May 15, 2006

Interior Matters Brandon Tinianov

Comfort can fit into green builds

As green buildings become widely adopted in North America, evaluations of their comfort and suitability as rated by the first wave of occupants have become available. The findings of the Center for the Built Environment at UC Berkley show that green buildings lead their traditional counterparts in many facets of building comfort, including air quality, thermal comfort, cleanliness and general occupant satisfaction. In fact, acoustical performance is the only area in which green buildings lag in performance behind traditional building types.

Although rarely discussed, acoustical comfort is critical to ensure worker health and productivity. Research by the American Society of Interior Designers (ASID) shows that 71 per cent of surveyed workers feel that noise is the main factor of workplace distraction. Of the same workers polled, 81 per cent feel they would be more productive in a quieter environment and 52 per cent find existing office noise levels stressful. The problem of acoustical comfort needs to be addressed.

When green building designs succeed in so many important ways, why are they failing with regard to acoustical comfort and noise control? The reasons are threefold: natural ventilation, radiant cooling and a reluctance to use fibrous materials.

Natural Ventilation — Green buildings have revolutionized passive ventilation in modern design by using the ‘stack effect’ in multistorey buildings. This technique creates paths for fresh air to enter occupied spaces low on exterior walls, flow across the occupied spaces and paths for exhaust air to vent into central locations such as atriums and towers. Natural temperature differences allow for the building to breathe passively without fans or ductwork. Unfortunately, these large paths allow all of the sound to move freely between offices no matter what the type of wall.

Radiant Cooling — Another energy-saving technique used in green buildings is that of radiant cooling. In this case, the term refers to the use of exposed concrete slab ceilings throughout the building. During the day, lights and people heat the massive slab, keeping the working space cooler. At night, the slab gives off this stored heat, warming the cool building. The acoustical problem occurs when drop ceilings are eliminated to expose the slab. The hard concrete reflects sound, creating a reverberant, gymnasium-like environment. Noise levels increase and productivity falls.

Fibrous Materials — A final acoustical concern in current green building design is a reluctance to use popular fibrous absorbers such as fiberglass.

This often leads to the use of reflective walls and cubicle dividers, which create a detracting environment with little privacy. While other green fibrous materials are available (including recycled denim and cotton batting), their performance does not equal that of fiberglass. Designers must be aware of the material differences and allow for greater surface coverage within the occupied spaces.

These problems can be overcome. To do so, building owners and green designers must be aware of possible issues early in the design phase. An acoustical professional should be consulted during the initial design phase to point out and rectify the issue of acoustical comfort before a retrofit is warranted. In addition, the stakeholders should consider the building materials, not only for their recycled content but for their acoustical properties. The comfort, productivity and health of the next wave of green building occupants depends on these choices.

Bandon Tinianov is Vice President, Engineering with Quiet Solutions. He is a recognized expert in architectural acoustics, P.E., and INCE Board Certified.

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