Imperial Fire Solutions Cover sheet
Technical submission · Q20293-IFS-DS-TS-001 · Rev 00

60 Queen Victoria St

Fire Resistant Ductwork to BS EN 1366-8 & 9. To supply and install fire resistant smoke extract ductwork for 120 min integrity & insulation.

60 Queen Victoria Street, City of London
60 Queen Victoria St
Phoenix MEclient
25 Aug 2026date of issue
P. Fachoriginator
IFS-DSsystem, BS EN 1366-8 & 9
From Imperial Ductwork Services LtdEquipment Fire Resistant DuctworkManufacturer Imperial Ductwork Services Ltd
Accredited & certified
Imperial Ductwork Services LtdLPCB LPS 1531ASFPWarringtonfire FIRASISO 9001ISO 14001ISO 45001RoSPA President's Award 2025Institution of Fire Engineers affiliateEfectis certifiedCEUKCA
Document transmittal
From
Imperial Ductwork Services Ltd
To
Phoenix ME
Equipment
Fire Resistant Ductwork
Ref
Q20293-IFS-DS-TS-001
Date
25 August 2026
Manufacturer
Imperial Ductwork Services Ltd

To supply and install Fire Resistant Smoke Extract Ductwork manufactured to BS EN 1366 Part 8 & Part 9 for 120 min Integrity & Insulation.

Specification ref
Not stated on the transmittal

Note: In the absence of technical submittals being returned within 15 days from issue indicating a formal approval status, IDSL will proceed to mitigate any further delay based on acceptance of this technical submittal.

Supporting documentation issued
(i)Equipment Specifying Schedule
(ii)Manufacturers Data
(iii)Design Check Calculations
(iv)Certified Performance Levels
(v)QA / QC Documents
(vi)Sample Enclosed
(vii)Builders Work Requirements
(viii)Assembly & Installation Details
(ix)O&M Instructions
(x)List of Recommended Spares
(xi)Deviation Schedule
(xii)Other
Approvals
PartySignDate
M&E Contractor
Main Contractor
Services Consultant

Use the approval response at the end to return your status.

02 · Product description

The IFS-DS system

Following a substantial investment programme, Imperial Ductwork Services Limited are delighted to propose the IFS-DS fire resistant ductwork system, for single compartment smoke control ducts, multi-compartment duct systems and ventilation ducts, including kitchen extract systems.

Single compartment ducts are tested to BS EN 1366-9:2008. They passed at pressure level 3 (−1500 Pa ambient, −500 Pa under fire), achieving a 2 hour classification (E600 120) without losing cross-sectional area or exceeding a leakage rate of 5 m³/h/m³.

Multi-compartment ducts give the same level of performance but are tested to BS EN 1366-8, achieving EI 120.

Tested with a range of components, the systems cover a direct field size range up to 1250 × 1000 mm or Ø1000 mm under BS EN 1366-1 and BS EN 1366-9, classified to BS EN 13501-4.

IDSL hold third party accreditation for installing fire-resistant ductwork and dampers under BRE LPS 1531, and Warrington Fire FIRAS for installing fire-resistant ductwork systems.

The system supplied and installed by IDSL with Imperial Fire Solutions will be classified to BS EN 13501-3 for ventilation ducts and BS EN 13501-4 for smoke control ducts. Where applicable, ducts will carry the relevant CE / UKCA mark.

IFS-DS fire resistant duct sections
1250×1000mm smoke control ducts
2500×1250mm ventilation ducts
Ø1000mm circular
Level 3−1500 Pa ambient, −500 Pa fire
CE markUKCA markEFR-2501-0452 · 1812-CPR-2293 · 2822-UKCA-CPR-0235
Formal test & performance criteria
Test standardDuct typeField (size)ClassificationClassification standard

Reading a classification: tap each part.

03 · Project scope

60 Queen Victoria St

Cundall mechanical services drawings, marked up by IFS to show the fire resistant smoke extract ductwork in scope.

04 · Test classifications

Test classifications

Two Efectis France classification reports (notified body 1812) to EN 13501-4:2016.

