Green Design and the Acoustic Performance of Contact Centers
| Published: November 07, 2013 | Comments
The demands of serving customers in real time and meeting performance targets make contact centers one of the most challenging environments in which to work. Add a problem such as poor acoustics to the equation and the stress levels climb even higher.
Representatives must cope with coworkers constantly talking around them, as well as noise arising from people walking by, telephones ringing, office equipment, building mechanicals and more. These distractions are detrimental to a profession that requires good listening skills and accurate information to be taken. Noisy environments also heighten tension and lower morale, contributing to absenteeism and turnover rates – already serious issues for many centers.
In addition, because it affects representatives’ performance, noise can impact a customer’s experience. Stressed employees are less able to manage negative emotions or display empathy. Noise can also contribute to an unpleasant calling experience by broadcasting over the telephone. Given that contact centers are increasingly a company’s first line of contact with current and future customers, these factors can ultimately affect satisfaction and loyalty.
In other words, design choices that have a detrimental effect on acoustics can end up costing a contact center a lot in the long run. Often, these decisions are made with good intentions, but without full understanding of their impact, as is often the case with many of the current tactics used to improve airflow, energy efficiency and access to daylighting in green buildings.
Therefore, when planning a LEED® certified or ‘green’ contact center, it is important to understand how to minimize the negative impact common sustainable design strategies have on speech intelligibility and noise control. The ABC Rule provides a good framework for this discussion. This acronym stands for the principal methods used by acoustic professionals to achieve effective acoustics: absorb, block and cover.
Absorptive materials reduce the volume of noises reflected back into a space, the length of time they last and the distance over which they travel.
Because the ceiling is usually the largest uninterrupted surface in a facility, using a good absorptive tile is important. Select a ceiling tile with at least a 0.75 Noise Reduction Coefficient (NRC) for open plans. In closed space, use tiles with a high Ceiling Attenuation Class (CAC) because they are better at containing noise. Most manufacturers suggest a rating of 35+ indicating a high-performing tile suitable for private offices. Ideally, tile coverage should be uninterrupted (i.e. no openings or cloud-style designs).
However, many green buildings have open ceilings. If the intention is to use the exposed deck as a heat-sink to help control the temperature within the building, it is important to research whether this decision will have the desired heating/cooling benefits or the ceiling tile will be eliminated without cause. If cost is the reason for eliminating the tile, it is key to look beyond initial savings. For example, the Ceilings and Interior Systems Construction Association (CISCA) found that while suspended ceilings cost more upfront, they showed significant energy savings over their life due to HVAC efficiency and better light reflectance.
If an exposed structure is still desired, to treat a percentage of the deck with an absorptive material or vertical baffles.
Workstation panels should be absorptive, particularly if there is no acoustical ceiling tile. However, if cost is a concern, just use absorptive panels on the inside of the partitions above the work surface, reducing the reflection of the occupant’s voice into the neighboring workspaces.
If the space is narrow in order to promote natural light penetration, use absorptive panels on select walls in order to prevent noise from ricocheting between the exterior wall and the core.
Footfall noise on hard flooring is a particularly intrusive noise that is difficult to address once generated. Therefore, use soft flooring to reduce it, at least in high traffic areas.
Blocking prevents noise from travelling through the air, through partitions, under, over and around obstructions, and by means of penetrations, such as ducts.
If there is no ceiling, build walls to the deck. If there is a suspended ceiling, walls can stop at the ceiling. Walls should have a high Sound Transmission Class (STC) rating to prevent airborne noise transmission. Do not locate penetrations such as outlets back-to-back on opposite sides of a wall. Ensure the STC rating of doors and interior windows at least meets the wall standard.
Many of these requirements also apply to demountable wall systems, which are often used to enclose spaces in green buildings. These systems may have lower STC ratings than conventional walls and the joints between the panels may provide conduits for noise. Address any gaps along the ceiling, exterior walls and floor during installation or they will easily transmit noise.
In open plans, using workstation partitions above seated head height (60 to 65 inches) is essential to attenuate the noises passing to an occupant’s nearest neighbors. If the partitions are lower, they provide very little acoustical value.
However, in green buildings partitions are often lowered or eliminated altogether in an effort to increase window access and daylighting. In these situations, use partitions that rise to 48 inches and are topped with a further 12 inches of glass. This format provides the physical barrier needed between close neighbours, while not impeding daylighting. The top 12 inches introduces a reflective surface, but the reduction in absorption relative to the increase in physical blocking is an acceptable compromise. Also ensure the panels have a high STC rating and are well-sealed along any joints, with no significant openings between or below them.
HVAC systems should be designed in such a way that they do not compromise acoustic isolation.
We have all heard the old adage ‘silence is golden’ and, indeed, many people believe they will achieve effective acoustics by implementing just the first two strategies involved in the ABC Rule, which simply reduce and contain noise. However, just as with lighting and temperature, there is a comfort zone for the volume of sound and it is actually not zero. For this reason, the final step of the ABC Rule involves ensuring that the background sound level in the space is sufficient.
The background sound level in most conventional offices is already too low. The use of high-efficiency heating and cooling systems means that it is generally even lower in green buildings. Conversations and noises can easily be heard, even from afar, and are more disruptive. These problems are exacerbated when open windows are used to assist with air circulation, allowing exterior sounds to drift inside. In some cases, different strategies are used along the exterior and core, creating variable acoustic conditions across the space.
A sound masking system is used to replenish the background sound level and maintain it at an appropriate volume.
This technology consists of a series of loudspeakers, which are installed in a grid-like pattern in or above the ceiling, and a method of controlling both their zoning and output. Unlike airflow, the sound the loudspeakers distribute is continuous and has been specifically engineered to increase speech privacy. Masking also covers up intermittent noises or reduces their impact by decreasing the amount of change between baseline and peak volumes, improving overall acoustical comfort. It also decreases the amount of noise customers hear over the telephone, providing a more pleasant calling experience.
Research shows a strong connection between the use of sound masking and increased productivity in contact centers. While the return on investment for each location varies, one independent expert indicates that the average is between 6,000 and 9,000 percent (Kingsland).
Using a sound masking system can also help support other sustainable endeavours, especially when included in the project’s design stage. For instance, masking increases noise isolation in open areas. Natural ventilation can be employed without affecting speech privacy and the amount of noise disruptions occupants experience. It can also pave the way for using more open plan space and demountable wall systems, contributing to the space’s flexibility and reducing waste following future renovations.
Planning for acoustics early in the design process provides the opportunity to focus on maximizing occupant satisfaction from the outset and avoid the costs – not to mention the headaches – that arise when Indoor Environmental Quality (IEQ) issues must be fixed later on. For those project teams that potentially lack the budget for an acoustical consultant, this article provides a clear list of the required steps and technologies, which is preferable to ignoring acoustics altogether. Indeed, improving noise control and reducing speech intelligibility makes a contact center an easier place to work, helping representatives provide customers with efficient, accurate and professional attention.
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