4.5 sports

SECTION 12

SPORTS LIGHTING

Though difficult visual tasks, such as following a fast-moving black

hockey puck, a small white golf ball, or the sharp point of a fencer's foil,

are encountered in sports, the necessity for concentration is not likely to be

of long duration, and far, rather than near, vision is used mcs tfrequently.

The exact nature of the seeing tasks, which varies over a wide range fromsport to sport, has been standardized to some degree within each sport bythe development of playing rules by local and national athletic organiza-

tions. These groups frequently specify the required characteristics anddimensions of equipment and playing areas.

The existence of such playing area standards has made it feasible to

develop standard lighting plans for many types of playing areas, even

though exhaustive research has not been devoted to the basic problems en-

countered. The best known sports lighting standards are those of the

National Electrical Manufacturer's Association which are being studied

by the I.E.S. Sports Lighting Committee.On the basis of practical experience with installations throughout the

United States, the N.E.M.A. Standards have been improved from time

to time, and by investigation of the fundamental problems it is expected

that means for additional improvement may be developed.

Seeing Problems in Sports

The following factors, which influence light and vision relationships in

all lighting application fields, are recognized as variable in sports lighting,

whereas in other fields they often are assumed to be constant:

Size (minutes)

Object of regard '

Background

Location

PathVelocity

Average brightness

Brightness pattern

( Location

Observer \ Path

[ Velocity

The objective of a sports lighting installation is to control the brightness

of the object and the background to the extent that the object will be

visible, regardless of its size, location, path, and velocity, for any observer

location, path and velocity. In a majority of sports this objective is

achieved by illumination of vertical rather than horizontal surfaces.

Objects to be seen. Dimersions and reflectances cf typical objects that

require the visual concentration cf player, official, and spectator are listed

in Table 12-1 with the usual range of distances over which each must be

observed.

NOTE: References are listed at the end of each section.

12-2 I E S LIGHTING HANDBOOK

Table 12-1. Approximate Dimensions, Reflectances, and Viewing

Distances for Various Objects Used in Sports

SPORT OBJECT DIMENSIONS(inches)

APPROXI-MATE RE-

FLECTANCE*(per cent)

RANGE OF VIEWINGDISTANCES

(feet)

Player Spectator

Badminton Bird Feathers 2! long ce-

mented to f half

sphere

SO 1-65 20-100

Baseball Ball 9 to 9j (circumference) 75 1-400 25-700

Softball Ball 12 (circumference) 75 1-250 20-350

Basketball Ball 30 to 32 (circumference) 30 1-90 10-150

Bowling Ball 27 (circumference) 10 1-85 10-115

Foot racing Man 69 ± 7 (high) Dependson cos-

tume

5-330 30-400

Football Ball 21J to 214 (short cir-

cumference)28 to 28| (long cir-

cumference)

30 1-300 0-450

Golf

HockeyTable tennis

Ball

PuckBall

Not less than 1 .6S

(diameter)3 (diameter) 1 (thick)

4! to 4f (circumfer-ence)

SO

1

80

5-900

5-2001-35

20-920

10-30010-70

Tennis Ball 2! to 2f (diameter) 75 1-120 1 10-120

'Values given are for clean new equipment. Multiply by ?| to get average value for equipment in use.

In many games, a large portion of the playing skill developed by practice

is the ability to estimate accurately object location, path, and velocity,

which vary from play to play. The apparent location, path, and velocity

of an object are influenced by the object-background brightness relation-

ship and by the angle subtended by the object at the observer's eye. These

factors are affected in turn by the uniformity of illumination over the object

surface, by the uniformity of illumination throughout the object path, bythe object surface reflectance, by the background brightness pattern, andby the observer's locations.

Background brightness. In many sports the normal background against

which an object must be viewed by a player comprises all surfaces or space

above, below, and on all sides of the player's position. Because a ball

or other object may move rapidly through the field of view, the backgroundbrightness, if it is not uniform, may vary rapidly. For example, outdoors

in daylight a baseball may be viewed against the relatively dark shadedgrandstand area at one instant and in the next be silhouetted against the

sky or sun. A football may be viewed against dark green grass, white

snow, clear sky, a mottled pattern of spectators> or a player's jersey.