Classification · horizontal & vertical smoke exhaust ducts E I 120 (ve ho) S −1500/+500 Pa Multi Rectangular four-sided smoke exhaust ducts in galvanised steel insulated with ISOVER mineral wool. Inner section 0 × 0 up to 1250 × 1000 mm (w × h), vertical and horizontal.
Delivered
24 March 2025
Sponsor
Imperial Ductwork Services Ltd
Laboratory
Efectis France, Maizières-lès-Metz
Signed
C. Salsi / R. Stouvenot
Reference of the fire tests
Test numberLabDateStandard
EFR-22-003538Efectis FR06/10/2023EN 1366-1:2014
EFR-22-003497Efectis FR08/06/2023EN 1366-1:2014
EFR-22-003559Efectis FR10/01/2024EN 1366-1:2014
EFR-22-003554Efectis FR17/11/2023EN 1366-1:2014
EFR-22-003562Efectis FR04/04/2024EN 1366-8:2004
Horizontal duct: galvanised steel§6.2.1
  • Galvanised steel sheet, max. segment length 1340 mm, 1 mm thick. Leakage class C to EN 1507.
  • Slide-on flanges or continuous girth flanges (30 mm), Ø10 mm holes in the corners. Slide-on flanges fixed with HENROB R50743CH06 self-pierce rivets Ø5 × 7.5 mm at 150 mm centres; CGF fixed by stitching.
  • Joined with M10 × 30 mm screws and nuts in the corners and joint bolt clamps at max. 150 mm centres.
  • Flange face: TPIN153SWH (ARBOSEAL) intumescent tape 15 × 3 mm plus a bead of Product 58 acrylic mastic.
Horizontal duct: reinforcement§6.2.2
  • Segments ≥ 800 mm: external L stiffeners 50 × 40 × 1.6 mm at mid-length, Ø4.8 × 16 mm rivets at max. 150 mm.
  • Internal stiffeners: M10 rod in a Ø21 mm conduit sleeve through the full height, with 75 × 3 mm plate washers inside and out.
  • ≥ 800 mm: one stiffener at each extremity (330 mm from edge), two at mid-length, one at each quarter length and mid-width. ≤ 800 mm: one at each extremity and one at mid-length/mid-width.
Horizontal duct: supports & insulation§6.2.3–6.2.4
  • Unprotected hangers at max. 1100 mm: L 50 × 50 × 5 mm bearer under the duct, two M10 rods at Lduct + 50 mm.
  • Two layers of ULTIMATE U Protect Slab 4.0 Alu1 (ISOVER), 60 mm each at 65 kg/m³ (120 mm total), 175 mm joint offset.
  • Stud-welded pins Ø3 × 64 mm (1st layer) and Ø3 × 132 mm (2nd layer), Ø30 mm washers, max. 285 mm spacing. ISOVER Fire Screws 200 mm at corners, max. 285 mm. 90 mm aluminium tape on edges and joints.
Horizontal duct: wall penetration§6.2.1 (wall)
  • Opening (w + 100) × (h + 100) mm through a group A plasterboard wall to EN 1363-1:2020, EI 120: 130 mm thick, 2 × 15 mm type F boards each side, 70 mm mineral wool at 90 kg/m³, steel studs.
  • Gap max. 50 mm filled with ISOVER slab 65 kg/m³, 60 mm, covered with Protect BSF; first insulation layer glued to the wall with Protect BSK.
Vertical duct§6.3
  • Same 1 mm galvanised construction and flanges as horizontal. Exposure i→o: TPIN153SWH tape plus Product 58; exposure o→i: KERAFIX 2000 (CH Materials) tape 20 × 3 mm.
  • Segments ≥ 800 mm: external 50 × 40 × 1.6 mm stiffeners at mid-length; one internal M10 stiffener at mid-height/mid-width per segment and two per segment junction.
  • Insulation: one layer of ULTIMATE U Protect Slab 4.0 Alu1, 100 mm, 65 kg/m³, pins Ø3 × 114 mm at max. 260 mm (largest sides) and 190 mm (smallest sides). Cover strips 300 × 40 mm, or a 40 mm × 1500 mm sleeve each side of the slab, pinned with Ø3 × 155 mm at max. 285 mm.
  • Slab penetration: opening (w + 100) × (h + 100) mm through 150 mm aerated concrete at 550 kg/m³; 50 mm gap filled with 60 mm ISOVER slab and Protect BSF; glued with Protect BSK. Fixed both sides with 40 × 40 × 4 mm steel corners, rivets at max. 100 mm and Ø7.5 × 120 mm concrete screws at max. 100 mm.
  • Connection between two ducts made as the duct body; secondary duct fixed with Ø4.8 × 16 mm stainless rivets at max. 150 mm.
Direct field of application§8
  • Rectangular four-sided ducts. Horizontal results apply to vertical ducts with ho/ve classification to 13501-3, tested horizontally to EN 1366-8.
  • Pressure: result at −500 Pa in duct A applies from −500 to +500 Pa if integrity is met in the duct B test.
  • Sizes up to 1250 × 1000 mm (EN 1366-8:2024 §13.3).
  • Vertical ducts: any number of storeys if supports are ≤ 5 m apart and the 8:1 buckling ratio is met.
  • Supports in steel, stressed no higher than the table below. Expect about 40 mm elongation for unprotected 1.5 m hangers. Flexible and rigid supporting constructions covered.
Max. stress (N/mm²)t ≤ 6060–120120–240 min
Tensile, vertical components963
Shear, screws class 4.6 (EN ISO 898-1)15105
Appendix drawings
05 · Certificate of Constancy of Performance

