Evaluating Lighting in Premises Liability Disputes Expert Article

Adequate illumination is often a topic in premises liability claims. In this article, Architect & Premises Safety Expert Doug Peden discusses the standard of care for artificial illumination and the role that it has in maintaining a safe environment.

Premises Liability Lighting Expert Witness

Was Ambient Illumination Adequate With Respect to a Slip, Trip, or Fall Event?

To answer this question, it’s important to understand the environment in which the incident occurred and the details regarding how the incident transpired. The standard of care for illumination within the built environment will vary based on the location (ex. indoor vs. outdoor) and the expected use (ex. movie theater vs. shopping mall). It may also be important to understand the use of adjacent areas and lighting conditions encountered by users immediately prior to the incident.

Through an onsite analysis performed by an expert specializing in premises safety, it’s possible to arrive at a reliable answer based on scientific principles and established standards.

The Standard of Care for Illumination Levels

For sighted people, illumination provides the sensory cues required to navigate their surroundings in a reasonably safe manner. Without adequate illumination, the potential for bumping into things, tripping, or misstepping on objects or changes in the walking surface level increases dramatically.

Adequate illumination is essential for:

  • Safe egress from a building
  • Reading printed material and directional signage
  • Expanding the visual environment
  • Drawing attention to hazards

Measuring Artificial Ambient Illumination

There are two primary ways that artificial illumination is measured: output at the source of illumination, and ambient light levels experienced on a surface. In premises liability disputes we are principally concerned with the latter because the question is often whether or not illumination levels were adequate at or near the location of an incident.

Ambient lighting levels are most commonly measured in Foot-candles (Fc), a term coined and accepted based on the historical use of candles for internal lighting. One foot-candle historically represents the amount of illumination provided by a single, ordinary candle that is provided on one square foot of surface area.

The ability to reliably and comfortably identify specific objects within a space typically requires between 10 and 50 Fc. Because we cannot dependably control natural lighting, artificial ambient level lighting systems are typically designed to be variable between these two values. For specialized task requirements, localized task lighting is often provided. For an interior work environment for office or industrial activity, the artificial ambient lighting system is typically designed to provide between 20 and 50 Fc.

Historic studies show that approximately one Fc is required for people to safely navigate an unfamiliar environment. One Fc has been shown to allow the average sighted person to readily identify vertical objects and elevation differences of the ground or walking surface. Depending on the condition of the localized built environment, more illumination may be required, or less may be adequate.

Indoor Lighting Standards

Modern building codes provide requirements for the lighting levels of a means of egress. Industry standards of care are broader than the model codes by providing information on adequate and required illumination in various areas for different tasks. In many projects it is the role of the architect to understand these standards and apply them in an appropriate way to provide users with the illumination required to perform those tasks and enable safe passage throughout the built environment. The failure to provide adequate illumination through a combination of natural and artificial means, or just by artificial means within areas intended for pedestrian use may contribute to slip, trip, and fall incidents or potential wayfinding mishaps.

Outdoor Lighting Standards

Standards for artificial illumination apply to outdoor lighting as well. As an example, illuminating the means of egress within a building at all times that it is expected to be occupied is essential, and is mandated by code. Because egress extends to a public way, code compliant lighting must be maintained along that path.

With adequate ambient lighting, occupants can identify doorways, corridors and other people within the environment while making their way to the exit. However, the lack of adequate illumination may deny them the visual feedback they need to navigate the area safely. Lighting fixtures should be spaced and operated in a manner to provide adequate ambient lighting to the area to avoid overly bright or unduly dark spots.

Many outdoor environments such as parking lots, streets, sidewalks and paved walkways are not adequately illuminated for safe walking. Recommended levels vary based upon the type of environment. When artificial illumination is provided in an outdoor environment, lighting fixtures are spaced at a distance and height to illuminate the walking surface in a reasonably uniform manner.

Investigating Lighting in Premises Liability Disputes

Our experts can help to determine the standard of care for artificial ambient lighting as it applies to the environments people use on a daily basis, including commercial, industrial and workplace settings, recreational areas, restaurants, retail stores, office buildings, parking lots, and the paths of egress from each. Forensic analysis of a premises incident can sometimes go beyond the adequacy of lighting to also include the way that lighting was controlled and maintained. For energy efficiency, it is becoming increasingly common to see timers, motion sensors, and ambient light detectors used to control lighting in both interior and exterior spaces. Our experts can address these components to ensure that all of the relevant technical aspects are sufficiently reviewed.

Depending on the incident environment, experts from our Premises Safety or our Facilities Engineering group are the most common solution to incidents that may involve adequate illumination, but we can draw from a range of other specialty disciplines to address specific or unusual circumstances.

Please contact us to discuss your case with an expert.

Featured Expert

Douglas W. Peden, Architecture, Construction & Premises Safety Expert

Douglas W. Peden, RA, NCARB

Architecture, Construction & Premises Safety Expert
Doug is a registered architect in New York with more than 30 years of professional experience. He provides investigations, reports, and testimony in matters pertaining to premises safety, construction… read more.


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