Armstrong Education Segment Solutions Enhancing the Learning Environment Through Better Acoustics About Us
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ARMSTRONG EDUCATION SEGMENT SOLUTIONS ENHANCING THE LEARNING ENVIRONMENT THROUGH BETTER ACOUSTICS ABOUT US Armstrong World Industries, a global leader in design and breadth of India and has sales offices in a few cities that manufacture of ceilings and has a history of more than are strategically located close to our customers. 150 years; our innovative product designs, solutions and Armstrong has a joint venture suspension system services enable our customers to deliver the exceptional manufacturing plant (WAVE) located in Pune. We service interior spaces they envision. Armstrong offers innovative our customers through our 5 regional warehouses supported interior solutions that help to enhance comfort, save time, by our state-of-the-art central warehousing facility at improve building efficiency, overall performance and Bhiwandi, near Mumbai. Armstrong offers the broadest create beautiful spaces. portfolio of acoustical ceilings in mineral fibre, metal, wood, Our India office has been serving the market for more than soft fibre and translucents.We endeavour to offer a ceiling 50 years and is headquartered in Mumbai. Armstrong has products for every space and can offer custom solutions to presence in more than 100 cities across the length and meet your design and aesthetic needs. 2 INDEX OF CONTENTS Challenges in modern education facilities.............................................................................................................................5 Acoustics in school: An overview.........................................................................................................................................6 Reverberation tool: Hear the difference.................................................................................................................................7 GRIHA - Guidelines for education facilities ...........................................................................................................................7 A ceiling for every space.....................................................................................................................................................8 Success stories..................................................................................................................................................................9 Reference projects in India ...............................................................................................................................................12 Do more with your ceilings................................................................................................................................................13 Contact us.......................................................................................................................................................................16 3 CHALLENGES IN MODERN EDUCATION FACILITIES On average, students hear only 3 out of 4 words in the Classroom* Poor acoustic design in classrooms results in high reverberation. As a result, at least 25% of what a teacher says is lost to the students. Trying to hear in a poor acoustical environment is like trying to read in a room with the lights off: stress increases, concentration decreases and learning is impaired. This is especially true for younger students for whom english is a second language and for those with hearing impairments. The correct reverberation time is achieved by having the correct amount of sound absorbing material within the space for its intended purpose. * Acoustical Society of America [ASA], 2000 Inverse Square Law 80 +15 dB 60 +9 dB Signal +3 dB 40 Background Noise -3 dB loudness, dB loudness, 20 0 3 6 9 12 15 18 21 24 27 30 Speakers/signal source-to-listener distance (SLD) Sound gets transmitted between classrooms from corridors outside and from the floors above. We need to have proper walls and partitions to avoid sound travel between the classrooms and from corridor to classroom. Ceiling inside the classroom will provide extra 35dB sound insulation for noise above the classroom. Apart from sound blocking, sound absorption of the surfaces of the space becomes important in open plan area, lobby and corridor to reduce noise in the classroom. Many teachers are losing significant life expectancy by teaching in stressful environments day after day. The average noise in a classroom in India is 65 decibels. In order to make themselves heard over the noise in the classroom, teachers need to talk at 75 db. As noise goes up, the teacher’s heart rate goes up. This is not good for the teacher, as 65 decibels is the threshold for the danger of myocardial infarction or a heart attack. In fact many teachers are losing significant life expectancy by teaching in environments like this day after day. 4 ACOUSTICS IN SCHOOL: AN OVERVIEW What is reverberation? Direct Sound A reverberation is prolonged reflection of sound energy The sound of a teacher’s voice traveling directly from the off the surfaces and objects of a given space. The harder teacher to the student is direct sound. It is always beneficial the surface the longer it takes for reverbaration to subside. in terms of speech intelligibility because it is not affected by anything in the room, making it clear and distinct. What is reverberation time (RT)? A measure for rating the quality of the sound environment Reflected Sound within an architectural space, and it appropriateness for Reflected sound takes longer to reach the listener than direct various uses. Specifically, the reverberation time is the time sound because its path to the listener is longer. Reflected it takes for reflected sound within a space to decrease by sound can be good or bad depending on the time delay. 60 dB after the sound was made, for instance, the time it Shorter reflections are prefered for spaces meant for teaching. takes before you cannot hear a loud clap. An RT60 < 1 sec. Plantroom Noise is beneficial for good speech intelligibility, whereas Aircraft Noise & Vibration RT60 > 2.5 sec is appropriate for symphony music. Wheather & Rain Noise Ductborne Noise Fan Noisy Break-Out/Break-In Why is it important? Corrdors of Ductborne Noise Traffic Noise & Vibration It is an indicator of quality of sound with lower RT’s preferred Noise Through Door & Walls for speech intelligibility (means the degree to which speech Playground can be understood) and relatively longer RT’s preferred while Ductborne Noise Noise listening music. Teachers and students will do their best in Plumbing Noise an environment that is conducive to learning. A poor acoustical environment (Read: Room with inappropriate RT) Background Noise will often increase stress and decrease concentration, Any sound that is generated outside the building, such as especially with younger children. playground activity, traffic and planes can be considered background noise. It generally intrudes in the classroom by way of the windows. Within the building, an HVAC system, Without Acoustical Ceiling fan and corridor noise can contribute to background noise. Are the students getting same quality learning, while paying the same fees? Unlike background noise which remains relatively constant around a room, the teacher’s voice (signal) varies greatly depending on where that teacher is located and where the SNR Sound incidence angle is not uniform hence last row student’s cannot hear speech clearly. (Signal to Noise Ratio) is being measured. This is because sound decreases over distance; specifically it drops 6 decibels for every doubling of distance. It is called “Inverse Square Law” for sound. High NRC Acoustical Ceiling What the teachers are also to be mindful is that they need to raise their voice level to ensure that the last benchers are hearing and understanding. Which make her voice not only Acoustical Wall Panel harsh but she compromise on articulation of words / voice modulation in her delivery of a session. Which affects the quality of learning. Sound incidence angle is uniform hence speech can be clearly heard in the room without reverberation & background noise. 5 REVERBERATION TOOL: HEAR THE DIFFERENCE To help demonstrate the beneficial effect of acoustical treatment in classrooms, we’ve developed a web-based, interactive Reverberation Calculator that allows you to actually hear the difference in sound quality before and after treatment. It will even provide recommendations for a new space or an upgrade to an existing space. To access the calculator, simply log on to www.armstrong.co.in/reverbtool and follow the prompts regarding a description of the space and its surface materials. The program will first calculate the current reverberation time and allow you to hear the quality of the sound. Following selection of acoustical treatment options, it will then allow you to hear the difference in sound quality and reverberation time. MODEL CLASSROOM STUDY CONDUCTED IN INDIA # Study conducted by Jost’s Engineering Company Limited with Bruel & Kjaer instruments. This is a Denmark based firm. The procedure followed to conduct Model classroom study : Stage 1 – Acoustical parameters for existing classroom Name of Insti- Room RT RT BNL BNL Ceiling and objective feedback of the occupants tute / School Size (m3) Before After Before After Solution 1. Measuring back-ground noise in the classroom during Fine the school hours. Saraswati Mandir 181 1.63 0.57 59 49.6 Fissured - Mumbai 2. The RT of current un-treated classroom, will be measured Hi NRC either before 6 o’clock in the morning or after 11 o’clock Central University Fine in