Many factors must be considered, from effectiveness, safety, and environmental to review by panning authorities, when designing lighting systems for automatic transaction units.
Automatic transaction units (ATUs) are everywhere and we use them all hours of the day and night. The most familiar ATU is the automatic teller machine (ATM). To meet functional and security lighting requirements for night time use, adequate illumination that is perpendicular to the task must be provided so that user can identify the correct function he or she wished to conduct at the site.
In addition, many of these units include video surveillance equipment that require proper lighting for the camera to record images and shielding to prevent glare for the security and protection of the user.
Importance of effective lighting
Proper lighting is a major tool allowing the accurate, rapid, and safe usage of the ATU.
Signage. The first thing necessary for good lighting is that it identifies the location of the unit(s), usually through the use of signage. If outdoors, the graphic should be designed to be visible during the day without illumination; during the evening, the sign should be brighter than the background for rapid identification. This will vary with the brightness of the surrounding areas.
When indoors, the signage should be three to five times brighter than the surrounding illumination. Many times the signage is built into the unit and there is no control of its brightness.
Function area lighting. The lighting of the ATU's function areas is something we do have control of. First, we should consider the light source (lamp), which should be a high efficacy (lumens out/watts in) source with relative long life. The lighting system at most ATUs will operate at least half of every day on average, which amounts to over 4380 hrs per year.
Light sources having less than 40 lumens per watt will cause excessive energy usage to meet the required lighting levels. Those with a life rating of less than 10,000 hrs will require excessive maintenance. (A nonfunctioning light will probably result in the unit not being used.)
Light sources that do meet these illumination needs are full-sized fluorescents (usually 4 ft), compact fluorescents (over 15W), and small wattage (up to 150W) metal-halide (M-H) or high pressure sodium (HPS) lamps.
Of all the sources, the HPS lamp (clear or diffused) provides the highest lumens/watt ratio and the longest lamp life. But, these lamps have a poor-to-fair color rendering factor (22 CRI). The deluxe HPS lamp (65 CRI) has better color rendering, but efficacy is reduced by approximately 35%.
When selecting a lamp and ballast system for outdoor applications, you must make certain that the system has the ability to start and maintain lamp operation at the lowest temperatures normally experienced in the area. (All sources except incandescent require a ballast for starting and operating.)
If fixtures with M-H or HPS lamps are used, they should be equipped with an auxiliary incandescent lamp to compensate for the restarting time of the HID lamp (approximately 8 min for M-H and 1 min for HPS lamps).
Once the light source has been selected, the next concern is the fixture or luminaire selection. For indoor installation, the most important concern is that the fixtures be compatible with the architectural design. You can use almost any fixture type at interior locations to provide illumination at the level required, and with the correct direction and necessary control. There is greater concern when lighting ATUs for outdoor locations.
Usually, the only places to mount lighting figures outdoors are on walls. For such installations, they can be mounted on the same wall in which the ATU is installed, on other parallel or perpendicular walls, or on a pole located in the immediate area.
Fixtures used for ATU lighting have many requirements beyond providing adequate illumination.
* They should be vandal resistant to prevent breakage and partial or total loss of illumination.
* They should be, at a minimum, damp (moisture) labeled.
* Where exposed to rain, they should be raintight.
* They should have shielding to prevent direct glare in all directions.
In some instances, there may be a design review organization (members could be from the local municipality, representatives from the building's owner, and/or representatives from the financial institution itself) that will review and pass judgment on the style and size of the fixtures and/or on the amount of illumination provided, and possibly on the mounting provisions that would be used.
Lighting objectives
Process area lighting. ATU illumination should provide adequate light for the process areas, including the ATU's keyboard, card and receipt slots, and the transaction area. ([ILLUSTRATION FOR FIGURE 1 OMITTED] on page 43) Not only does this allow rapid and accurate ATU usage, it also minimizes glare on the video screen so as to not obscure instructions or information.
