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24. INDOOR ENVIRONMENTAL QUALITY

Minimum IAQ Performance

Prerequisite 1. The required baseline for indoor air quality (IAQ) is defined in four sections of ASHRAE 62.1-2004, Ventilation for Acceptable Indoor Air Quality. Buildings that are naturally ventilated, i.e., those relying on windows or "passive ventilation," as well as buildings that rely on mechanical equipment or "active" ventilation are covered in that standard. For passive buildings, occupiable spaces must be within 25 feet (7.6 m) of a window (or roof opening) which must provide a "vent" area equal to at least four percent of the occupied floor area. These requirements are standard operating procedure in many places; the four percent requirement has been embedded in the International Building Code (IBC) since its inaugural 2000 version; prior codes and regulations, going back to the New York State Tenement House Act of 1901, actually required a greater percentage of floor area for the area of ventilation openings (i.e., the operable parts of windows). According to the LEED guidelines, when this minimum four percent vent area requirement is met, "no additional design effort or capital cost will be required to meet this prerequisite."¹ In other words, this prerequisite for IAQ sets the bar pretty much where it has already been lowered.

Even so, major problems concerning naturally ventilated spaces in Sibley Hall were created by the design and construction of Milstein Hall: on the one hand, the need for protected openings in the fire barrier between the Milstein Hall and Sibley Hall rendered those openings inoperable; on the other hand, Milstein Hall itself blocked access to fresh air for basement, first-floor, and second-floor Sibley Hall windows on Sibley's north and east facades. Remarkably, mechanical ventilation for those spaces in Sibley Hall affected by the construction of Milstein Hall was not specified as part of the Milstein Hall design, and was installed only after I brought these code violations (and unhealthy conditions) to the attention of Cornell.

There is a conflict between indoor air quality (IAQ)—one of the major elements within the broader category of indoor environmental quality (IEQ)—and energy use. This conflict comes about because fresh air is more expensive to produce (more energy-intensive) than recycled stale air. In a hot, humid, air-conditioned environment, fresh air needs to be both cooled and dehumidified, processes that consume a great deal of energy. In a cold climate, fresh air needs to be heated, a process also requiring energy. In both cases, air filters are often required to remove contaminants—such filters must be periodically replaced, adding to the cost. To the extent that the energy needed to produce this fresh air is created largely from fossil fuels, global warming gases are also released. This conflict is noted, but not resolved, within the LEED guidelines.

A larger question is why indoor environmental quality issues are even included within a green building rating system at all, as they have either no direct impact, or a negative impact, on energy use and global warming. Ideologies from the right and from the left both miss the point.

Ideologies on the right. LEED's market-driven rationale is that "Americans spend an average of 90 percent of their time indoors, so the quality of the indoor environment has a significant influence on their well-being, productivity, and quality of life."² In other words, breathing fresh air rather than contaminated air is useful for human health, so providing it, at least to the extent required by most building codes, should be a prerequisite for any green building. And in case a building owner/developer is tempted to skimp on this provision, LEED makes the dubious claim, supported by dubious research, that business "productivity" is improved when workers are healthier. The fallacy in this argument is easiest to see where workers do not get paid sick leave (this includes approximately half of all full-time private sector workers in the U.S.). When sick workers don't get paid, productivity (a measure of output per amount invested) doesn't necessarily suffer, since either remaining workers will pick up the slack, actually increasing productivity, or temporary workers will fill in, either improving productivity or leaving it unchanged. The suffering of workers—admittedly increased by conditions of poor air quality—cannot simply be equated with reduced productivity of capital.

Even where a certain allowance is made for sickness (e.g., company policies or legislation mandating a certain number of "sick days"), this simply becomes the new baseline factored into business calculations; in this context as well, improved worker health due to improved IAQ does not necessarily translate into increased rates of output (productivity).

