What is a Foot Candle?
A great place to start is with the definition. For those of you who may not be familiar with them, a foot-candle is a measurement of light intensity. One foot-candle is defined as enough light to saturate a one-foot square with one lumen of light.
If that sounds vaguely like the definition of a lumen, you aren’t wrong. Both lumens and foot-candles are measurements of light intensity.
While lumens measures the amount of light created by a lighting fixture, foot-candles is a measurement of the amount of light that reaches a surface area.
In accordance with other factors, foot candles allow electricians and facility managers to carefully and thoughtfully develop an effective lighting plan.
After all, it doesn’t matter how much light a bulb emits if none of that light reaches the desired surface area.
Why Are Foot Candles Important?
Foot candles are an extremely important part of designing an effective lighting setup. They are the only way to tell if an area is actually receiving the intended light levels.
And, although this is important in any type of business, it’s especially important for commercial and industrial facilities to have appropriate lighting levels for both employee safety and efficiency.
It’s so important, in fact, that OSHA has specific foot candle requirements for certain spaces and industries.
Foot Candles versus LUX – What’s the difference?
Foot candles and lux are both light measurement readings. They are just represented by different scales. Essentially, 1 foot candle = 10.77 lux and 1 lux = .0929 foot candles.
Recommended Light Levels
Lighting systems are not equal. What may be ideal for one location may be unsuitable for another. For instance, a big box store does not need the same amount of light as a packaging warehouse. Even if two facilities have the same square feet, the activities carried out may be different. The work performed in a building usually dictates the fixtures required for illumination. This is why a “one size fits all” approach is never recommended when choosing lighting. OSHA requires workplace lighting measurements in foot candles. In this article, we’ll give foot candle recommendations for different types of environments.
Understanding Lighting Plans
A Photometric Study, or Lighting Plan, is a report detailing the light levels and light distribution for a location, either indoors or outdoors. It’s done by software that’s was specifically created to do so.
Lighting Plans allow you to simulate a space, add lighting fixtures, and set mounting heights and fixture locations within the software model.
The software calculates light levels and how balanced the light is and produces a report showing average, max, and min foot candles.
For this discussion, the numbers we discuss are the average recommended foot candles. Just as important are the max/min ratio the study calculates. The higher this number is, the more spotty the lighting.
So it’s one thing to hit the recommended average. It’s another to design a lighting solution with even light distribution. A lighting plan study will provide you with this information.
COMMERCIAL and INDUSTRIAL APPLICATIONS
Recommended Foot Candles for Manufacturing and Warehouse Facilities
Coarse Material Processing
Medium Material Processing
Fine Material Processing
Extra Fine Material Processing
Wrapping, Packaging and Labeling
Exacting Assembly and Inspection
General Food Processing
Warehousing – Inactive Area
Warehousing – Active – Large Items
Warehousing – Active – Small Items
