ACOUSTIC COMFORT

ACOUSTIC COMFORTREPORTED BY:PORLAY, MARETSHAMBSA-4AINTRODUCTIONThe acoustical environment of a workspace is typically given little or no attention during project planning and design.FUNCTIONALITYAESTHETICSProviding a comfortable environment for employees contributes significantly to their optimum performance and reduced absence.WORKSPACE COMFORTa combination of factors that includes daylighting & electrical lighting, indoor environmental quality, temperature, and acoustics.The attack on our ears in the workplace came from traffic noise, mechanical equipment in adjacent spaces, and copiers, phones, and voices within the workspace.BUILDING ACOUSTICS is given low priority because it competes for limited project with a number of other project goals, including:sustainable design/development, physical security/anti-terrorism, information technology/telecommunications, and building automation and controls.Several common noise problems affect these occupancies:Too much noise outside the building entering the spaceToo much noise from adjacent spaces, andLack of sound control in the space itself.SITE SELECTIONA satisfactory indoor acoustical environment actually starts by knowing what is going on outdoors. Follow these guidelines when selecting a site for an office building or educational facility:Avoid sites in high noise areasairfields, highways, factories, and railways.Ensure compatibility with existing facilitiesdo not site a school in an industrial area, for example.

Traffic and aircraft noise affect the quality of the interior listening environment.Determine what else is planned for the site in the future. Your building may be the first one built, but if future buildings are acoustically incompatible with yours, significant remediation measures may be necessary to return the interior sound environment to an acceptable level.When the site is predetermined and is too noisy for an office building or educational facility:incorporate appropriate sound control measuresavoid through-the-wall, package terminal air conditioners orient quiet spaces away from outside noise sources.To protect the spaces in a building from noise from a nearby highway or railway, lay out the building so that restrooms, mechanical and electrical equipment rooms, and other less noise-sensitive spaces are adjacent to the roadwayIn designing a campus near high noise activity, locate gymnasiums and other less noise-sensitive facilities closer to the noise source and place buildings needing quiet surroundings in the shadow of those facilities.GLAZINGWindows and glazingare key elements of the building envelope. It allow daylight to enter the space, reject heat and glare, control sound and, for some projects, and explosion resistant.

Multiple glazing types are for many projects based on the building orientation, proximity of disturbing noise sources, and defenselessness assessments and risk analysis.

A. OPEN OFFICE ENVIRONMENTSOpen office environments provide greater flexibility than enclosed offices by using easy to relocate low-height, moveable partitions or systems furniture to form individual workspaces, rather than employing full-height permanent partitions.

These factors have led to an increased use of open office environments in both the federal and private sectors.

Acoustical problems have surfaced in open office environments causing employees distraction, stress, and interference with telephone conversation and normal work routine.

Over 60 percent of occupants in cubicles think acoustics interfere with their ability to get their job done.

Common complaints included: acoustics (too noisy, not enough privacy), thermal comfort (limited temperature control), and daylighting (too much glare and light spill).Contributors to unacceptable noise in the workspace include indiscriminate use of speakerphones, low partition heights, ringing phones, noisy copy machines, and office chatter.Solutions:Specify acoustical ceilings with noise reduction coefficient (NRC) of 0.75.Choose systems furniture with a 60 inch minimum height and have sound absorbing surfaces on both sides.Avoid placing lighting fixtures directly over partitions - they reflect sound to the adjacent cubicle.Locate copy machines in separate rooms away from offices and provide separate ventilation to minimize ozone in the workspace.The ideal office environment would give workers individual control of temperature, lighting, and acoustics in their personal workspace.B. CONFERENCE ROOMS AND PRIVATE OFFICESMost workplace environments should have quiet havensplaces where private conversations can occur without being heard in adjacent rooms or passageways for employee matters, contract negotiations, classified discussions, etc.Some problems that occur in private offices:inability to have private discussionscan hear sounds through partitionstoo noisy in roomcan hear sounds from air return registers

Sound can travel over partition walls and through the suspended acoustical ceiling. To be an effective sound barrier between rooms, partitions need to extend to the structural deck.Solutions:Extend walls from floor to structural deck above.Insulate partition cavity/increase partition sound transmission class (STC).Specify NRC of 0.75 for ceiling tiles.Employ ducted air return system.Do not locate mechanical equipment rooms next to offices and conference rooms.STC (Sound Transmission Class) ratings are used to describe the performance of assemblies in reducing airborne sound.

While higher than current Code requirements, the STC ratings presented in the chart below will provide enhanced building comfort.C. CLASSROOMSClassrooms are environments designated for learning, not just for school-age children, but for adult trainingas well. Classrooms have become multimedia communications environments,Good acoustics for learning support easy verbal communication, which requires low noise levels and very little reverberation. In the past, classrooms may have been constructed without adequate consideration of sound acoustical principles. Sources of noise hampering students' concentration include:outside of the school (vehicular traffic and aircraft flyover)the hallways (foot traffic and conversation)other classrooms (amplified sound systems and inadequate partition sound transmission loss)mechanical equipment (compressors, boilers, and ventilation systems), andinside the classroom itself (reverberation).APPLICATIONDaylighted offices and classrooms HVAC noise issues Natural ventilation Sound masking Sustainability and acoustics Fire safety

EMERGING ISSUESDirectional sound is a new technology in fire safety. It is an audible means to lead people to safety. The varying tones and intensities coming from directional sound devices offer easy-to-understand cues for finding the ways out. Advantages of directional sounders:can lead people of all languages to exitaudible clues can direct people with visual impairmentsespecially helpful in smoke-filled environmentsupward or downward sweeping tones alert occupants to go up or down stairways to exit building.THE END