WHAT IS SBS?

Sick building syndrome (SBS) is a combination of ailments (a syndrome) associated with an individual's place of work (office building) or residence. A 1984 World Health Organization report into the syndrome suggested up to 30% of new and remodeled buildings worldwide may be linked to symptoms of SBS. Most of the sick building syndrome is related to poor indoor air quality.
Sick building causes are frequently pinned down to flaws in the heating, ventilation, and air conditioning (HVAC) systems. Other causes have been attributed to contaminants produced by outgassing of some types of building materials, volatile organic compounds (VOC), molds, improper exhaust ventilation of ozone (byproduct of some office machinery), light industrial chemicals used within, or fresh-air intake location / lack of adequate air filtration.
Symptoms are often dealt with after-the-fact by boosting the overall turn-over rate of fresh air exchange with the outside air, but the new green building design goal should be to avoid most of the SBS problem sources in the first place, minimize the ongoing use of VOC cleaning compounds, and eliminate conditions that encourage allergenic, potentially-deadly mold growth.

Symptoms

Building occupants complain of symptoms such as sensory irritation of the eyes, nose, throat; neurotoxic or general health problems; skin irritation; nonspecific hypersensitivity reactions; and odor and taste sensations.

It is possible for a dozen sick occupants to report a surprising array of individual symptoms, which may be dismissed as unconnected. The key to discovery is the increased incidence of illnesses in general with onset or exacerbation within a fairly close time frame - usually within a period of weeks. In most cases, SBS symptoms will be relieved soon after the occupants leave the particular room or zone. However, there can be lingering effects of various neurotoxins, which may not clear up when the occupant leaves the building. In particularly sensitive individuals, the potential for long-term health effects should not be overlooked.

Causes

The contributing factors often relate to the design of the built environment, but primarily, Moisture is the culprit. Exterior and demising wall cavities very often receive continuing loads of moisture due to unintentional, high humidity airflows through a building's matrix. Often such moisture is trapped and hidden within these cavities where it builds to 70% and 95% moisture saturation by weight. There are few if any, mechanisms that operate to dry out such wall cavities.

If such airflows are of hot, humid air, this moist, warm air may reach a dewpoint surface, especially if indoor temperatures are maintained much below about 78 degrees F. At this degree of moisture saturation, in this dark, undisturbed wall cavity space, most all molds, including stachy, thrive. Molds and bacteria rarely coexist. Molds produce generally toxic substances that create unwelcome, unhealthy environments for bacteria and insects, as well as human beings. The toxic substances generated by mold growth may become aerosolized, released and distributed to a much greater range by these unintentional airflows through the building's matrix until they may be inducted into the air conditioning and heating distribution systems and ultimately discharged into the breathing zone. These unintentional airflows create the toxicity and obscure the true source of toxicity and earthy odors as they distribute it.

Mechanical ventilation in a hot, humid climate may deliver water vapor into a building at the rate of approximately one pound of water per day for each cubic foot per minute per day of unconditioned outdoor ventilation air delivered.

Radon mitigation by mechanical ventilation in hot humid climates, (Florida) is known to create gradual increases in moisture saturation that suddenly lead to mold problems when moisture saturation of a favored mold food material reaches 70% by weight. This increasing moisture saturation process may take a few months or as long as four or more years.

The uninformed or poorly informed assume that the air conditioner will successfully remove such moisture, and it may if it is operating efficiently. Many air conditioners do not, and almost all of them decline in their ability to dehumidify efficiently over time. Residual moisture remains and soaks into materials as if they were sponges, on a march toward full saturation. In hot, humid climates, the worst months for mold are October, November, December and early spring...when air conditioners rarely operate and moisture saturation increases most rapidly.

Identification and termination of these unintentional building matrix airflows has rarely been recognized and acted upon, hence heroic efforts to heal the sick building have been largely unsuccessful. Out of a sense of frustration with enormously expensive and ineffective healing approaches, total building destruction is sometimes selected as a way out.

With proper application of currently available instrumentation, identification of unintentional building matrix airflows is relatively easy, quick and inexpensive for a knowledgeable, experienced, building science practitioner. Pressure and micropressure management can result in immediate odor and toxics distribution system termination. With application of correct technology, and often without installation of any additional equipment, relying only on what is already there, within hours of completion a sick building can begin a gradual drying out process to heal itself completely.

As Joe Lstiburek has said, the approach of building disassembly and rebuild or destruction on one hand (expensive) or micropressure management on the other (much less expensive) is decided by who is paying. Micropressure management correctly applied has the potential to eliminate the true cause of the sick building.
The other approach rarely addresses the cause and treats the symptoms only.

• Indoor air quality (including smoking where not prohibited)
• Toxic mold
• Artificial fragrance, such as dryer sheets
• Poor or inappropriate lighting (including absence of or only limited access to natural sunlight)
• Poor heating or ventilation
• Microbial or mite contamination of HVAC systems.
• Bad acoustics
• Poorly designed furnishings, furniture and equipment (e.g. computer monitors, photocopiers, etc.).
• Poor ergonomics.
• Chemical contamination.
• Biological contamination.

To the owner or operator of a "sick building", the symptoms may include high levels of employee sickness or absenteeism, lower productivity, low job satisfaction and high employee turnover.

Prevention

• Pollutant source removal or modification to storage of sources.
• Replacement of water-stained ceiling tiles and carpeting.
• Institution of smoking restrictions.
• Use paints, adhesives, solvents, and pesticides in well-ventilated areas, and use of these pollutant sources during periods of non-occupancy.
• Increase the number of air exchanges, The American Society of Heating, Refrigeration & Air Conditioning Engineers recommend a minimum of 8.4 air exchanges per 24 hour period.
• Proper and frequent maintenance of HVAC systems
• UV-C light in the HVAC plenum

Clarification of the link between a sick building and employee health has and will likely continue to result in increased worker's compensation and personal injury claims. Business owners will likely find increasingly happy customers and a better bottom line with successful healing of sick buildings.