Fire Curtain Installation — What Architects and Consultants Need to Know

A fire curtain's performance on the day it is needed depends as much on correct installation and coordination as it does on the certified product itself. Unlike a fire door, which is a self-contained unit installed into a prepared opening, a fire curtain is a system — head box, guide rails, bottom bar, fabric, motor controller and power supply — that needs to be coordinated with the structure, the false ceiling, and the building's electrical and fire alarm systems before installation can begin.

Head Box Clearance and Coordination

The head box houses the curtain in its retracted position and must be sized to accommodate the full drop of fabric when fully wound. For large-drop curtains — BÖLDT's larger automatic curtain models support drops up to and beyond 25 metres — the head box itself can be a substantial element that needs to be coordinated with structural beams, services routing, and the false ceiling void above the opening. This coordination needs to happen early: a head box that is sized after the ceiling void has already been fixed by other trades is one of the most common causes of installation delays on fire curtain projects.

Guide Rail Specification

Guide rails run vertically at each side of the opening and guide the bottom bar and fabric edges during deployment, maintaining the seal at the perimeter. Guide rails are manufactured from galvanized steel with a galvanized or powder-coated finish, matching the head box and bottom bar. Alignment of the guide rails — both verticality and the gap between rail and adjacent structure or finishes — is critical, as any deviation can cause the curtain to bind during deployment or leave a gap in the seal at the edge.

Power Supply Requirements

BÖLDT automatic fire curtains require a 230V AC supply from a dedicated isolator, provided by the client/electrical contractor, feeding the motor controller. While the curtain's fail-safe deployment does not depend on power being maintained — gravity deployment occurs precisely when power is lost — the motor and controller do need a reliable supply for normal retraction and reset operations after testing or after a deployment event. The motor controller is typically located adjacent to the head box, within the false ceiling void, and needs to be accessible for commissioning and maintenance.

BMS Integration and False Ceiling Coordination

The fire/smoke alarm signal that triggers curtain deployment is provided by the client's fire alarm system (F/A signal) and needs to be coordinated with the BMS contractor and fire alarm installer at design stage — including confirming the signal type, the deployment logic (which curtains deploy on which alarm zones), and any sequencing with smoke extraction or pressurisation systems. The false ceiling itself needs an opening sized to the head box, typically with an access panel for maintenance, and the ceiling grid around the opening needs to accommodate the curtain's pitch dimension (typically 600–1000mm depending on configuration) without conflicting with light fittings, sprinkler heads or diffusers in the same zone.