PRB Articles


Give Lumens A Checkup

Lights--by their very nature and makeup--deteriorate over time. It is a proven fact that poorly maintained lamps lose at least 10 percent light output per year. Factors such as weather, surrounding temperature and use and maintenance all play a role in the rate at which a lamp ages. Consequently, lamps lose the ability to give off the same amount of light they gave the previous day. To increase the life expectancy of lights and avoid an accumulation of dead spots on courts, several maintenance protocols should be followed.

Defining A Foot-Candle

A foot-candle is a unit of illumination used to measure the light output in candela per square foot, according to Tennis Courts: A Construction and Maintenance Manual, written by the United States Tennis Association (USTA) and the American Sports Builders Association (ASBA). This unit of measurement is still used at many recreational sites to evaluate the light output of court lamps. Terms and other units of measurement--such as lux, lumen, candlepower and radiance--all help build the discussion on defining a light source, but the usual measurement is foot-candles. (While I could digress here for a moment and attempt to sort out some of the debate on the measurement of light, I will leave that discussion for another day.)

The USTA and the ASBA have recommended average levels of foot-candles for tennis courts. Recommendations are based on the type of play on the court:

· Class 1--Professional play involving broadcast television: 125+ average maintained foot-candles are recommended.

· Class 2--Non-broadcast play involving college, satellite and challenger play: 75 average maintained foot-candles are required.

· Class 3--High schools, tennis clubs and parks/recreational: 50 average maintained foot-candle level is expected.

· Class 4--High schools, tennis clubs and parks/recreational: 30 average maintained foot-candles are required.

(Note: Classes 3 and 4 are interchangeable, based on skill level and spectator requirements. In fact, parks/recreational and tennis clubs can even be found in Class 2, due in large part to the type of play on the courts.)

Another item that has an effect on tennis-court light levels is the average age of the players. Since older players require higher light levels, some suggest replacing lamps when they have reached 75 percent of their rated life-expectancy. Following this protocol will keep older players in the game.

Measuring Light Output

There are various light meters on the market to accurately measure light output. While they range in simplicity and price, all of them will ultimately give you a better understanding of your light coverage. The local utility company also may be a good resource for training and rental of these devices. I have found utility companies eager to assist with measuring and improving lighting/electrical use at parks. Another resource is the USTA, which recommends the “Light Meter Reading Diagram,” a valuable tool for taking precise measurements of lamp outputs around courts.

The depreciation of the amount of light a lamp produces is similar to the idea of driving a new car off the lot. The rate at which this takes place is called the light-loss factor (LLF). It is generally accepted by most manufacturers that a lamp will depreciate 20 to 40 percent over its life span. Factors like weather, outside temperature, use and maintenance all add to the LLF of a lamp. Keep in mind you have an effect on the rate at which lamps decrease their light output--frequently switching lamps on and off also will shorten their lifespan.

Developing A Maintenance Routine

Consistent, quality routine maintenance proves to have a tangible effect on extending the life of lamps. According to the Illuminating Engineering Society of North America’s Sports and Recreational Lighting Manual (IESNA RP-6-01), “With proper maintenance, the overall performance of the lighting installation can be greatly improved.” It goes on to clarify: “more light delivered per dollar, better energy management, pride of ownership, improved morale, [and] potential for reduced capital investment.” In general, at the time of design, a light installation should have a maintenance manual prepared. If one was not prepared or cannot be found, it is never too late to organize a maintenance schedule.

A good place to start is with the manufacturer. There are specific recommendations regarding the maintenance and replacement of lamps. Following the guidelines also can help with attempts to recoup money from bad lamps. Additionally, a manufacturer will have specifics on the frequency and types of maintenance practices necessary to keep lamps performing at their best.

In the meantime, here are some general practices for maintaining tennis-court lamps:

· Remove dust using a damp cloth (this also will help eliminate static electricity when cleaning the lenses).

· Follow the manufacturer’s recommendations.

· Never handle lamps with bare hands, as the oil from your skin can greatly reduce the efficiency and life of a lamp.

· Follow the maintenance schedule originally created for the lamps at installation, or create your own. It is a fact that regularly cleaned lamps outperform those that are not by up to 30 percent.

· Keep accurate records of cleaning, maintenance and replacement schedules.

According to Gary Gordon, Director of Field Service with Musco Lighting, “A yearly inspection, or routine maintenance program, can be very beneficial to any sports-lighting system. It can bring any unforeseen issues with the facility to the attention of the maintenance staff, especially after long periods of idle time during winter months.”

It is also a good idea to check the luminary aiming during maintenance to ensure that the installation continues to perform as originally designed. Light structures can shift and/or sag over time, moving the light off the court and creating possible dead spots. If you have ever had a player tell you about dead spots on the courts, it may not be the intensity of the lamp, but the direction of its focus.

Simplifying The Process

When developing a maintenance schedule, consider the type of equipment necessary to do the work. Many times the proper equipment (crane/boom trucks with buckets) to perform maintenance and replace lamps is not readily accessible. This can sometimes create difficult--if not impossible--decisions for facility managers. Lamps mounted in groups on high towers also make a challenging situation: they may be difficult to reach, but should be considered when replacing one lamp to replace them all. The frequency of group replacement will depend on the type of lamp, economic viability and the overall condition of the surrounding lamps in the installation.

Record-keeping is an important part of maintaining court lighting at specific levels. For example, by keeping track of each court’s light use, it can be more readily determined if a lamp has aged properly, or if there are other forces at work shortening its expected life. More often than not, this type of record-keeping is already being done. Most tennis facilities have a system by which they place patrons on the courts. This same system can be utilized to review and evaluate court lighting use. With many parks departments tightening already reduced budgets, don’t lose money on lights simply by not researching and tracking them. I recall standing on a tennis court with my staff many years ago, debating when we had installed various lights. It was a healthy discussion, but one that left me puzzled and confused. Some of the major items to review are:

· Dates that lamps are replaced and/or installed

· Maintenance (scheduled and otherwise)

· Lamp use

· Manufacturer warranties.

Keeping accurate records will help recoup some of the costs associated with operating tennis-court lights. A general rule of thumb is that most light installations lose at least 10 percent output per year through lack of cleaning and maintenance. Why be a part of a statistic that ultimately takes dollars out of the budget? Make the maintenance of tennis-court lights a part of a routine maintenance schedule.

Steve Yeskulsky is a CPRP currently working in the parks and recreation industry in Sarasota, Fla. He can be reached via e-mail at syeskulsky@verizon.net

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