Workshop LightingComments (2)
Bright strategies for better woodworking
By Larry Johnston
Whether you’re setting up a new workshop or improving your existing one, providing adequate light ranks as a top priority. In fact, a lighting overhaul constitutes the single most cost-effective upgrade for many shops. Insufficient light and glare—common shop-lighting problems—hinder vision and cause eyestrain. Doing tasks that require accurate measurements and precise tool setups in dim, shadowy (or harsh, glaring) light often leads to disappointing results, even if you’re using the latest and best tools and equipment. Bad lighting poses safety hazards too.
Finally, know that good lighting gains importance with increasing age. A 55-year-old person usually needs twice as much light to see as well as a 20-year-old. Read on as we help you see your shop in a new light.
Shop lighting: a two-part approach
Good shop lighting hinges on two components: ambient and task lighting. Ambient lighting is the overall illumination in a room. Task lighting focuses additional light on a work area when the need for accuracy or precision calls for greater contrast or visibility, such as when hand-cutting joinery or carving details. Many power tools now include built-in task lights, such as drill-press lights that shine on the bit and workpiece.
A few simple calculations and some basic lighting rules will help you establish ambient lighting that ensures a comfortable, safe, and efficient workspace. If your shop is in a garage or outbuilding, install windows and skylights to take advantage of natural daylight, but consider the natural light a bonus for sunny days; you’ll still need adequate electric (or artificial) lighting for working on cloudy days and at night. After establishing the ambient room lighting, add task lighting as needed.
Figure 1: Light Positions and Glare
A bare incandescent bulb casts light into your eyes and onto the reflective tool top.
Reflectors on overhead lights shield your eyes, but still add glare to a shiny surface.
Light from above and behind reflects away from you, illuminating the surface and eliminating glare.
Start with ambient light
The first step in lighting your shop is to provide proper ambient light. Suspended fluorescent fixtures with two 4-foot tubes adapt well to most shop layouts and are easy to install. Other styles of fluorescent lights or incandescent fixtures may also work. Any fixtures you use should include reflectors to direct the light downward; a light-color ceiling helps brighten the room too.
Fluorescent fixtures that incorporate electronic ballasts provide more light for less energy consumption than those with old-style magnetic (transformer) ballasts, although they cost more initially. The electronic ballast makes less noise, reduces annoying fluorescent flicker, and starts tubes instantly in cold rooms. The T8 tubes specified for those fixtures last longer and show less light drop-off as they age. Consider upgrading old fixtures with electronic ballasts and T8 tubes.
Arrange fixtures in a regular pattern across the shop ceiling, so light will fall evenly on your work surfaces. Install ceiling fixtures so they will be slightly behind you as you stand at a workbench, stationary tool, or other work surface. Because light reflects off a surface at the
same angle it strikes the surface, this placement will reflect light away from you, reducing glare
(Figure 1). Placing lights perpendicular to the length of a work surface also minimizes glare. Locate the lights close enough together to prevent dark zones between fixtures. For ideal spacing for the fixtures and their height above work surfaces, hang one fixture at the installed height. Then, with other lights off, turn on the test fixture and note the extent of its light spread.
Improperly positioned lights reflect into your eyes, so you end up moving around like a bobble-head doll to see clearly.
How much light do I need?
The desirable ambient lighting level for your shop depends on the work you do, especially for precision work. The table below shows recommended light levels for different situations. If you are over 55 or your shop has a lot of dark, nonreflective surfaces, opt for the higher value in each case.
Note that illumination, the amount of light falling on a surface, is measured in lux (lx), defined as 1 lumen per square meter. A square meter equals 10.76 square feet. For example, full daylight (not in direct sunshine) provides 10,000 to 25,000 lx. (The foot-candle, a U.S. unit of illumination, equals 1 lm per square foot or 10.76 lx.). See Recommended Light Levels below.
Light output, expressed in lightbulb or fluorescent tube wattage is more accurately measured in lumens (lm). Watts, a measure of electrical power consumed, doesn’t always equate directly to light output. Check out Light Output For Various Sources to compare light sources by their output in lumens instead. Consult the packaging or the manufacturer’s Web site for specifications of particular tubes or bulbs.
