Don’t have language skills/knowledge to fill in the missing pieces Children rely more on “bottom-up” processing Younger children require better signal quality to understand speech well

14. Double Jeopardy Noise has more detrimental effect on Children learning in non-native language ESL, immersion Children with learning disabilities Children with behavioural, attentional difficulties Hard-of-hearing children (temporary, permanent) Cumulative effects?

15. Ideal listening environment Teacher’s voice is clearly audible Little background noise Good room acoustics Good attenuation of sound from outside noise sources Reverberation (“echo”) in the classroom Not too little, not too much

16. Acoustic characteristics of the ideal listening environment Recommended noise level of unoccupied classroom: ANSI S12.60: 35 dBA Teacher’s voice (relaxed) 60 dBA Reverberation time (RT) between 0.4 and 0.6 sec SNR +15 dB Children may add another 10-20 dB of noise to the classroom Reverberation time is the time it takes for sound to be reflected back to its source.Children may add another 10-20 dB of noise to the classroom Reverberation time is the time it takes for sound to be reflected back to its source.

17. Are the acoustic conditions of our classrooms adequate? In general, no! Noise, reverberation time & estimated speech intelligibility (RaSTI) in most occupied classrooms are unacceptable (ASHA, 1990; Pekkarinen & Viljanen, 1990) Average levels from 43 classrooms (Bradley, 2005) Teacher’s voice (signal): 59.5 dBA (+ 5.5 )* Noise: 49 dBA (+ 7.3)* Mean SNR: +11 dB Bradley study: Eastern Canadian classrooms Measured in 43 Cdn classrooms mostly in small towns, rural settings Urban settings – likely higher outdoor noise levels Warmer climate – open windows, more outdoor noise in class Bradley study: Eastern Canadian classrooms Measured in 43 Cdn classrooms mostly in small towns, rural settings Urban settings – likely higher outdoor noise levels Warmer climate – open windows, more outdoor noise in class

18. SNR in Canadian classrooms (Bradley, 2005) For Grade 1, 9.1% had ideal SNR For Grade 3, 39.9% For Grade 6, 51.5%

19. Effects of poor SNR Students Poor understanding Decreased attention Decreased performance Reading deficiencies Reduced motivation Delayed language acquisition Teacher Contributes to increased vocal strain by teachers Other Fewer verbal interactions between teachers, students More time spent repeating instructions/information and less material covered

20. Impact of poor acoustic environment on teachers’ voices Teachers must adjust voices to be audible above background noise > 40 dB Vocal adjustments contribute to increased vocal fatigue/strain Teachers with occupational voice problems Teacher’s voice quality and therefore the speech signal are compromised, resulting in a poorer student performance Noise levels above 40 dB affect voice use (Pekkarinen & Viljanen, 1990; van Heusden, 1979; Brewer & Briess, 1960; Hetu et al, 1990) Teachers with occupational voice problems present compromised speech signals resulting in poorer student performance (Rogerson and Dodd, 2005)Noise levels above 40 dB affect voice use (Pekkarinen & Viljanen, 1990; van Heusden, 1979; Brewer & Briess, 1960; Hetu et al, 1990) Teachers with occupational voice problems present compromised speech signals resulting in poorer student performance (Rogerson and Dodd, 2005)

21. Occupational hazard? Teachers make up 3.8% of the population in BC Approximately 17% of patients seen for voice disorders at the Pacific Voice Clinic (VGH) are teachers A disproportionate number of teachers experience voice problems Voice problems may lead to Teachers requiring time off work Occupational injury claims

22. Summary of effects of classroom acoustics Poor classroom acoustics are a significant barrier to learning have the greatest impact on younger children and those with special learning requirements contribute to the high incidence of voice disorders among teachers

23. What can be done? Reduce noise levels in the classroom Identify and address noise sources where possible Acoustic treatment of rooms Increase signal quality Sound field amplification (not necessarily helpful if reverberation is excessive) Vocal/speech strategies for teachers Mandate acoustic standards in the BC school building code Noise sources: fish tanks, computers, projectors, Heating ventilation and air-conditioning system (HVAC) OFF Tennis balls on chair feet Noise sources: fish tanks, computers, projectors, Heating ventilation and air-conditioning system (HVAC) OFF Tennis balls on chair feet

24. New and renovated schools Increase awareness of classroom acoustics and noise issues among architects, school officials and administrators Locate new schools away from noise sources (traffic) Apply ANSI standards in the BC school building code Design with appropriate room size, ceiling height, sound separation between rooms Ventilation fans outside of the classroom Appropriate use of absorptive vs. reflective materials to keep reverberation times between 0.4 and 0.6 sec.

25. Existing schools Reduce interior noise sources Classroom management Tennis balls on the feet of chairs and desks Improve reverberation and sound absorption: Acoustic tiles, carpeting Improve sound separation between classrooms, hallways Windows

26. Conclusion Excessive noise and reverberation are significant barriers to effective learning, particularly for younger children and those with special learning needs An adult may not fully appreciate students’ level of difficulty in a classroom situation because adults hear better in noise than children do SNR of +15 dB is critical for an optimal learning environment Excessive noise in the classroom contributes to vocal strain in teachers Classroom noise and acoustics needs to be properly addressed during the design, building and retrofitting of schools

27. What needs to be done? Incorporate classroom ANSI acoustic standards into provincial school building standards Ensure that contributions of noise to teacher voice problems are recognized by 3rd party insurers

28. Additional information ASA: ANSI S12.60 (2002) Classroom acoustics standard http://www.asa.aip.org Lay paper on classroom acoustics: www.cllrnet.ca/Docs/RESOURCES/Lay_paper_02_international-modified.pdf CAA-ACA: Canadian Acoustical Association: http://www.caa-aca.ca/ Canadian acoustical consultants et al. http://www.caa-aca.ca/MainFrame.htm IRC/NRC:Acoustical design of rooms for speech http://www.infosource.nrc-cnrc.gc.ca/reports/ctus/ctu51e.pdf

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