July 18, 2026 Shopify API

Passive Fire Protection for Plumbers and Electricians — Intumescent Pipe Collars, Fire Sleeves, and Sealing Penetrations Under Part B

Why Passive Fire Protection Matters for Trades

Every time a plumber runs a waste pipe through a partition wall or an electrician feeds a cable bundle through a floor joist, they create a potential breach in a fire compartment. Under Building Regulations Part B and the associated Approved Document B (ADB), these penetrations must be sealed to maintain the fire resistance of the structural element — otherwise a two-hour fire-rated wall becomes worthless the moment a 40mm waste pipe passes through it.

For most residential projects, Building Control sign-off includes checking that penetration seals are in place. On commercial and multi-occupancy work, passive fire protection (PFP) is a non-negotiable element of the fire strategy. This guide explains what products are available, which situations require them, and how to install them correctly.

The Regulatory Framework

Approved Document B (England and Wales)

Approved Document B sets out the functional requirements of Building Regulation B3 — the internal spread of fire. Section 7 (Concealed Spaces) and Section 8 (Openings and Fire-Stopping) deal directly with penetrations through fire-resisting elements. Key requirements:

Any opening made in a fire-resisting wall, floor, or ceiling must be fire-stopped to the same fire resistance rating as the element itself.
Thermoplastic pipes (most plastic waste, soil, and overflow pipes) penetrating fire-resisting elements must be protected with intumescent pipe collars or sleeves — plastic burns away in a fire, leaving an open hole if not protected.
Steel and copper pipes do not require intumescent protection in the same way (they don't burn), but any gap around them must still be filled with a fire-rated sealant or intumescent mortar.
Cables and cable bundles passing through walls and floors must be sealed with intumescent cable transit systems or fire-rated foam.

Scotland and Northern Ireland

Scotland follows Technical Handbooks (Section 2) and Northern Ireland Regulations Part E — the functional requirements are equivalent, though product certification routes differ. LABC-assessed and NHBC-assessed products are generally accepted across all jurisdictions.

BS 9999 and BS EN 1366

For commercial premises, BS 9999:2017 (Code of Practice for Fire Safety in the Design, Management and Use of Buildings) references passive fire protection in detail. Penetration seals are tested to BS EN 1366-3, which specifies test methodology for fire-stopping systems. Products should carry a third-party certification — CERTIFIRE or LABC Registered Detail are the most common marks you'll see on packaging.

Product Types and When to Use Each

1. Intumescent Pipe Collars

The most common PFP product for plumbers. An intumescent pipe collar is a plastic or steel housing containing an intumescent graphite compound. When exposed to fire, the compound expands dramatically — typically 20:1 — crushing the thermoplastic pipe as it softens, sealing the opening within minutes.

When to use: All thermoplastic pipes (uPVC, PP, ABS, HDPE) passing through fire-resisting walls and floors. This includes:

40mm and 32mm waste pipes through bathroom walls
50mm and 110mm soil and vent pipes through floors between flats or between ground floor and first floor in houses with a habitable loft conversion
Overflow pipes from cisterns where they penetrate a fire-resisting element
MDPE blue water pipe where it enters a building through a fire-resisting wall (note: MDPE does need a collar where the penetration element is fire-rated)

Sizes: Collars are sold by pipe OD. Common sizes: 32mm, 40mm, 50mm, 55mm, 75mm, 82mm, 110mm. Always check the collar datasheet for the pipe OD range — nominal sizes vary by manufacturer.

Installation:

Make the penetration hole the minimum size needed for the pipe.
Slide the collar over the pipe before final connection where possible, or use a split-design collar (most modern designs are split for retrofit fitting).
Position flush with the face of the wall or floor — on floors, fit one collar on each face if the floor thickness is under 150mm and the collar's tested depth doesn't cover the full thickness alone. Check the product's specific installation datasheet (PID).
Fix with the screws or anchor bolts supplied — do not use alternatives unless the PID specifies otherwise.
Fill any residual gap around the collar with the specified intumescent mastic or fire-rated mortar.

