NCC 2019 Volume One
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Part H1 Class 9b buildings
Part H1 contains Deemed-to-Satisfy Provisions additional to those contained in Sections C, D and E for Class 9b buildings.
The Deemed-to-Satisfy Provisions of this Part apply to every enclosed Class 9b building or part of a building which—
is a school assembly, church or community hall with a stage and any backstage area with a total floor area of more than 300 m2; or
otherwise, has a stage and any backstage area with a total floor area of more than 200 m2; or
has a stage with an associated rigging loft.
To clarify which Class 9b buildings are subject to Part H1, and to what extent they are subject.
Stages used for live performances can contain high fire loads due to the props, scenery, lighting, and the like used in such productions. Such props and scenery are often also stored in backstage areas, which adds to the fire load.
In general, Part H1 applies to specified enclosed Class 9b buildings which:
Part H1 does not simply apply to stage and backstage areas, but also to seating areas and aisle lighting.
H1.4 applies to all Class 9b buildings, whether or not they are enclosed, and regardless of size.
H1.7 applies to all Class 9b buildings which are enclosed, regardless of their size.
A theatre, public hall or the like must—
have a sprinkler system (other than a FPAA101D or FPAA101H system) complying with Specification E1.5; or
To protect the audience in a theatre or public hall from a fire on the stage.
H1.2 does not apply to all theatres and public halls. See H1.1 to determine which buildings need to comply with H1.2. A stage and backstage area of a theatre or public hall has a high fire load due to the storage of props and scenery/etc.
The audience must be protected from this fire source by either:
A proscenium wall must comply with Specification H1.3.
To set out the detailed construction requirements for a proscenium wall.
The construction details for a proscenium wall are contained in Specification H1.3.
In a seating area—
the gradient of the floor surface must not be steeper than 1 in 8, or the floor must be stepped so that—
a line joining the nosings of consecutive steps does not exceed an angle of 30° to the horizontal; and
the height of each step in the stepped floor is not more than 600 mm; and
the height of any opening in such a step is not more than 125 mm; and
if an aisle divides the stepped floor and the difference in level between any 2 consecutive steps—
exceeds 230 mm but not 400 mm — an intermediate step must be provided in the aisle; and
exceeds 400 mm — 2 equally spaced intermediate steps must be provided in the aisle; and
the going of intermediate steps must be not less than 270 mm and such as to provide as nearly as practicable equal treads throughout the length of the aisle; and
the clearance between rows of fixed seats used for viewing performing arts, sport or recreational activities must be not less than—
300 mm if the distance to an aisle is not more than 3.5 m; or
500 mm if the distance to an aisle is more than 3.5 m.
To enable the evacuation of an audience from the seating area.
Under H1.1(b)(i), H1.4 applies to all Class 9b buildings, both enclosed and open. This means that it applies to theatres, open-deck spectator stands, sporting stadiums, and the like, wherever the public is seated to view an event.
H1.4(a) deals with the height difference between the floors supporting seats in a theatre and the like. The maximum slope of the floor of 1 in 8 is consistent with D2.10(b)(ii).
This slope cannot be used in aisles required to be accessible by people with disabilities. In such a case, the maximum slope of the aisle is 1 in 14, as required by AS 1428.1.
The maximum gap of 125 mm stipulated in H1.4(a)(iii) is consistent with D2.13(a)(iv).
Figure H1.4(1) and (2) illustrate methods of complying with H1.4(a) and (b).
It is often impractical to require the standard minimum width of a path of travel to an exit of one metre between rows of fixed seating. H1.4(c) allows a reduced width in such cases. This width is based on studies of movement between rows.
Distance between the seats should ordinarily be measured:
H1.4(c) applies only where the public is seated on fixed seating to view an event.
To enable safe egress from the stage and backstage areas of a theatre.
A stage and backstage area of a theatre or public hall has a high fire load. It is also a potential fire source due to stored props, scenery, lighting, special effects, and the like.
Because of the recognised fire hazard, proscenium walls and curtains are required to separate the stage and backstage areas from the audience.
To maintain this fire separation:
A stairway that provides access to a service platform, rigging loft, or the like, must comply with AS 1657.
To set out the requirements for stairways to service platforms, rigging lofts, and the like.
Stairways to service platforms, rigging lofts, and the like must comply with AS 1657.
In every enclosed Class 9b building, where in any part of the auditorium, the general lighting is dimmed or extinguished during public occupation and the floor is stepped or is inclined at a slope steeper than 1 in 12, aisle lights must be provided to illuminate the full length of the aisle and tread of each step.
To make safe evacuation available from theatres.
H1.7 applies to enclosed Class 9b buildings where:
In case of an evacuation, and when the lights are dimmed or extinguished during a performance, H1.7 requires the installation of aisle lights to avoid people tripping on steps, or falling on a ramp.