2. “First we shape our schools, then they shape us.”then they shape us.”

3. How big is the problem?  Experts believe that as many as one-third of all students miss up to 33 percent of the oral communication that occurs in the classroom.  Experts have concluded that an SNR of +15 dB throughout the classroom provides the acoustical environment necessary for all students to fully perceive oral messages.

4. Classroom Acoustics Teachers have difficulty teaching and students have difficulty learning in noisy classrooms. The quality of the acoustical environment is vital to all students since they must be able to understand the teacher to learn effectively. Selection of the proper acoustical treatments can play a critical role in increasing the signal-to-noise ratio and reducing reverberation time.

5. 28% of our nation’s schools list noise as the #1 problem. Noise causes students to miss one- third of spoken communication in class. Noise interferes with speech intelligibility. The effort to counter noise creates vocal fatigue in teachers. Classroom Acoustics Source: Coalition For Classroom Acoustics

6. What’s the ANSI Standard S12.60-2002 all about? Acoustical Design Criteria For Classrooms ANSI S12.60 reverberation time, maximum acceptable 0.6 seconds [at 500, 1000, 2000 Hz] The maximum permissible background-sound level for "typical" classrooms is 35 dBA, with a maximum reverberation time of 0.6 to 0.7 second (depending on room volume).

7. Studies Show: Some classrooms today have reverberation times as high as 2.8 seconds. Some classrooms today have background noise levels as high as 66 dBA.

8.  Background noise is the effect of all sound sources, from both outside and inside the classroom, excluding students and teacher.  High levels of background noise can mask speech sounds, thus reducing speech intelligibility.  Background noise is measured in dBA. Background Noise

9. Black arrows are direct sound. [Direct sound is good for intelligibility.] Red arrows are reflected sound. [Reflected sound may compromise intelligibility.] Sound In Rooms

10. When you reduce reflected sound, you lower the reverberation time. Treat the room with high NRC ceilings and use low face weight carpet. Instantaneous activity noise levels are reduced by 23% with carpet vs. VCT. Reducing Reflected Sound

11. Sources Of Background Noise

12. Ceiling  Suspended ceiling.  High NRC 0.70/high CAC 40.  ¾" mineral fiber panels. Ref. ANSI S12.60, 0.6 seconds max.  500 Hz, 0.60 seconds  1000 Hz,, 0.56 seconds  2000 Hz, 0.52 seconds BeforeAfter Ceiling  Spray-up fiberglass insulation.  Approximately ½" thick.  Approximate NRC 0.25. Ref. ANSI S12.60, 0.6 seconds max.  500 Hz, 1.3 seconds  1000 Hz, 1.09 seconds  2000 Hz, 0.85 seconds When reverberation isn’t uniform, speech sounds “boomy.” When reverberation is uniform, speech sounds “natural.” The “before” classroom did not meet the ANSI standard for reverberation time at all three frequencies. The new “after” ceiling meets the standard at all three frequencies.

13. Indirect Full Spectrum Lighting Light bulbs are typically classified as "full spectrum" when they have a CRI (Color Rendering Index) around 90 and a Kelvin temperature around 5250K.

14. What is Kelvin Temperature? Kelvin Temperature indicates a specific hue or color of a light source. Scientist William Kelvin developed this temperature rating scale in the late 1800’s. Kelvin took a cube of black carbon, heated it and recorded the color hue at certain temperatures. 0° Kelvin is pure black while 8,000 – 10,000° Kelvin represents a cloudy day. 5,000 – 5,500° Kelvin represents noonday sunlight. 2,500 – 3,000°K represents normal, indoor tungsten lighting, and 3,200° represents standard fluorescent lighting. What is Color Rendering Index (CRI)? The Color Rendering Index is a scale (100) that represents how closely a light source depicts or reflects an object’s true color. As a general rule of thumb, the higher the CRI, the more accurate an object will appear. In the lighting industry, a CRI of 85 or higher depicts a truer color.

15. Cool White vs. Full Spectrum Lighting Note: An incandescent bulb with its color temperature of 2800 Kelvin has a CRI of 100.

16. How does lighting affect students? Improved mood Enhanced mental awareness, concentration and productivity Superior visual clarity and color perception Better sleep Super-charged immune system More energy Reduced eye strain and fatigue with a glare-free and comfortable reading environment Greater learning ability

17. Harmful Effects of Standard Fluorescent Lighting Few doubt the advantages of newer lighting technology over standard fluorescent lighting developed decades ago. Standard technology’s focus was on efficiency— how to produce the most light for the least cost. The problem is that this technology produced lighting with a green or purplish hue. Worse yet, the cheaper magnetic ballasts cycle at a frequency which is perceptible by the brain, and causes many people to become sick or nauseated. Those prone to epileptic seizures are more susceptible when in this light, and some people get migraine headaches. In Europe, Germany has gone so far as to ban cool-white fluorescent lights from government offices.

18. Non-differentiated Wall