Veiling reflections and burned-out lamps at a swimming pool prevent clear observation of a drowning victim. Good illumination is critical for pool safety.
"Let there be light" is a statement as old as Genesis. Yet, even in broad daylight, there may not be enough of it to prevent tragedy. A recent accident and its forensic investigation tells the tragic story.
The body of a young swimmer was found floating in a guarded Olympic-size indoor public swimming pool one late afternoon. Much to everyone's dismay, the lifeguard on duty swore he did not see the boy in the water. To solve this tragic mystery, the owner called our forensic engineering firm in to determine the causes leading up to the fatality. It took our design skills and engineering knowledge to determine the contributing factors leading to the drowning. After several days of inspecting the pool, each time late in the afternoon, we identified and documented various probable points of concern.
The architect, who designed the pool five years earlier, had specified continuous unshaded heat absorbent glass panels on the front and rear walls of the pool. These panels extended 24 in. down from the ceiling. Located at the deep end of the pool near the northeast corner, the lifeguard sat behind a desk on a non-elevated chair at the designated lifeguard station. Illuminated by indirect lighting fixtures, the pool also received natural light via windows and an underwater lighting system.
The 12 indirect lighting fixtures consisted of fixture "boxes," each containing two 1500W tungsten-halogen lamps. Each lamp had a lumen rating of 35,000; as such, the total initial source lumens for indirect illumination was 840,000.
There were 14 underwater lamps (two rows of seven fixtures with PAR lamps) along the length of the pool. We inspected these fixtures and found six of them (43% of the underwater illumination) out of service. And, the location of the burned out lamps was the area where the body surfaced.
The room walls featured black paint from the floor line to a point 6 ft from the floor, while the upper wall surfaces were white. The floor was dark ceramic tile, and the bottom of the pool had white tile with black lane markers.
During our site observations, we saw that sunlight through the windows caused a glare on the water's surface. At our request, the lifeguard entered the pool and placed himself exactly where the drowning victim surfaced. We then sat at his station and watched. Due to the rays of sun coming through the windows (which had no awning or shading), we couldn't see the lifeguard. The veiling reflections on the water at that part of the pool (where the drowning occurred) prevented the observation. Contributing to the problem were the burned out lamps in the underwater light fixtures. The loss of light from the non-functioning lamps prevented the bottom of that part of the pool from being illuminated. Because of these factors, the reflection of the sun in the water was more effective than it should have been.
To illustrate the condition, we prepared a sketch to document our observations. We concluded there were several factors critical to life safety that impact the design and operation of a swimming pool lighting system beyond the basic selection of lighting fixtures. They include: * Orientation of the building relative to the sun's declination; * Analysis of the impact of awning and/or shades on glare; * Testing and maintenance of all lighting systems that include periodic group lamp replacement; * Placement of lifeguard(s) at elevated station(s); and * Removal of any desk at lifeguard station(s) so that the lifeguard can concentrate on swimmers.
In the course of this assignment, we reviewed standards for lighting of indoor swimming pools adopted by the Illuminating Engineering Society (IES); we also looked at Engineering Report No. 29, presented by the Sports Lightin g Committee of the Netherlands Institution for Illuminating Engineering.
It's critical to life safety that lighting designers be aware of the factors that may reduce the performance of their design. And, lighting for sports activities requires extra design considerations. You must closely study factors such as reflections (caused by both artificial and natural illuminations). And last but not least, officials should mandate that owners properly maintain lighting systems at all sports areas. Remember, even a baseball, if not seen during a night game, can cause serious head injury.