Studies that purport to show productivity gains due to increased indoor air quality are often flawed, in that they do not actually measure productivity, but rather measure health improvements which are then carelessly extrapolated into productivity claims. For example, given a potential reduction in respiratory illness of 9 percent to 20 percent based on improved indoor air quality, one scholarly study concludes that "16 to 37 million cases of common cold or influenza would be avoided each year in the US. The corresponding range in the annual economic benefit is $6 billion to $14 billion."³ This so-called "benefit" is calculated by multiplying the average wages of the workers studied (apparently $375 per sickness) by "16 to 37 million" incidents of colds or flu per year. But it is not at all clear that this "benefit" is lost, or, if it is lost, who the loser is: to repeat the point already made, when sick workers are not paid, productivity may actually increase (as fellow workers pick up the slack), or at least stay more or less the same as replacement workers are hired.

Another criticism of productivity claims is that "worker productivity goes up when employees move to a new office space, but that the result is often short-lived." In other words, "since most green buildings have been around for less than five years, any long-term studies of costs and productivity are simply not yet available."⁴ I haven't been able to independently verify this claim.

Practices that damage worker health have always been perfectly compatible with both productivity and profitability. It is always state intervention (40-hour work week, child labor laws, and so on) that establishes the baseline conditions for acceptable damage to worker health that promotes growth of the economy as a whole. While it may be true that competition for the highest-level elite workers impels owners in such industries to offer higher-quality interior environments, low levels of indoor air quality for the rest of the work force threaten neither productivity nor profitability.

Ideologies on the left. Criticism from the left focuses, not on alleged productivity gains, but on the other two aspects of sustainability attributed by the LEED guidelines to improved indoor air quality: "well-being" and "quality of life." Left ideologues can point to LEED-rated prisons (the Federal Prison Camp in Butler, NC is the country's first LEED-certified prison⁵) or military facilities (the U.S. army has been committed to building LEED-silver since 2006⁶) and argue that the criteria of "well-being" and "quality of life" are voided of all useful meaning when they embrace building practices through which humans are incarcerated or killed. Extrapolating further, Jeff Dardozzi in Monthly Review has written: "The logic of LEED is that it can be applied to any building, regardless of social context and the consequences of the activity taking place within the structure. A nuclear weapons factory, a biological warfare lab, or a concentration camp could carry a platinum rating. Guantánamo could be redeemed by virtue of bike racks, orange jumpsuits made from recycled fiber, cattle prods energized by photovoltaics, and water-boarding conducted with reclaimed grey-water."⁷

But this type of criticism is flawed in its implication that LEEDrated buildings, whether real or hypothetical, are uniquely problematic. Exploitation, damage, and destruction of both humans and environments is systemic, not an aberration at the fringes of "green" building design that could be corrected by prohibiting prisons and military facilities from getting their coveted LEED certificates. Rather, the activities within virtually all LEED-rated buildings as well as within virtually all non-LEED-rated buildings contribute to the destructive outcomes associated with market economies: there is no other game in town.

Environmental Tobacco Smoke Control

Prerequisite 2. Environmental Tobacco Smoke (ETS ) is another name for secondhand smoke. There are three options for compliance with this LEED prerequisite: either prohibit smoking in the building and limit outside smoking to designated areas at least 25 feet (7.6 m) from entries or windows; or allow smoking inside within designated smoking areas which are sealed, depressurized, and exhausted to the exterior while also having the same outside smoking limits as in the first option; or, for residential occupancies only, prohibit smoking in common areas, limit outside smoking as in the other options, make sure all penetrations between dwelling units are sealed, and either weatherstrip doors to corridors or maintain positive pressure in corridors relative to dwelling units.

This is a bit strange to have in a sustainability guideline, since it is impossible to assess its impact over time. Nothing prevents the current building owner, or a new owner, from changing a smoking policy once the LEED certification is awarded. On the other hand, smoking is already prohibited in many buildings by state or local law. In the case of Milstein Hall, existing campus regulations cover essentially the same ground as this LEED credit.