SPORTS LIGHTING 12-3

With electrical illumination from a few high candlepower sources con-

centrated on an outdoor playing field and filling the space above to a limited

altitude only, most of the background area is relatively dark and great care

must be taken to be sure that in addition to providing relatively uniform

illumination the sources are so placed that the number of times a ball mustbe viewed against them during games is small.

Indoors, as, for example, in a squash court with white walls, ceiling, andfloor, and with indirect illumination, the background brightness is muchmore uniform.

Observer location. In designing lighting for sports, careful consideration

should be given to the requirements and comfort of each of three observer

groups: players, officials, and spectators, whose orientation with respect

to the object differs. The normal fields of view of each group differ also

and in the case of player and official there may be no fixed location. Theprobable variation in location and field of view will be different for each

sport.

In providing adequate illumination of proper quality for one group, if

possible no glare should be introduced into the field of view of the other two.

Quality and Quantity of Illumination

Diffuse illumination, such as that provided by an overcast sky on an

outdoor playing field during the day or that provided by an indirect elec-

tric lighting system in an interior with high reflectance ceilings, walls, andfloors, is considered to be of excellent quality for sports. Indoors the

design problems are quite similar to these encountered in other interior

occupancy areas. Outdoors the problem is more difficult, and it has been

necessary to develop practical minimum diffusion standards which will

provide satisfactory results. See Fig. 12-lc.

Number and location of sources. The shape and surface characteristics

of the object to be seen and its probable orientation with respect to the

observer are important factors in establishing minimum diffusion stand-

ards. Fortunately, balls with diffuse surface reflectance are the mostcommon objects to be viewed. A point light source located in such a

position that its central axis forms an angle of not more than 30 degrees

with the observer's line of sight (apex at the ball) will for practical purposes

illuminate the entire ball surface facing the observer. (See Fig. 12-la.)

If the angle is in-

creased to 90 degrees,

the ball will remain

lighted over half its

visible surface, as

shown in Fig. 12-16.

Figure 12 lc shows the

same tennis ball lighted piQ. 12-1. Appearance of tennis ball lighted in differ-

from above by two ent ways: a. by single source 30 degrees to right of line of

nmntsnnrw that form sight ; b. by single source 90 degrees to left of line of sight

;

porn isources inanormc by light from two sources above and at 85 degrees

angles of 85 degrees from line of sight, and by light reflected by the ground.


with the line of sight and from the ground by reflected light. It appears

that the arrangement shown in Fig. 12-lc will provide illumination satis-

factory for more observer locations than will the others. However, in

the practical case the specific source locations selected will be these which

offer the best compromise between desired illumination diffusion andminimum glare in the majority cf observer locations.

It is necessary that illumiraticn at points throughout the entire space

above the playing area through which a ball may travel be fairly uniform

(with no sharp changes in level), since a fast-moving object passing quickly

from a light to a dark srace will appear to accelerate. This occurs whenthere is inadequate overlap in floodlight beams. Such a condition distorts

the player's judgment of ball trajectory.

Illumination level. In establishing the recommended illumination levels

practical variables, which are considered in relaticn to the basic questions

of object size and brightness and time available for seeing, include the

following:

Speed of play (novice, expert, semiprofessional, professional).

Distance to spectators.

Orientation of spectators.

The values given in Table 12-2 have been found satisfacte ry when the

proper quality of illumination is provided at the playing level and also (in

some sports) in the space above.

Daylighting for Sports

Daylight usually provides adequate illumination to permit satisfactory

participation in morning and afternoon outdoor contests even en cloudy

and overcast days.

The daylighting principles set forth in Section 9 should be applied in

the design of gymnasiums and other interiors used for indoor daytirre

athletics. To prevent skylight and window breakage glass shculd le

screened. Since screening may have a very low trarsmittance, the utiliza-

tion factor for screened windows will be low (15 to 60 per cent dependirg

on screen transmittance characteristics).