2. Intumescent Fire Sleeves (Wrap)

Fire sleeves — also called intumescent wraps — are flexible strips of intumescent material that are wrapped around a pipe and fixed in place within the penetration. They're especially useful where collars won't fit (very close to a wall face, congested areas) or where a collar would obstruct pipework access.

They work on the same principle: the wrap expands in fire, constricting the softening pipe. They need to be installed to the specific depth stated in the product datasheet — typically 150–200mm minimum depth within the wall or floor construction.

Common applications: Retrofit sealing of existing penetrations (without dismantling pipework), tight spaces where collar flanges can't be accommodated, or penetrations through hollow-core concrete floor slabs.

3. Cable Transit Systems

For electricians, the primary PFP challenge is cable bundles. A conduit full of cables passing through a fire-rated floor acts as a chimney. Solutions include:

Intumescent cable transit frames: Modular blocks (sometimes called "cable transit blocks" or "MCTs") that sit in a pre-cut opening in the wall or floor. Individual cable bays are filled with intumescent blocks sized to the cable or left filled with solid filler blocks for unused positions. When fire heats the blocks, they expand and crush or seal around the cables.

Fire-rated foam (intumescent foam): Aerosol or gun-applied expanding foam with intumescent properties — suitable for loose cables in conduit or through masonry. Not suitable for all situations; check the product certification for your specific substrate and element type. Never substitute standard polyurethane expanding foam (e.g. Pu foam) — it is not fire-rated and will make the penetration worse.

Fire-rated cable conduit systems: Where cables run in steel conduit, the conduit itself provides some protection, but the end of the conduit where it terminates in a box or trunking still needs fire-stopping around it. Use intumescent putty pads (fibre pads with intumescent gel) around conduit entry points where the back-box or trunking is recessed into a fire-resisting wall.

See our guide to cable trunking and conduit for first-fix routing decisions that minimise penetrations.

4. Fire-Rated Intumescent Mastic and Sealants

Even where a collar or sleeve is fitted, residual gaps around the collar flange or between the pipe and opening must be filled. Use a CERTIFIRE-certified intumescent mastic — typically a gun-applied sealant in cartridge form. Standard acrylic or silicone sealants are not fire-rated and must not be used for this purpose.

For metal pipes (copper, steel), where no intumescent collar is needed, the gap between pipe and penetration still requires filling with intumescent mortar or mastic rated to the required period. A 5mm annular gap around a 15mm copper pipe through a 30-minute wall still needs proper PFP treatment.

5. Fire-Rated Access Panels

Where pipework or cabling requires future access through a fire-resisting element (e.g. the isolation valve for a concealed cistern supply), the access panel itself must maintain the fire rating of the wall. Standard decorative access panels are not fire-rated — use panels specifically tested and certified to the relevant resistance period (typically EI30 or EI60). The certification will state which wall constructions the panel has been tested within.

Fire Resistance Periods: What You Need Where

The required fire resistance period depends on the building use and the element being penetrated:

Building Type / Element	Minimum Period
Houses — floor between storeys	REI 30
Houses — floor to habitable loft conversion (escape route)	REI 30
Flats — separating floors and walls between flats	REI 60
Flats — floors within a flat (internal)	REI 30
Commercial — staircase enclosures (up to 18m)	EI 30 (structure REI 60)
Commercial — compartment walls/floors (office, retail)	REI 60 minimum
Healthcare, care homes, high-rise (>18m)	REI 60–120 (fire strategy dependent)

Notation: R = structural adequacy, E = integrity, I = insulation. Most PFP product datasheets quote the EI value for the penetration seal. Always match the collar's tested performance to the element's required period.

Installation Best Practice

Before You Start

Identify the element type. Is it a stud-and-plasterboard partition (one layer each side? Two layers?), a block wall, a concrete floor slab, or a timber joist floor with plasterboard ceiling? Each construction type has different tested combinations — check the product Installation Data Sheet (IDS) before purchasing.
Establish the required fire resistance period from the drawings or Building Control specification.
Minimise penetrations. Route services to share penetrations where possible (a group of small pipes in one opening can sometimes be sealed with a single large collar or a proprietary multi-pipe transit).

