A smoke shaft on a 14-storey residential block gets shifted 400mm on site to clear a structural beam. On an ordinary job that’s a site query, a marked-up drawing and a note in the O&M. On a higher-risk building it’s a change control decision with a legal category attached, and getting that category wrong is the sort of thing that surfaces months later when the completion certificate application lands on a regulator’s desk.
The Building Safety Act 2022 replaced building control as most contractors knew it for one class of building. Here’s what the gateways actually ask of a smoke control system, where the evidence has to come from, and what changes in how the job is run.
The Three Gateways and Which Buildings They Catch
The regime has three checkpoints.
Gateway 1 sits in planning. A fire statement has to accompany the planning application for a relevant building, and the Building Safety Regulator is a statutory consultee. It covers what the planning system can influence: site layout, fire and rescue service access, water supply for firefighting. Smoke control rarely features in detail, though it can bite where the strategy depends on shaft position, plant location or a roof-level discharge the massing has to accommodate.
Gateway 2 is building control approval, and it has to be granted before higher-risk building work starts.
Gateway 3 is the completion certificate, and it has to be issued before the building is occupied.
Gateways 2 and 3 are set out in the Building (Higher-Risk Buildings Procedures) (England) Regulations 2023, which sit under the Building Safety Act 2022 and alongside the Building Regulations 2010 as amended. The Building Safety Regulator is the building control authority for this work. There is no local authority or approved inspector alternative.
The definition catches more than people assume. For the design and construction stages, a higher-risk building is one at least 18 metres in height or with at least 7 storeys that contains at least two residential units, and also a care home or hospital meeting the same height condition. That last part trips teams up, because care homes and hospitals sit inside the gateway regime but outside the in-occupation duties in Part 4 of the Act. A care home goes through Gateways 2 and 3 and then has no Principal Accountable Person and no statutory golden thread duty in occupation, which makes the handover arrangements a contractual question rather than a legislative one.
One governance change worth knowing: the Building Safety Regulator became a standalone body on 27 January 2026, having previously been hosted by the Health and Safety Executive. The functions and the gateway process are unchanged. The letterhead isn’t.
Gateway 2: Approval Before Anything Is Built
The application is made by the client and has to be accompanied by a defined set of documents: site plans, the plans needed to show the work would comply with the Building Regulations, a competence declaration, a construction control plan, a change control plan, a mandatory occurrence reporting plan, a Building Regulations compliance statement, and the fire and emergency file. Where occupation of part of the building before completion is proposed, a partial completion strategy goes in too.
The Regulator has up to 12 weeks to determine an application for a new higher-risk building and up to 8 weeks for work to an existing one, unless a longer period is agreed. Work must not start until approval is granted. Processing delays have been widely reported across the industry since the regime went live, and the Regulator has published performance data and improvement targets, so check the current position rather than planning off a number you read last year.
The consequence for smoke control is bigger than the paperwork. Gateway 2 assumes the design is finished, not developed. The old sequence, where a smoke control specialist is appointed after the frame is up and reverse-engineers a compliant design around whatever shaft the structure left behind, does not survive this process. If the design isn’t resolved when the application goes in, either the application is weak or the design changes later, and later changes now have a procedure attached.
What Gateway 2 Demands of the Smoke Control System
Four things carry the weight.
Fire strategy coherence. The compliance statement has to explain how the design meets the functional requirements, and the smoke control design has to say the same thing as everything else in the pack. If the fire strategy describes a mechanical shaft clearing the corridor at a stated extract rate, and the M&E layouts show a natural shaft with an AOV at head, that inconsistency is visible to anyone reading both documents. The same applies to zone boundaries, the assumed detection strategy, door and vent free areas, and any assumption the strategy makes about how quickly a corridor clears. Where the solution is fire engineered rather than following the guidance in Approved Document B, BS 9991 or BS 9999, the modelling, the input assumptions and the acceptance criteria all need to be in the submission. An engineered solution with no stated acceptance criteria cannot be assessed, and cannot be commissioned against anything at Gateway 3 either.
Evidence of product performance. The Regulator is assessing whether the building as designed complies, which means named products with test evidence behind them, not a schedule of generic descriptions. The relevant product standards run across the BS EN 12101 series: Part 2 for natural smoke and heat exhaust ventilators, Part 3 for powered ventilators, Part 6 for pressure differential systems, Part 8 for smoke control dampers, Part 9 for control panels and Part 10 for power supplies. The document that proves performance is the Declaration of Performance, with the classification string on it. A brochure is not a DoP.
“Or equal approved” has always been a way of deferring the product decision to the buying stage. Under this regime the deferral has a cost, because substituting a product after approval is a controlled change, and a substitution that alters a classification (a different leakage pressure class, a different tested orientation, a lower operating temperature) is not like for like however well it fits the hole.
