Key to Acoustical Factors in Architectural Design
This key to acoustical factors in architectural design accompanies the article, “The Importance of Acoustics in Architectural Design”
Exterior Sound Isolation – Create a building façade and site design to adequately shield interior spaces from exterior noise sources such as traffic, airplanes, trains, mechanical equipment, and neighbor activities. This practice requires site noise analysis and design of fences, building placement, building façade, and window glazing.
Interior Wall Sound Isolation – Identify noise sensitive adjacencies and spaces for which sound privacy is desired. Generate wall partition assemblies that are compatible with overall desired sound isolation performance. Sound isolation will be governed by mass, resilient decoupling, damping materials, and large air cavities in framed assemblies. Doors and room penetrations (i.e. junction boxes or ducts) must be considered in conjunction.
Floor Ceiling Assembly Sound Isolation – Establish spaces for which vertical airborne sound isolation is needed. Design floor ceiling assembly to provide appropriate sound privacy. Ceiling penetrations such as recessed can lights, sprinklers, and speakers need special optimization to provide aggregate sound isolation value. Coordination is required with finished floors and ceiling transitions between rooms.
Floor Ceiling Assembly Impact Noise Control – Design flooring system to minimize impact noise from footfalls being audible to spaces below. This scope may incorporate special consideration for wall framing as well related to structural sound transmission. Usually a combination of mass and resilient cushioning is needed. Coordination with floor heights between rooms is needed for unimpeded circulation. Wood framed buildings require more care than steel and concrete structures due to structural vibration transmission.
Sound Leakage Paths – Penetrations in walls, floor, and ceiling must be appropriately sealed to reduce sound leakage paths. Penetrations may include junction boxes, plumbing pipes, HVAC ducts, sprinkler pipes, light fixtures, speakers, and low voltage chases. Enclosures, closed-cell foam, putty, and acoustical caulk are generally needed to seal the holes fashioned in a room’s construction.
Plumbing Noise Control – Design solutions to minimize vibrational noise and airborne noise from supply and waste plumbing pipes, showers, dishwashers, washing machines, and toilets. This will entail decoupling hardware at structural attachments, wrapping the pipes in materials, and scrutinizing architectural placement and routing. Water pressure should be tailored to applications. Pumps may require special consideration for airborne and vibrational noise impacts.
HVAC Noise Control – Design HVAC system to provide appropriate air velocities and to attenuate fan noise propagation. Airhandling units will require vibrational decoupling from building structure. Acoustical liner inside ducts, duct silencers, resilient duct connections, duct thickness gauge, and boxing-in duct chases should all be optimized per design target for overall background noise in spaces. Cross-talk between rooms through duct paths should be minimized.
Electrical Noise Control – Switching equipment, power transformers, solar inverters, and light fixtures can be sources of bothersome noise. Appropriate sound enclosures, resilient decoupling, and review of architectural placement should be optimized. Dimming systems should be designed to specific applications. High voltage cabling routing relative to low voltage signal paths should be optimized to minimize induced noise and hum.
Building Vibration Control – HVAC airhandlers, pumps, elevators, washing machines, transformers, exercise equipment, and audio systems can create structureborne vibration noise in the building which can be tactilely felt and heard as audible airborne sound upon reradiating from constructed assemblies. Partition assembly mass, resilient decoupling, and flexible connections to devices are needed to minimize vibrational noise impacts.
Garage Door Noise Control – Motors to operate garage doors and the associate door track system can routinely be bothersome noise sources to adjacent spaces. Garage doors should be selected based on application sensitivity, and after-market acoustical remedies should be applied to reduce related noise impacts. Special ceiling or wall construction may be required to contain airborne sound as well.
Site Noise Containment – Outdoor backup electrical generators, HVAC airhandlers, chillers, spas, pool equipment, and audio systems may require sound attenuation to make the noise source non-nuisance sound level for both the site and the neighbors. Depending on the municipality there are very likely noise ordinances for how much noise may be acceptable at the property line. Enclosures, barriers, exterior-grade sound absorption finishes, product selection scrutiny, and optimization of sound directivity may be needed to provide sound comfort, neighbor harmony, and city code compliance. Design systems to adequately attenuate exterior sound levels.
Interior Finishes and Reverberation – Reverberation quantifies how long sound reflections will remain audible in a space from a sound event. Large volume spaces and spaces with very hard sound reflecting finishes will have long reverberation decay times. Excessive reverberation diminishes sound comfort, speech intelligibility, and program audio. Interior spaces should have the interior finishes tuned to establish an appropriate degree of reverberation decay. Reverberation can be predicted mathematically, computer modeled, and acoustically measured in situ. Establish design criterion for target decay time and generate acoustical material treatment scheme with finishes and surface area coverage to tune the room based on target reverb time.
Audiovisual Media Spaces – Speakers’ directivity / sensitivity / power handling / response, room reverberation decay, background noise, discrete sound reflections, room resonances, and speaker placement all strongly influence the audible quality of AV systems. Any space to have good quality AV performance needs interior acoustical optimization to ensure desired performance of the sound system. Additionally, sound isolation and control of background noise may be of relevance to client goals. Deployment of microphones and speaker phones also require special acoustical considerations.
Dedicated Home Cinemas – The goal of a dedicated home cinema is to translate the director’s artistic statement of audio, video, and acoustical performance directly into the home so the viewer can experience that reference level performance. Home cinemas have the most rigorous of acoustical requirements and highly skilled execution of specialty construction. Background noise, sound isolation, sound containment, acoustically treated interior, standing wave bass resonances, rattle free performance, and optimized speaker locations all play critical roles in overall performance. Produce architectural, MEP, audiovisual, interiors, lighting, and integration documents to expression theater construction.
Home Recording Studios – Similar to home cinemas, home recording studios have very demanding audio, video and acoustical performance targets. Applications of studios can vary widely depending on production needs, music type, ensemble size, and technology deployment. Engage detailed programming phase with the client to understand project needs. Create detailed construction documents and specialty multi-discipline coordination as needed.
Construction Oversight of Specialty Acoustics – Special acoustical and audiovisual construction routinely employ advanced construction methods and materials that may not be immediately familiar to general contractors and subs. Supply construction administration support of responding to Requests For Information and Product Submittals. Travel to the project site to review construction milestones and provide summary field reports of findings and corrections. The room will only perform as well as it is built per design documents; this requires diligence and oversight.