Industrial Lighting

In industrial settings where safety is a primary concern, many engineers acknowledge the significance of proper lighting. Adequate illumination is also a key factor in maintaining high worker productivity.

Artificial illumination is a costly commodity in some industrial plants. Improper application of lighting standards can result in excessive lighting that waste energy. By consulting the available literature, one can learn how to implement lighting modifications and energy conservation techniques that can save on lighting expenses.

Questions frequently asked by industrial clients reveal a need for information about appropriate lighting standards. The underlying motivation is the need to provide adequate illumination, based upon accepted standards, at the lowest possible cost. This technical brief is offered as guidance to industries in meeting these needs.

Principles of Good Lighting

A plant's illumination system should meet certain minimum requirements in order to be cost-effective. Energy optimization, better productivity and safety are major goals to keep in mind when evaluating any lighting system. Significant increases in productivity can be achieved by lighting modifications that actually decrease the annual cost of electric illumination.

Among the major direct and indirect benefits adequate lighting provides are: improved visibility, upgraded aesthetics, better employee morale, reduced absenteeism, less eye fatigue and headaches, enhanced security, improved quality control and fewer rejects. All of these factors contribute to increased productivity and worker safety.

Convert to More Efficient Light Sources

There is excellent savings potential in most plants from converting present lighting systems to more efficient light sources. A condensed comparison of light sources is shown in the table below.

CONDENSED LAMP DATA
Lamp
Nominal
Watts
Initial
Lumens
Nominal
Length
Approximate
Hours Life
Standard F40CDW
40
3150
48°
20,000+
Energy Efficient Lamp
34-35
2800-3050
48°
20,000+
Standard F96T12
75
6300
96°
12,000+
Energy Efficient Lamp
60
5400-6000
96°
12,000+
Standard F96T12/CW/HO
110
9200
96°
12,000+
Energy Efficient Lamp
95-98
9100
96°
12,000+

Industrial Lighting Standards

A survey of available literature reveals that the most widely used industrial lighting standards are those developed by the Illuminating Engineering Society of North America (IES). In 1915, the IES issued the first guidelines for lighting levels in industry, "The Code of Lighting: Factories, Mills and Other Workplaces." This document evolved into the American National Standard Institute's "Practice for Industrial Lighting" (ANSI #RP-7-1983). The ANSI standard, adopted from IES, is based on meeting safety requirements while maximizing productivity and energy conservation. Various factors affecting the quality of lighting, including contrast, brightness, light distribution patterns and color rendition are part of the ANSI standard.


ANNUAL ENERGY SAVINGS
(4000 hrs., 6c/KWH)
CASE
REDUCE KW
KWH
$
A
14
56,000
 $4,200
B
16
64,000
 $4,800
C
68
272,000
$20,400
D
59
236,000
$17,700

The IES Lighting Handbook, 1984 Reference Volume and 1987 Applications Volume provides a comparative listing of lighting levels for specified tasks. Light levels are given in footcandles, a quantity that is measured with a lightmeter.

Most present day lighting standards derive from the IES and ANSI criteria. Using lighting levels set by these organizations as baseline information, many industries have successfully adopted lower illumination levels without sacrificing any of the benefits of good lighting, while the energy-savings possibilities may be attractive, other factors must be considered. In particular, employees involved in certain types of tasks find the light coloration from some of the more efficient sources, (particularly high-pressure sodium) objectionable, so that use of the most desirable economic option may not be possible. Consultation with manufacturers and lighting consultants will often prove helpful.

Excerpts from "Recommended Levels of Illumination"¹
Area And Task
Footcandles
Paper Manufacturing  
Beaters, grinding
30
Finishing, cutting
50
Hand Counting
70
Paper machine reel, inspection
100
Rewinder
150
Warehousing, Storage  
Inactive
5
Active:  
Rough Bulky
10
Medium
20
Fine
50
Clothing Manufacture  
Receiving, storing, shipping, winding, measuring
30
Pattern making, trimming
50
Shops, making
100
Textile Mills - Cotton  
Opening, mixing, picking
30
Carding and drawing
50
Slubbing, roving, spinning, spooling
50
Beaming and splashing on combo Gray goods
50
Denims
150
Inspection
 
Gray goods (hand tuning)
150
Denims (rapid moving)
500
Automatic tying-in
150
Weaving
100
Drawing-in by hand
200
Machine Shops  
Rough bench and machine work
50
Medium bench and machine work, ordinary automatic machines,
rough grinding medium buffing and polishing
100
Fine bench and machine work, fine automatic machines,
medium grinding, fine buffing and polishing
500
Extra-Fine bench and machine work, grinding fine work
1000

¹ Engineering Society of North America, 1977