It is interesting to note that mandatory building codes are rarely written by a governmental agency. Instead, organizations such as the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) or the National Fire Prevention Agency (NFPA) convene committees of experts who review available data and relevant recent events and make recommendations on how building and design practices should be tweaked to improve the safety, energy efficiency, environmental impact, or some other characteristic of the built environment.

The resulting model standards are published and distributed. At this point, compliance with a particular model standard is not mandatory, it is voluntary. The standards are reviewed by governmental bodies at the federal, state, and local level. When, or if, the standard is adopted by a government body, it becomes an enforceable mandate that applies to the buildings that will be constructed within that government’s jurisdiction. For example, in 2011 the Department of Energy (DOE) recognized the ASHRAE/IES Standard 90.1-2010 as the new national energy standard. All states in the United States must be in compliance by October 18, 2013, which means that every state must put a commercial building energy code that is at least as stringent as the ANSI/ASHRAE/IES 90.1-2010 energy standard into place by that date.

Because the ASHRAE/IES Standard 90.1-2010 was adopted by a federal agency, the DOE, it uniformly affected every neighborhood in the nation, but not all code adoptions result in such sweeping change. There are over 30,000 individual jurisdictions in the United States. While there is some degree of hierarchy, federal mandates can override state mandates and states can override municipalities, there can still be significant variability, even between neighboring jurisdictions. It is the responsibility of the designer to find out what the minimum building standards are required by the local authorities.

Beyond the autonomy that can be exercised at even the most local level, there is another reason why keeping track of the applicable codes is an ongoing challenge for design teams. The standards are periodically reviewed by committee, updated, as needed, and published, where they are again reviewed by various government bodies and either adopted or not. Simply keeping track of which version of which standards have been implemented in a particular jurisdiction often requires some investigation.

Typical Illumination Requirements for Means of Egress

There are a few different standards that address design minimums for means of egress. Arguably the most widely adopted standard was written by the International Code Council® (ICC). The ICC was formed to combine many model code committees into one basic body. The ICC issues the International Building Code (IBC), which covers a broad scope of design topics that include: interior finishes, structural design, plumbing systems, elevators and conveying systems, means of egress and much more.

The IBC is revised every three years. Most recently, versions of the IBC were published in 2006, 2009, and 2012, with the next edition of the code coming in 2015. As of October 2013, 38 states had recognized the IBC 2009 or IBC 2012 as either effective statewide, adopted statewide with limitations, or adopted by local governments within the state. That adoption rate puts the 2009 IBC in contention as one of the most widely adopted and implemented construction codes in U.S. history.

Grand Park: Los Angeles, California Photo courtesy of Intense Lighting

Due to the wide-scale adoption of the IBC 2009, the requirements outlined in the standard for means of egress could be assumed to be the most typical requirements for means of egress in place in the United States. Chapter 10, section 1006, entitled Means of Egress Illumination states that lighting system along the path of egress must provide “at least an average of 1 foot-candle and a minimum at any point of 0.1 foot-candle, at the floor level.” The standard sites a few exceptions, which include auditoriums, theaters, concert halls, etc., where “illumination levels at the walking surface is permitted to be reduced during performances to not less than 0.2 foot-candles, provided that required illumination is automatically restored upon activation of a premises fire alarm, where such a system is provided.”

The Movement to Put More Light on Exterior Steps, Ramps and Paths of Egress

Buildings cannot be designed to prevent every type of unforeseeable emergency or life threatening event, but providing passageways that enable building occupants to exit a building safely, even if it must be done quickly, in a crowd, or under duress is critical. Unfortunately, the rare, but catastrophic building events, such as the attack on the World Trade Center in 2001, highlight the importance of safe stairs, stairwells, and emergency exits in the built environment. In addition, the National Safety Council reports that over 200,000 people visit hospital emergency rooms annually to treat injuries that occurred on steps, which has lead many in the business of building safety to wonder if there is something else that could be done to provide safer exterior steps, ramps, and paths of egress.

Stair and stairwell safety have been the subject of detailed scientific research that has generated a respected body of published results and general speculation that has generated some interesting anecdotal evidence. Time and time again it has been proven that improving the illumination levels around the stairs, improved the visibility of the stairs, which improved the public’s ability to safely navigate the stairs.

Whether in response to these findings, or simply in addition to them, some of the expert committees for organizations like the NFPA and the American National Standards Institute (ANSI) have decided to increase the minimum level of illumination recommended at the floor surface, also referred to as at the tread.