As the link between building occupants and building owners, facility managers (fms), are on the front line of better indoor air quality (IAQ). The expansion of the green building movement has brought increased awareness and the desire for improving or maintaining IAQ and indoor environments during building design, maintenance, and operations.
Building owners may wish to be educated about how, where, and when to achieve better IAQ. Fms have an important role in developing a roadmap for good IAQ at the building level and informing their owners of its benefits.
In making the case for implementing better IAQ, there are three steps fms can take: increase their knowledge on IAQ; become involved as a key team member in facility design or retrofits; and help with the practical concerns of building owners, including the need for energy efficiency and a consideration of the effects of climate change on IAQ practices.
Underfloor Air Distribution Provides A Breath Of Fresh Air
By Scott Alwine, LEED AP
In commercial structures across the country, designs vary inside and out according to owner preference and occupant requirements. But with increasing frequency, even the most disparate structures reflect a common and growing interest in green construction and its impact on indoor environmental quality (IEQ). The desire to improve indoor air quality (IAQ), increase energy efficiency, and reduce their carbon footprint is bringing facility managers (fms) in every sector—healthcare, education, manufacturing, entertainment, and retail—to the sustainability table in search of cost effective solutions to the challenge to go green.
One such solution—raised access floors—can attractively provide sustainable, high performance benefits in a cost-effective manner in both new construction and retrofit applications. This solution brings with it improvements to IAQ, personal comfort, acoustics, energy efficiency, daylighting, and aesthetics even as it ensures reductions in operating costs and downtime associated with technological and organizational changes.
What Is Access Flooring?
An access floor is a raised system comprising an understructure and welded steel floor panels filled with lightweight cement. The understructure provides positive positioning and lateral retentions, assuring that the floor installs quickly and is soundly supported on all contact points. The 24″ square floor panels use typical finished floor heights from 2″ up to 24″ on an understructure that offers a height adjustment leveling device to ensure the floor is level, even when the slab is not.
The real benefit of the system, however, is the underfloor pathway created by the raised floor panels. This type of service distribution system provides housing for modular wiring, passive or active zone cabling and heating, and HVAC service.
A building design that uses the pathway as a plenum for underfloor air distribution (UFAD) eliminates the need for overhead ductwork and dropped ceilings and replaces a conventional HVAC distribution system that forces cool air from the ceiling to the occupied zone, typically identified as the space from floor level up to 6′. Instead, floor mounted diffusers supply fresh, cool air from the underfloor plenum directly into the occupied zone. In the process, warmer, contaminated air is carried to the ceiling by natural convection and removed through return outlets in the ceiling, keeping it from circulating back into the occupied zone and diluting or mixing with clean air as it enters the space.
Because a UFAD system supplies air from the floor without passing through the warmer air near the ceiling, air can be delivered at warmer temperatures. This one directional airflow coupled with the warmer cooling temperatures not only provides more effective ventilation, but it also allows more fresh air to be brought into the building during expanded economizer hours. The resulting ventilation can exceed the ASHRAE 62.1-2004 rate by as much as 30% and help achieve LEED IEQ credit two by delivering fresh air directly to the occupants’ breathing zone.
Comfort is also improved, because building occupants can easily adjust air direction and volume according to individual preferences. And when it’s time to reconfigure the office building, the portability of these air diffusers makes the move easy, enabling fms to plan their spaces around functional requirements without being limited by fixed, inflexible services.
Underfloor Air At Work: A Healthier Option
Flexibility was the primary reason that the Podiatry Insurance Company of America (PICA) selected a raised floor system for its corporate headquarters in Nashville, TN. Hired to build and manage the 102,000 square-foot commercial office building, JC Blakely, CFM, PICA corporate facilities manager, described the PICA culture as one that works in teams and requires the ability to move people and offices around.
“For this reason, the combination of raised access floors and moveable walls was attractive to the organization and has already proven to be invaluable,” says Blakely. “Since the building opened in 2008, I would estimate we have moved at least 10% of the building’s walls, which was definitely made easier by the raised access floors.
“But what really amazed us were the side benefits that the UAFD system has provided. We have saved approximately 38% of our HVAC costs, because we’re not running fans as hard.”
The static pressure required for an UFAD system is typically .05-inch wg, which is significantly less than the amount of the pressure required to force air through rigid ductwork in an overhead system. As a result, the HVAC system uses less fan energy while the increased supply temperature can expand the use of the economizer. For the building owner, this means a reduction in HVAC energy costs.
“We can also attribute energy savings to the fact that we don’t have to provide 55°F supply air,” Blakely added. “Instead, we’re running supply air at approximately 60°F to 61°F.
