Fire rated louvre doors

Fire rated louvre doors ventilate plant rooms and risers while holding a fire rating of E 60 or E 90. ArxBridge supplies and installs them across the UK where the ventilation design needs airflow through a compartment wall.

• E 60 and E 90Integrity ratings for louvred doors
• EN 1634-1Fire resistance test standard
• Ventilation with ratingAirflow through a compartment wall
• Steel constructionBlades and frame in folded steel

The basics of fire rated louvre doors

A fire rated louvre door is a steel door whose leaf carries louvre blades that pass air in normal use and maintain the fire rating in fire conditions. It solves the plant room problem: the room needs ventilation for heat and fumes, and the wall around it needs a fire rating. The Fire range overview sets out the related solid and dual-rated products.

These doors go in boiler rooms, generator enclosures, electrical substations, risers and bin stores: anywhere the fire strategy draws a compartment line around a room that also needs air. The rating is E 60 or E 90 for integrity; insulation (EI) is not expected of a ventilating door, because the airflow path cannot insulate.

As with every fire door, the rating belongs to the tested doorset: blades, leaf, frame, seals and ironmongery together. Test evidence to EN 1634-1 must name the louvre configuration.

Which rating do you need for fire rated louvre doors

The choice follows the compartment wall rating: the door matches the wall. Where the wall needs EI rather than E, a louvred door is the wrong product and a solid fire rated steel door with a separate ventilation strategy is needed. The fire ratings guide explains the E and EI distinction.

E, not EI. A ventilating door cannot insulate. If the strategy demands EI, specify a solid door and ventilate another way.

Construction of fire rated louvre doors

The leaf is a steel frame holding banks of louvre blades. The blades carry intumescent material that stays inert in normal use and expands in the heat of a fire, closing the airflow path and restoring the integrity of the leaf. The blade angle also sheds water and blocks direct sightlines in normal service.

The frame is a folded steel section with intumescent seals at the perimeter, fixed into the structural opening. Hinges, locks and any panic hardware are fire tested items; the louvre section itself is the part of the door the test scrutinises most closely.

Free area is the key dimension: the ventilation engineer sizes the door from the airflow calculation, and the tested free area must not be reduced on site by added mesh or blanking. Finish is powder coat; external doors get a weathering assessment.

Combining fire rated louvre doors with other ratings

Security is the common pairing: plant rooms hold valuable equipment, so the door may need LPS 1175 forced entry resistance alongside its fire rating. Steel louvred doors covers the security-rated side, and fire and security doors explains how combined ratings are evidenced.

Blast is the other pairing on high-risk sites: blast resistant louvred doors ventilate while holding an EXV class, and the two performances can be combined where the evidence covers both.

Weather performance for external doors is assessed separately from fire: the blade profile determines rain resistance, and the specification should state both.

Where to use fire rated louvre doors

Utilities and energy sites use them on substations and switch rooms. Data centres use them on generator and UPS rooms where the fire load is high and the kit needs air.

Healthcare estates use them on boiler houses and plant decks away from wards. Education campuses use them on energy centres and bin stores.

Where the plant room sits inside a blast line, the blast resistant louvred door is the alternative; where no air is needed, use a solid fire rated steel door.

What sets the cost and lead time for fire rated louvre doors

Free area drives size and therefore cost: a large ventilation demand means a large door or multiple doors. The E 90 build needs more intumescent and deeper sections than E 60.

Security and blast pairings add engineering and evidence, each with its own test reports to check. External weathering details add fabrication steps.

Coordinate the ventilation design with the door schedule early. A late change to the airflow rate can mean a different door size, and louvred doors are made to measure.

How to specify fire rated louvre doors

1. Get the ventilation rate. The ventilation engineer states the required free area for each room.
2. Take the fire rating from the strategy. E 60 or E 90, matched to the compartment wall.
3. Add the other ratings. Note any forced entry, blast or weather performance the door needs.
4. Demand the evidence. Ask for EN 1634-1 test reports naming the exact louvre configuration.
5. Protect the free area. State in the specification that no mesh or blanking may be added on site, and book installation before finishes close the opening.