The indoor environmental quality (IEQ) of a building has a significant impact on occupant health, comfort, and productivity. Among other attributes, a sustainable building maximizes daylighting, has appropriate ventilation and moisture control, optimizes acoustic performance, and avoids the use of materials with high-VOC emissions. Principles of IEQ also emphasize occupant control over systems such as lighting and temperature.
When constructing cost-effective buildings, it is easy to forget that the success or failure of a project may rest on its indoor environmental quality (IEQ). Healthy, comfortable employees are often more satisfied and productive. Unfortunately, this simple truth is often lost, for it is easier to focus on the first-cost of a project than it is to determine the value of increased user productivity and health. Facilities should be constructed with an appreciation of the importance of providing high-quality, interior environments for all users.
As a species, we have progressed from an outdoor hunter-gatherer existence to one where 90% of the typical American’s life is spent indoors. For many of us, we have evolved where the indoor realm is our natural environment.
IEQ encompasses indoor air quality (IAQ), which focuses on airborne contaminants, as well as other health, safety, and comfort issues such as aesthetics, potable water surveillance, ergonomics, acoustics, lighting, and electromagnetic frequency levels. IEQ improvements to an existing building can occur at any point during the use of a building.
During the facility/renovation design and development process, federal projects must have a comprehensive, integrated perspective that seeks to:
Facilitate quality IEQ through good design, construction, commissioning, and operating and maintenance practices;
Value aesthetic decisions, such as the importance of views and the integration of natural and man-made elements;
Provide thermal comfort with a maximum degree of personal control over temperature and airflow;
Supply adequate levels and quality of ventilation and outside air for acceptable indoor air quality;
Prevent airborne bacteria, mold, and other fungi, as well as radon, through building envelope design that properly manages moisture sources from outside and inside the building, and with heating, ventilating, air-conditioning (HVAC) system designs that are effective at controlling indoor humidity;
Use materials that do not emit pollutants or are low-emitting;
Assure acoustic privacy and comfort through the use of sound absorbing material and equipment isolation;
Control disturbing odors through contaminant isolation and removal, and by careful selection of cleaning products. Pursue energy efficient strategies to remove harmful odors while recovering the energy used in conditioning the interior environment;
Create a high-performance luminous environment through the careful integration of natural and artificial light sources; and
Provide quality water.
Facilitate Quality IEQ through Good Design, Construction, Renovation and O&M Practices
Acceptable IEQ is often easiest to achieve if “source control” is practiced, not only during building construction, but also over the life of the building. For example, the designer may select building products that do not produce noxious or irritating odors, do not contain volatile organic compounds (VOC), and design exterior entrances with permanent entryway systems to catch and hold dirt particles.
Refer to the ASHRAE Indoor Air Quality (IAQ) Guide: Best Practices for Design, Construction, and Commissioning for guidance on addressing IAQ during building design and construction. The ASHRAE IAQ Guide was developed by an ASHRAE appointed team of building professionals and world class IAQ experts with funding support from the U.S. Environmental Protection Agency.
Refer to the Indoor Air Quality Scientific Findings Resource Bank (IAQ-SFRB) for scientific information about the effects of IAQ on people’s health or work performance. The IAQ-SFRB is being developed by the Indoor Environment Department of the Lawrence Berkeley National Laboratory with funding support from the U.S. Environmental Protection Agency.
The Operations & Maintenance (O&M) and cleaning staff can also avoid creating IEQ problems by choosing less noxious materials during repair and cleaning activities. While HVAC systems may be designed to isolate operations (kitchens, dry cleaners, etc.) from other occupancies, the O&M staff ensures that pressure differentials are maintained to avoid the undesirable flow of contaminants from one space to another. See also WBDG Sustainable O&M Practices.
Value Aesthetic Decisions
Appreciate the importance of providing windows in all occupied spaces for view and natural ventilation. See also WBDG Aesthetics and Productive—Promote Health and Well-Being. Ensure that these windows have proper solar glare control, and encourage occupants to not close the blinds for the worst condition and leave them closed because of apathy.
Design spaces around basic human needs, ancient preferences, and connections to the patterns of nature and the mind. See also WBDG Psychosocial Value of Space.
Demand that individual buildings or facilities are consciously integrated into their natural and man-made context. See also WBDG Sustainable—Optimize Site Potential.
Provide Thermal Comfort
Use ASHRAE Standard 55—Thermal Environmental Conditions for Human Occupancy as the basis for thermal comfort. See also WBDG Productive—Provide Comfortable Environments.
Evaluate the use of access floors with displacement ventilation for flexibility, personal comfort control, and energy savings.
Understand moisture dynamics as a key criteria in the selection of wall and roof assemblies. See also WBDG Air Barrier Systems in Buildings.
Evaluate the benefit of specifying high-performance windows to increase mean radiant temperature (MRT).
Consider external conditions impacting thermal comfort.
Easily maintained window treatments also provide occupants individual control to both thermal and light exposures from the sun.
