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Americans spend approximately 90% of their time indoors1 and as a result their comfort, health, and work performance rely heavily on indoor environmental quality, or IEQ.2 The indoor environment of an office facility is affected by a combination of conditions:
Thermal conditions — temperature and humidity
Lighting — amount, type, and color
Acoustics — noises and volume
Ventilation — air content and quality
Maintaining each of these conditions within prescribed and standardized ranges will contribute to improved overall IEQ and occupant satisfaction. The personal ability to control these conditions also can lead to higher occupant satisfaction. Since IEQ is embedded in all aspects of building design and operations, any changes to building design or operational practices can have significant impacts on interior conditions. Thoughtful integration of an IEQ strategy can lead to healthier occupants and positively impact vision, mood, and comfort factors, thereby increasing performance, satisfaction and reducing absenteeism and healthcare costs.
IEQ components
Facilitywide
Acoustical comfort is achieved when the workplace provides appropriate noise levels for interaction, confidentiality, and concentrative work. This does not mean that the space should be silent, however, as both planned and spontaneous interactions are necessary for team building and relationship development. Sound can be managed through a combination of absorption, blocking, and covering strategies to create a productive indoor environment:
Absorption technologies include acoustic ceiling tiles, carpeting, curtains or hanging partitions that mitigate the traveling of sound waves.
Blocking strategies involve interrupting, through conscious space designs such as conference rooms and zoning, sound traveling from noise-generating sources.
Covering acoustic strategies mask workspaces that are too quiet to be acoustically comfortable with low and uniform levels of background noise.
Mitigating strategies for excessive outdoor noise, including envelope measures, such as better windows, or HVAC baffles at the outdoor air intake and exhausts.
Real-time sensing or periodic spot measurements of sound levels throughout the workspace can be an effective strategy, particularly to verify that sound management strategies implemented in the building are functioning as intended as occupants use the space.
Lighting strategies can be used to identify separate acoustic zones. For example, brightly lit corridors may facilitate spontaneous conversations while task lighting areas identify focused working zones.
Improper ballast function can lead to a distracting buzzing sound. Check for noise levels when inspecting light function or replacing bulbs.
HVAC
Sound boots integrated into HVAC ductwork can help control the transfer of sound from one area to another.
Overly noisy air diffusers, fan-powered variable air volume boxes, or other equipment can be distracting in the workplace. For this reason, limit the use of small, high-velocity duct work.
HVAC noise can provide a desirable level of white noise, dampening unwanted sound propagation if designed properly.
Ductwork provides an avenue for sound to travel from space to space and may cause unwanted transfer of conversations
Specify quiet HVAC systems to provide noise levels consistent with the Architectural Graphic Standards and prevent potentially costly mitigation or remediation measures.
Up to 24 pounds of dirt can be tracked in by just 1,000 people during a 20-day work period, costing on average $500 to remove per pound.3 Dust, dirt and pollutants can be carried into buildings on people’s footwear, contributing to contaminated air and reducing the life of interior flooring. Entrance airlocks with “walk-off” mats help buildings avoid tracking contaminants.
When dirt is captured at the entrance, less water is needed for cleaning elsewhere in the building.
HVAC
Entryway systems provide source control for dirt and dust for the outdoors, thereby reducing strain on air filtration systems.
In order to reduce exposure to potentially hazardous chemical, biological and particulate contamination, implementation of a healthy cleaning maintenance plan is essential. The healthy cleaning plan should specify the purchase and use of non-toxic, low or no-volatile organic compound, or VOC, cleaning equipment and materials as well as assess the effectiveness of the custodial staff. The plan should integrate into building policies and standard operating procedures and ensure the upkeep of building materials and systems is performed in an environmentally sensitive manner for the benefit of both the environment and the occupants within the space.
System relationships
Lighting
Dirty lighting fixtures may provide less light to the space.
Water
Healthy cleaning plans help avoid toxins and pesticides from entering the building’s water stream that eventually leaves as sewer discharge.
Moisture control measures should be taken as part of the maintenance plan to avoid mold and mildew
Use non-toxic bathroom and kitchen cleaning products to protect water quality.
HVAC
Regular inspection and maintenance of filters will ensure longer equipment lifespan and a cleaner and more comfortable indoor environment and help reduce dust and dirt accumulation indoors.
High MERV rated filters trap more airborne particulates but may increase the overall energy demand of the fan system, depending on filter design, the use of pre-filtration, and other factors.
