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10-82

I

E

S

LIGHTING

HANDBOOK

FIG.

10-57.

A dormitory room

lighted

for

study

hour.

Dormitory

Rooms

Except

in

special

schools

as

in

military schools, perhaps)

there

should be

few

differences between the

lighting

goals for dormitories and

those for

similar rooms in the home bedrooms and living rooms).

See pages

10-36

and

10-42.)

Most

of

the

differences

are

associated

with

lack

of

decoration,

uniformity,

ease

of cleaning, and similar factors

few

of

which deal directly

with

the quantity and

finality

of illumination.

See

Fig.

10-57.)

Military

dormitories

may

tend

more

toward

general

illumination from

ceiling

fixtures

rather

than

localized illumination

from

portable

lamps. Under

such conditions,

general-office

lighting

standards

should

be

followed.

See

page

10-52.)

The

lighting

of

dormitory rooms

should satisfy

two dissimilar

require-

ments

:

1.

Contribute

to

a

comfortable

and

attractive

relaxation

atmosphere.

2.

Provide

the

30-footcandle

classroom illumination level

recommended

for

study purposes.

Portable lamps

at

each desk and

lounge chair

maj^

be

adequate if they

distribute

enough light

throughout

a

room

to bring

brightness

ratios within

the

classroom limits.

COMMERCIAL

AND

PUBLIC BUILDINGS

Almost any structure

except

a

residence

might fall into

the

category,

commercial

and

public

buildings,

but

the

term

usually

is

construed

by

illuminating

engineers

to

mean theaters,

banks,

libraries,

and

museums,

and

the

public

portions of

office

buildings, hotels, churches,

concert

halls,

hospitals,

and similar

large areas

of

high turnover and

intermittent

oc-

cupancy.

Modern

lighting design is

co-ordinated

with

the

architectural

theme

in

public

buildings

more often

than

in

other

structures.

The

char-

acteristic

public-occupancy

areas of such

buildings

include

lobbies,

audi-

toriums,

w

r

ork and

service

areas,

corridors,

stairways, and

so

forth.

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INTERIOR

LIGHTING 10-83

Office

Buildings

The

lobby

of an

office building

usually

is

at

street

level.

The

simplest

type

is

a

wide

hallway

giving

access to

the elevators

or

stair wells.

More

elaborate

lobbies may

be used

as

an

exhibit

hall

by groups

occupying the

building.

Many

have shops located

along

the

sides.

See

Fig.

10-58.

From

a

visual standpoint, decorative

lighting that produces

10

footcan-

dles

in

a

lobby

usually

may be

considered

sufficient

for

safe

passage

of

pedestrians, provided

there

is

auxiliary lighting

at

directory boards,

and

directional signs,

and

adjacent

to

the

elevators and

stair wells

as

a

safety

measure.

However,

since most

office

buildings

have

their maximum

traffic

in

the daytime, 5

footcandles

may be found insufficient to

provide

satis-

FIG.

10-58.

Illumination

in

public-building

lobbies.

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10-84

I

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LIGHTING HANDBOOK

factory

visual

adaptation

as

the visitor steps

into the lobby

from

out-

of-doors from

an

illumination

level approaching

10,000

footcandles

in

direct

sunlight).

This necessity

for

adaptation combined

with

the

ad-

vertising

value

of higher levels

and brighter surroundings has led

many,

building designers

to

provide higher

levels of

illumination

20

footcandles)

In hallways

and corridors

of

ordinary

ceiling

height

less than

30

feet)

luminaires should

be spaced

not

more than 20 feet apart. No branch

corridor

should be

without

a

luminaire.

A

luminaire located at

a

main

corridor junction

will

serve

two branches not

more

than

10

feet

deep.

For

safety

in

such

locations,

at

least

two lamps should

be

used in each luminaire.

No

entrance

to an

elevator

or

a

stair well should

be

more than

10

feet

from

a

luminaire. The

recommended average

illumination

level

for

elevators, and stair

wells,

is 10 footcandles, assuming

high-reflectance

sur-

faces. The lumieaire and layout should provide

such

a

uniform

level

that

the maximum

value

at

any place

in

the

room

is not

greater than three

times

the

minimum.

Theaters

Theater-lighting

design begins

outdoors

with

the combination decorative

facade

with display

cases

which identifies

the

entrance. Part

of

this en-

trance is the

marquee.

Sources in the

marquee often provide

a

high

il-

lumination

level around the

box

office. This level

is

reduced

along

the

traffic lane

into

the threater

so that

the

theatergoer s eyes may

become

adapted

gradually

to the lower levels inside.

Theater lobbies are passageways

between

the street and the foyer. An

illumination

level

of

20

footcandles is

desirable

in lobbies.

The walls

and

ceilings

should

have

a

high

brightness

up

to

50 footlamberts) .

At

signs

announcing

current

or

coming attractions 20

to

40

footcandles

should be

provided

by

local

lighting for accent. The luminaires

may

be

ceiling-

mounted spotlights,

or

lamps

and reflectors

attached

to

the signboard.

Foyers

are areas

where

traffic

is

distributed

into

the auditorium.

An

illumination

level of

10 footcandles

is

recommended.

This

is

sufficient

for

recognition

of acquaintances, for safe

movement, and

to

arouse

interest

in the decoration, and

yet

permits

quick adaptation to

the lower

audi-

torium

level.

In larger theaters,

a lounge

or promenade may

separate

the lobby and

the foyer.

The

illumination level in such

an area should

fall

between

those of the

lobby

and the foyer.

In the

auditorium proper,

three

rules should

be

observed:

1)

bright-

nesses

should be low;

2)

sources

should

be placed out

of the

normal

field

of

view

from

any

seat

in

the house;

3)

in

motion-picture

theaters

the

light

should

be

so

controlled that

a

minimum

falls

upon

the

screen. See

Fig.

10-59.) Stray

light

reduces

contrasts

in

the screen image.

Brightness

up to

10 footlamberts

may

be used

between

the

acts.

Luminaires

should

be

located

as

far

outside the field

of

view

as

practicable.

See

also

Sec-

tion

14.

To relieve

brightness contrasts

between

the

screen

and its

immediate

surround and

thus

contribute to eye comfort,

a

low

brightness

of

approxi-