Warehousing – Active – Medium Items
Warehousing – Active – Fine Items
Shipping and Receiving Area
Receiving and Shipping Dock
Receiving and Staging
Maintenance and Shop Areas
Warehouse with Aisles
Recommended Foot Candles for Automobile Manufacturing and Sales
|Final Assembly, Finishing, Inspection||200 fc|
|Body and Chassis Assembly||100 fc|
|Body Parts Manufacturing||100 fc|
|Frame Assembly||50 fc|
|Service Area||25-100 fc|
|Sales Lot (Exterior) – Lighting Zone 3 (urban)||10-40 fc|
|Sales Lot (Exterior) – Lighting Zone 2 (suburban)||10-30 fc|
Recommended Foot Candles for Food Service Facilities
|Cashier Stand||20-50 fc|
|Cleaning Areas||10-20 fc|
|Dining Areas||5-20 fc|
|Food Courts||30 fc|
|Food Displays||30-100 fc|
|Kitchen, Food Prep||50-100 fc|
Recommended Foot Candles for Work Shops
|General Work / Storage||30 fc|
|Production Work with some detailed tasks||50 fc|
|Production Work with fine detailed tasks||70-90 fc|
Recommended Foot Candles for Hotels
|Bedrooms – Reading||20-50 fc|
|Corridors, Elevators, Stairs||10-20 fc|
|Front Desk||50-100 fc|
|Linen Room – General||10-20 fc|
|Linen Room – Sewing||100-200 fc|
|Lobby, General||10-20 fc|
|Reading and Working Areas||20-50 fc|
Recommended Foot Candles for Laundries
Recommended Foot Candles for Libraries
|Ordinary Reading, Stacks||20-50 fc|
|Book Repair and Binding||20-50 fc|
|Study and Note Taking, Cataloging, Card Files, Checkout Desk||20-100 fc|
Recommended Foot Candles for Garages and Garage Workshops
|Hobby Work||30 fc|
|Work with limited detailed tasks||30-50 fc|
|Work with fine detailed tasks||70 fc|
Recommended Foot Candles for Printing
|Photo Engraving, Etching, Blocking||20-50 fc|
|Color Inspecting||100-200 fc|
|Composing Room||50-100 fc|
Recommended Foot Candles for Retail
|Circulation Area Stockroom||10-30 fc|
|Department Store||20-80 fc|
|Discount Warehouse, Drug/Convenience||25-100 fc|
|Merchandising, Self-Service||200 fc|
|Shopping Mall||30 fc|
Recommended Foot Candles for Woodworking
|Rough Sawing and Bench Work||20-50 fc|
|Sizing, Planing, Rough Sanding, Medium Quality Machine and Bench Work, Gluing, Veneering, Cooperage||20-50 fc|
|Fine Bench and Machine Work, Fine Sanding and Finishing||50-100 fc|
Recommended Foot Candles for Offices
|Open Cubicle Space||30 fc|
|Reception Areas||10 fc|
|Conference Rooms||30 fc|
|Video Conferences||50 fc|
Recommended Foot Candles for Hospitals – Medical Facilities
|Patient Waiting Areas||10 fc|
|Nurse Stations||30 fc|
|Lobby Areas||5 fc|
|Medical Record Areas||50 fc|
|Stair Areas||10 fc|
|Emergency Rooms||50-100 fc|
|General Nursing Station||30|
Recommended Foot Candles for Airplane Hangars
|General Work / Storage||30 fc|
|Aircraft Maintenance with some detailed tasks||30-50 fc|
|Aircraft Maintenance with fine detailed tasks||70-100 fc|
|Drilling, Riveting, Screw Fastening||75 fc|
|Final Assembly||100 fc|
Recommended Foot Candles for Banks
|Writing Areas||20-70 fc|
|Teller Stations, Posting and Keypunch||50-150 fc|
Recommended Foot Candles for Clothing Manufacturers
|Receiving, Storage, Shipping, Winding, Measuring||20-50 fc|
|Pattern Making, Trimming||50-100 fc|
|Shops, Marking||50-200 fc|
|Cutting, Pressing||100-500 fc|
|Sewing, Inspection||200-500 fc|
Recommended Foot Candles for Electrical Equipment Manufacturing
|Insulating, Coil Winding, Testing||50-100 fc|
Recommended Foot Candles for Foundries
|Annealing Furnaces||20-50 fc|
|Core Making||50-200 fc|
|Inspection – Fine||100-500 fc|
|Inspection – Medium||50-100 fc|
|Pouring, Sorting||50-100 fc|