1812-CPR-2293

Efectis France · notified body 1812

Revision 25-0 · Regulation (EU) 305/2011 (CPR)

Efectis certified
Product
Smoke and heat control systems: smoke duct sections
Reference
IFS-DS
Placed on market by
Imperial Ductwork Services LtdSargasso, Five Arches Business Estate, Maidstone Road, Sidcup, Kent DA14 5AE
Manufacturing plant
Dartford & Erith, UK
Standard
EN 12101-7:2011, Annex ZA, System 1
First issued
8 July 2025Saint-Aubin · Y. Le Tallec, Certification director

Efectis performed initial type-testing, initial factory and FPC inspection, and carries out continuous surveillance. The certificate allows CE marking while test methods, FPC requirements, product and manufacturing conditions are unchanged.

Annex: field covered
Duct sections forMulti-compartments
Shape / orientationRectangular · horizontal or vertical
Maximum size1250 (w) × 1000 (h) mm
Material1 mm galvanised steel
Transverse joint30 mm flanges; TPIN153SWH 15 × 3 mm or KERAFIX 2000 20 × 3 mm tape; Product 58 mastic
StiffenersExternal 50 × 40 × 1.6 mm · internal M10 rods in Ø21 mm conduit
InsulationULTIMATE U Protect Slab 4.0 Alu1, 65 kg/m³
Penetration sealingISOVER 65 kg/m³, 60 mm, Protect BSF paint
Horizontal supportsL 50 × 50 × 5 mm, two M10 at Wduct + 50 mm, max. 1100 mm
ClassificationE I 120 (Ve Ho) S −1500/+500 Pa Multi
Field of applicationPer report EFR-24-004007 Revision 1
06 · Declaration of Performance

DoP No. IFS-DS-002

Product-type
IFS-DS Rectangular Multi-Compartment Smoke Control Ductwork
Intended use
Fire resisting multi-compartment smoke control ductwork tested to BS EN 1366-8, incorporating grilles, access panels, attenuators and VCDs
Manufacturer
Imperial Ductwork Services LtdSargasso, Five Arches Business Estate, Maidstone Road, Sidcup, Kent DA14 5AE
System of AVCP
System 1
Harmonised standard
BS EN 12101-7:2011
Notified body
Efectis France, no. 1812Certificate 1812-CPR-2293
Signed
R W Chapman4 Copthall Avenue, London EC2R 7DA · 24 July 2025
Reference
DOP.002.12-25.V2.0
Declared performance
Essential characteristicsPerformanceSpecification
Integrity
Insulation
Smoke leakage
EI120 (Ve-Ho) S 1500 MultiBS EN 12101-7:2011
BS EN 13501-4:2016

Issued under Regulation (EU) No 305/2011 under the sole responsibility of the manufacturer.

