OPERATING ROOM EQUIPMENT.
_Construction and Ventilation._--The operating room should be built of
fireproof material, such as cement, brick, or tile. If it is of wood, it
may be made nearly fireproof by lining the inside with heavy sheet iron.
It will be well if asbestos is placed between the sheet iron and the
wood which it covers. All woodwork, whether window frames, doors, or
shelving should be thus lined. It may be taken as practically certain
that sooner or later one or more reels of film will be burned in the
room and every precaution should be taken to prevent the fire from
spreading. If this is done there will probably be no serious results,
for in the past there have been so many film fires which have been
successfully confined to the operating room that audiences have become
pretty well accustomed to them. If all operating rooms are strongly
built and of ample dimensions, with all openings as small as
practicable, it will help to inspire confidence in the audience and
there will be but little likelihood of a panic.
The chief danger is to the operator. It is true that he is generally to
blame, but it is not always possible even with the utmost care to
prevent a fire. Above all the operator should be given every possible
chance to get away in case of fire. An operator who feels that he can
get away at the last moment is far more likely to stay and fight a fire
than one who is penned up in a coop from which it is difficult to get
out rapidly. There are in existence, at the present time, operating
rooms where it is necessary to crawl on hands and knees some twelve or
fifteen feet to get from the machine to the exit, and where the exit is
by means of a trap door at the head of a ladder. Such operating rooms
are an abomination and no self respecting operator would work in one of
them.
The entrance and exit from the booth should be by means of a door at the
right hand or crank side of the machine. The door should be self closing
and should open into a space having a floor level with the floor of the
operating room. The door should preferably be kept closed but if the
provision illustrated in Figure 128 is made there can be no serious
objection to leaving the door open for ventilation. A thin bar of iron
is fastened to the door by a screw eye and is used to block the door
open. A person rushing out will naturally knock this away and the door
will close. The door could also be arranged to be held open by means of
the strings, to be described later, which hold the shutters in place.
The ventilation of the operating room should be by means of a fireproof
duct leading to the outer air. This flue should preferably extend above
the highest point of the roof and should be of good size. The smoke from
burning film is heavy and does not rise very fast but it is generated
with extreme rapidity. Film burns at a temperature of 284 degrees
Fahrenheit. If it is incased in a tank and fire communicates with it,
the whole body of the film will be raised to this temperature in a very
short time and will burn with the rapidity of an explosion. In the
magazines, which are in general use in the newer houses, the combustion
will be slower but nevertheless will take not more than about one
minute.
It has often been suggested that a motor be provided in the ventilating
flue, this motor to be kept running during the time the machine is in
operation. This would no doubt help clear away all smoke very quickly
but there is no assurance that it will be running at the time when it is
most needed. A simple way to help out the ventilation without the
expense and noise of a motor, would be to arrange the ventilating flue
directly above the arc lamps so that heat rising from these would cause
a draft. This can be further helped out by locating all resistances in
this flue. They will then be out of the way in a safe place and assist
in ventilating the room. The ventilating flue will need to be fitted
with a damper for use in cold weather. This damper should be arranged to
open by gravity and be held closed by a string connected to the shutter
strings so that the damper may open when the shutters close.
The floor of the operating room is a very important part of it. It
should, above all, be extremely rigid so that the machine may be
fastened solid and thus obviate any vibration which will cause movement
of the picture. All floors that are constructed of wood are somewhat
elastic and aid this vibration. Movement of the picture is especially
noticeable and annoying to those compelled to sit close to it. Floors
must furthermore be lined with fireproof material and the only material
used is sheet iron which, upon the floor, is very noisy and can hardly
be nailed sufficiently to eliminate the noise. A metal floor lining has
the further disadvantage of affording a good “ground,” so that any one
standing upon it and touching a live part of the lamp is liable to
receive a severe electrical shock. It will also soon wear through, make
pockets to catch dirt, and allow a fire to communicate with the woodwork
beneath it. The best floor material is cement, but this, when wet, also
becomes a fairly good conductor and shocks may easily be obtained while
standing upon it. There is no reason, however, why it should ever be wet
in an operating room and it is therefore advisable to use cement.
