FM Issue: Deconstructing IAQ
By Richard D. Purtell
Published in the November 2007 issue of Today’s Facility Manager
Followingthe energy crisis of the 1970s, indoor air quality (IAQ) has been aspecific focus in the development of standards and building codes inthe U.S. and worldwide. At that time, the trick was to find a balancebetween saving energy (allowing less energy to escape a building) whileensuring that the conservation methods did not adversely affect thequality of indoor air. As buildings became tighter, air filtrationsystems became more complex…and more critical.
Buildingstandards such as the Model Energy Code (first published in 1983), andits successor, the International Energy Conservation Code (which wasdeveloped by the International Code Council, or ICC, in 1998), haveincluded ventilation rate requirements on the up tick as the energyefficiency of buildings has increased over the years.
TheAmerican Society of Heating, Refrigerating, and Air-ConditioningEngineers (ASHRAE) also developed and promulgated Standard 62,Ventilation for Acceptable Indoor Air. ASHRAE standards are thedocuments that have been most widely used by building engineers andothers dealing with indoor environmental issues.
But asfacility professionals adapted codes and standards to meet air qualitydemands, the notion of what IAQ means has also evolved. Today, thefocus is, or should be, on the overall indoor environment, not just theair that is breathed.
In the past few years, science andregulatory documents, i.e. standards and codes, have evolved to dealwith the indoor environment in a more holistic way. Facility managers(fms) are no longer just dealing with the introduction of outside air,but they must also evaluate the quality of outside air introduced, theelimination of specific contaminants, and many other factors.
The Fortress Effect
Withevents like 9/11 and the subsequent anthrax attacks in the fall of2001, security has now become a more vital part of the IAQ equation.Protecting building occupants against potentially harmful or evenlethal toxins from the outside air is often a high priority for a fm orbuilding engineer. The great challenge then is to protect those peoplein the building while still maintaining appropriate fresh airventilation in order to preserve a healthy and comfortable indoor workenvironment—not always an easy task.
There are many variablesthat affect air intake, such as the location of intake grates. InWashington, DC and many other cities, intake grates are often locatedon sidewalks in front of buildings. In some older buildings, they areeven situated near the offloading sections of buildings.
Thispositioning can be undesirable, because it puts intake vents in placeswhere they can potentially capture unhealthy fumes from trucks andother offloading vehicles. Some buildings have begun intaking air fromroofs, but that outside rooftop air may lead to higher levels of ozone.
Fmscan beef up air intake filtration as part of a building security plan.While this can help protect against toxins and contaminants, the heavyfiltration process can also reduce the amount of outside air beingcirculated through the building, often defeating the purpose.
Thereare other alternatives, such as installing ultraviolet filtrationsystems, but they tend to be more expensive and can sometimes belimited by system design considerations. [For more on this subject,read “What To Do When ‘Something Stinks In Here’ by Ronald Cox, whichappears below.]
Finding The Clean In Green
Itmight seem counterintuitive, but when it comes to a building’s indoorhealth, “green” air doesn’t always equal clean air. Energy efficientbuildings are usually tight buildings with high efficiency windows thatallow very little energy to escape. Increased ventilation is often theremedy, but when that air is pulled in from the outside, it must becooled or heated and humidity must be controlled, which can offsetenergy savings and increase utility costs.
IAQ research anddevelopment currently under way by the U.S. Department of Energy (DOE)is focused on developing new ventilation strategies that simultaneouslyimprove IAQ and reduce the energy impact of increased ventilation. Thegoals of the DOE’s IAQ project include reducing ventilation energydemands by 50% by 2020 without degrading IAQ, revising and improvingventilation standards and building codes, and enabling energy efficientbuilding practices that have a low risk of creating IAQ problems.
Someof the DOE’s ventilation strategies will concentrate on different waysof improving overall building ventilation. A hybrid ventilationapproach is one strategy. This is a combination of natural ventilationsystems and mechanical ventilation systems to reduce energy.
Alternatively,task ventilation strategies focus on the part rather than whole,offering personalized ventilation systems that deliver clean air rightto the work station. Another option, demand control, focuses on ways tovary ventilation rates depending on occupancy and pollutant sources.
Green IAQ Standards
The current emphasis ongreen buildings has led several relevant organizations to developmultiple standards dealing with the elements of green buildings andgreen techniques:
- ASHRAE and the U.S. Green Building Council(USGBC) are cooperating on the development of a green building standardfor commercial buildings.