07 · Accreditations

Accreditations

LPCB

LPCB LPS 1531 installer approval

Scope: Appendix 5 fire rated ductwork systems; Appendix 6 fire resisting dampers.

Certificate
1654PI, issue 02
Standard
LPS 1531: Issue 1.2
Issued
27 Feb 2024 (first 14 May 2021)
By
BRE Global Ltd
Held in force by regular surveillance
FIRAS

FIRAS certification scheme

Application of passive fire resisting products using ducting, from 07/11/2023.

Certificate
GI8248, issue 1
Issued
07/11/2023
Valid to
07/11/2028
By
Warringtonfire
ASFP

ASFP contractor member

Association for Specialist Fire Protection.

Membership
3371/C
Expiry
05/09/2025
Signed
Mike Ward, MD
Institution of Fire Engineers

Institution of Fire Engineers

Affiliate organisation.

08 · QA procedures

Quality assurance

ISO 9001

ISO 9001:2015 certificate of registration

Provision of installation, and contracting of ductwork ventilation systems, and fire solutions within the UK.

Certificate
253359
Initial / latest
29 May 2024
Expiry
28 May 2027
By
British Assessment Bureau (UKAS 8289)

Quality Procedure 15: Fire Rated Installation

Q-15000 Rev 7 · 08/2025

Objective & scope15.0–15.1

15.0 To ensure all projects under the control of IDSL follow the quality procedures and control required to maintain traceability through the installation period of all fire-resistant ductwork and dampers.

15.1 Applies to all contracts and site staff, without exception, for fire rated installations and standard DW144 / DW145 installations.

Definitions15.2–15.6

15.2 Estimating: refer to procedure 1.

15.3 Fire resistant ductwork performs smoke control and ventilation (e.g. kitchen extract); its primary function is fire compartmentation, meeting load-bearing, integrity and insulation criteria evaluated to BS EN 1366.

15.4 FDs, FSDs & SCDs maintain compartmentation and prevent the spread of fire and smoke; SCDs also help extract smoke from the room of incident.

15.5 VCDs control airflow and must match the fire resistance of the system they are installed in, evaluated to EN standards.

15.6 Manufacture: to DW144 (procedure 5); fire rated items per the specialist manufacturer, including DW172 kitchens and DW145 dampers. IDSL fire resisting ductwork is made at Imperial Ductwork Manufacturing.

Handover & technical submittals15.7

Project Handover Meeting before works start (Contracts Engineer, Manager, Director, Estimating Manager, CAD, QS and IFS), with a Contract Handover Document. IDSL must ensure any contractual agreements to the design are noted and corrected against the main contract document. Technical submittals are updated as the design changes.

Estimating issues drawings highlighted to the IDSL colour coding. The QS files the handover document with the Quality Control Manager on the "1.0 Fire Rated Schedule". All IDSL insulation is Isover, ordered via IDSL.

The Contracts Engineer prepares the submittal with data sheets, specification references, integrity and insulation durations, scope, drawings and the test standard basis. BS EN 1366 Parts 1, 8 or 9 are the primary standards; BS 476 Part 24 assessments should not be used. Submittals are reviewed by IFS, issued to the client and design team, and uploaded to Procore and the IDSL server.

Drawings, fixings & materials15.7

CAD reads the fire rated specification and Fire Strategy before drawing; issues outside IDSL control are raised with the client. FDs, MFSDs, FSDs and SCDs are labelled individually with a specification table; drawings carry an LPS number.

A project-specific pull test is arranged to select fixings and supports. Bespoke items such as fans, attenuators and risers are discussed with IFS.

Batch numbers and manufacture dates of all products are recorded with the QA Manager. The first tube of each box of curing product is checked; part-cured product is not used. An insulation sample is checked on each project for 65 kg/m³. Signed delivery sheets are returned to the QA Manager.

Labour, inspection & insulation15.7

All labour installing fire rated ductwork, FDs, FSDs and SCDs must be trained, with evidence issued to the Quality Control Manager on every project; all managers are inducted on IDSL fire resisting products (Fire Rated Installation Induction and Certificate).

Site inspections by the specialist manufacturer and internal team take place before and after insulation. Isover is fixed with welded pins, so RAMS include hot works. Insulation is 2 × 60 mm (120 mm), overlapped between sections.