The floor of the operating room should be kept clear as far as possible.
Careless operators often allow their take-up magazines to become
deranged and when they fail to work, allow the film to run on the floor.
A thousand feet of film scattered loosely about occupies considerable
space and is very likely to become badly tangled in case there is
anything on the floor for it to tangle with. The writer has witnessed
cases where it was necessary to take some of the film outside of the
booth in order to get it straightened out. Any operator who has been in
a similar predicament will appreciate the advantage of having every
possible obstacle to a speedy re-adjustment removed. Above all,
resistances and other sources of heat should be kept off the floor.
Every moving-picture machine requires at least two openings; one through
which the picture is projected, which need not be very large; another
through which the operator must view his picture, and this must be large
enough to allow him to sit in comfort while watching the picture. In
some operating rooms the opening through which the picture is projected
is closed by a metal funnel which covers the opening and extends back
enclosing the front of the projecting lens. This arrangement is very
simple in the case of machines in which the revolving shutter is behind
the lens. With many machines, however, this shutter works in front of
the lens and the funnel would have to be extended so as to enclose the
revolving shutter.
There is no reason why strong clear glass could not be used in the
operator’s peep hole. This would of course interfere slightly with the
clearness of his vision for focusing, but every operator should be
provided with an opera glass for this purpose anyway, so that this
objection would be easily overcome.
The same considerations which apply to motion-picture machines also
applies to stereopticon lamps.
In the more pretentious houses a spot light is generally maintained.
This is for the purpose of illuminating vaudeville performers. The
opening, provided for this lamp, must be large enough to allow the light
to follow an actor about the stage, and glass cannot well be used in it.
The best color for the operating room is green but it must be a dull
dark green. Every vestige of light maintained in the room helps dull the
vision of the operator to the light upon the screen. There is,
furthermore, much light reflected from the film where the light strikes
it and it is unavoidable that the operator should be bothered by this at
times. All other light should be kept away from his eyes while the
picture is running.
All of the openings in the room must be equipped with fire shutters.
These are generally made of heavy iron and are arranged so that, if
necessary, they can be instantly released and made to close all the
openings, thus preventing the escape of fire and smoke into the
auditorium.
[Illustration: FIGURE 130.]
The best arrangement of such a shutter is illustrated in Figure 130 at
_A_. The shaded portion shows the opening; above is the iron slide,
preferably one-sixteenth inch metal held up by a string. At the top is a
step which will prevent the shutter from being pulled up out of the
guides, for many operators would do this if the step were not there.
It is best to mount the shutter on a large piece of heavy metal which
can then be bolted to the wall of the room. The hole in the wall can
then be cut to the right proportions. When the machine is in place the
shutter can be placed very accurately. In this way it will be possible
to arrange for the smallest possible opening through which the machine
can work.
Making up the shutter, as suggested above, is further of great advantage
in old operating rooms of flimsy wood construction. If the guides in
such places are fastened independently to the wall it is possible that
they will not always remain in line with each other. A slight giving of
the flimsy wall on one side may cause them to bind the shutter and
prevent its free descent. If the metal on which the shutter guides are
mounted is strong and heavy and the guides themselves substantially
made, there will be but little chance to get them askew.
In that part of the guides in which the shutter runs there must be no
screws, rivets, or anything else that could work loose and obstruct the
shutters. Good methods of making up the guides are shown in Figure 130,
at _B_ and _C_. They should be loose enough to work without lubrication.
At the bottom there should be a bumper to stop the fall at the proper
place. This bumper should be padded with some fireproof or slow-burning
material and should be narrow. If it is made wide the operator is apt to
use it as a shelf for tools or other things and this would prevent it
from closing properly in case of fire.