The heating, ventilation, and air conditioning, or HVAC, system regulates much of the thermal conditions within the office space. Temperature, humidity, air speed, and air quality influence indoor comfort and health. Ensure that space conditions are appropriate for the activity occurring in the space. Adequate ventilation rates can improve performance on cognitive work and reduce illness symptoms by replacing contaminated air with filtered air from the outdoors.4 Humidity must be controlled for occupant comfort and health, especially mold growth prevention. The HVAC system requires energy to perform these functions. Balance personalized occupant comfort with energy consumption, thermal controls, and frequent feedback cycles to create a successful strategy. During favorable outdoor conditions, natural ventilation can be combined with or used as an alternative to mechanical HVAC systems.
Commissioning and maintenance of HVAC mechanical components, including the regular changing of filters and duct cleaning, is critical to maintain both indoor air quality and HVAC system efficiency.
System relationships
Lighting
Waste heat from lighting fixtures may require additional HVAC cooling loads to bring the room conditions to a comfortable level.
HVAC
Creating a comfortable workspace does not have to require extra energy. Explore the HVAC whole building system to learn about ways to provide comfort with efficient strategies.
Design air distribution and return air components of the ventilation system to promote air circulation and comfort in the occupied space.
Ensure adequate filtration of outdoor air to prevent contaminants from entering the building.
Consider locating external ventilation air intakes away from pollutant sources such as idling cars, garbage dumpsters, exhaust air grills, and other pollutant sources.
An IEQ management plan should encompass strategies to maintain air quality during construction or renovation projects, integrate a healthy cleaning and integrated pest management program, and incorporate occupant feedback for continuous evaluation. Renovation projects can introduce dust particulates, VOCs, or mold throughout the building which may lead to health issues during occupancy. Pre-occupancy flush outs and proper management of building materials, such as avoiding prolonged water and particulate contamination, can limit human exposure during use. Integrated pest management, or IPM involves managing indoor pests in an economically preferable way that protects human health and surrounding environment through preventative measures, monitoring and maintenance of identified pets, and minimized use of least-toxic chemical pesticides in targeted areas for a targeted species.
Real-time IEQ sensing could be a strategy to understand the day-to-day fluctuations of IEQ parameters of interest and could identify potential buildings operation issues or factors that may be impacting human health and performance. Sensing requires planning and an understanding of the IEQ factor you want to track. This will help inform the location of sensors, the number that are needed to adequately understand the conditions in a given space and time, and the length of time that sensors need to be in place to provide an adequate picture.
System relationships
Water
Moisture in buildings is a major contributor to mold growth and poor indoor air quality. Take preventive and remedial measures to reduce indoor air moisture content before and after occupancy.
Bulk water intrusion is a major contributor to mold growth and poor indoor air quality. Make sure your IEQ management plan includes inspection and mitigation of plumbing leaks or leaks in the building envelope, especially near windows.
HVAC
Flush-outs after any construction or renovation project will remove gases and particulates that could otherwise be harmful to occupant wellbeing.
During partial-building renovations, isolate HVAC systems serving construction areas to avoid contaminating other areas of the building.
Flush-outs require additional energy and demand on the ventilation system, often for several days.
Periodic filter replacement and duct cleaning can help provide improved indoor air quality and improve HVAC performance and efficiency. This should be done as part of a regular maintenance and commissioning program for your building’s HVAC system.
The lighting system plays a significant role in the overall indoor environmental quality of the office space.5,6 Evenly distributed interior lighting tailored to specific functions, through a combination of indirect and direct light fixtures supplemented with natural light from windows and light shelves, creates a comfortable and adequately lit environment to work. Optimizing daylighting and providing views to the outdoors has further demonstrated to increase productivity and reduce absenteeism.7 Integration of shading and glare reduction strategies avoids eye-strain while individual lighting controls and task lighting gives occupants the ability to control their lighting conditions.
System relationships
Lighting
A lighting strategy that supports a healthy and productive indoor environment can also save on energy consumption through minimizing electrical lighting loads and maximizing the use of daylighting.
Task lighting, if left on for long periods while no one is around (such as overnight), can waste large amounts of energy. Consider connecting task lighting to occupancy sensors.
HVAC
Waste heat from lighting fixtures may require additional HVAC cooling loads to bring the room conditions to a comfortable level.