Recommended Foot Candles for Iron & Steel Manufacturing
|Stock, Hot Top, Checker Cellar, Calcining||10-30 fc|
|Building, Slag Pits, Stripping Yard||20 fc|
|Control Platforms, Repairs, Mixer Building||30 fc|
|Rolling Mills||30-50 fc|
|Tin Plate||50 fc|
|Motor Room, Machine Room||30 fc|
Recommended Foot Candles for Machine Shops
|Rough Bench||20-50 fc|
|Medium Bench, Rough Grinding, Buffing||50-100 fc|
|Fine Bench||200-500 fc|
Recommended Foot Candles for Paint Shops
|Spraying, Hand Art, Stencil||20-50 fc|
|Fine Hand Painting and Finishing||50-100 fc|
Recommended Foot Candles for Paper Manufacturing
|Beaters, Grinding||20-50 fc|
|Finishing, Cutting||50-100 fc|
|Hand Counting||50-100 fc|
|Paper Machine Reel, Inspection||100-200 fc|
Recommended Foot Candles for Sheet Metal Works
|Tin Plate Inspection, Galvanized, Scribing||100-200 fc|
Recommended Foot Candles for Textile Mills
|Cotton Picking, Carding, Roving, Spinning||50 fc|
|Beaming and Slashing||150 fc|
Recommended Foot Candles for Convention Centers, Exhibition Halls and Venues
|Main Convention Area||30-90 fc|
|Smaller Meeting Rooms||30-50 fc|
|Washrooms and Restrooms||5 fc|
Recommended Foot Candles for Schools
|College Lecture Halls||50-100 fc|
|Smaller School Gymnasiums||30-50 fc|
|Larger School Gymnasiums||50-100 fc|
Recommended Foot Candles for Baseball and Softball Fields
|Collegiate (Televised)||100 fc||70 fc|
|Collegiate||70 fc||50 fc|
|High School||50 fc||30 fc|
|Little League||50 fc||30 fc|
|Recreational||30 fc||20 fc|
Recommended Foot Candles for Tennis Courts
|College Televised||90-120 fc|
|Competition Level||50-80 fc|
|Club Level||30-60 fc|
|Recreation Level||20-35 fc|
Recommended Foot Candles for Horse and Riding Arenas
|Outdoor Recreational Arena (Starter)||5-10 fc|
|Outdoor Recreational Arena (Mid-Level)||10-20 fc|
|Outdoor Recreational Arena (Pro Level)||20-50 fc|
|Indoor Recreational Arena (Starter)||10-20 fc|
|Indoor Recreational Arena (Advanced)||20-40 fc|
Recommended Foot Candles for Football Fields
|College Televised||80-150 fc|
|Large High School||50-70 fc|
|Smaller High School||30-50 fc|
|Pop Warner||30-50 fc|
Recommended Foot Candles for Basketball Courts
|Community Center Courts||30 fc|
|Backyard Courts||10-20 fc|
Recommended Foot Candles for Indoor Hockey Rinks
|Professional Leagues||100-150 fc|
|Junior League Televised||70-10 fc|
|Junior League Un-televised||50-70 fc|
|Recreational and Local Tournaments||20-40 fc|
Recommended Foot Candles for Gymnasiums
|General Exercise and Recreation||30 fc|
|Locker Rooms||10-30 fc|
|Exhibitions, Matches||50 fc|
OSHA Lighting Requirements
OSHA, or Occupational Safety and Health Administration , was created to protect workers by ensuring that working conditions were safe and as risk-free as possible.
As a part of their safety initiative, OSHA developed standards to make sure that all commercial and industrial workplaces have lighting that is adequate and effective, without having a glare or being excessively bright.
Glare and excessive lighting, which can cause headaches and eyestrain to individuals’ overtime. Read more about OSHA guidelines from the United States Department of Labor.
|OSHA warehouse lighting requirements||5 fc|
|OSHA emergency lighting requirements||5 fc|
|OSHA temporary lighting requirements for construction||5 fc|
|OSHA lighting requirements for manufacturing||10 fc|
|OSHA industrial lighting requirements||10 fc|
|OSHA outdoor lighting requirements||3 fc|
|OSHA parking lot lighting requirements||3 fc|
How do lumens become a foot candle?