Electric Illumination for Indoor Sports

The walls and ceilings of interiors used for sports provide a means for

controlling background brightnesses, assist in diffusing the available light,

and make possible a variety of convenient lighting ecjiiipment arrange-

ments. The design and calculation procedures outlined in Section 8 are

applicable to interiors used for sports. However, in addition to luminaire

mounting height, spacing, and lumen output, and illumination uniformity

on a horizontal reference plane, which are important factors in most in-

stallation plans, it is necessary in designing sports lighting to consider also

the following factors:


1. Observers have no fixed visual axis or field of view and may be ex-

pected to look frequently at the ceiling and luminaires and in every other

direction at some time during a game.2. The object of regard will have no fixed location, being viewed from

time to time on the floor, near the ceiling, or almost anywhere in between.

3. It is particularly important for observers to be able to estimate ac-

curately object velocity and trajectory.

Table 12-2. Recommended Illumination Levels for Sports

AVERAGE ILLUMINATIONMAINTAINED IN SERVICE ON

HORIZONTAL PLAYING SURFACE(footcandles)

SEE FIG.

archery (on target)TournamentRecreational

10

512-2

BADMINTONTournamentClubRecreational

302010

12-3

BASEBALLMajor LeagueAA and AAA LeagueA and B LeagueC aiidD LeagueSemipro and Municipal LeagueOn seats during gameOn seats before and after game

Infield Outfield

150 10075 5050 3030 2020 15— 2

5

12-15

BASKETBALLCollege and professionalHigh schoolRecreational

503010

12-9

billiards (on table)TournamentRecreationalGeneral area (surrounding table)

503010

12-5

BOWLINGTournamentRecreational

General On the pins

20 5010 30

12-6

BOWLING ON THE GREENTournamentRecreational

10

5

boxing or wrestling (ring)

ChampionshipProfessionalAmateurSeats during boutSeats before and after bout

500200100

2

5

12-7


Table 12-2. Recommended Illumination Levels for Sports—Continued

CROQUETTournamentRecreational

AVERAGE ILLUMINATIONMAINTAINED IN SERVICE ON

HORIZONTAL PLAYING SURFACE(footcandles)

SEE FIG.

CURLINGTournamentRecreational

FOOTBALLClass Index: Distance* from nearest sideline

to the farthest row of spectatorsI Over 100 feet 100 12-14

II 50 to 100 feet 50III 30 to 50 feet 30IV Under 30 feet 20

V No fixed seating facilities 10

*It is conceded generally that distance between the spectators and the play is the first consideration in de-

termining the class and lighting requirements. However, the potential seating capacity of the stands shouldalso be considered and the following ratio is suggested: Class I for over 30,000 Spectators; Class II for 10,000 to

30,000; Class III for 5,000 to 10,000; and Class IV for under 5,000 spectators.

GOLF DRIVINGGeneral on the tees

On vertical surface at 200 yardsPractice putting green

10

3

10

12-13

GYMNASIUMSExhibitions and matchesGeneral exercisingLockers and shower rooms

302010

12-9

HANDBALLTournamentClubRecreational

302010

12-3

HOCKEYCollege or ProfessionalAmateur LeagueRecreational

50

2010

12-12

HORSESHOESTournamentRecreational

10

5

RACINGBicycleMotor (midget auto or motorcycle)HorseDog

20202020

RIFLE RANGEOn targetFiring line

Range

Outdoor Indoor

30 5010 10

5

12-2


Table 12-2. Recommended Illumination Levels for Sports—Concluded

AVERAGE ILLUMINATIONMAINTAINED IN SERVICE ONHORIZONTAL PLAYING SUR-

FACE (footcandles)

SEE FIG.