Plants not only reduce stormwater runoff, they also cut energy costs by reducing heat island effects – and that’s just when they’re outside the building. Plants offer many health benefits inside the building as well including the ability to clean air and reduce psychological symptoms, such as workplace fatigue. Make sure you know the official policy on plants in your workplace and consider the impact of interior plants on interior moisture levels in the building.
Daylighting uses light originating from the sun as a substitute for electrical lighting. The best proven lighting strategy is to employ layers of light — using daylight for basic ambient light levels while providing occupants with additional lighting options to meet their needs. An effective daylighting strategy appropriately illuminates the building space, through side-lighting and top-lighting apertures such as windows and skylights, without subjecting occupants to glare or major variations in lighting levels. Daylight can be reflected into the interior of the space using light shelves at the building’s perimeter or light tubes from the roof. Daylighting can reduce energy consumption from lighting and provide a visually stimulating and productive environment for occupants.
Daylighting analysis
A critical first step to optimizing the benefits of daylight, including to occupants’ circadian rhythms, is understanding daylighting conditions. A daylighting analysis is a simulation of daylight levels within a space at various times of the day and year and can inform the placement and size of windows and skylights in new construction projects, as well as the treatment of windows, use of space, design of electric lighting systems, placement of furniture and selection of colors and finishes in any project. A daylighting analysis using lighting simulation software can simulate daylight illuminance levels and patterns, model how to integrate electric lighting based on available daylight, identify when and where glare may need to be controlled, and estimate energy savings. Daylighting analyses are best conducted by a professional lighting consultant as early as possible in the design process.
Integrating daylighting with electric lighting and controls
Daylight-responsive lighting controls are an essential component of any daylighting strategy. Photosensor controls that adjust the level of electric lighting according to the amount of daylight available will yield the greatest benefit. Switching controls turn some or all of the electric lighting off when there is sufficient daylight. Dimming controls modulate the electric lighting depending on the available level of daylight.
Operation and maintenance
Key to the success of an effective daylighting strategy is the education and engagement of occupants and operations and maintenance personnel. Commissioning is important to ensure that the daylighting controls and electric lighting are properly installed and configured. Occupants should be educated about acceptable levels and benefits of daylight and the features of the daylighting strategy. This not only contributes to occupant comfort but empowers occupants to be advocates for the proper operation of the lighting system and controls. Operations and maintenance personnel must be educated about all aspects and components of the daylighting strategy and how to continually evaluate the system’s performance, as well as trained on the functionality and maintenance requirements of the electric lighting and controls.
System relationships
HVAC
Climate conditions, glazing selection, and the placement of windows and skylights affect heating and cooling loads. Poorly implemented daylighting techniques can lead to overheating of a space and an increase in cooling loads.
Reflective coatings on windows can reduce heat gain in the summer.
Glass has a lower insulation value than other building components, allowing a higher rate of heat transfer to the outdoors. Be sure to specify windows with higher insulation values, which may include those with double- or triple-paned glass.
Windows and skylights with integral blinds or shades offer some maintenance benefits but can cost more and may have a lower insulation value.
Lighting
Maximizing the use of daylighting and reducing electric lighting according to the amount of daylight available can reduce energy consumption.
The lighting system plays a significant role in the overall indoor environmental quality of the office space.8,9 General lighting is designed to provide a substantially uniform level of illuminance throughout an area, exclusive of any provision for special local requirements.10 General lighting selection should be driven by efficiency, lamp life, color quality of the light, and its intended use with a combination of direct or downward and indirect or upward light sources. The ceiling layout impacts the effectiveness of a general lighting scheme. Use a non-uniform lighting layout to give more visual stimulation and appeal, supplemented as appropriate with daylighting, task lighting and accent lighting.
Optimizing daylighting and providing views to the outdoors has been demonstrated to increase occupant performance and reduce absenteeism.11 Integration of shading and glare control strategies avoids eye strain while individual lighting controls and task lighting gives occupants the ability to control their lighting conditions.
Task lighting is directed to a specific surface or area, providing illumination for visual tasks.10 In the office environment, providing task lighting at individual workstations and desks allows occupants control of their visual space and could reduce the need for general lighting.
Accent lighting is directional lighting to emphasize a particular object or surface feature, or to draw attention to a part of the field of view.10 Selective illumination, often located in entrance and lobby areas, can improve wayfinding, add brightness, create dramatic effects, and highlight points of visual interest.