1. Understanding Lumens
What is a lumen? A lumen is a measurement of light created by one bulb, lamp or fixture. We use lumens to indicate the brightness of a bulb or fixture – how much light it produces. Lumens is a far more accurate representation of the light’s capacity than watts used to make light.
The take-away: lights produce lumens.
2. Converting Lumens to Foot Candles
In the simplest sense, you can install 1 light in a room above the floor and using a light meter, walk around the floor taking foot candle measurements. The amount of light directly under the installed fixture will be brighter than the light in the corners.
Using this same room, install 4 fixtures evenly throughout the room. As you walk around the room, everything is brighter. The light meter is showing higher foot candle measurements throughout the room. The corners are brighter.
That’s all this is. Lights produce lumens, and as you add more lights, the foot candle measurements increase throughout the space
The take-away: the more lights you add, the higher the foot candle readings will be.
3. Lumens per Square Foot
What are lumens per square foot? By definition, 1 lumen per square foot is 1 foot candle. This means that:
20 lumens per square foot = 20 foot candles
40 lumens per square foot = 40 foot candles
100 lumens per square foot = 100 foot candles
Just like the conversation of lux above, lumens per square foot is just another representation of what a foot candle is
So why do we think of lighting in terms of foot candles and not lumens per square foot? Mostly because the tools we use to create lighting plans provides us results in foot candles. However, its easily to convert the foot candle measurements we provide to lumens per square foot measurements.
4. Lighting Plan Software – How it works
Lighting plan software is a computer generated lighting model that understands the physical characteristics of how many lumens a light produces and how it distributes its light. The software allows you to install lights in a software “space”, and run calculations by simulating foot candle readings on the ground. Its extremely accurate, and the report generated provides details on light levels and light balance within the space.
The take-away: we provide free lighting plans for our commercial and industrial customers, electricians and electrical contractors. Scroll to the bottom of this page to ask for yours.
5. Understanding Light Efficiency – this is what saves you money
Even amongst LEDs, not all bulbs are created equal. Though they are all more efficient than options like fluorescents and metal halide options, not every LED is equally efficient.
This is another reason why it’s important to pay attention to the lumens of an LED light instead of the watts. In many cases, a higher quality LED with lower wattage can produce a brighter light than one with a higher wattage.
Let’s explain this showing 2 different LED Lights.
The first fixture produces light at 130 lumens per watt. The second produces lights at 180 lumens per watt.
To produce 20,000 lumens, the first light uses 153.84 watts of electricity. The second light only needs 111.11 watts.
The difference of 42.73 watts. This is what saves you money on your lighting bill.
Both lighting products above create the same amount of light, or lumens.
Efficacy, or light efficiency, is another important thing to factor into a light purchase. A more efficient light may cost more at the time of purchase, but over the life of the product, your utility bill will be lower.
And the amount you save with a lower utility bill will far exceed any additional purchase cost. If you want to learn more about LED lumens and all that goes into them, we’ve summed it up nicely in this post.
How to choose the right fixture to meet the foot candle requirements
Now that you have an understanding of what the foot candle levels might be for your project, how does that translate into buying the right fixture, or right type of fixture. That’s where we help. LED Lighting Supply provides 2 distinct services:
1. We provide free lighting plans
2. We supply the lights for your project
Determining the right light to produce the right amount of foot candles is not guess work. We use industry-leading lighting plan software to calculate light levels within indoor and outdoor spaces to meet specific light levels the customer may have. Understanding foot candles is one thing. Picking the right fixture, the right amount of fixtures and achieving the right light levels with even, balanced, non-shadow lighting is another. That is why we provide lighting plans for our industrial and commercial end users, contractors and electricians.
About the Author
Cory Peterson is Director of Sales & Marketing at LED Lighting Supply where he focuses on improving customer experience and revenue operations. Cory writes about commercial & industrial lighting, along with topics important to contractors and facility managers. In his free time, Cory enjoys traveling, snorkeling, exercise and cooking.