“A-1” Occupancy Fire-Resistant Proscenium Curtains

General Definition

A fire-resistant proscenium curtain is a specially designed fire barrier that separates the stage from the audience in theaters and performance spaces.
- These curtains help prevent the spread of fire and smoke from the stage area to the seating areas, allowing occupants more time to evacuate safely.
- In Group A-1 occupancies (e.g., theaters, auditoriums, and concert halls), fire-resistant curtains are a critical component of fire safety systems, ensuring fire containment and life safety in performance venues.

Building codes such as the International Building Code (IBC) and the Building Standards Law (BSL) of Japan regulate fire resistance, activation mechanisms, and emergency backup requirements for these systems.

Element	IBC Section 410.8.2 (USA) – Fire-Resistant Proscenium Curtains	BSL Article 35 (Japan) – Fire Protection for Stage Areas
Requirement for Fire-Resistant Proscenium Curtain	– Required for theaters with stage heights exceeding 50 feet (15.2m).	– Mandatory in all enclosed stages exceeding 50 m² (538 sq. ft.). (Stricter than IBC.)
Minimum Fire-Resistance Rating	– Must have a minimum fire resistance of 1 hour.	– Requires a higher fire resistance of 2 hours. (Stricter requirement.)
Automatic Closing Mechanism	– Curtains must close automatically upon activation of the fire alarm system.	– Same requirement, but must also close upon activation of manual override.
Activation Trigger Requirements	– Activated by heat detection, fire alarm, or smoke detection system.	– Stricter; requires activation upon heat, smoke, and emergency power failure.
Emergency Power Backup	– Curtain system must be connected to emergency power supply.	– Same as IBC, but with longer backup power duration requirements.

Requirement for Fire-Resistant Proscenium Curtain:
- IBC requires proscenium curtains only in theaters with stage heights over 50 feet (15.2m).
- BSL enforces stricter requirements, mandating them in all enclosed stages over 50 m² (538 sq. ft.).
Minimum Fire-Resistance Rating:
- IBC mandates a 1-hour fire resistance rating for proscenium curtains.
- BSL enforces a stricter 2-hour fire rating. (Stronger fire containment.)
Automatic Closing Mechanism:
- IBC requires automatic closure upon activation of fire alarms.
- BSL enforces the same requirement but also mandates closure via a manual override system.
Activation Trigger Requirements:
- IBC activates the curtain through heat detection, fire alarms, or smoke detectors.
- BSL mandates activation via heat, smoke, and emergency power failure conditions. (More comprehensive.)
Emergency Power Backup:
- Both IBC and BSL require emergency backup power, but BSL enforces longer backup duration.

Issue	IBC Recommendation	BSL Recommendation
More Inclusive Curtain Requirements	Require proscenium curtains in all enclosed stages exceeding 50 m², similar to BSL.	Maintain current requirement but clarify exemptions for open-air venues.
Higher Fire-Resistance Ratings	Increase minimum fire resistance from 1 hour to 2 hours for better fire containment.	Ensure curtain material meets strict international fire safety standards.
Stronger Activation Triggers	Implement a fail-safe trigger mechanism to close curtains upon emergency power failure.	Improve public awareness of manual override options.

Requirement for Fire-Resistant Proscenium Curtain:
- IBC: Only required for stage heights exceeding 50 feet (15.2m).
- BSL: Stricter required in all enclosed stages over 50 m² (538 sq. ft.).

Minimum Fire-Resistance Rating:
- IBC requires a 1-hour rating.
- BSL enforces a stricter 2-hour rating.

Automatic Closing Mechanism:
- Both IBC and BSL require automatic closure upon fire alarm activation.
- BSL also mandates manual override closure.

Activation Trigger Requirements:
- IBC: Activated by heat detection, fire alarm, or smoke detection.
- BSL: Stricter—activates via heat, smoke, and emergency power failure.

Emergency Power Backup:
- Both IBC & BSL require emergency power backup, but BSL enforces a longer backup duration.

BSL enforces stricter fire-resistant proscenium curtain requirements than IBC.
BSL requires fire curtains for all enclosed stages over 50 m², while IBC mandates them only for stages over 50 feet high.
BSL enforces a higher fire-resistance rating (2 hours) compared to IBC (1 hour).
BSL requires additional activation triggers, including emergency power failure, while IBC only requires heat and smoke activation.
Both codes ensure automatic closure upon fire alarm activation, but BSL mandates an additional manual override system.