Provide Ventilation and Maintain Acceptable Indoor Air Quality
Design the ventilation system to meet or exceed ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality. Work closely with the Mechanical Engineering team to strike a balance between optimal fresh air and energy efficiency using either the ventilation rate procedure (VRP) or the indoor air quality procedure (IAQP). Also, consider the USGBC LEED pilot credit #68, where a survey of building occupants is performed to determine their satisfaction with the interior air quality.
Implement a construction management program that ensures key ventilation components are protected from contamination during construction. Ensure that construction filters placed in ductwork and mechanical equipment are routinely inspected and replaced as needed. Do not install carbon filters until all construction work, including dry wall and painting, has ceased.
Commission HVAC systems to validate and document design performance intent. Review commissioning report to ensure that adequate ventilation rates have been achieved prior to initial occupancy. One Commissioning technique that can be employed over the life of the building is the use of a well maintained carbon dioxide monitoring system that will continually provide diagnostic feedback on the actual amount ventilation provided in the most densely occupied spaces. HVAC system should be installed with filters with a Minimum Efficiency Reporting Value (MERV) of 11 for residential, commercial, telecommunications and industrial facilities. MERV 13-16 is preferred for smoke removal, general surgery, hospitals, and other healthcare facilities.
Consider a building design with a natural ventilation or hybrid component to both reduce energy consumption and to make some provisions for ventilation even if external power were not available (a measure of resiliency). Use of natural ventilation component is dependent on relative humidity being within an acceptable range.
Investigate the use of separate outside air and conditioned air distribution systems. A good description of various types of heating and ventilation systems can be found at: WBDG High-Performance HVAC and Natural Ventilation.
Ensure fresh air intakes are located away from loading areas, exhaust fans, and other contamination points, preferably on roofs.
If building is close to a large roadway source, consider the location of the fresh air intakes or possible breaks that may help reduce impact of the outdoor air on the indoor environment.
Ensure parking lot/garage usage cannot generate pollutants that affect fresh air intake or pedestrian traffic. Prevent vehicles idling near the facility during normal operations. If there is a below grade parking garage, consider using monitored values of both carbon monoxide and carbon dioxide to control the fans to reduce exposures to not only the carbon monoxide but also the respiratory irritants of oxides of nitrogen and unburned hydrocarbons.
Investigate the use of a permanent air quality monitoring system. ASHRAE acceptable level of carbon dioxide (CO2) for an indoor office environment at 20 cfm per person equates to no greater than 530 ppm greater than outdoors. While outdoor CO2 levels used to range from 300 to 400 ppm many years ago, increasing atmospheric CO2 levels in the last few decades are now at least 400 ppm. Even remote locations, such as on a mountain top in Hawaii, exhibit CO2 levels above 400 ppm. If Demand Controlled Ventilation is employed, either rely on sophisticated algorithms to automatically review and interpret the monitoring data and/or have it periodically reviewed by an IAQ expert. Carbon monoxide (CO) levels in office environments should be below 9 ppm. OSHA regulates levels of CO for industrial locations.
Coordinate ventilation and air filtration with chemical, biological, and radiological concerns and locate outside air intakes so they do not conflict with physical security requirements. See also WBDG Air Decontamination.
During operation, either develop a plan for identifying needed filter media replacement or replace filter media on a regular schedule.
Provide Energy Recovery Ventilation systems for needed ventilation air as a standard feature in new construction which is typically highly insulated and extremely airtight.
Prevent Radon Entry, Airborne Bacteria, Mold, and Other Fungi
Prevention of mold and fungi is dependent upon effective HVAC and building envelope design and construction. The HVAC system must be able to control interior humidity conditions over a wide range of outdoor conditions. The system must be designed to have the capacity to dehumidify at the 1% Humidity Ratio and mean coincident dry bulb temperature, and control interior humidity at both extreme and low load conditions. The building envelope must be carefully designed to prevent intrusion of water and to dry if intrusion should occur. It must also incorporate barriers that control vapor and air infiltration.
Carefully consider the envelope of the building to prevent moisture infiltration. See ASHRAE IAQ Guide.
Investigate and remediate immediately when there is a mold or moisture problem, either from high humidity, a leak, or flood. See EPA Guidance.
Ensure the number of spores in the indoor air is less than the outdoor air. It is recommended that there should be less than 700 spores in a cubic meter of air.
In areas where it is prevalent, include measures to test for radon and control and mitigate radon buildup.
Limit Spread of Pathogens
For health care facilities:
Implement proper maintenance procedures to prevent nosocomial infections.
Consider removing restroom doors to reduce the chance of acquiring infections.
Use Safer Materials that have Less Hazardous Ingredients and are Low-emitting
Look to EPA’s Recommendations of environmental performance standards and ecolabels
Limit the use of volatile organic compounds (VOCs) in such products as cleaners, paints, sealants, coatings, and adhesives. See also WBDG Evaluating and Selecting Green Products.
Avoid products containing formaldehyde, i.e., carpet, wall panels, cabinetry.
Remove asbestos-containing material or contain it in a manner that precludes the possibility of future exposure.
