Fire Dampers

Our range covers circular in-duct fire dampers and intumescent fire protection for ductwork and air transfer openings: BSB FD-C circular single-blade fire dampers from 100mm to 315mm (externally resettable, ES-classified to BS EN 1366-2 with reduced smoke leakage, air control tested to BS EN 1751), Systemair PKI in-duct circular fire dampers from 100mm to 200mm (EIS to EN 1366-2, up to 120 minutes, 72°C thermal fuse), FläktWoods KSOF air valves with integral fire damper for MVHR and MEV terminals (CE-marked to EN 15650), and circular intumescent fire blocks from 100mm to 200mm and square intumescent fire blocks from 150mm to 600mm (tested up to 60 minutes in timber doors and up to 120 minutes in walls and ductwork).

Certification and fire rating vary by product type, and each product page lists the standards, rating and datasheet for that item. We don't currently stock rectangular multi-blade fire dampers, but we can source them to order for project work. Trade pricing, UK stock and next-day delivery available. Email hello@efans.co.uk or call 0161 399 3825 for a quote, sizing help or wholesale pricing.

Frequently asked questions

Where are fire dampers required?

Wherever ductwork passes through a fire compartment boundary, meaning fire-rated walls, floors, and partitions. Approved Document B of the Building Regulations requires that penetrations through fire-separating elements are protected to maintain the compartment's fire resistance. In practice, this covers ductwork in offices, schools, hospitals, care homes, hotels, and residential blocks of flats. If you're running a duct through any wall or floor that has a fire rating (typically 30, 60, 90, or 120 minutes), you need a fire damper at that penetration. The damper's fire rating must match or exceed the rating of the element it passes through.

What's the difference between a fire damper and an intumescent fire block?

A mechanical fire damper (like the BSB FD-C or Systemair PKI) has a moving blade that closes when the thermal fuse releases, and it can be reset and tested after activation. They're used in active ventilation ductwork where airflow is continuous during normal operation. An intumescent fire block has no moving parts: it's a collar or sleeve containing intumescent material that expands in a fire, crushing and sealing the duct penetration. Intumescent blocks are typically used on passive ventilation openings (air transfer grilles between rooms), extract terminals, and smaller duct penetrations. They're simpler and cheaper but can't be reset, so once activated they're replaced. The two product types are tested and certified to different standards, so check the specification on the product page against what your Building Control officer or fire strategy requires.

How often do fire dampers need testing?

BS 9999 recommends annual inspection and testing of all fire dampers. This involves a visual check of the damper and its access panel, followed by a drop test: releasing the blade to confirm it closes fully, then resetting it. Some insurers and local authorities require six-monthly testing in higher-risk buildings like hospitals and care homes. Every test must be recorded with the date, damper location, result, and the name of the person who carried out the inspection. If a damper fails its drop test, it must be repaired or replaced immediately, as a stuck-open fire damper is a serious fire safety breach.

Do I need an access panel for each fire damper?

Yes. Building Regulations and BS 9999 both require that every fire damper is accessible for inspection and testing. In practice, this means fitting a duct access door or building in a ceiling access panel directly adjacent to each damper. A fire damper that can't be reached for its annual drop test is non-compliant. This is one of the most common issues found during fire risk assessments: dampers installed above fixed ceilings with no access. Plan the access at design stage, not as an afterthought. The access panel must be large enough to see the damper blade, operate the test release, and reset the mechanism.

What size fire damper do I need?

The fire damper must match the duct size at the point of penetration. For circular ductwork, specify the damper by the duct's internal diameter. The BSB FD-C range covers 100mm to 315mm in eight sizes, and the Systemair PKI range covers 100mm, 125mm, 150mm and 200mm. For rectangular ductwork, multi-blade fire dampers are sized to match the duct cross-section. We don't stock these as standard but can source them to order, so send us the schedule. For passive air transfer openings not connected to ductwork, use intumescent fire blocks: circular blocks for round openings, square blocks for rectangular openings. Always match the fire rating of the damper to the fire rating of the wall or floor it's installed in, so a 60-minute wall needs at least a 60-minute damper.

Can I use intumescent fire blocks on MVHR systems?

Yes, intumescent fire blocks are commonly used on the individual room supply and extract terminals of MVHR and MEV systems. The air valve with integral fire damper we stock combines a standard adjustable air valve with a fire damper in the back of the terminal. This means you get airflow control and fire protection in one unit, without needing a separate mechanical fire damper at every room terminal. They're particularly useful in residential blocks of flats where each flat's ventilation terminals penetrate the fire compartment between the flat and the communal riser or ceiling void. Confirm the required rating with your fire strategy or Building Control officer before specifying.

Do you supply fire dampers for commercial projects and trade accounts?

Yes. eFans supplies M&E contractors, ventilation installers, fire protection specialists and facilities teams across the UK. Send us a drawing, damper schedule or brief and we'll check sizes against the duct layout, quote the matched dampers and access doors, source anything outside our stock range, and arrange next-day or scheduled delivery to site. Email hello@efans.co.uk or call 0161 399 3825 for trade pricing on multi-damper orders.

For the full background on types, regulations and testing, read our fire damper guide.