Cause and effect. The written cause and effect matrix belongs in the design submission, not in a commissioning engineer’s folder six months later. It needs every input, every output, the zone map it refers to, the interlocks with fire alarm, lifts, dampers and any mechanical ventilation that has to shut down, the sequence for firefighter control, and the lockout logic. If the design uses primary zone lockout, the matrix has to say what happens on a second detection and why. This document is the specification that Gateway 3 commissioning is tested against, so an incomplete matrix at Gateway 2 guarantees an argument at handover.
Competence and the three plans. The competence declaration, construction control plan, change control plan and mandatory occurrence reporting plan are not smoke control documents, but they determine how the smoke control package is managed. The change control plan is the one that matters most on site, because it sets out how the project will categorise and process changes. Get that plan written in a way the site team can actually follow, or every drawing revision becomes an argument. On competence, be ready to evidence who designed the system, who will install it and who will commission it, which for smoke control usually means third party certification or membership of a recognised scheme rather than a general M&E qualification.
Change Control: When the Smoke Control Drawings Move
Once approval is granted, changes fall into three categories.
| Category | What it means | What the client must do |
|---|---|---|
| Recordable | A change that does not meet the notifiable or major threshold | Record it in the change control log and keep the log up to date |
| Notifiable | A change affecting the design of the building or compliance with the Building Regulations | Notify the Regulator, and do not carry out the change until that notification has been made |
| Major | A change with a significant impact on the design or the fire strategy, which would significantly alter or undermine the basis of the original approval | Apply for building control approval, determined within six weeks unless a longer period is agreed, and do not carry out the change until it is granted |
The categories are defined by effect, not by trade or by cost, so the judgement sits with the principal designer and the client, informed by the fire engineer. It is not a call for the installer to make on site. But the installer is usually the first to know a change is happening, so flag it early and in writing.
For smoke control, the changes that reach for the fire strategy are the obvious candidates. Moving a shaft. Changing the free area of a vent. Changing an extract rate. Switching a shaft from natural to mechanical or the reverse. Redrawing zone boundaries. Rewriting a line of the cause and effect. Anything that alters what the strategy assumed about how smoke leaves the building is at least a conversation with the principal designer, and quite possibly a six-week application.
At the other end, replacing an actuator with a different model of identical certified performance, no change to opening geometry, no change to stroke or force, and no change to the panel configuration, is the sort of thing a change control plan should be able to handle as a record.
Between those two poles is where projects get into trouble, and the trouble is almost always in the same direction. Teams under-categorise to avoid the delay, the work proceeds, and the mismatch stays buried until the completion certificate application requires an updated change control log that has to reconcile with the approved documents and the as-built condition. The six weeks you saved in month nine costs you considerably more in month twenty-six.
Gateway 3: The Completion Certificate
The completion certificate application has to be accompanied by a notice stating the date the work was completed, the site plan, the plans needed to show compliance, the agreed construction control plan, change control plan, mandatory occurrence reporting plan, compliance statement and fire and emergency file, the updated change control log, and signed compliance declarations from the principal contractor and principal designer. Where those declarations cannot be obtained, the client has to explain why. The Regulator has eight weeks to determine a valid application, and the building cannot be occupied until the certificate is issued.
Everything in that list points at the same question: was it built as it was approved, and can you prove it?
For a smoke control system, the proof is the commissioning record. The design guidance in BS 7346-8, BS 9991 and BS 9999 sets out what commissioning should cover, and the standard the Regulator is applying is compliance with the Building Regulations as approved, so the commissioning record has to demonstrate performance against the design criteria rather than confirm that things move.
What that looks like in practice:
- Component tests. Every actuator, damper, fan, panel, detector head and interface individually proved, with model and location recorded.
- A fully witnessed cause and effect test. Every line of the matrix, not a sample of lines. The tested matrix, signed and dated, is the record.
- Measured performance against the design criteria. Extract volumes, pressure differentials with the door opening force and air velocity criteria for pressure differential systems, and confirmed geometric or aerodynamic free areas where the design relies on them. Numbers, not adjectives.
- Fire service interface tests. Firefighter control panel operation, override behaviour, and the indication a crew would actually see on arrival.
- Secondary power supply proving. Standby autonomy demonstrated in line with BS EN 12101-10 and the design duration.
- Defect close-out. The defects raised, the remedial work, and evidence that anything remedied was retested rather than signed off on assurance.
- As-installed drawings that match the building. Including any changes that went through change control, cross-referenced to the log.
A commissioning certificate that reads “system tested and found to operate satisfactorily”, with nothing behind it, is not evidence of compliance and never was. It was simply never tested this hard.
