Safety curtain

A safety curtain (or fire curtain in America) is a fire safety precaution used in large proscenium theatres. It is usually a heavy fibreglass or iron curtain located immediately behind the proscenium arch. Asbestos-based materials were originally used to manufacture the curtain, before the dangers of asbestos were widely known. The safety curtain is sometimes referred to as an iron in British theatres, regardless of the actual construction material.
Occupational safety and health regulations state that the safety curtain must be able to resist fire and thereby prevent (or at least hinder) fires starting on stage from spreading to the auditorium and the rest of the theatre, reducing injuries to audience members and members of staff.
The curtain is extremely heavy and therefore requires its own dedicated operating mechanisms. In an emergency, the stage manager can usually pull a lever backstage which will cause the curtain to fall rapidly into position. Alternatively, heat-sensitive components can be built into the rigging to automatically close this curtain in case of fire. Finally, it may be released electronically with the activation of the building's fire alarm system. It can also be flown in and out, as regulations in some jurisdictions state that it must be shown to the audience, to prove its effective operation, for a certain amount of time during every performance. This usually occurs during the intermission.
In smaller theatres, a safety curtain is not usually required. Specifically, most United States building codes only require a fire curtain in theatres with a stage height of more than . The heavy, flame-retardant house tabs can provide some degree of fire separation.
In the UK, it is a requirement that a safety curtain must be fully down within the proscenium opening within 30 seconds of being released. In 1794 the Theatre Royal, Drury Lane became the first theatre to feature an iron safety curtain. Several other serious fires, notably that at the Theatre Royal, Exeter in 1887, led to the introduction of safety curtains on a wider scale.
A very early example of a safety curtain installation in the United States was at the New Fifth Avenue Theatre (New York City) which opened in 1873. Chicago's 1903 Iroquois Theatre fire resulted in over 600 deaths when the theater's safety curtain got stuck midway down, along with other structural deficiencies in the building.
Related stage fire safety devices.
The safety curtain can be combined with other safety devices, such as:
In the event of a fire, the use of smoke doors and fire curtains means that the stage area effectively functions as a chimney. The heated air rises and leaves through the smoke doors, and this puts the building into negative pressure, which in turn draws fresh air in through any open exit doors. Patrons waiting to exit will have fresh breathing air until the exit doors close. The exit doors which open out will be drawn closed tightly by this draft once they are no longer held open by evacuees. Once the doors are closed, the fire loses its oxygen source. If the doors are then opened again, a backdraft can occur.