All of the shutters must be normally self-closing and must be held open
by some arrangement which can readily be worked by the operator; or, in
case he fails to close them, they should be arranged so that the flames
will cause them to close automatically. This is often arranged for by
simply attaching a light strong string to each shutter, running it
through a hook eye directly above and attaching it to a master string
which is led over every place at which there is thought to be a
likelihood of fire. The idea is, that the first spread of flames shall
strike this string and by burning it, release all of the shutters. In
order to enable the operator to drop the shutter perhaps before the
flames have spread at all, the string is carried to the door and
fastened so that he, on leaving the room, may quickly release it. It is
even better to carry it still farther so that one can release it from
the outside.
Some people have recommended that these strings be soaked in oil to make
them more inflammable and tarred rope has even been made mandatory for
similar purposes in ordinances. This might make the string more readily
inflammable, but it would at the same time make it last longer. A string
or rope so treated would act like a lamp wick and the better soaked or
tarred it might be, the longer would it last and thus fail to its
purpose.
[Illustration: FIGURE 131.]
The principle of the arrangement of strings is shown in Figure 131. The
string is fastened at the door in a manner allowing of easy and quick
removal. Instead of the strings, light chains may be used provided that
at a sufficient number of places fusible links are inserted. Such links
are made up of an alloy which melts at a low temperature and allows the
shutters to drop just as they would in the case of a string burning in
two.
In many cases the strings are run over grooved pulleys. This is,
however, inadvisable. Experience has proved that very often the string
has come out of the groove and is wedged in between the shaft of the
pulley and the side so that it will not allow the shutter to descend at
all. A substantial hook eye is much better than any pulley. The strain
being taken off the string when it separates, there is no friction and
it slides through the eyes very readily. The door and the vent flue may
all be brought under control of the same string so that all will operate
together, the vent of course opening while the others close.
Where there is but one door there is little need of connecting it with
the shutters, since, if it is provided with spring hinges it will
naturally close after the operator has passed through it. In some
operating rooms, however, there are two doors and both are often found
open. In case of fire in such a booth it is extremely likely that one of
the doors would be left open unless it is provided with some automatic
manner of closing.
At _D_, Figure 130 is shown a shutter, provided with strong spring
hinges, which closes over the opening from the outside. Such shutters
should not be used where there is room for the drop shutters. Where it
is necessary to have them, they should always be arranged on the outside
of the booth; if on the inside there is too much chance of obstacles
being in the way to prevent their closing.
It is very desirable that all of the shutters be closed after each show.
If this is done there will be strong assurance that they will be in
working order in case of need and this is about the only way in which
they can be kept in order. The string arrangement above described is,
however, not well suited to this purpose unless each shutter string be
detachable from the main string. There are also various other ways of
accomplishing this which will readily suggest themselves to the
operator.
In every operating room there should be ample provision for keeping
tools but it is advisable to have all tools, that are not kept in the
lockers, on hooks instead of shelves. It is best to limit the amount of
shelving to what is actually necessary. Shelving offers great temptation
for the accumulation of rubbish. There must be a shelf upon which to
locate the rewinding apparatus and upon which to place the machine while
looking it over or making repairs, also a shelf to hold a small vise,
etc. But this is all; any additional shelving will be inexpedient. A
locker for tools can easily be arranged under the rewind shelf. A good
safe place is an encouragement to an operator to keep a supply of good
tools and nothing is more essential to the proper management of a
machine than good tools.
If the operating room is large enough, it may also contain a locker for
clothes but this should be fireproof. Preferably, however, the clothes
locker should be outside of the room, since a film fire gives one but
little time to pick up clothes or anything else.
There should, further, be a metal pail or receptacle of some kind for
hot carbons taken from the lamps from time to time. A wise operator will
also provide himself with a small receptacle in which he can keep the
pieces of film which he finds it is necessary to cut out of films
received from the exchanges. The inspection of films in the exchange is
often very perfunctory and many lengths are left in that should be cut
out. Cutting them out and saving them for a time will often help an
operator to win out in disputes with his film exchange. There are
operating rooms which have film boxes built into the wall in fireproof
manner, some of them even surrounded by water. At the present time there
are a number of good portable boxes on the market so that this is
unnecessary.