ROQUETournamentRecreational

2010

SHUFFLE BOARDTournamentRecreational

10

5

SKATINGRinkPark, lagoon, or pond

5

1

12-12

SKEET SHOOTTarget (vertical surface at 100 feet)

Firing point (general)

3010

12-2

SKI PRACTICE SLOPE .5

SOCCERProfessional and college

High schoolAthletic field

302010

12-14

SOFTBALLProfessional and championshipSemiproIndustrial leagueRecreational

Infield Outfield

50 3030 2020 10

10 5

12-16

SQUASHTournamentClubRecreational

302010

12-3

SWIMMING POOLSGeneralUnderwater

10

5 watts per square foot of

pool surface

12-8

TENNISTournamentClubRecreational

Lawn Table

30 5020 3010 20

12-4

TRAP SHOOTINGTarget (vertical surface at 150 feet)

Firing point (general)3010

12-2

VOLLEY BALLTournamentRecreational

2010

12-D


Design Recommendations

Factors 1 and 2 page 12-5 make it particularly desirable to provide large-

area, low-brightness luminaires such as these utilizing fluorescent lamps.

High wall, ceiling, and floor reflectances will be appropriate also, since they

are likely to result in reduced brightness ratios in all possible fields of view.

Considerable object-background contrast is necessary for good visibility.

Factor 3 calls for high-reflectance surfaces also, since interreflections

contribute materially to light diffusion and therefore to illumination uni-

formity on and above the reference plane. Uniformity is necessary if

object velocity and trajectory are to be estimated accurately.

If fluorescent lamp luminaires are recommended, it is essential that they

be operated on lead-lag ballasts or on three-phase circuits so that the visi-

bility of moving objects will not be reduced by stroboscopic effect.

Aerial sports. Archery, badminton , basketball, handball, squash, tennis,

and volley ball are included in this classification. Such sports may require

that observers look toward the ceiling during a large portion of the playing

time. In planning general lighting installations for these sports every

effort should be made to select, locate, and shield the light sources to avoid

introducing glare into the observer's view, i- 2 - 3 - 4 (See Figs. 12-2, -3,

and -4.)

Low-level sports. Billiards, bowling, fencing, curling, shuffleboard, skat-

ing, swimming, boxing and wrestling, and other sports in which observers

in the normal course of play do not look upward are called low level sports.

General lighting may be planned more easily for these sports than for the

aerial type, since luminaire brightness is less critical. 5 - 6 - 7 (See Figs.

12-5, 12-6, 12-7, and 12-8.)

Arenas and gymnasiums. In these areas uniform^ distributed general

illumination usually is provided over the entire playing floor so that basket-

ball, volley ball, track and field events, gymnastics, fencing, calisthenics,

hockey, or dancing may be accommodated. 8,

9

-10 (See Fig. 12-9.)

When high-caliber play in tennis, badmintcn, and other small court

games is contemplated, supplemental y illumination should be provided

on the ccurt.

Since arenas are likely to be public exhibition places, the principles of

stage lighting presented in Section 10 may be applied to the boxing ring or

playing fleer.

Maintenance. If it is likely that lamp operating time will be of the

order of 200 hcurs per year or less, a ccst analysis should be made to deter-

mine the relative advantage of operating incandescent lamps at a voltage

10 per cent above their rating.

To prevent breakage it may be necessary to cover otherwise unprotected

luminaires with wire mesh. This will reduce their efficiency and should be

compensated for in the design by multiplying the luminaire efficiency by the

average transmittance of the mesh.

Good practice. Table 12-2 lists recommended illumination levels for a

number of sports and refers to line and photc graphic illustrations showing

sports lighting installations.


i

—

DISTANCE

a

T10 FT

As /

10 FT

K^•S-^-"

SCALE, FEET/

10 20 30 40 /

I I I I—I /

/

* !

38 i

ia i

Iri

BAFFLED,in

r~ '

la in

k-

! ^>"

** i***^,'

In In

la In i<£

- 75 FT —=^- TF

FIRINGPOINT

TK'-TARGET

FIG. 12-2. Lighting for various types of shooting: a. Archery, one 10- to 18-degree

beam spread floodlight required per target.