ApplicationInsulationRating
EN 1366 Part 1 Supply120 mm120 min
EN 1366 Part 1 Extract120 mm120 min
EN 1366 Part 1 Kitchen Extract120 mm60 min
EN 1366 Part 8 Smoke Extract120 mm120 min
EN 1366 Part 1 Smoke Make Up Supply60 mm120 min
EN 1366 Part 9 Smoke ExtractUninsulated, only in the final compartment

The specification must always be checked. Penetration openings are insulated with Isover and fire batted before IDSL fit penetration seals both sides.

Leakage testing15.7

All fire-resistant systems are 100% leakage tested during installation (where of sufficient volume) to meet BS EN 12101-7:2011 Annex B Table B.1, as acknowledged in the IFS/Efectis email of 03/08/23, using Document 3001 Air Leakage Test Sheet with Form 5.

Testing follows BESA DW 145. Each file holds the witnessed test sheet, drawings and the test machine calibration certificate, flow rates to ISO 8501:2007 at 1.2 kg/m³.

09 · Construction & installation details

Ductwork & access doors

Manufacturing notes
  • All dimensions in millimetres; 1.0 mm GSS sheet throughout; all fixings steel.
  • All stiffening corners fixed with a mechanical fixing; HENROB fixings at 100 mm maximum spacing.
  • All internal splitters welded in place; only Product 58 acrylic mastic for sealing.
  • CGF flanges with G clamps at max. 150 mm centres, gasket and auto stitching.
  • Stiffening: up to 670 mm length none; 671–1340 mm S4 four-sided stiffener. Ducts over 1000 mm high: see IFS-TS/DS-M/SE-8/200 series.
Tie-rod locations (DIAP, SE-8/100)
Duct widthAcross width A / B / CLength < 670 A / B / CLength 671–1340 A / B / C
0–400KOFs required, refer to IFS-TS/DS-M/SE-8/101
401–500½W / – / –1st flange / – / –1st flange & ½L / – / –
501–700½W / – / –1st flange / ½W / –1st flange & ½L / 1@¼L & 1@¾L / –
701–1250⅔W / ½W / ⅓W1st flange / ½W / 2nd flange1st flange & ½L / 1@¼L & 1@¾L / ½L & 2nd flange
Access door sizes (insulated, IFS-TS_DS-T-012)
150 × 300 × 150200 × 200 × 150200 × 300 × 150300 × 300 × 150300 × 400 × 150400 × 400 × 150450 × 300 × 150450 × 450 × 150

IFS access panel with housing. The uninsulated version (T-013) uses an Ace Filtration access panel.

Sealants & intumescent products
Envirograf · AP058-01-2022

Product 58 AM intumescent mastic

Intumescent acrylic high pressure mastic: a permanent flexible joint against fire, smoke and toxic fumes. Over-paintable; fits a standard skeleton gun.

Max. joint
40 mm
Touch dry
approx. 15 minutes
Clean tools
warm water
Health
Non hazardous; goggles and protective clothing; keep out of drains
Arbo · Fixmart data sheet V01

Arboseal intumescent tape

Preformed intumescent strip on synthetic rubbers; expands and chars under flame to block fire and smoke.

Size
15 × 3 mm × 12 m reel
Application
+5 to +50 °C
Service
−25 to +50 °C · 20 years+
Compliance
BS 476-22:1987, Warrington C118002, TRADA IT349
Storage
12 months unopened, cool and dry
Rolf Kuhn GmbH · SDS rev. 1.1, 25.03.2019

Kerafix 2000

Acrylic-latex bound AES-wool (alkaline-earth silicate fibre) paper for heat insulation, seals and expansion joints and fire protection systems.

Hazard
Not classified (EC 1272/2008); no warning label
Melting point
> 1200 °C; does not burn
PPE
Goggles EN 166, nitrile gloves EN 374, P2 mask if dust
Handling
Avoid dust; no compressed air or sweeping
Storage
Cool, dry, frost-free; away from acids
Product 58: metres of gap sealed per tube
10 · Fixings & supports

Fixings & supports

IFS-DS fire resistance duct support guide (IFS-DS-01-TS-05 Ver 2.0) and riser bracketry.

