NCC 2019 Volume One Amendment 1
Specification H1.3 Construction of proscenium walls

Specification H1.3 Construction of proscenium walls

1. Scope

This Specification contains the requirements for the construction of proscenium walls for theatres, public halls, or the like.

This Guide does not address, in detail, every provision in this Specification. However, there are some comments which should be made.

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 and scenery, etc.

Specification H1.3 deals with how to provide fire separation by a proscenium wall between the stage and backstage areas, and other parts of the building, including those occupied by an audience.

Height and extent of a proscenium wall—fire wall

The height and extent of a proscenium wall are similar to those of a fire wall. Any openings in it must be suitably protected to prevent the spread of a fire to the audience side.

Proscenium curtains

An important part of avoiding the spread of fire from the stage is the protection of the opening to the stage. Protection must be provided while still permitting the audience to view a performance.

Since the opening is too large to protect with an automatically-closing fire door, the aim of providing protection while maintaining functionality is achieved by the use of a proscenium curtain. Clause 6 of the specification gives two alternative options for such a curtain.

2. Separation of stage areas, etc

(a)

Dressing rooms, scene docks, property rooms, workshops, associated store rooms and other ancillary areas must be—

(i)

located on the stage side of the proscenium wall; and

(ii)

separated from corridors and the like by construction having an FRL of not less than 60/60/60, and if of lightweight construction, complying with Specification C1.8.

(b)

The stage and backstage must be separated from other parts of the building other than the audience seating area by construction having an FRL of not less than 60/60/60, and if of lightweight construction, complying with Specification C1.8.

(c)

Any doorway in the construction referred to in paragraphs (a) and (b) must be protected by a self-closing –/60/30 fire door.

3. Proscenium wall construction

A proscenium wall must—

(a)

extend to the underside of the roof covering or the underside of the structural floor next above; and

(b)

have an FRL of not less than 60/60/60, and if of lightweight construction, comply with Specification C1.8.

4. Combustible materials not to cross proscenium wall

Timber purlins or other combustible material must not pass through or cross any proscenium wall.

5. Protection of openings in proscenium wall

Every opening in a proscenium wall must be protected—

(a)

at the principal opening, by a curtain in accordance with Clause 6 which is—

(i)

capable of closing the proscenium opening within 35 seconds either by gravity slide or motor assisted mechanisms; and

(ii)

operated by a system of automatic heat activated devices, manually operated devices or push button emergency devices; and

(iii)

able to be operated from either the stage side or the audience side of the curtain; and

(b)

at any doorway in the wall, by a self-closing –/60/30 fire door.

6. Proscenium curtains

A curtain required by Clause 5 must be—

(a)

a fire safety curtain—

(i)

made of non-combustible material; and

(ii)

capable of withstanding a pressure differential of 0.5 kPa over its entire surface area; and

(iii)

so fitted that when fully lowered it inhibits the penetration of smoke around the perimeter of the opening, from the stage; or

(b)

a curtain—

(i)

having fire hazard properties complying with Specification C1.10; and

(ii)

protected by a deluge system of open sprinklers installed along the full width of the curtain.