There’s a programme point buried in this. Smoke control is a late trade sitting behind power, fire alarm and finishes, so its commissioning window is the one that gets compressed when the job runs late. Under the old regime you could reach practical completion with commissioning partly outstanding and finish it in the defects period. You cannot occupy a higher-risk building before the completion certificate is issued, and the Regulator has eight weeks to consider the application. Compressed commissioning is now a delay to income.
The Golden Thread Handover
At Gateway 3 the information stops being a project file and becomes a statutory record. For a building in scope of Part 4, the client hands the golden thread to the Principal Accountable Person, who registers the building with the Regulator before occupation and then holds, maintains, updates and provides that information on request. Failing to pass it on when responsibility changes hands is a criminal offence.
The smoke control content of that handover is the design, product, installation, commissioning and change records already described, plus the things the building will need on day one: the operation and maintenance manuals, the system logbook opened and ready, the named person responsible for daily checks, and the inspection and test schedule the building will run to. We’ve set out the full documentation picture in The Golden Thread and Smoke Ventilation.
The requirement is for information that is accurate, accessible and kept up to date, in electronic form. A folder of 400 scans named sequentially satisfies none of those tests. Whoever inherits it will not find the damper certificate when the Regulator asks for it, and the value of the record is precisely its retrievability.
The operational half of the thread is easier to keep alive when the control equipment produces its own record. Panels that log events, tests and faults with a timestamp remove the reliance on someone writing in a book, and open protocol equipment that any registered smoke control contractor can maintain avoids the situation where the records live with one company. Vent Trade’s O Range panels log events for this purpose and are maintainable by any registered smoke control contractor.
What to Hand Over and What to Demand
The same list read from two sides.
| What the contractor produces | What the client or PAP should refuse to accept without |
|---|---|
| Smoke control design drawings and calculations | Version numbers that match what was granted at Gateway 2, or a change control entry explaining the difference |
| Declarations of Performance for every installed product | Model references that match what is physically on site, with the full classification string |
| Cause and effect matrix, tested | Every line witnessed and signed, dated, with the engineer named |
| Commissioning results | Measured values against the stated design criteria, not a pass or fail tick |
| Change control log | Every entry categorised, with the Regulator correspondence attached for notifiable and major changes |
| As-installed drawings and O&M manuals | A record that survives a site walk against it |
| System logbook and inspection schedule | Opened, with the daily check responsibility named and the annual inspection scope defined |
| The golden thread package | Structured, electronic, searchable and transferable |
Handover is the strongest position a housing provider will ever be in on this. Once the certificate is issued and the contractor is off site, the missing damper DoP is your problem, and reconstructing it years later is expensive when it’s possible at all. That is the same failure mode we described in What Grenfell Changed in Smoke Ventilation Specification: the evidence has to exist at the point it is created, because it cannot be manufactured afterwards.
Practical Takeaway
Finish the smoke control design before the Gateway 2 application, including the cause and effect matrix and named products with Declarations of Performance. Make sure the fire strategy, the architectural drawings, the M&E layouts and the smoke control calculations describe the same building. Write a change control plan the site team can follow, then use it, and categorise honestly rather than optimistically, because the change control log has to reconcile with the as-built at Gateway 3. Protect the commissioning window in the programme and commission against the design criteria with measured results, full matrix witnessing and evidenced defect close-out. Then hand the whole record over in a structured electronic form that the person receiving it can actually search.
None of this is new engineering. It’s the same smoke control design and the same commissioning that a competent team was doing anyway. What changed is that the evidence now has to exist, in order, at two fixed points, and nobody can move into the building until the second one is satisfied.
Further Reading
- The Golden Thread and Smoke Ventilation: What the Building Safety Act Means for You
- What Grenfell Changed in Smoke Ventilation Specification
- Commissioning Best Practices for Smoke Ventilation Systems
- How to Build a Smoke Control Asset Register from Scratch
- Smoke ventilation glossary
- Smoke Control Handover: The Documents to Demand Before Practical Completion
- Cause and Effect Matrices Explained
Sources
Official guidance and standards referenced in this article:
- Building Safety Act 2022, legislation.gov.uk
- The Building (Higher-Risk Buildings Procedures) (England) Regulations 2023, legislation.gov.uk
- Building control approval for higher-risk buildings, GOV.UK
- The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023, legislation.gov.uk
- Approved Document B (fire safety), GOV.UK
- Smoke Control Association
Supplying a Higher-Risk Building Project?
We stock BS EN 12101 certified smoke control panels and smoke ventilation equipment with the Declarations of Performance and test certificates your Gateway 2 submission and golden thread record need, held in the UK at Poole with next-working-day despatch on most lines. Our technical team can check a product schedule against your fire strategy before the application goes in.
Call 01202 725 689 or email info@vent-trade.co.uk.