Outdoor Air Delivery Monitoring

Credit 1. The idea of this credit is to monitor indoor air quality by measuring CO₂ levels either directly in densely-occupied spaces, i.e., those with at least one person per 40 square feet (12 square meters), or in non-dense spaces at points where air is exhausted. CO₂ levels do not, by themselves, define indoor air quality, but they are a convenient indicator of potential IAQ problems—convenient both because high CO₂ levels may indicate the presence of other pollutants, and also because CO₂ levels are relatively easy to measure. On the other hand, such readings are not conclusive:

The relationship between the concentrations of CO₂ and other indoor contaminants depends on the sources of these other contaminants. The rate at which CO₂ is generated in a space depends on the number of people, their size and their level of physical activity. If other contaminants are generated at a rate that also depends on the occupancy level, then CO₂ may be a good indicator of the concentrations of these contaminants. However, only some contaminants are generated at a rate that depends on occupancy, and many contaminant sources are not a function of occupancy, for example emissions from building materials and contaminants entering a building from outdoors. Carbon dioxide concentrations do not provide any information on the concentration of contaminants emitted by occupant-independent sources.⁸

To get this LEED point, any CO₂ reading measured above 10 percent of the setpoint must set off an alarm to maintenance personnel or occupants. This is another instance where the baseline for LEED compliance is set arbitrarily low—so low, in fact, that EQ Credit 2 for increased ventilation (coming up next) mandates more fresh (make-up) air than would be required for Credit 1. And even Credit 2 is viewed as a compromise between what is needed and what is "practical." Milstein Hall gets one point here.

Increased Ventilation

Credit 2. The requirements for this credit vary for active and passive systems. For mechanically-ventilated spaces, one must provide 30 percent more outdoor air than mandated per ASHRAE 62.1-2004 (i.e., 30 percent more than Prerequisite 1 requirements). For naturally-ventilated spaces, one must comply with "Carbon Trust Good Practice Guide 237 (1998)" as well as some requirements of the "Chartered Institution of Building Service Engineers (CIBSE) Applications Manual 10:2005, Natural Ventilation in non-Domestic Buildings," while demonstrating compliance with either the CIBSE recommendations or the "macroscopic, multi-zone, analytical model" in ASHRAE 62.1-2004, chapter 6.

This increased ventilation rate is admittedly lower than what research findings suggest would be necessary to achieve acceptable IAQ, i.e., 25 cubic feet per minute (11.8 liters per second) per person ventilation rates, equivalent to an increase of 50 percent over the ASHRAE (and Prerequisite 1) requirements. The LEED commentary admits that "30% was chosen as a compromise between indoor air quality and energy efficiency." In other words, one can get two LEED points for IAQ without adequately protecting occupant health. Actually, some experts feel that, even though "there is no magic number for ventilation rate/person… there are demonstrated health benefits from increasing ventilation up to 50 cfm (24 L/s)/person."⁹ This amount of fresh air is twice as great as the hypothetical upper limit suggested, but not even required, by LEED in their discussion of the subject.

The idea that increased ventilation rates necessarily improve indoor air quality is however—and paradoxically—questionable, since overventilation, especially in hot, humid climates, can overwhelm mechanical systems, with the result being mold growth and, as a result, worse indoor air quality.¹⁰

Milstein Hall, in any case, does not satisfy the fresh air criteria for this credit.

Construction IAQ Management Plan

Credits 3.1 and 3.2. Two points are available for dealing with IAQ at the (a) construction and (b) pre-occupancy phases—Milstein Hall gets only 1 point for the construction phase. The pre-occupancy phase credit was denied because Cornell did not test for 4-Phenylcyclohexene (4-PCH), a gas released from carpets and fabrics with styrene butadiene rubber (SBR) latex backing material.

During construction, a plan must be developed with the following goals: comply with Sheet Metal and Air Conditioning contractors National Association (SMACNA) IAQ guidelines, 1995, chapter 3; protect absorptive materials from moisture; provide filters for any building air handlers used during construction with a minimum efficiency reporting value (MERV) of 8 at each return grille; replace these filters prior to occupancy; specify low-toxicity paints, carpets, etc. (also covered in EQ Credit 4); and ventilate VOC-emitting materials directly outside.

