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 wastes 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 Table 1.
Table 1
| 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, soon to be replaced with a 1990 version). 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 -- quantity 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.
Table 2
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