The recommended levels of illumination for carrying out tasks at an ATU, as listed in the IES Lighting Handbook, 8th Edition, 1993, are based upon an Illuminance Category of C, which has a mid-range level of 15 footcandles (fc), or 150 lux. This level is not on a horizontal surface but is on the actual face of the ATU. The best way to provide this lighting is from both ends of the transaction area, not directly overhead or in front of it. Such two-source directional lighting allows sufficient light while reducing the shadowing effect that can occur during the actual transaction.
Surrounding area lighting. The next lighting concern is the area immediately around the ATU. This area has many functions: finding items in wallets and purses, locating and preparing forms for the transaction, and retrieving any dropped or misplaced items.
Per IES, lighting levels in ATU writing areas inside a bank are based upon an Illuminance Category of D, with a mid-range level of 30 fc, or 300 lux.
For outdoor ATUs, the light from fixtures and other sources should result in approximately 7 1/2 fc (75 lux) at a 10-ft radius from the unit. This design meets the IES recommended level for service type areas.
Lighting to serve CCTV coverage
Video camera surveillance for the safety of those approaching and departing the area and for identification of persons performing the transactions also occurs in the service area. This task requires lighting a space from 3 to 6 1/2 ft above ground and from in front of one or more units to a 10-ft semicircular approach area, as shown in Fig. 2. The illumination level should be a minimum of 5 fc (50 lux). This amount of illumination allows the closed circuit TV (CCTV) camera lens to be set for the entire area without continuous adjustments of the aperture due to low light levels at the perimeter.
For CCTV operation, you should select light fixtures that minimize any direct brightness in the user's eyes, which may cause temporary loss of vision. Some installations have the camera located behind or adjacent to the ATU, allowing viewing of the person approaching and using the system. This operation is relatively easy to illuminate, using the same fixtures as those used for lighting the ATU itself.
There are some installations where the cameras are set behind and to the side of the person using the equipment. This position views the person's back while they are using the unit and their front as they are leaving. In this case, a supplemental source of light, located near and aimed in the same direction as the camera, is necessary to illuminate the plane of action.
Illumination to provide safe passage
Now that you've provided IES recommended illumination levels so that a person can carry out financial transactions rapidly, accurately, and safely, your work is done, right? Wrong!
You still have to provide illumination for the safe and secure passage of the ATU user to his or her vehicle. For secure passage, the design should consider the possibilities of tripping over curbs or obstructions; bumping into branches; dealing with a rapid change in grade; and/or slipping on surfaces. The term "safe" refers to protection against mugging, robbing, etc.
The fact that the area may contain landscaping, berms, hard and soft paths, areas in which to hide, high foliage, and adjacent structures, all lead to the reality that there is no single easy way to illuminate the ATU area without producing disabling glare. The following are some suggested safe passage lighting methods.
* Floodlighting from above with fixtures spaced at a distance not exceeding 2.5 times the fixtures' height above grade.
* Path lights mounted almost on grade to approximately 10 ft high.
* Uplights into the foliage of trees or large bushes and where the light is reflected onto the paths.
* Various combinations of the above methods.
In areas with normally low lighting levels (2 to 3 fc or 20 to 30 lux), it's very important to be able to distinguish color difference. A person wearing a blue jacket can be difficult to notice against a green- or brown-colored bush or structure, but with good color rendering sources, this task is easily accomplished, even at low lighting levels. It's recommended that the light sources used have a color rendering index (CRI) of at least 65 to allow for color discrimination.
Make sure that you select fixtures and locations that will not ca use disabling glare to the user. Even with the highest lighting levels and the best color rendering, a person leaving or approaching the ATU area will not feel safe and secure and may not return if they experienced a temporary disabling glare.
State and municipal laws and regulations
In many cases, laws, regulations, and environmental issues are directly at odds with each other. In 1990, the State of Calif. passed Assembly Bill 633, which establishes rules to promote "safe" use of ATMs. This law is being used as a model code and has been adopted, almost intact, by at least 10 cities and states in the U.S. It establishes a lighting level of 10 fc on a banking transaction unit's face as well as in an area 5 ft away from the unit. (This distance is below what is really needed.)