LAMP DISTANCE

250-watt, G-30 bulb Up to 30 yards

500-watt, G-40 bulb 30 to 50 yards

1,000-watt, G-40 bulb 50 to 100 yards

b. Skeet, eight 18- to 35-degree beam spread floodlights with 1,000-watt clear PS-52

bulb lamps are mounted 20 feet above the ground, c. Rifle, *300-watt general service

lamp in an indirect luminaire. ** 200- or 300-watt clear bulb general service lampsbehind beams or baffles or in angle reflectors. *** For each group of five targets,

two floodlights with horizontal spread lenses and 750- or 1,000-watt clear bulb gen-

eral service lamps.


A

FRONT WALL

3FT u. 6 FT_»j A CTUN. r2iN.*| 4"

6 FTrna a—

f

6FT

5^FT

I*—I0^FT--J5FT

M is^ft «

k— II FT—*\

s tr-

INCANDESCENT

tt

tt

tt"

tt-

T

i i i i i

FLUORESCENT

I I I

I I I I I

20 FT *

44 FT

*' S

V k*<'

T

FIG. 12-3. Lighting for small court games: a. Squash, ten ceiling-mounted Glas-steel diffuser type luminaires with wire guards or four 1,000-watt indirect reflectors

with netting protection may be used as shown in plan and photograph respectively.

b. Handball, eight 750-watt Glassteel diffuser type luminaires or sixteen three-lamp40-watt direct flourescent type luminaires may be recessed or ceiling mounted behindwire guards, c. Badminton, outdoors four 70° beam spread floodlights per courtmounted 20 feet above ground may be used with 500-watt clear PS-40 bulb generalservice lamps.


K50 FT —

I

A

TTf

12 FT MIN. 96 FTMIN.

^--^--------"^4j^>

120 FT

Double Courts

Mount twelve 70° beam spread 1,500-watt

floodlights 30 feet above ground

Single Courts

Move poles on line BB to line adjacent to

court. Use 1,000-watt lamps.

FIG. 12-4. Lighting for tennis courts: a. layout for tournament play; b. play-ground installation of eight 1,000-watt floodlights. Two floodlights are mounted oneach of the four poles 30 feet above the courts, c. indoor court installation of onehundred forty 200-watt lamps in angle reflectors. Reflectors are mounted at wall-ceiling intersection. Roof and sidewall windows provide daylight for daytime play.


MINIMUM PLAYING AREA9 FT X3I FT -v

Table Tennis

Club Plan (above)

5 II 22 29 29-• • • • •

17 28 31 32 34 31

2 6v-<- 14

22 33T\ 41

31 yv4l 38

44- ^46 40 n

—4*— 5 FT— -*4*—

Q

Billiard Table

Lamp FluorescentIncandes-

cent

Luminaire Direct

(louvered)

Direct

(louv-

ered)

No. of Lu-

minaires 2 2

Location Over table

center

line

Over table

center

line

Mtg. hgt.

(above

table) 2 ft 6 in. 2 ft 6 in.

No. and ra-

ting of

lamps

Four 40-

watt

Two 200-

watt

Luminaires 10 deep cone or bowl

shades

Location 6 ft above table

Illumination by

10 inside-

frosted fila-

ment lamps

(upper figures for club

play)

150-watt lamps operated

5 volts above rating

(footcandles)(lower figures for tourna-

ment play)

200-watt lamps operated

10 volts above rating

FIG. 12-5. a. Typical lighting

layouts for championship table

tennis and a home ping pong table,

b. Typical lighting layout for a

billiard table.

Home Plan

Luminaires 2 or 4 deep cone or bowl

shades

Location 4£ ft above table

Illumination by

150-watt in-

side - frosted

(upper figures for recrea-

tional play)

2 lamps

filament

lamps

(footcandles)

(lower figures for skilled

play)

4 lamps


FIG. 12-6. Typical bowling alley lighting installa-

tions.

FIG. 12-7. Lighting layout for

a boxing and wrestling ring.

Floodlights with 40- to 70-degree

beam spread for 1,500 watt lamps

are mounted 15 to 18 feet above

the ring. Number required

:

Class A—20; Class B—12; Class

C—8.

