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1947-48 Theatre Catalog, 6th Edition, Page 161 (149)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 161
Page 161

1947-48 Theatre Catalog, 6th Edition, Page 161

supported at the ends and quarter points by means of cables or ropes passing through sheaves attached to the roof structure. The cables will lead from the sheaves through a head block at one side of the stage and at this point the cables will be secured to a bridle arrangement which in turn will be attached to the raising or lowering cable. This will be operated by a hand winch located at the proper height above the stage floor. Bolts through the masonry wall of the stage should be provided during construction to secure the brackets for the winches and head blocks.


The projection booth is the most important space in a motion-picture theatre and the designer should be familiar with its operation, and the necessary equipment which must be installed. He should also be familiar with the regulations and codes which apply to its construction and layout, and check with the safety requirements for the protection of the operators and the public. Standard requirements which cover this section of the theatre have been adopted by the American Society of Motion Pics ture Engineers and these standards, if followed, will comply with most codes. However, some state and local codes have special regulations which should be investigated before starting construction.

Level of Floor

If the auditorium ceiling or other conditions of design do not allow for the location of the projection room floor to permit headroom above the top level of the mezzanine or balcony, then the floor of the projection room must be raised sufficiently to prevent interference with the light beams from the projection ports by patrons passing in front.

The height from the floor of the projection room to the center of the projection port will vary with the equipment which is to be used and the steepness of the projection angle. The height, if the beam is level, will be 48 inches and will decrease to approximately 30 inches as the height of the projection room floor increases above the screen.

The floor of the projection room should be raised above that of the top level of the mezzanine, stadium, or balcony, to provide for a 7-foot clearance under the light beam.

Proiecfion Room Slab

On account of the many different runs of conduit required for the necessary a. c. and d. c. wiring to the projection room equipment, particularly in instances where three projection machines are installed and perhaps a spot or effect machine, it is almost impos' sible to install this conduit, which in some cases must be 2 inches without having to cross the runs. It can readily be seen that it is almost impossible to conceal these runs in an ordinary 4or 6-inch door slab. It is a very good policy to drop this floor slab 6 inches and provide for anthracite cinder or lightweight concrete fill to bring the floor to the correct level. It is, of course, possible to conceal this conduit in a suspended ceiling under the door slab,


TABLE ZeDistance from floor to center ,line of projection ports and to center line of observation posts at various projection angles.

Distance from Projection lgisjfgggm'; Floor to Center Angle Line of

Line of (D931. Beg) Projection Ports observation

Ports (Feet)

-6 51 v ' 64 e4 50 63 -2 49 62 0 48 61

2 47 60

4 46 59

6 45 58

8 44 57 10 43 56 12 42 55 14 ' 41 54 16 40 52 18 38% 51 20 371/; 50 22 361/: 50 24 35 1/2 50 26 34 49

but the first method will be found the most satisfactory and convenient. Very often it will be found that the type and amount of equipment will not have been decided upon at the time the structural slab is scheduled to be installed, therefore if provision is made for the conduit to be installed after the slab is poured, there will be no delay in the construction schedule.

Ceiling A 10-foot ceiling in the projection booth is desirable and in many cases

mandatory. Minimum depth from front to rear wall 10 feet-12 is much better.

A length of about 14 feet is required for two projection machines, but if space is available, 20 feet is more advantageous.

Port holes in the booth must be protected by automatic and hand-operated fire-proof shutters which are tripped by fusible links and also by manual release at each exit from the booth. Optical glass in the projection ports and plate glass in the observation ports will exclude both noises from the theatre. Acoustical treatment of the ceiling and the walls above the wainscot for absorbing noises in the booth is desirable when the booth is located near the seating area.

Projection Ports

Each projection machine will require two openings or ports through the front wall of the booth, one for the light beam and one for the projectionist. The size of these ports are sometimes regulated by code or fire regulations, but the average and ample size is 10 inches by 10 inches for the projection port and 10 inches by 12 inches for the observation port.

The location of the center of these ports above the floor of the projection room will be governed by the angle of projection which in turn varies with the difference in elevation of the prof jection room floor and the center of the picture. Table 2 gives the average height of these openings for the different projection angles. These will vary somewhat with different type of equipment.

The size of the ports referred to above is that on the booth side of the wall. The ports should be flared or beveled towards the auditorium, on the bottom and both sides of the port opening.

FIGURE 224nm stadium (or balcony) rail should be of solid masonry construction and finished with cement plaster or linoleum, and should proiecl above the level of the firs! row floor 2 feet 4. inches. The solid portion of the rail can be reduced. with an open ornamental metal or wood railing. on lop. An open railing for the full height is not desirable. Plain piping is sometimes used for the railing.







1947-48 Theatre Catalog, 6th Edition, Page 161