Immediately before occupancy, a plan for the second LEED point (Credit 3.2) requires that fresh air be supplied at a rate of 14,000 cubic feet per square foot (4,267 cubic meters per square meter) of floor area, with the internal temperature at least 60° F (16° C) and relative humidity no more than 60 percent, before the building is occupied. Where occupancy needs to happen before such a "flush-out" can be completed, different—but equivalent—procedures are specified.

Optionally, one can test the air quality before occupancy to comply with these maximum pollutant levels: formaldehyde at no more than 50 parts per billion; particulates (PM10) at no more than 50 micrograms per cubic meter; total volatile organic compounds (TVOC) at no more than 500 micrograms per cubic meter; and 4-phenylcyclohexene (4-PCH) at no more than 6.5 micrograms per cubic meter—this last requirement applies only when styrene butadiene rubber, used commonly as a carpet backing, is installed in the base building.

The LEED rationale for improving IAQ, discussed in relationship to Prerequisite 1, is repeated here: increasing worker productivity translates to "greater profitability for companies." The trade-off between energy cost and indoor air quality is made explicit elsewhere in the LEED guidelines, so that the claim here that IAQ improvements, in and of themselves, lead to "greater profitability" is contradicted by the admission that the added costs of heating and cooling fresh air may outweigh any productivity gains.

Low-Emitting Materials

Credits 4.1–4.4. The intention of this credit is to reduce the emission of harmful contaminants associated with various building materials. One point is available in each of the following four categories applicable, in general, to interior construction only:

• Adhesives and sealants must comply with South Coast Air Quality Management District (SCAQMD) Rule #1168 and, for aerosol adhesives, with Green Seal Standard for Commercial Adhesives GS-36.
• Paints and coatings must comply with SCAQMD VOC limits for clear wood finishes, floor coatings, stains, sealers, shellacs; Green Seal Standard GS-11 for paints, coatings, and primers; and Green Seal Standard GC-03 for anti-rust paints.
• Carpet systems must comply with requirements of the Carpet and Rug Institute's Green Label Plus program, while simultaneously meeting the adhesive standards listed above.
• Composite wood and agrifiber products must be produced with no added urea-formaldehyde resins; since exterior products are commonly made with phenol formaldehyde which, unlike urea-formaldehyde, does not off-gas at normal temperatures, they are considered acceptable under these guidelines. Included are such things as plywood, particle board, medium-density fiberboard, and so on.

Milstein Hall gets points for the first three of these categories, but not without some difficulties: it is likely that some of the "green" products used—for example, form-release agents applied to formwork surfaces in contact with newly-cast concrete—caused unexpected and unacceptable discoloration of the finished concrete surface which, in turn, required extra materials and work. The third credit is awarded because a token amount of "Bentley Prince Street" carpet, used only at the bottom level of the auditorium, is certified to meet the requirements of Green Label Plus (fig. 24.1). The last of these credits was not awarded, possibly because of plywood or other urea-formaldehyde emitting wood products used inside the building.

Indoor Chemical and Pollutant Source Control

Credit 5. This credit seeks to reduce the ongoing contamination of occupied space, not from construction materials, but from exterior pollutants and interior processes that release hazardous gases. Milstein Hall gets this point by complying with all of the following:

• Provide 6-foot long entry mat, grate, grille, etc. to capture dirt and other particulate matter.
• Treat any space in which hazardous gases or chemicals are present much like designated smoking areas (Prerequisite 2): floor-to-deck sealed partitions, negative pressure, and direct exhaust to the exterior. "Convenience" copiers and printers are excluded.
• Where mechanical ventilation is used, process both supply air, and any return air that will become supply air; and use pre-occupancy filters with MERV = 13 or better (not just MERV = 8 as in Credit 3).

