Sick Building Syndrome

Sick Building Syndrome

Sick Building Syndrome (SBS) is a real term used by health officials to describe real conditions in a building where occupants experience health and comfort effects that surface ONLY when they are in a building.

The symptoms will disappear when the occupants leave the building for any length of time.

Complaints may be localized in a particular room or area or they can be building-wide.

Up to 30 percent of new and remodeled buildings worldwide may be the subject of excessive complaints related to indoor air quality (IAQ). While this condition can be temporary, many buildings have long-term problems.

Indicators of Sick Building Syndrome include:

  • Building occupants complain of symptoms associated with acute discomfort, e.g., headaches; eye, nose, or throat irritation; dry cough; dry or itchy skin. More severe symptoms can include dizziness and nausea; difficulty in concentrating; fatigue; and sensitivity to odors.
  • The cause of the symptoms is generally due to indoor air quality issues.
  • Most of the complainants report relief soon after leaving the building.

Note that these complaints may result from other causes. These may include an illness contracted outside the building, acute sensitivity (e.g., allergies), job related stress or other psychosocial factors.

That being said, studies show that symptoms may be caused or exacerbated by indoor air quality problems.

Causes of Sick Building Syndrome

It should be noted that radon and asbestos are not considered to be among the causes of sick buildings. These issues cause long-term diseases which occur years after exposure. This isn’t to say these are not serious health risks; both should be included in any comprehensive evaluation of a building’s IAQ.

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The following are the cause of (or contributing factors to) sick building syndrome:

  • Inadequate ventilation: In the early and mid 1900’s, building ventilation standards called for approximately 15 cubic feet per minute (cfm) of outside air for each building occupant, primarily to dilute and remove body odors.

The 1973 oil embargo drastically changed that standard. , National energy conservation measures called for a reduction in the amount of outdoor air provided for ventilation to 5 cfm per occupant.

In many cases this was found to be inadequate to maintain the health and comfort of building occupants and is thought to be an important factor in SBS.

Responding to these issues, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recently revised its ventilation standard to provide a minimum of 15 cfm of outdoor air per person (20 cfm/person in office spaces).

  • Chemical contaminants: Most indoor air pollution comes from sources inside the building. This can include adhesives, carpeting, upholstery, manufactured wood products, copy machines, pesticides, and cleaning agents. All may release volatile organic compounds (VOCs), such as formaldehyde. For more information, see VOCs; Carbon Monoxide; Formaldehyde.

Poorly located air intake vents, windows, and other openings may allow outdoor air to enter a building. For example, pollutants from motor vehicle exhausts; plumbing vents, and building exhausts (e.g., bathrooms and kitchens) can enter the building, affecting the building’s IAQ.

  • Biological contaminants: Bacteria, molds, pollen, and viruses are types of biological contaminants.

These contaminants may breed in stagnant water that has accumulated in ducts, humidifiers and drain pans, or where water has collected on ceiling tiles, carpeting, or insulation. This is often the underlying cause of SBS.

Physical symptoms related to biological contamination include cough, chest tightness, fever, chills, muscle aches, and allergic responses such as mucous membrane irritation and upper respiratory congestion.

One indoor bacterium, Legionella, has caused both Legionnaire’s Disease and Pontiac Fever.  For more information, see Biologicals and Mold.

These elements may act in combination, and may supplement other complaints such as inadequate temperature, humidity, or lighting. Even after a building investigation, however, it’s possible the specific causes of the sick building syndrome complaints may remain unknown.

Indoor Air Quality Investigation

This procedure is best characterized as a cycle of information gathering, hypothesis formation, and hypothesis testing. It generally begins with a walkthrough inspection of the problem area to provide information about the four basic factors that influence indoor air quality:

  • The occupants
  • The HVAC system
  • Possible pollutant pathways
  • Possible contaminant sources.

The initial walkthrough: This should allow the investigator to develop some possible explanations for the complaint. At this point, the investigator may have sufficient information to formulate a hypothesis, test the hypothesis, and see if the problem is solved. If it is, steps should be taken to ensure that it does not recur.

However, if insufficient information is obtained from the walk through to construct a hypothesis, or if initial tests fail to reveal the problem, the investigator should move on to collect additional information to allow formulation of additional hypotheses.

The process of formulating hypotheses, testing them, and evaluating them should continue until the problem is solved.

Air sampling: Although air sampling for contaminants might seem to be the logical response to occupant complaints, it seldom provides information about possible causes. It often is not required to solve the problem and can even be misleading. Contaminant concentration levels rarely exceed existing standards and guidelines even when occupants continue to report health complaints.

Solutions to Sick Building Syndrome

Solutions to sick building syndrome usually include some combinations of the following:

  1. Pollutant source removal or modification: Examples include routine maintenance of HVAC systems, e.g., periodic cleaning or replacement of filters; replacement of water-stained ceiling tile and carpeting; proper venting of contaminant source emissions to the outdoors; storage and use of paints, adhesives, solvents, and pesticides in well ventilated areas, and use of these pollutant sources during periods of non-occupancy.

Often overlooked is allowing time for building materials in new or remodeled areas to off-gas pollutants before occupancy.

  1. Increasing ventilation rates: This is often the most cost effective means of reducing indoor pollutant levels. Simply increase the fresh air flow into the building.

Many HVAC systems are not operated or maintained to ensure the proper ventilation rates are provided. In many buildings, IAQ can be improved by operating the HVAC system to exhaust local pollutants that accumulate in specific areas such as rest rooms, copy rooms, and printing facilities. (For a more detailed discussion of ventilation, read Fact Sheet: Ventilation and Air Quality in Offices)

  1. Air cleaning can be a useful addition to source control and ventilation. However, it does have certain limitations.

Particle control devices such as the typical furnace filter are inexpensive but do not effectively capture small particles.

High performance air filters capture the smaller, respirable particles but are relatively expensive to install and operate.

Mechanical filters do not remove gaseous pollutants. Some specific gaseous pollutants may be removed by adsorbent beds, but these devices can be expensive and require frequent replacement of the adsorbent material.

In sum, air cleaners can be useful, but have limited application.

If you suspect that your facility is experiencing SBS, you really cannot afford to wait to get a definitive answer. Contact a company that specializes in this and get the problem identified and eliminated.