1. N.B.C. OF INDIA
SOUND INSULATION
Trees with heavy foliage planted on both sides of carriageway help slightly to muffle the noise, provided the
foliage extends for a considerable distance (30 m or above).
Noisy rooms should be separated from quiet ones, if possible.
FIRE AND LIFE SAFETY
All buildings depending upon the occupancy use and height shall be protected by fire extinguishers, wet
riser, down-comer, automatic sprinkler installation in accordance with the provisions of NBC.
Automatic fire detection and alarm facilities shall be provided, where necessity, to warn occupants early of
the existence of fire, so that they may escape, and to facilitate the orderly conduct of fire exit drills.
Fire doors with 2 h fire resistance shall be provided at appropriate places along the escape route and
particularly at the entrance to lift lobby and stair well.
Internal stairs shall be constructed of non combustible materials throughout.
2. Area required: The floor area of the hall including, gangways (excluding the stage ) should be calculated on the basis of 0.6
to 0.9 sq. m per person.
Height and volume: The average height may vary from 6 m for small halls to 7.5 m for large halls. The volume per person
required to be provided should normally range between 3.5 to 5.5 m. Suitable volumes for different types of auditoriums are
given below.
Cubic metres per person
A) PUBLIC LECTURE HALLS.
B) CINEMAS OR THEATRES
C) MUSICAL HALLS OR CONCERT HALLS
3.5 to 4.5
4.0 to 5.0
4.0 to 5.5
Max. Distance from the curtain wall: In the case of theatres a person with normal vision should be able to discern facial
expressions of the performers. In order to satisfy these condition, the distance of the ‘farthest seat from the curtain line
should not normally exceed 23 m.
Stage: The size of the stage depends upon the type of performance the hall is to cater for. It would be large for theatres,
while it would be comparatively small for cinema halls which again depends on the size of the screen.
Balcony: Where a balcony is provided, its projection into the hall should not be more than twice the free height of the
opening of the balcony recess.
Doors and windows: The external noise level is high, properly fitted doors and windows should be provided. Their rebates
should preferably be lined with draught strip rubber or felt.
Line of sight: The elevation of the balcony seats should be such that line of sight is not inclined more than 30 degrees to
the horizontal.
Angle of floor: As an empirical rule the angle of elevation of the inclined floor in an auditorium should not be less than 8
degrees.
3. Foyers, crush halls, attached rooms: All the enclosed spaces, such as foyers, lounges, flanking verandas,
etc., adjacent to the auditorium showable be isolated from the main hall by suitable ( well fitting ) doors so
that the acoustics of the hall are not influenced by these rooms;
• The foyer area, depend on the size and seating capacity of the auditorium. At least 20% of the seating
area of the hall 1s recommended for foyer.
• For lobby and lounge, areas at least corresponding to 10 % of the seating area in the hall are
recommended.
Seating:
• The distance of the front row works to about 3.6 m for drama and it should be 4.5 m or more for
cinema purposes.
• The width of a seat should be between 45 cm and 56 cm.
• The back to back distance of chairs in successive rows of seats shall be at least 85 cm. If extra comfort
is required, higher spacing may be provided which shall vary between 85 cm and 106 cm.
• Seats should be staggered sideways in relation to those in front so that a listener in any row is not
looking directly over the head of the person in front of him.
Sound amplification system: a loudness of speech level of about 60 to 70 db. is required for comfortable
listening. For this level can be obtained, the volume does not exceed 1400 cubic m and the max. distance from
the speaker to listener is of the order of 23 m.