Follow careful lead-safe work practices during renovations with thorough clean-up. Follow EPA’s Renovation, Repair, and Painting regulatory requirements, using certified contractors and lead-safe work practices.
Create safe, convenient, and secure storage spaces for housekeeping chemicals. See also WBDG Sustainable O&M Practices.
If an area in an occupied building is being renovated, consider isolating and negatively pressurizing the construction area if work is being performed that would result in dust, fumes, or odors. If conditioned air is required due to high end finishing work, the air should be directly exhausted to the exterior environment and not returned to the fan.
Ensure office equipment installed emit minimal odors or pollutants.
Assure Acoustic Privacy and Comfort
Minimize noise through the use of sound-absorbing materials, high sound transmission loss walls, floors, and ceilings, and equipment sound isolation. See Architectural Graphic Standards, 11th Edition, section on Acoustical Design for more information. See also WBDG Productive—Provide Comfortable Environments and Acoustic Comfort.
Consider sound masking systems. These systems introduce an unobtrusive background sound that reduces interference from distracting office noise. Note that some level of HVAC “noise” can serve as a background white noise source, eliminating the need for sound masking systems.
Avoid the use of small diameter ducts with high velocity airflow.
Control Disturbing Odors through Contaminant Isolation and Product Selection
Directly exhaust copying and housekeeping areas, and provide added return air grills in these areas. This will help limit lower atmosphere ozone generation, commonly associated with duplicating and printing processes. Ozone acts as a power oxidant. It can attack surfaces of certain elastomers, plastics, paints, and pigments; and aid in sulfide and chloride corrosion of metals. Possible health hazards caused by ozone include eye and mucous membrane irritation as well as chronic respiratory disease.
Minimize disturbing odors through contaminant isolation and careful selection of cleaning products.
Ensure maintenance procedures are in place to remove all trash and recyclables from the building on a regular basis rather than storing them within the building for prolonged periods of time.
Prohibit smoking in all areas of the building. Environmental Tobacco Smoke (ETS) is a known carcinogen.
In special cases where smoking is permitted, e.g., federal judge’s private chambers, ensure that the spaces:
Have lower pressure than adjacent areas;
Comply with ASHRAE Standard 62.1 for proper ventilation;
Are isolated from the return air system of surrounding areas to prevent pollutants from spreading to other areas.
Use/Effectiveness of Air Cleaners.
Create a High—Performance Luminous Environment
Use daylighting for ambient lighting wherever feasible.
Supplement natural light with integrated, high-performance ballasts, lamps, fixtures, and controls.
Substitute magnetic fluorescent lamps with high-frequency electronic ballasts to reduce flickering.
Reduce direct glare from both natural and man-made sources in the field of view—particularly in spaces with highly reflective surfaces, such as visual display terminals (VDTs).
Use task/ambient systems that provide reduced levels of diffuse, general illumination, and supplement with task lighting. Most people do not need lighting in excess of 300 lux (a unit of illumination).
Use light color on walls and locate windows properly.
Provide dimming fixtures where possible combined with appropriate task lighting so that occupants can reduce lighting levels to their preferred lumens. Dimming the lights will both save electricity and the heating load that lighting demands of the building’s HVAC system. Often the lighting levels are designed to the most demanding user; all other occupants are forced to adapt to levels that are higher that desired.
Provide Quality Water
Comply with EPA Safe Drinking Water Act (SDWA) for the levels of various metals and bacteria in potable water systems.
For newly installed or temporarily suspended domestic water systems, follow “start-up” procedures by flushing all downstream outlets.
Conduct periodic ‘maintenance flushing’ to proactively control drinking water issues.
Control domestic water temperature to avoid temperature ranges where legionellae grow: keep domestic water temperatures above 140°F (60°C) in tanks and 122°F (50°C) at all taps (faucets and showers).
Design cooling tower and building air intake placement so air discharged from the cooling tower or evaporative condenser is not directly brought into the facility’s air intake.
Consider a closed loop system instead of an open system to reduce the potential of exposure at the cooling tower.
Be Aware of Exposure to Electromagnetic Fields (EMF)
Electromagnetic fields (EMF) are generated by forces associated with electric charges in motion, and by microwaves, radio waves, electrical currents, and transformers. EMF are thought to cause cancer, however there is insufficient evidence to prove this. There are no federal standards limiting occupational or residential exposure to EMF at this time, only various U.S. and International voluntary occupational exposure guidelines. Nevertheless, facility designers and managers should consult the following resources to find out the latest scientific research and recommendations on dealing with EMF exposure:
Institute of Environmental Health Sciences, Electric and Magnetic Fields
World Health Organization (WHO), Electromagnetic fields (EMF)
Balance IEQ Strategies with Security Requirements
Since the terrorist attacks of 9/11, building owners and occupants have placed greater emphasis on facility security and safety. However, security and safety measures must be considered within a total project context, including the project’s environmental goals. Several indoor environmental quality strategies, such as dedicated ventilation systems and tight building envelopes, can be employed to help designers achieve an integrated, high-performance facility. See also WBDG Balancing Security/Safety and Sustainability Objectives.