Keeping light real
Light sources, whether natural or artificial, vary in light color. Color in lighting varies as well with the kind of light fixture (incandescent, halogen, fluorescent). You can buy fluorescent light bulbs that range from reddish-yellow to bluish-white. This so-called “light temperature” is measured in degrees Kelvin (K). For example, candlelight measures 1,800 K;
an incandescent light bulb, 2,800; a tungsten-halogen light, 3,800; and daylight from 4,000 to 12,000. The lower the Kelvin temperature, the warmer or redder the light. When selecting fluorescent tubes for a shop for board matching, sanding, and finishing, you want something that mimics warm daylight. Go with fluorescent tubes in the 5,000-5,500 K range.
Calculating ambient light
For a quick estimate on ambient light needs in your shop, allow one 4' fluorescent fixture with two 32-watt T8 tubes for every 100 square feet to light the shop to about 600 lx. To figure more precisely, follow these steps:
1 First, measure the length and width of your shop. Multiply the length times the width to find the area in square feet.
2 Determine the level of illumination you want (see Recommended Light Levels). A woodworker who does precise work, such as laying out dovetails by hand, might want a 1,000 lx or higher. You can add task lighting to pump up the illumination at a workstation.
3 Divide the area in square feet by 10.76 to convert to square meters.
4 Multiply the area in square meters by the desired lighting level in lux to determine how many lumens are required to light the area to the selected level.
5 Divide the result from Step 4 by the light output in lumens for the source you are using (see Light Output For Various Sources) and round the answer to a whole number. The result is the number of bulbs or tubes you need to provide the light you want. For a shop that measured 20 × 24', we calculated needing (16) T8 32-watt tubes (eight two-tube fixtures) for good ambient lighting.
Tackle task lighting last
Task lighting puts light right where you need it. You can use a portable lamp, such as the clamp-on style shown at right, in many situations. Combined with a simple shop-built stand like the one shown at far right, one of these lamps might be all you need for task lighting in an average shop. A 250-watt halogen work lamp offers similar versatility. You can easily hang lamps equipped with clamps from the ceiling in a basement shop with open joists too.
A magnifying lamp comes in handy for a carving workstation or on a workbench. You can position the lamp right over your work and look through the magnifying lens for an up-close view of small details. You can substitute a swing-arm desk lamp if you just need the light without the magnifying lens. Either type of lamp can clamp onto a surface or you can stick the stem into mounting holes drilled in appropriate places.
Tool manufacturers often supply task lights designed for particular tools. Sometimes, you can attach a wooden cleat or bracket to a tool so you can affix a light with a clamp. Task lighting is incorporated into the design of many newer power tools.
Keep a flashlight handy in the shop too. A compact flashlight with LEDs puts out a lot of light, and batteries will last a long time. When you need to make adjustments under a router table or find a tool accessory in the back of a cabinet, you’ll be glad to have a little extra light. A camper’s headlight is useful too, when you want to keep both hands free, as when you’re installing jointer blades or a dado set.
This simple 6-foot stand can hold one or more clamp-on lamps to shed light on specific tasks.
Wiring Tips For Shop Lighting
Install shop lights on one or more separate 15-amp circuits. The number of fixtures you can run on a 15-amp circuit depends on each fixture’s current draw in amps, which may be listed on the fixture data plate or packaging. (If not, divide the power consumption in watts by the voltage to find amperage.) Then, total the current draw for all fixtures on a circuit. Lighting is considered a continuous load, so limit the total amperage to 80% of the circuit rating, or 12 amps for a 15-amp circuit.
You can wire some convenience outlets into the lighting circuits, but don’t run your major tools on the same circuits. That way, if the table saw or jointer overloads the circuit and trips the breaker, the shop lights won’t go out at the same time. In a large shop, wiring the lights in zones allows you to shut off the lights in a particular area if you’re not working there.
Place a light switch at each entrance to the shop. A motion-sensing switch that turns on the lights when you walk in might seem handy for those times when you have both hands full of tools or materials. But beware: this kind of switch can plunge you into darkness if it thinks the room is empty, as it might if you remain relatively motionless for awhile, standing at the workbench studying a plan, for instance. A better bet might be to install a motion-sensing security light in addition to the general shop lights.
Good article to a point. The basic ideas are sound, but the whole article needs an update. Led fixtures are far superior to any form of fluorescent, and they don't expose the user to potentially dangerous chemicals.
I was surprised and disappointed that LED lights were not discussed. LED’s last longer, don’t produce heat, light at any temperature, don’t have the environmental issues, and save money.
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