Common Mistakes

Using the wrong collar size. If the collar's tested pipe OD range doesn't match your pipe's actual OD (not nominal bore), it won't perform correctly. A 110mm nominal pipe may have OD 110mm or 114.3mm depending on standard — check.
Fitting collars after plastering. The collar must sit flush against the wall or floor face — fitting after the final finish coat means the collar is proud by the plaster thickness. Plan the collar position before plasterboarding or finishing.
Using PU foam as fire-stopping. Standard polyurethane expanding foam is combustible and must never be used as a fire-stop. Always use products marked fire-rated or intumescent.
Neglecting the anchorage. Many collar failures in fire tests are fixings failures. Use the screws and anchors specified in the IDS, into the substrate the product was tested in. A collar fixed into plasterboard with a single plasterboard screw will not perform to its rated period.
Omitting the mastic fill. Even a correctly fitted collar leaves a small annular gap. Fill it with the specified intumescent mastic; this is part of the tested assembly.

Record-Keeping

On commercial and multi-residential projects, maintain a passive fire protection schedule: for each penetration, record the element type, resistance period required, product used (name, manufacturer, certification number), pipe/cable size, date of installation, and installer name. This is increasingly required under the Building Safety Act 2022, particularly for higher-risk buildings (over 18m or 7 storeys). Even on smaller projects, a photo log of PFP installations is good practice and may be required by your contractor or main contractor's quality plan.

Which Products Are CERTIFIRE Certified?

CERTIFIRE is the UK's leading third-party certification scheme for fire protection products, operated by Warringtonfire. A CERTIFIRE mark (CF number) on a product means it has been independently tested and the manufacturer's production quality is audited. When Building Control or a fire engineer specifies "CERTIFIRE-certified intumescent collar", the CF number lets them verify the product meets the stated performance.

Leading manufacturers with CERTIFIRE-certified ranges include Pyroplex, Specified Air Solutions (SAS), Envirograf, Nullifire, and Rockwool (for mineral wool backing products used in combination with collars).

LABC Registered Details are an alternative route — products are registered with Local Authority Building Control and listed in the LABC product library. These are commonly accepted across England and Wales.

PFP and the Building Safety Act 2022

The Building Safety Act 2022 (in response to Grenfell) introduced significantly enhanced requirements for Higher Risk Buildings (HRBs) — residential buildings over 18m (approximately 7 storeys). For HRBs:

A Principal Designer and Principal Contractor must be appointed, responsible for ensuring building safety compliance during design and construction.
A Building Safety Manager is required once the building is occupied.
A Golden Thread of Information — digital records of all fire safety-relevant items including passive fire protection installations — must be maintained throughout the building's life.

For tradespeople working on HRBs, this means any PFP installation must be documented, photographed, and passed to the Principal Contractor for inclusion in the Golden Thread. Simply fitting the collar and moving on is not sufficient — the record must exist.

Even outside HRBs, the 2022 Act widened the "responsible person" definition under the Fire Safety Order (FSO) 2005. Landlords and managing agents now have explicit accountability for passive fire protection in communal areas of multi-occupancy buildings.

Practical Checklist for Trades

Before signing off any penetration through a fire-resisting element:

Is the element fire-resisting (check drawings / spec)?
What fire resistance period is required?
Is the pipe thermoplastic? If yes, fit an intumescent collar. If metal, seal the gap with fire-rated mastic/mortar.
Is the collar the correct size for the pipe OD (not nominal bore)?
Is the collar suitable for this substrate and element construction (check IDS)?
Is the collar flush with the wall/floor face and correctly fixed per IDS?
Is the annular gap filled with specified intumescent mastic?
For cables: is the transit system correctly installed and all unused positions filled?
Photograph the installed PFP before it is concealed.
Record product name, CF/LABC number, pipe size, date, and installer on the PFP schedule.

Shop Fire, Heat & Smoke Alarms at APM Electricals — Trade Counter, Acton W3

APM Electricals stocks a full range of passive fire protection materials and fire safety products for trade professionals. Same-day collection from our Acton trade counter.

Browse our full Fire, Heat & Smoke Alarms range at apmi.uk. Visit us at 24 Western Avenue, Acton, London W3 7TZ or call 020 8702 8080.

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