Lighting system components are lamps; fixtures, including reflectors, diffusers, and lens; ballasts for some types of lamps; and controls. LED lamps have become common in most workplace environments, but fluorescent and high-intensity discharge or HID lamps may be preferred for certain applications. Consider the lamp, fixture, and appropriate controls, as well as ceiling, floor, and wall surface reflectance values, to maximize light levels while minimizing energy consumption.
Minimizing waste heat from lighting fixtures allows the cooling system to run more efficiently.
Building materials and components, including but not limited to paints, coatings, adhesives, sealants, agrifiber products, flooring systems, furniture and office equipment, are all potential sources of indoor air contamination. These contaminants can be odorous and potentially irritating and/or harmful to the health, comfort, and wellbeing of occupants. Specification of low-emitting materials is important to creating a healthy indoor environment free of VOCs and added-urea formaldehyde. Consider flushing out, with a minimum volume of outdoor air, newly finished or furnished spaces to remove pollutants before occupancy. In addition, protect soft absorbent materials, like carpets and fabric, from exposure to moisture. Office equipment known to emit pollutants such as VOCs, such as printers and copiers, should be isolated from offices and workstations, centralized to reduce the number of locations, and have separate, dedicated ventilation to quickly remove pollutants.
System relationships
HVAC
Low-emitting materials release fewer pollutants into the air, which reduces the filtration required to maintain indoor air quality. Refer to the ASHRAE 62.1 IAQ Appendix.
Employ effective source control to balance ventilation-related energy consumption and maintaining indoor air quality.
Occupant comfort and satisfaction can be optimized by providing some level of occupant control over air flow, temperature, lighting levels, and noise. Thermal conditions, including temperature, humidity, and air flow, should allow for personalized adjustments through integration of individual thermostats, localized diffusers and fans, or operable windows. Similarly, task lighting or dimming of general lighting at workstations creates flexibility for occupants to alter illumination levels.
Thermal controls and the design of HVAC system zoning can reduce overall energy consumption while optimizing opportunities for occupant comfort.
Carbon dioxide sensors allow adjustments to the supply of fresh air to spaces according to occupancy.
Provide training to occupants on how to use controls and the benefits of controlling thermal conditions.
Natural and mixed-mode ventilation strategies can reduce the amount of energy needed to condition the workspace.
Lighting
Task lighting and dimming allow users to adjust illumination levels, often saving energy in the process.
Provide training to occupants on how to use controls and the benefits of controlling light levels.
Lighting controls need occasional recalibration.
Interior blinds or shades on windows can provide control of daylighting in the space, reducing glare and contributing to occupant satisfaction.
Views to the outside, particularly views offering a connection to nature, are highly desired by building occupants. Like other features such as daylight, fresh air, and plants, views to the outside fulfill a human need for contact with the natural world — or biophilia. Biophilic design focuses on how to deploy a variety of natural features that create positive physiological, cognitive, social, and psychological experience, including stress reduction, enhanced mood, improved performance, and varied sensory experience.
3 Facilities Magazine, “The Importance of Entryway Matting”
4 Fisk, W.J, ”Health and Productivity Gains from Better Indoor Environments and Their Relationship with Building Energy Efficiency.” Annual Rev. Energy Environ. 25 (2000): 537-66
5 Committee to Review and Assess the Health and Productivity Benefits of Green Schools, Review and assessment of the health and productivity benefits of green schools: an interim report. 2006, National Research Council, National Academy of Sciences.
6 Heschong-Mahone Group, Windows and classrooms: a study of student performance and the indoor environment. 2003, California Energy Commission: Sacramento, CA.
7 Milton, D.K., P.M. Glencross, and M.D. Walters, “Risk of sick leave associated with outdoor air supply rate, humidification, and occupant complaints”. Indoor Air, 2000. 10(4): p. 212–21.
Traveler reimbursement is based on the location of the work activities and not the accommodations,
unless lodging is not available at the work activity, then the agency may authorize the rate where
lodging is obtained.
Unless otherwise specified, the per diem locality is defined as "all locations within, or entirely
surrounded by, the corporate limits of the key city, including independent entities located within
those boundaries."
Per diem localities with county definitions shall include"all locations within, or entirely
surrounded by, the corporate limits of the key city as well as the boundaries of the listed counties,
including independent entities located within the boundaries of the key city and the listed counties
(unless otherwise listed separately)."
When a military installation or Government - related facility(whether or not specifically named) is
located partially within more than one city or county boundary, the applicable per diem rate for the
entire installation or facility is the higher of the rates which apply to the cities and / or counties,
even though part(s) of such activities may be located outside the defined per diem locality.
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