The law also requires 2 "candlefoot power" at a radius of 50 ft from the unit on all walkable surfaces. (The law does include the definition for "candle foot power" as "the light intensity of candles on a horizontal plane at 36 inches above ground level," which is actually the definition of horizontal footcandles.) Nowhere in the law does it address how to provide the required illumination. Many installations use floodlights installed on walls above a transaction unit, at approximately 15 ft above grade, and aimed almost horizontally to produce the 2 fc at the plane 36 in. above the ground. This results in projecting relatively horizontal light, producing glare.
These types of installations are referred to as "glare bombs" and are probably causing more problems from glare than any safety provided.
A final concern is the impact of excess light distribution, which can effect the local environment. Uncontrolled lighting that crosses property lines can deliver undesired illumination and glare on a neighboring property. Additionally, light that is generated from a fixture above a line parallel with the ground can produce light pollution into the atmosphere, effecting night time telescope observation as well as enjoyment of the night sky.
As such, you must carefully investigate the various factors that impact the lighting system for your ATU installation and then provide proper solutions, whether for an interior or exterior operation. The selection and location of the light sources; the effectiveness of the light to provide safety and functionality for the user; the impact on the surrounding areas; all must go into the installation planning. In many cases, a computer generated point-by-point illuminance plot of the lighting, as well as a model to show possible areas of discomfort or disability glare, will be helpful to the client and the planning authorities before the design is finalized. The Financial Facilities Committee of the IES is presently working on a design guide to provide more recommendations and information for lighting ATMs. This document, when finished, will address all types of electronic transaction units.
SUGGESTED READING
Books
IES Lighting Handbook, 8th Edition, 1993. Illuminating Engineering Society of North America. N.Y.
For ordering information, call 212-248-5000.
RELATED ARTICLE: WHAT'S AN ATU?
In today's commercial environment, many transactions are made using credit or debit cards, and an increasing majority are being made electronically without direct contact with sales or banking personnel: This step forward in electronic transactions is an expansion of the automatic teller machine (ATM), which was originally developed for banks and savings and loan organizations and allows people to make financial transactions 24 hours a day.
Typical ATU transaction activities include inserting an envelope, receiving paper money or tickets, and accepting and verifying a printed receipt.
All of these functions are included within a vertical space of approximately 2.5 ft wide by 2.8 ft high with an approach area in front for access, preparation, transaction, and departure. The most active part of the approach area is a semi-circle within a 10-ft radius of the ATU.
The equipment itself consists of a panel board with buttons that serve distinctly different functions. The first thing you notice as you approach it is the video screen, which provides step-by-step instructions on usage, as well as transaction information. It requires shielding to prevent glare on the screen, allowing instructions on the use of the keyboard to be seen. And, the keyboard and location of the credit/debit card input slot should easily be seen.
These devices are now in facilities other than banks and savings and loans institutions. They are located in many countries around the world as local currency dispensers to reduce the need for prepurchasing foreign currency when traveling. Automobile gasoline stations are incorporating their functions directly at the pump island to expedite transactions for the self-service customer and to reduce staff. Retail stores, including markets, are having ATUs built into checkout stands to provide faster and more accurate sales. These units are also finding their way into the transportation and entertainment areas, allowing the user to obtain tickets for airlines, trains, buses, as well as theatrical and entertainment functions. These are just a few of their uses and they can be located anywhere, inside or out-of-doors, where power and telephone lines can be provided.
Hyman Kaplan, P.E., is Vice President & Chief of Lighting Design at Belden, Inc., Consulting Engineers, San Leandro, Calif. Mr. Kaplan is the chair of the Illuminating Engineering Society (IES) Financial Facilities Committee and is active in the energy committees of both IES and the International Association of Lighting Designers (IALD).