- The Green Building Initiative(GBI) is developing a guideline (a standard that is not written inmandatory language suitable for adoption as a building code ormandatory regulation) for commercial buildings.
- AmericanSociety for Testing and Materials (ASTM) is developing a standard forsustainable design and construction of commercial buildings.
Manyof these initiatives focus on several aspects of the indoorenvironment, including pest control and maintenance of indoor plants.While it can sometimes be difficult to control what contaminantscontractors bring into a building, these new standards may give fms theguidance they need to notify contractors of procedures they must followany time they are inside or on-site.
Oneof the greatest daily challenges with regard to maintaining a healthyindoor environment is keeping the numerous indoor pollutants in check.Emissions from equipment and furnishings can affect health and comforton many levels, and the culprits can be found in the essential officeequipment and materials that keep a business running. Off gassing ofcontaminants, fumes from machine operation, and continuous operation ofequipment are just a few of the most common causes of indoor pollution.
Eventhe seemingly innocuous office printer may be a noxious contributor.The August 1, 2007 issue of Environmental Science and Technologyreported that a recent Australian study found that nearly 30% ofprinters tested emitted high levels of ultra fine toner particles,creating a workplace health hazard akin to the dangers associated withcigarette smoke. Although the study sample was small (just 62printers), it did reiterate the concern that indoor pollutants do notonly originate from obvious sources—paint fumes, mold, dust particles.
However, in the August 7, 2007 Time magazine article, “Is Your Printer Making You Sick?”,Coco Masters notes, “The good news was that 60% of the printers theytested, including eight HP LaserJet 4050 models, four Ricoh Aficiomodels, and one Toshiba Studio, did not emit any particles. But of the40% that did, many, such as the HP LaserJet 1320 and 4250 models, wereclassified as ‘high-level emitters.’”
Beyondthe essential task of safeguarding building occupants from the healthrisks associated with indoor pollutants, maintaining a clean andcomfortable indoor environment is considered by many to be conducive toproductivity and happiness. ASHRAE addresses building comfort in itsStandard 55, which deals exclusively with thermal comfort in the indoorenvironment. Studies by the U.S. Environmental Protection Agency (EPA)have shown that improved IAQ can result in higher productivity andfewer lost work days.
With many Americans spending up to 90%of their time indoors (and many spending most of their working hours inan office environment), the need to create a comfortable and healthyenvironment is a practical consideration as much as a workplaceresponsibility.
It’s a mix of direct and indirect factors thataffects the overall indoor environment, from moisture and humiditylevels to heat or glare from sunlight to odors and noise. Much of itcomes down to occupant sensitivity and perception. Indoor plants andflowers may create a pleasant aesthetic experience for some employeesbut may have adverse affects on those with allergies.
Eachperson has different sensitivity triggers, and it is impossible toplease everyone, but there are steps that can be taken to enhance abuilding’s overall indoor environment, from the everyday things likedisposing of garbage promptly to more sophisticated measures likedeveloping an IAQ management program available to building occupants.Sometimes something as simple as adjusting the humidity level by anotch or two can maintain comfort levels without expending energy byturning up the HVAC system.
In some ways, the perfect indoorenvironment is the one that goes unnoticed, because it lacks theoffending odors, allergens, and temperature variations that distractemployees. But fms know that it’s frequently the undetectablepollutants—the infamous odorless, colorless, and tasteless variety—thatare often the biggest concern.
Balancing safety, comfort, andenergy efficiency is a major challenge. While the goal of attaining theperfect indoor environment may seem elusive, there are practical, easyto implement strategies to ensure that everyone can breathe a littleeasier…and maybe even work a little more productively.
What To Do When “Something Stinks In Here”
By Ronald Cox, CAFS
Odorsand gaseous contaminants can permeate a building, leading to a varietyof potential health effects and less than ideal working conditions.Fortunately, most harmful gaseous contaminants can be removed from thebreathing air inside buildings with source removal/reduction, properventilation, and an effective gas phase air filtration system.
Themost recognizable form of gaseous contaminants in commercial buildingsis odors. But not all gaseous contaminants are detectable by occupants.Gaseous contaminants in commercial buildings may include carbonmonoxide, nitrogen oxides, sulfur dioxide, polycyclic aromatichydrocarbons, human and cooking odors, and carbon dioxide.
