During the early 1990s, OSHA conducted public hearings and solicited public comments on a proposed rule on indoor-air quality. Based on the observation that modern buildings tend to limit the infiltration of outside air and that this leads to the buildup of indoor contaminants, OSHA submitted a comprehensive proposed rule. The bulk of public attention was focused on the anti-smoking aspects of the rule, which became obviated by self-regulation and state laws. Though OSHA withdrew its formal indoor-air quality rule, it continues to publish guidance and recommendations on the issue.
Section 5(a)(1) of the Occupational Safety and Health Act mandates a hazard-free workplace. A hazard is designed as anything recognized as causing or likely to cause death or serious physical harm. Comfort, or discomfort, is not considered to be a hazard, so an employer cannot be cited under OSHA for office temperatures that do not rise to the level of a hazard.
The OSHA technical manual titled "Recommendations for the Employer" gives the most specific mention of office temperature. The language is not a binding regulation, only a recommendation for standard procedure. According to Section III, Chapter 2, Subsection V of the publication, office temperature should be maintained in the range of 68 to 76 degrees Fahrenheit.
In addition to office temperature, OSHA's recommendations for air quality in the workplace include a level of humidity between 20 and 60 percent and the treatment of air through the use of filters, electronic cleaners or chemicals. The air in the office should also be efficiently ventilated and free from contaminants.
In addition to OSHA regulations (or the lack thereof), employers can look to a publication on office temperature by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). As with OSHA regulations, in "Thermal Environmental Conditions for Human Occupancy," temperature is dealt with as an issue of comfort rather than hazard. In this case, rather than providing a discrete temperature range, thermal comfort is defined as feeling neither too hot nor too cold while wearing a normal amount of clothing. Though the ASHRAE guidance is non-binding, maintaining this level of thermal comfort will certainly prevent temperature from becoming a hazard in OSHA terms.