Ventilated Doors: How to Keep Air Moving Without Compromising Security

A ventilated door, also referred to as a louvred door in common usage — is a door fitted with a louvred grille that allows air to circulate freely between two spaces, whilst maintaining its core functions: physical closure and, where required, fire resistance or security performance.

These doors are essential wherever a room needs to breathe: plant rooms, boiler rooms, LV switchgear rooms (MCC/LVDB), bin stores, car parks, server rooms and battery rooms.

The challenge seems contradictory at first glance. Cutting an opening into a door appears to weaken it by definition. That is precisely where the difference lies between a grille bolted on as an afterthought and a certified, tested louvred grille that is engineered into the door from the outset.

Why Do Some Rooms Require a Ventilated Door?

Certain spaces generate heat, humidity or gases that must be managed continuously — both for occupant safety and to protect the equipment inside. A solid, airtight door is simply not an option.

Common applications include:

• Plant rooms and boiler rooms: heat dissipation and combustion air supply.
• LV switchgear and transformer rooms (MCC/LVDB): equipment cooling.
• Bin stores and storage areas: odour control and prevention of gas build-up.
• Server rooms and battery rooms: temperature management and hydrogen extraction.
• Car parks: ventilation along traffic routes.

In each case, the door must ventilate, but it must also perform as a security or fire door.

A louvred grille introduces an opening, which can conflict with other requirements:

• Security: a poorly designed grille becomes a weak point — a potential attack vector.
• Fire compartmentation: a permanent opening undermines a fire barrier unless the grille closes under heat (the intumescent principle).

The answer is not to “add a grille” to a standard door. It is to design the door around the required performance from the start. This is the core principle behind Heinen’s Metal+ Inside concept: a common tubular steel structure on which fire resistance, security rating and ventilation are combined as required — performance à la carte.

2. The Punched Louvred Grille — Fire Resistance and Security Combined

Developed in-house by Heinen, this grille consists of louvres embossed directly into the door’s cover plates. The finish is identical to that of the leaf (Magnelis® ZM 250 galvanised steel or stainless steel 304/316), for seamless visual integration.

• Security performance (to EN 1627–1630):
  CR2 and CR3 — no dimensional restriction (excluding free egress); CR4 — up to a module height of 235 mm.
• LPS 1175 D10 compliance (a loss-prevention standard widely recognised by UK insurers): up to a grille size of 320 × 200 mm.
• Fire rating: EI₁ 30 / EI₂ 30 and EI₁ 60 / EI₂ 60 (intumescent version).
• Combined fire + security on a single grille: possible up to 510 × 310 mm.
• Standard format: height 235 mm (15 louvres), width equal to leaf width minus 210 mm. Bespoke sizing is available for non-fire-rated doors.
• Positioning: bottom, top, top and bottom, or full-leaf coverage.
• Free air area: dependent on leaf width; the fire-rated version reduces airflow by approximately 31%. Example: a 900 mm leaf provides approximately 3.34 dm² free area (or ≈ 2.30 dm² in the fire-rated version).

Important: both grilles are integrated during door manufacture.

Louvred grilles are available as an option across most Metal+ configurations:

• Single leaf swing door
• Double leaf swing door
• Rebated single leaf door
• XXL swing door
• Double door without door priority

All available in Magnelis® ZM 250 galvanised steel or stainless steel 304/316, to bespoke dimensions.

Because they address a universal challenge — keeping a room ventilated without sacrificing security — Heinen ventilated doors are specified across virtually every sector:

• Culture, education and sport: museums, schools and leisure centres all house boiler rooms and plant rooms that need ventilating, in buildings where aesthetics matter as much as fire safety.
• Energy and nuclear: critical plant rooms combining ventilation, access control and security rating — transformer rooms, battery rooms and spaces requiring heat or hydrogen extraction.
• Retail and distribution: technical rooms in large commercial premises (refrigeration plant, LV switchgear, bin stores) where airflow must be maintained without compromising fire compartmentation.
• High security: data centres, sensitive sites and custodial facilities, where the punched louvred grille combines ventilation, forced-entry resistance (CR2–CR4, LPS 1175) and fire rating in a single door.
• Industry: process plant protection with heat and atmosphere management — boiler rooms, process areas and electrical switchrooms.
• Car parks: ventilation of traffic routes and plant rooms, for exhaust gas extraction and equipment cooling.
• Residential and commercial: apartment blocks and office buildings whose bin stores, boiler rooms, LV switchgear rooms and shared car parks require controlled, discreet ventilation.
• Social and healthcare: hospitals, care homes and social housing, where plant rooms demand ventilation, hygiene and fire safety in equal measure.
• Transport: plant rooms in rail, airport and road infrastructure — signalling rooms, LV switchgear and tunnels.