Somegaseous contaminants are volatile organic compounds (VOCs). VOCs may beemitted by paints and lacquers, paint strippers and cleaning supplies,pesticides, building materials/furnishings, copiers and printers (notethe recent Australian study mentioned in the main article), and craftmaterials.
According to the U.S. Environmental ProtectionAgency (EPA), concentrations of many VOCs are two to five times higherindoors than outdoors, and elevated concentrations can persist in theair.
Health effects of VOCs may include:
- Eye, nose, and throat irritation;
- Loss of coordination;
- Liver, kidney, and nervous system damage; and
- Allergic skin reaction.
These effects can be a drain on personal productivity, may increase absenteeism, and may result in additional medical costs.
Source Reduction And Removal
Pollutantsource removal or reduction can resolve IAQ problems related to gaseouscontaminants when sources are known and control is feasible. Whensource removal is not possible or practical, the following steps can betaken to reduce the amount of gaseous contaminants.
- Safely discard partially full containers of old or unneeded chemicals.
- Buy limited quantities of VOC-emitting products.
- Use sealants on all exposed surfaces of paneling and furnishings.
- Allow building materials in new or remodeled areas to off gas before occupancy.
- Adopt integrated pest management techniques to reduce pesticides.
- Store food properly, and dispose of garbage promptly.
Onetechnique for controlling gaseous contaminants is to dilute them withoutdoor air. The American Society of Heating, Refrigerating andAir-Conditioning Engineers (ASHRAE) has a ventilation standard(62-1989) to provide a minimum of 15 cubic feet per minute (cfm) ofoutdoor air per person (20 cfm/person in office spaces). Up to 60cfm/person may be required in some spaces (such as smoking lounges).
Dedicatedexhaust ventilation systems isolate and remove contaminants bymaintaining negative pressure in the area around the contaminantsource. Local exhaust can be linked to a piece of equipment (forinstance, a kitchen range) or used to treat an entire room (smokinglounge, rest room, or custodial closet).
Fms should avoidrecirculating air from areas that are strong sources of contaminants.Activities that produce odors and gaseous contaminants should beconfined to locations maintained under negative pressure. Finally,external vents should be located well away from the fresh air intake ofthe HVAC system to avoid recontamination.
Gas Phase Air Filtration
Airfiltration is usually most effective when used with source control orventilation. However, filtration may be the only approach when thepollution source is outside the building, and the gaseous contaminantsare brought in through the fresh air ventilation system.
Gas phase filtration may be recommended for:
- Newly constructed buildings;
- Newly remodeled buildings (new wallpaper, paint, carpets, etc.);
- Newly installed furnishings;
- Areas where large volumes of photocopying are conducted;
- Areas where solvents are used (laboratories, nail salons, spas, etc.);
- When employees complain of eye and respiratory irritation; and
- When source control and ventilation control have not resolved odor issues.
Controllinggaseous pollutants requires specialized air filtration products.Traditional particulate air filters—even HEPA filters—are not effectiveat removing gaseous contaminants.
Most gas phase airfilters are made with activated carbon, one of the strongest physicaladsorbents known, making it an excellent material for creating a freshand clean smelling environment. Some filters with activated carbon aredual-layer filters. The upstream layer filters particulates andprotects the carbon layer from particulate loading to ensure maximumodor removal. The downstream layer absorbs and retains gaseouscontaminants.
In two-stage HVAC filtration systems,particulate pre-filters in the MERV 7 to 8 range protect higherefficiency final filters. In environments with significant gaseouscontamination, final filters may be replaced with granular bed or deeppleat carbon filters. If this option is used, the HVAC system must haveadequate fan capacity to handle increased airflow restriction.
Typically,gaseous contaminant levels are low to moderate, and single stagepleated gas phase filters may be used. These filters are more expensivethan traditional pleated filters, but they remove the entire spectrumof airborne contaminants: particulates and gases. Facilityprofessionals should select a filter that has a particulate filtrationlevel of at least MERV 7 as long as the HVAC system has adequate fancapacity.
With the growing concern about indoor airquality, facility managers should let occupants know that thebuilding’s filtration system has been upgraded to remove particulateand gaseous contaminants. This may be one of the most cost-effectiveand valuable upgrades a building can make.