Does your flashlight measure up?
August 3, 2008
Almost any discussion on safety involves avoidance of risk. To avoid danger one must be able to detect the threat.
Flashlights enable us to carry and introduce light where it is not otherwise available, therefore reducing risk. They can improve productivity by facilitating completion of tasks where fixed lighting is not available or feasible. Flashlights can also illuminate areas that are sheltered from fixed lighting.
If the benefit of a flashlight is the illumination it provides, then understanding the standards and methods used to measure light output is very important. Fixed lights, or bulbs, have historically been rated or measured in watts. Typically, a greater number of watts relates to a higher output in light. The terms and measurements used to rate flashlights have evolved as technology has advanced. Most flashlights were formerly constructed with incandescent bulbs, while the more advanced lights now incorporate LEDs or light-emitting diodes.
LEDs are the fastest developing light source technology to hit the flashlight market and, many believe, superior to incandescent bulbs. LEDs have an expected life of 100,000 hours or more depending on the manufacturer and conditions for use. LEDs are not impervious to shock but are extremely durable and, as a consequence, more useful for rigorous work conditions.
With more widespread use of LEDs in flashlights has come a more advanced approach to measuring light output in lumens or lux. Lux ratings arise from measurement taken at the center of the light beam, indicating how well the light is projected over a distance, not the overall brightness of the flashlight. A lumens test measures the overall brightness of a flashlight, which involves a rating of total light output in every direction. An oversimplified explanation of a lumens rating is a measurement of light emitted by a source on the inside of a sphere. Lumen ratings are standardized and if the tests to establish output are conducted by qualified laboratories, the numbers are very useful in comparison of flashlights.
Many manufacturers now offer lumens and/or lux ratings on their packages, Web sites and sales literature. A full moon on a clear night can be measured as 0.25 lux, and in comparison, sunlight on an average day can be measured up to 100,000 lux. Some advanced flashlights can be rated as high as 3,000 to 5,000 lux.
The flashlight as a productivity or safety tool should be evaluated for properties other than light output. The usefulness of a flashlight is its ability to produce and place light when and where light is needed. As a result, battery life is a crucial element in the flashlight’s ability to not just deliver but to sustain light as needed. LEDs create a very bright light from little power, making LEDs much more energy efficient, which will save the consumer money.
There is not presently a standard or an agreement on rating battery life. Light output measurements are typically captured with batteries that are near full capacity of charge. Light output tends to fall over a curve as the batteries are depleted with use. Although a manufacturer can indicate that battery life may be 100 hours, there is not a standard to identify the minimum light output that is useful. In evaluating battery life claims, it is wise to note that most users are likely to replace batteries when the output falls to perhaps 50% of the amount generated with fresh cells.
There are many different sizes, shapes and technology in flashlights on the market today. Flashlights might involve the ability to focus or concentrate light on a small area, while others offer the capability to adjust from flood to spot illumination. Manufacturers also employ technology that automatically delivers a focused beam at the center with flood illumination over a much wider area. Some manufacturers have incorporated designs that prevent the normally cylindrical flashlight from rolling off a flat surface. Stabilizing and arranging light to the desired area can be accomplished in many ways and is an important factor in determining the usefulness of the light in the situation where it will be employed.
Durability & safety
Durability is another important factor to look at when deciding on a flashlight to fit your specific needs. Although LEDs are shock resistant, the materials used in construction and the care with which they are assembled contribute to the overall durability of the device. Many suppliers publish durability claims in drop test ratings, and the probability of having light, when and where it is needed, is increased with the durability of the device.
Other aspects of performance may need to be considered as conditions dictate. Some flashlights are constructed of materials that will not rust or corrode. Some are designed to be water resistant and others, waterproof. Manufacturers of waterproof flashlights often publish specifications to indicate to what depth the light will remain watertight and operational.
Flashlight safety ratings exist that qualify usage in conditions of specific risk. Where vapors, airborne debris or other dangers of explosion or ignition are present, only properly rated flashlights should be employed. Lights that are tested to insure that they will not be a source of spark or ignition should be used exclusively where those dangers may be present.
There have been significant leaps in flashlight technology. Selecting a flashlight that is appropriate for the task requires more understanding of ratings and specifications. Flashlight features, performance and cost alternatives are much greater than in the past. Careful selection can equip the user with a much better tool for both productivity and safety.