_Wiring of Operating Room._--Every operating room must have at least two
circuits run into it; one for the arc lamp and another for one or more
incandescent lights. In the larger cities an emergency lighting system
is required for all parts of the house used by the audience. This system
is always entirely independent of the main service and is supposed to
furnish sufficient light for the audience in case the other lighting
system should fail. It will be well if one light connected to the
emergency system is arranged in the operating room. If this is done,
there must be special provisions that no cords, fan motors, or portables
be connected to it. A short circuit, or trouble of any kind on this
light might put the whole emergency system out of operation. If such a
light is installed, it should be at the ceiling and protected by a
strong wire guard fastened to the outlet box. All wires carried into the
operating room should be in conduit, with the exception of the asbestos
covered wires used with arc lamps and resistances.
In addition to the incandescent light above mentioned, there should be
several other lights so arranged that good light can be obtained in any
part of the room. The color of walls being dark there is but little
reflection and a single light will only illuminate a small space. One
light should be arranged above the rewind reel and there is often
another arranged under a piece of glass in a shelf above which films are
patched. Only the best reinforced cord should be used and all work that
is stationary should be in conduit. Several outlets should be arranged
for portable cords so that one may have a light to bring down to the
take-up reel or close to the floor if necessary. Every incandescent lamp
in the operating room should be protected by a substantial wire guard
fastened to the socket.
Fan motors should be provided with strong brackets located near the
ceiling and close to the outlet from which the motor is to be run. Fan
motors should never be allowed upon the floor.
Where rewinding is to be done by motor, it will be well to arrange a
separate circuit for this motor independent of all lights. The
commutator part of the motor should be enclosed so that there may be no
possibility of a spark igniting the film.
[Illustration: FIGURE 132.]
Figure 132 is a sketch illustrating the arrangement of wiring by which
two arc lamps may be connected to mains of sufficient carrying capacity
for one only. _F_ is the fuse box in which the arc lamp fuses are
enclosed and may be large enough to accommodate a set of fuses for the
incandescent-lamp circuit also. In many cases these are, however, taken
from the house circuit since the meter rate for arc lamps is usually
different from that for incandescent lamps. _S_ is the main arc-lamp
switch by which the whole installation in the room can be cut off. This
is necessary especially if so-called compensarcs, economy coils, or
transformers are used, for these always take some current if left alive
even if the arc lamp be not burning. At _C_ is the resistance or economy
coil which serves for both lamps and at _S_ is the throw-over switch.
This switch is provided to make it impossible to burn the two arcs at
the same time as this would overload the small capacity mains. The above
is a cheap arrangement and is installed only where a set of mains exists
which is too small to supply more than one arc at a time. It is not to
be advised for a new installation because it is of great advantage to be
able to burn both arcs at the same time. When changing rapidly from one
machine to the other it is of advantage to have the second one on for a
short time before the first is off, not only to save a little time, but
also for bringing electrode points to the proper shape. Wherever it is
possible to do so always provide mains of sufficient size to feed all of
the arcs and give each lamp its own fuse, switch, and resistance or
transformer.
[Illustration: FIGURE 133.]
Figure 133 shows a method by which it is possible to arrange for either
one of two arcs to be run from a rectifier _R_, indicated by the square
at the left, or transformer _T_, at the right. In case rectifiers, heavy
transformers that cannot well be raised to the ceiling, or motor
generators are to be installed, they should be located in a separate
enclosure which must be fireproof.
In general, all of the wiring in the operating rooms must be installed
in accordance with the rules given in the chapter on Theater and Stage
Wiring. These are the rules of The National Board of Fire Underwriters
and are familiarly known as the “National Electrical Code,” or “N.E.C.”