“Just as importantly, our IAQ is exceptional. In our old building, it seemed that whenever someone got sick, the illness traveled through entire departments. In this building, we seem to have eliminated that problem. The air is just cleaner, since it’s being delivered directly to the breathing zone versus being forced down from overhead ducts along with all the particulates in the ceiling area. So fresher air is an added benefit of the UFAD system for which we are quite grateful.”
Blakely reports that building occupants also appreciate the comfort that a UFAD system offers. In an occupancy survey conducted six months after PICA employees moved into the facility, employees responded positively to questions regarding the HVAC system. “They feel comfortable and appreciate the ability to control the volume and direction of the air entering individual work spaces,” Blakely says.
“We have a vested interest in sustainable design, and the underfloor service distribution system supports that interest, offering flexibility for change and growth, energy savings, and improved IAQ and personal comfort,” he adds.
Advancements Increase Energy Savings
Today, advances in technology are extending the benefits of UFAD to the building perimeter. For example, recently introduced in floor chilled beam technology combines the benefits of UFAD with the efficiencies of water heating and cooling. Water pipes pass chilled and hot water through a heat exchanger or beam, which is then capable of heating or cooling air delivered to the space. This can reduce energy costs and avoid many of the concerns of an overhead chilled beam, including damage from leaking water lines and latent loads producing condensation. Instead, the beams bring chilled water under the floor to cool air directly at the perimeter of a building, where heat loss and heat gain can significantly impact energy use.
What does this mean for the fm? Increased energy savings, less potential for property damage, and better aesthetic appeal in the perimeter zone of the building, since the chilled beams allow for fewer air diffusers in the space.
UFAD: Leading In LEED Points
Since the system creates a healthy, productive, and flexible work environment, and improves energy efficiency, a sustainable, raised access floor can contribute to the accumulation of points for LEED certification in the following categories: Energy and Atmosphere, Materials & Resources, IEQ, and Innovation. Contributions can be realized for optimizing energy performance, material reuse, recycled content, increased ventilation, controllability of systems, thermal comfort, and daylighting.
The floor system also offers a competitive solution when compared to traditional service distribution methods. Fit out and operating cost savings can be attributed to:
• Voice and data cabling;
• Power wiring;
• Air distribution;
• Ceiling; and
• Time to occupancy.
Raised access floors respond to demands for flexibility, energy efficiency, and healthy work environments by offering fms an integrated, cost effective approach to the distribution of power, voice, data, and HVAC services.
In the process, they can provide interior space flexibility, improve IAQ, and enhance life cycle material savings, delivering a single solution that offers a range of green benefits.
Alwine is the marketing manager for Tate Access Floors, Inc. He is LEED AP and has eight years of experience in the building products and services industry.
Fortunately, there is excellent information available from a variety of resources outlining potential IAQ problems and solutions. Fms can use the material contained in these resources to serve their owners’ best interests and strengthen IAQ within their buildings.
The Lawrence Berkeley National Laboratory’s (LBNL’s) Indoor Air Quality Scientific Findings Resource Bank, sponsored by the U.S. Environmental Protection Agency, has a variety of readable, brief summaries on IAQ issues as well as key definitions. These summaries provide information and practical guidance on specific topics related to IAQ including impacts of building ventilation on health and performance; indoor dampness, biological contaminants and health; indoor volatile organic compounds (VOCs) and health; and impacts of indoor environments on human performance and productivity. For example, one of the links for information on indoor dampness has a section on “Implications for Good Building Practices” which contains a helpful summary of practices necessary to reduce dampness problems.
Building Air Quality: A Guide for Building Owners and Facility Managers, developed in 1991 by the EPA and the National Institute for Occupational Safety and Health, remains a good introduction to preventing, identifying, and resolving IAQ problems in public and commercial buildings. Fms can use this resource to further their comprehension developing an IAQ profile of building conditions and creating an IAQ management plan, implementing investigative strategies to identify causes of IAQ problems, and determining whether an IAQ problem has been resolved.
Indoor Air Pollution: An Introduction for Health Professionals summarizes the human signs and symptoms of health problems attributable to poor IAQ. This includes the effects of such pollutants as carbon monoxide and mold on building occupants.
Indoor Air Quality Guide: Best Practices for Design, Construction, and Commissioning serves as a comprehensive and practical resource aimed at helping achieve better IAQ in commercial and institutional buildings. The guide, published in 2009, contains helpful illustrations, including a number of cutaway building sections. These depict—to describe two of many examples—strategies for radon control at the ground level with potential ventilation paths and practical whole building strategies to limit the impact of emissions.
Photographs of real case study buildings depict practices to avoid, such as examples of weak points where water may intrude into the building envelope or poorly placed air intakes. The guide was developed by a team of IAQ experts in coordination with the EPA, American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), American Institute of Architects (AIA), Building Owners and Managers Association International (BOMA), Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA), and U.S. Green Building Council (USGBC).