<fe

&

y»

20 FTI

-26 FT J- +•

^


c

n n n n n n

c

B

i-cA

fu u

A L-B-+J

u u U u-Ic

WATER LINE

\: : : :;.:j

FIG. 12-8. a. Underwater floodlighting plan for swimming pools.

:

3 Watts per square foot outdoors.5 Watts per square foot indoors.

LAMPRATING*(wattsl

EQUIPMENT SPACING

A (ft)

^max (feet)

C (ft)

E (inches)

D>5 ft D<5 ft Min Max

250

4004 8 10 5 12 15

500

1,000

1,500

6 12 15 74' 2 18 24

O (/)|_ ui I

Oh

Zuil

rK

Z-

71

4 20 FT ORI MORE

_l .

SPACING NOT TOEXCEED 4TIMESMOUNTING HEIGHT

N]

Fig. 12-8b. Overhead floodlighting plan for outdoor swimming pools. Floodlights

are mounted 18-30 feet above the pool. Lamps should be selected to allow about

1.25 watts per square foot of lighted area.


FLUORESCENT LUMINAIRES

kl3 FT*}*13 FT*4*13 F

7 FT

9FT[*-I8 FT-*j<-I8 FI->|

i

i

0~f ^10 FTV

* 4INCANDESCENTLUMINAIRES

^>

+

4

4"

<

^

FIG. 12-9. a. Typical layouts for fluorescent and incandescent lamp luminaires

in a school gymnasium. Forty-two fluorescent lamp luminaires (two 100-watt lamps

each) or 15 incandescent lamp luminaires (one 1,000-watt lamp each) are mounted20 to 30 feet above the floor.

FIG. 12-9b. School gymnasium lighted by industrial type, high-bay incandescent

lamp luminaires.


Electrical Illumination for Outdoor Sports

Most large outdoor sports areas may be regarded, for lighting design

purposes, as large rooms with black walls and ceilings. Direct lighting pro-

vided by floodlights installed about the playing area usually is recommendedbecause overhead suspension of luminaires with symmetric distribution

often is not feasible.

Following the floodlighting design procedures in Section 8 (page 8-25) will

result in satisfactory illumination uniformity on a playing area, but the

first of the following three factors which are of particular importance in

sports lighting may require that illumination uniformity in the space abovethe playing area be checked also. 11, 12, 13 This may be done with the point-

by-point calculations procedure given also in Section 8. The important

factors are:

1. Observers will have no fixed visual axis or field of view.

2. Object will have no fixed location or no fixed orientation with respect

to the observer.

3. Observers should be able to estimate accurately object velocity andtrajectory.

Under conditions 2 and 3, an object may be seen with ease and comfort

by all observers only if light from several directions is incident upon it.

Also, source brightness in the observers' fields should be reduced by careful

floodlight location and aiming to minimize potential glare.

Floodlight selection. Floodlights are selected on the basis of photo-

metric and mechanical considerations. The approximate photometric

specifications will be established by the preliminary design calculations,

by the examples of current practice in figures preceding and in those

following, and by the balance between a small number of floodlights with

high lumen output and a larger number with smaller output arrived at on

the basis of desired results and economics.

Floodlights should be weather proof so that their operating character-

istics will not be affected by sun, rain, snow, and so on. Lamps in

open-type floodlights

should be protected

by reflectors or byhoods against rain,

snow, or hail. All

materials used should

withstand weathering

without objectionable

corrosion. Enclosed

(weather-tight) flood-

lights are preferable

for most applications

FIG. 12-10. Typical enclosed (a) and open (b) flood-when specular reflec-

lights designed for sports field application. Lamps are tors are required,

operated in vertical base-up position. (See Fig. 12-10.)


When floodlight lamps are to be operated at voltages above their rating,

as usually recommended when the annual hours of operation are to be of

the order of 200 or less, it is desirable to select a floodlight in which the lampwill operate at or close to the base-up vertical position after aiming.

Base-up burning reduces bulb-blackening and bulb-blistering failures. If

it is planned to operate lamps at voltages above their rating in open flood-

lights, it sometimes is necessary to use hard-glass lamps to prevent breakage

caused by wind-driven snow, rain, or hail.