Milstein Hall complies, in part, by outsourcing all the potentially hazardous equipment used in modern architecture programs to its neighbors— Sibley and Rand Halls. And in doing so, the hazards don't simply disappear: Sibley Hall's digital fabrication lab, for example, contains 3-D printers, some of which use material that is both toxic and carcinogenic. The manufacturer's instruction to use the printer "only outdoors or in a well-ventilated area" is addressed by installing transfer grilles between the adjacent corridor and the room. This strategy would be noncompliant except that several printers placed in the corridor allow the corridor to be labeled as a "room," and room-to-room air transfer, unlike corridor-to-room air transfer, is permitted (fig. 24.2).¹¹

Controllability of Systems

Credits 6.1 and 6.2. This credit consists of two points, one each for providing decentralized control of lighting and heating/cooling.

Lighting: To comply with Credit 6.1, lighting controls must be provided for 90 percent of occupants (individual users) and for 100 percent of all multi-occupant spaces, so that lighting can be adjusted to suit particular tasks according to individual preferences.

Milstein Hall embodies the exact opposite attitude, which shows up as well in Sustainable Site Credit 8 for light pollution reduction—the same non-controllable interior lighting that pollutes the night sky also influences the interior environment. Milstein is a glass box that is illuminated 24/7, even when the building is lightly occupied. Not only do students and faculty have no individual control over illumination levels from overhead lights, but glare from skylights has also proved to be a problem in certain locations on the studio level under the skylights. It appears to be practically impossible to control lights in areas where digital projection devices are used, or for individual workstations where lower light levels may well be preferred when working with computer monitors.

Thermal comfort (heating/cooling): To comply with Credit 6.2, "comfort control" must be provided for 50 percent of occupants (individual space users) and for 100 percent of multi-occupant spaces. Such controls can be hi-tech or low-tech (e.g., operable windows count), and can address any one of the four thermal comfort parameters: air temperature, radiant temperature, air speed, and humidity.

Milstein Hall has no such individual thermal comfort controls.

Thermal Comfort

Credits 7.1 and 7.2. This credit has a "design" and "verification" component, each worth one point. Milstein Hall gets them both.

Design: To comply with Credit 7.1, the project must satisfy ASHRAE Standard 55-2004 Thermal Comfort Conditions for Human Occupancy.

Verification: Compliance with Credit 7.2 is determined by surveying occupants 6–18 months after the building is completed. Per the ASHRAE standard cited above, 20 percent or greater occupant dissatisfaction requires that thermal issues be addressed and fixed. However, a survey conducted six months after occupancy will not necessarily reveal thermal problems that are seasonal in nature, e.g., overheating in the summer, or cold indoor temperatures in the winter. It also offers no guarantee that building operators will maintain adequate comfort levels in the years after such a survey is conducted.

Daylight and Views

Credits 8.1 and 8.2. This credit deals with glass and glazing from two points of view, and allows one point for each: first, bringing daylight inside and second, providing views to the outside.

Daylight: The basic criterion for this credit is to supply daylight to 75 percent of the building's regularly occupied interior spaces. This is defined in three different ways, any of which can be used to demonstrate compliance:

(a) Achieve a glazing factor (GF) of two percent measured at the back of all required spaces (i.e., in 75 percent of the building's regularly occupied areas). GF is calculated as: (window area / floor area) × (window geometry factor) × (actual T_vis / minimum T_vis) × (window height factor). In this equation, T_vis is the visible light transmittance defined as the ratio of transmitted light to total incident light (where "light" is the visible spectrum, i.e., having wavelengths of 380–780 nanometers). The minimum value is shown in Table 7, adapted from the LEED guidelines, along with geometry and height factors for five typical window/skylight configurations (from top to bottom: side light with daylight glazing, side light with vision glazing, top light vertical monitor, top light sawtooth monitor, and top light horizontal skylight).

(b) Use computer simulation to prove that daylighting provides 25 foot-candles of illumination (assuming clear sky, noon, equinox, measured 30 inches above floor) in the required 75 percent of spaces.