IAQ Considerations During The Design And Retrofit Process
During the design or retrofit process, recognition of the factors which contribute to good IAQ will help lead to improved IAQ during facility operations. Getting IAQ principles to the building design table will help bridge the transition between design and operations. Fms need a place at this table.
Indoor environmental quality (IEQ) is included as a thematic category in green building rating systems such as LEED, which has encouraged the traditional design team of owners, architects, and engineers to think about good IEQ early enough in the design process to make a difference. In LEED, IEQ planning typically results in improved daylight and views, systems controllability, and better thermal comfort. But what about IAQ?
LEED project teams often start to think about IAQ during construction. However, considering it early in the design process is the real key to later positive building performance.
Now that integrated design management principles encourage building owners to establish a multi-disciplinary design and operations team, fms should be at the table during design, bearing questions such as these:
- What are the building’s local climate characteristics and effects (prevailing winds, prevalence of atmospheric ozone, annual rainfall, and more) and their potential effects on IAQ?
- Where are the outdoor air intakes and air outlets in the building? Are they accessible for maintenance? What is near them that shouldn’t be?
- Is there enough spatial distance so the building occupants can walk off (or shed) most surface contaminants after entry?
- What are the facility’s passive ventilation strategies (operable windows, chimneys/stack effect)?
- What are the building’s permanent strategies for moisture control to provide human comfort, reduce the risk of mold, and increase the durability of the facility?
- Have minimum ventilation requirements been implemented to reduce moisture and exposure to pollutants from indoor sources by exhausting pollutants to the outside and ventilating with outdoor air?
- Has the team chosen low emitting products to reduce occupant exposure to chemical contaminants in indoor air through strategic product selection?
- Is there an Integrated Pest Management plan in place to minimize the need for chemicals for control of insects, rodents, and other pests?
- Are IAQ maintenance and housekeeping programs proposed? Good preventive maintenance and housekeeping habits are at the core of establishing and maintaining healthy IAQ in buildings.
The Concerns Of Building Owners
Fms, in acknowledging the range of concerns building owners face, can integrate solutions for these concerns with the pursuit of better IAQ. Commercial building owners in jurisdictions such as New York City and Washington, DC are under new mandates to report energy use at the building level.
Examples of legislation requiring benchmarking and annual reporting of energy use in public and private sector facilities are two interlinked District of Columbia legislative acts: the Green Buildings Act of 2006 and the DC Clean and Affordable Energy Act of 2008; and these are interlinked mayoral mandates of New York City’s Greater, Greener Buildings Plan. The pressure to achieve energy efficiency need not compromise good IAQ.
For example, fms know that an effective and achievable retrofit strategy is heat recovery, which can equally serve energy efficiency and IAQ goals. Having a heat exchanger between the inbound and outbound airflows can, if designed properly, reduce energy use, improve airflow, and enhance comfort.
Additionally, in retrofits or new construction, fms may want to suggest to owners that they consider displacement ventilation strategies. Displacement ventilation, relying on the ancient principles of buoyancy, can produce multiple positive outcomes such as reduced energy use, better thermal comfort, and improved IAQ.
The “New Normal”—Extreme Weather Events
Fms should be aware that buildings designed to operate under the existing climatic conditions may not function well under altered climatic circumstances. In June 2011, the Institute of Medicine released a report entitled Climate Change, the Indoor Environment and Health, commissioned by the EPA.The report points to three key findings:
- Poor IEQ is creating problems and impairs the ability of building occupants to work and learn;
- Climate change may further worsen existing indoor environment problems and introduce new issues; and
- There are opportunities to improve public health while mitigating or adopting to alterations in IEQ by climate change.
Fms can assist their owners in understanding these issues and in planning for the practical consequences of climate change for IAQ. For example, they may proactively flag maintenance issues for extreme weather events, where emergency applications of de-icers and other potentially toxic substances may be needed.
IAQ Impacts Human Performance And Productivity
An informative discussion of the economic impacts of indoor environments on human performance and productivity is available in The Lawrence Berkeley National Laboratory’s Indoor Air Quality Scientific Findings Resource Bank. The site’s examination of the cost effectiveness of improving indoor environments to increase productivity contains information that fms can use to make the economic argument for better IAQ. In addition, there are specifics to summarize and quantify the performance benefits of specific strategies, such as the advantages of good building ventilation.
Fms who take these steps and commit to educating themselves and their owners on the means and methods of achieving good IAQ can expect happier owners, healthier and more productive building occupants, and a lighter maintenance workload in a more durable, more problem free facility.