When a detailed cost analysis is not feasible, the following general rules

are recommended.1. If the installation is utilized 200 or less hours per year, operate lamps

10 per cent above rated voltage.

2. If the installation is utilized over 200 hours per year but less than

1,000, operate lamps 5 per cent above rated voltage.

3. If the installation is operated for total periods approaching rated lamplife (generally 1,000 hours) in one year, operate lamps at rated voltage.

It is important to note that it is intended that the voltages indicated are

to be available at the lamp sockets with the entire installation operating

at the time of day, week, and month in which they will be utilized most.

Aiming offloodlights. In any design much depends on the aiming of the

floodlights. In certain sports employing a symmetric field such as foot-

ball, the development of an aiming or "spotting" pattern is relatively sim-

ple, requiring merely that scale drawings be made showing the field and the

floodlight-beam-spread angles. From an end elevation view, the vertical

aiming of the floodlight beam axes may be determined to obtain uniform

lighting across the field together with sufficient "spill," "direct filament,"

or "beam-edge light" in the space above to provide uniformity to a height

of 40 to 50 feet above the field. In this connection, care must be taken to

minimize the amount of light from the upper portion of the floodlight beamsfalling in the opposite spectator stands. The plan view of the field makes it

possible to plan horizontal aiming of the floodlights to provide uniform

lighting in the longitudinal direction of the field. Rigorous calculation

methods make it possible to predetermine accurately the footcandle dis-

tribution provided by any given aiming pattern, but because such calcula-

tions are tedious, it is general practice to base spotting or aiming diagrams

on previous calculations and practical experience with similar fields.15

A typical football spotting diagram is shown in Fig. 12-1 la while Fig.

12-116 shows an end elevation view of the vertical beam coverage of twotypical floodlights aimed in accordance with the diagram. It will be noted

in this case that relatively wide beam floodlights (60 degrees) are used be-

cause the poles are close to the playing field. It will be noted also that

the upper parts of the beams of the tw-o sets of floodlights indicated fall in

the opposite stands. Bxnvever, since these are the wide beam type, the

candlepower in these upper portions (more than 16 degrees from beamcenter) will be low, and the spill brightness from them will be within com-fortable limits when evaluated with respect to the relatively high brightness

of the field itself.


MOUNTING HEIGHT-50FT («—75FT—»j

NOTE: EACH LINE INDICATES ONE FLOODLIGHT BEAM OFAPPROX. 60° SPREAD. AIM LIGHT BEAM AT END OFLINES ON FIELD.

FIG. 12-11. Typical floodlight spotting

(aiming) diagrams: a. Football field spot-

ting diagram for sixty 1,500-watt, 60-

degree beam spread floodlights mountedon ten poles, b. End elevation of two

floodlights aimed as indicated in a. c.

Spotting diagram for a semipro or a muni-

cipal class baseball field installation of

one hundred twenty 1,500-watt floodlights,

d. Spotting diagram for a Softball field

installation of forty-eight 1,500-watt, 50-

degree beam spread floodlights.

Similar diagrams are in general use for other sports. (See Fig. 12-1 lc

and Fig. 12-1 Id.)

There are several ways to put spotting or aiming information to use in

making an installation. First and most accurate is manual aiming of the

floodlight beam centers at predetermined spots on the playing area, as, for

example, on Fig. 12-1 la. This may be accomplished by using built-in

beam sights or by placing accessory beam sights against floodlights parallel

to their optical axes. Markers then are placed at the aiming points andthe sights aimed at these points by an engineer at the light.

A second aiming method is to calculate or determine graphically from

the aiming diagram the vertical and horizontal angular setting of each flood-

light. Most floodlights are equipped with degree scales which may then

be set to those angles. However, the accuracy of this method is limited, first

by tolerance in the leveling and aligning of mounting pole cross-arms andsecond by the difficulty of setting the wide pointers accurately at the proper

position on the cast scales, which generally have coarse graduations. Adifference of several vertical degrees may move the beam center 20 feet or

more on the field.

4.5 sports

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