Bosworth Instrument Training Sheet Series
Light Meters
What is a light meter?
A light meter measures the level (amount) of visible light (illumination) in a given area tested. Illumination is expressed in units of LUX (metric) and Foot candles (English).
Alternate Light Meter Terms
• LUX Meter
• Foot Candle (Fc) Meter
How do I measure and convert Foot candles, LUX, and Lumens?
The most common units of light measurement are LUX, Foot candles, & Lumens per sq. ft.
• Multiply Foot candles by 10.76891 to convert to LUX
• Multiply LUX by 0.09290304 to convert to Foot candles
• Foot candles = Lumens per sq. ft. (no conversion necessary).
Applications for specific lighting types
• Sodium: Highway, parking lots, security
• Tungsten: Daylight and incandescent lighting
• Mercury: Highways, parking lots, stadiums
• Fluorescent: Indoor lighting
Light Meter Applications
• OSHA work environment compliance
• Schools and other exam/test areas
• Sensitive antiques, museum exhibits, artwork, etc.
• Security lighting and nighttime ATM areas
• Computer and clean room standards compliance
• Photography and video applications
Do you have light meters that will measure both Lux and Foot Candles ?
• Yes- a great meter that does both is the Extech #EA31 Foot Candle/Lux Meter. It accurately displays light level in terms of Fc or Lux over four ranges.
I need to measure light level in a parking lot. Do you have a light meter that can accurately measure High Pressure Sodium Lamps as well as other types of light bulbs?
• Yes- The Extech #407026 offers 4 different selection modes- for enhanced accuracy-Tungsten/Daylight, Fluorescent, Sodium and Mercury lamps.
What are common Lux and Foot Candle levels. Do you have a chart ?
• See below for common LUX/Foot candle light levels in factories, hospitals, retail stores, restaurants and more.
Typical Light Levels
Showing both Lux and Foot Candles
Lux Level | Foot Candles | Factories | Lux Level | Foot Candles | Store | 20 to 75 | 2-7 | Indoor Emergency Stairs, Warehouse | 75 to 150 | 7-15 | Indoors | 75 to 150 | 7-15 | Exit/Entrance Passages | 150 to 200 | 15-20 | Corridor/Stairs | 150 to 300 | 15-30 | Packing Work | 200 to 300 | 23-30 | Reception | 300 to 750 | 30-75 | Visual Work: Production Line | 300 to 500 | 30-50 | Display Stand | 750 to 1,500 | 75-150 | Typesetting: Print Shop Inspection Work | 500 to 750 | 50-75 | Elevator | 1,500 to 3,000 | 150-300 | Electronic Parts, Assembly Line, Drafting | 750 to 1,500 | 75-150 | Show Window, Packing Table | | | Office | 1,500 to 3,000 | 150-300 | Storefront, Show Window | 75 to 100 | 7-10 | Indoor Emergency Stairs | | | Hospital | 100 to 200 | 10-20 | Corridor Stairs | 30 to 75 | 3-7 | Emergency Stairs | 200 to 750 | 20-75 | Conference, Dining or Reception Room | 75 to 100 | 7-10 | Stairs | 750 to 1,500 | 75-150 | Clerical Work | 100 to 150 | 10-15 | Sick Room, Warehouse | 1,500 to 2,000 | 150-200 | Typing, Drafting | 150 to 200 | 15-20 | Waiting Room | | | Home | 200 to 750 | 20-75 | Medical Examination Room, Dining Room | 100 to 150 | 10-15 | Washing | 750 to 1,500 | 75-150 | Operating Room, Emergency Treatment | 150 to 200 | 15-20 | Recreational Activities | 5,000 to 10,000 | 500-1000 | Eye Inspection | 200 to 300 | 20-30 | Drawing Room, Table | | | Stairs | 300 to 500 | 30-50 | Makeup | 30 to 75 | 3-7 | Emergency Stairs | 500 to 1,500 | 50-150 | Reading, Study | 75 to 300 | 7-30 | Indoor Gymnasium, Auditorium, Wash Room | 1,000 to 2,000 | 100-200 | Sewing | 300 to 750 | 30-75 | Class Room | | | Restaurant | 750 to 1,500 | 75-150 | Drafting Room, Laboratory, Library | 75 to 150 | 7-15 | Corridor Stairs | | | Beauty Salon | 150 to 300 | 15-30 | Entrance, Wash Room | 300 to 750 | 30-75 | Shaving, Hair washing Dressing | 300 to 750 | 30-75 | Cooking Room, Dining Table | 750 to 1,500 | 75-150 | Hair Dyeing, Makeup, Hair Dressing | 750 to 1,500 | 75-150 | Show Window | | | |
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