(c) Same as option (b), but use actual measurements of illumination levels on a 10-foot (3 m) grid instead of computer simulation. Only rooms that comply completely can contribute to the 75 percent area requirement.

Glare control is also a critical aspect of this credit; guidelines can be found in Table 7. It is unclear why the lack of such controls in Milstein's studio floor skylights did not prevent LEED from awarding this credit, in which Cornell claims compliance with a minimum two percent glazing factor in 100 percent of all regularly occupied spaces (Option 1).

Views: The basic criterion of Credit 8.2 is to provide a direct line of sight to outdoor space via "vision glazing," i.e., glazing positioned between 2'-6" (0.76 m) and 7'-6" (2.3 m) above the floor for 90 percent of the occupants of regularly occupied areas. The entire area of a single-person space counts if at least 75 percent of the space meets the sightline criteria; and the entire space does not count if less than 75 percent of the area complies. On the other hand, only the actual compliant areas (i.e., those areas within the room where sightlines can be drawn through windows) count in multi-occupant spaces.

Milstein Hall's upper-level studio is entirely open, except for an electrical closet that doubles as a projection screen. While students may be seated as far as 80 feet (24.4 m) from perimeter glazing, they still have a "direct line of sight" to outdoor space. That the point for this credit was not awarded is perhaps due to the 90 percent threshold criteria not being met.

Notes

¹ "Considerations," in "Indoor Environmental Quality, Prerequisite 1," USGBC, LEED 2.2 New Construction, 292.

² "Overview," USGBC, LEED Reference, 2009, 401.

³ William J. Fisk, "Health and Productivity Gains from Better Indoor Environments and Their Implications for the U.S. Department of Energy," E-Vision 2000 Conference (Oct. 11–13. 2000), Washington, D.C., https://www.osti.gov/servlets/purl/780590.

⁴ Anne Whitacre, "Another perspective on green," letter to the editor, Construction Specifier (Feb. 2008, 12) https://www.constructionspecifier.com/publications/de/200802/index.html.

⁵ Yuka Yoneda, "Bernie Madoff Serves Sentence at U.S.'s Only LEED-Certified Prison," Inhabit.com (website no longer available).

⁶ Paula Melton, "Army Targets Aggressive LEED, Green Building Goals," Environmental Building News (July 2011), here.

⁷ Jeff Dardozzi, "The Indiscreet Banality of the Bourgeoisie: The Church of LEED, Passive House, and the Dangers of Going Green," Monthly Review 62, no. 07 (December 2010), here.

⁸ Persily, "Indoor Air Quality and Carbon Dioxide" (my italics).

⁹ Schoen, P.E., "Indoor Air 2011." Schoen refers to conclusions reached by Hal Levin, Jan Sundell, and Eduardo Fernandez in a forum on "Ventilation Rates and Health" at the 12th International Conference on Indoor Air Quality and Climate sponsored by the International Society of Indoor Air and Climate (ISIAQ), June 2011.

¹⁰ "My insider's perspective (on Standard 62.2 at least) is that there is a lot of mileage to be made by scaring people about underventilation, and folks are rising to the occasion. Unfortunately, overventilation in hot, humid climates has led to more indoor air problems due to mold resulting from part-load issues than underventilation anywhere else… Doesn't anyone at the U.S. Green Building Council know anything about energy and part-load humidity?" Lstiburek, "Building Sciences: Energy Flow," (footnote, page 64).

¹¹ Sibley Hall's potentially hazardous digital fabrication lab addressed its noncompliant transfer of makeup air from a corridor into the room by adding several printers to the corridor and calling it a "room"; see Jonathan Ochshorn, "Egress, Toilets, and Carcinogens: Cornell's Transition Plans during Fine Arts Library Construction," Impatient Search (blog), updated Jan. 19, 2018, here.

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contact | contents | bibliography | illustration credits | ⇦ chapter 23 | chapter 24 | chapter 25 ⇨
 

First posted 27 Sept. 2023. Last updated 27 Sept. 2023.