11 · Fire stopping details

Fire stopping details

+100mmopening: duct width + 100 × depth + 100
50mmgap packed with 60 mm Isover and 2 mm Protect BSF
200mmmin. between openings (300 mm between ducts)
75mmmin. to an adjacent wall or slab
12 · Fire insulation

Isover U Protect

Tested to EN 1366-1 and EN 1366-8 and assessed to BS 476 Part 24: up to 2 hours for HVAC ventilation and smoke extract ducts, and up to 1 hour for kitchen ducts.

Saint-Gobain Isover · 001-473, 02 Aug 2024

U Protect Slab 4.0 Alu1

High performance ULTIMATE mineral wool slab for fire protection of rectangular ductwork, faced one side with black aluminium foil.

Reaction to fire
Euroclass A1 (EN 13501-1)
Max. service temp.
400 °C
Certification
UKCA / CE to EN 14303 · MW-EN-14303-T4-ST(+)400-MV2
Quality
ISO 9001 · ISO 14001 · EUCEB
External use
Not suitable
Product codeThicknessSizeSlabs/packm²/packkg/m²
Mean temp °C1050100150200300400
λ (W/m·K)0.0310.0350.0400.0470.0540.0720.096

IFS-DS uses 60 mm slabs in two layers (120 mm), highlighted.

U Protect components
Isover · APR-2024

Protect Black Tape

Reaction to fire
A2-s1,d0 (EN 13501)
Material
Black aluminium tape, inorganic glue
Tensile / adhesion
13 N/cm / 10 N/cm to steel
Operating
−40 to +130 °C
Processing
+5 to +30 °C, dry dust-free surface, use a spatula
Pack
90 mm × 100 m, 12 rolls
Isover · DEC-2022

Protect BSF paint

Fire
B2 (DIN 4102-4); forms a micro-porous insulating layer
Material
Solvent free, pH neutral, VOC free water-based dispersion; not CLP classified
Use
Stir; dilute up to 10%; brush, roller or spatula
Drying
Touch dry 4 h; fully dry 24–48 h
Processing
+5 to +30 °C
Pack / storage
15 kg bucket, 400 g cartridges ×12 · 18 months frost-free
Isover · DEC-2022

Protect BSK glue

Reaction to fire
Non combustible, A1
Material
Inorganic sodium silicate glue, VOC free
Use
Stir; dilute up to 10%; brush, roller or spatula
Hardened
~12 h at 20 °C, 50% RH
Processing
+8 to +30 °C
Pack / storage
8 kg bucket, 310 ml cartridges ×20 · 12 months at +15 to +25 °C
Rockwool · DBI Certification 2531

FIREPRO Ablative Coated Batt

Penetration seal, required as the first 60 mm layer in i8 (kitchen) systems.

CoCP
2531-CPR-CXO10265
Basis
ETA-22/0157 (EAD 350454-00-1104), System 1
Plant
CPA50052, Pencoed, Bridgend
Issued
21 Apr 2022 (first 10 Dec 2021)
13 · Volume control dampers

Volume control dampers

Advanced Air (UK) Ltd · ES-167 issue B

1500 Series volume control / smoke damper

A balancing damper for fire or smoke rated ductwork. Fully welded frame with enclosed linkage and bearings, so it can be covered by fire rated spray, boards or panels without affecting operation, or left unprotected. Integrity and stability for up to two hours when fully closed with no power to the actuator; the frame withstands a four hour exposure. Also a tested component in Efectis report EFR-25-002463.

Blades
1.6 mm galvanised mild steel (430 stainless optional), parallel or opposed
Frame
1.6 mm, 200 mm deep (180/195 optional), 30 mm flange (25/35 optional), button-locked corners
Size
100 × 100 mm min. to 1200 × 1800 mm max. single section; larger as multiple sections
Bearings
12.7 mm sintered bronze to 200 °C; stainless to 400 °C or 600 °C optional
Linkage
Fully enclosed, 90° operation, zinc electroplated
Seals
Semi or fully sealed; PVC to 80 °C or silicone to 175 °C optional
Operation
Hand locking quadrant, 230 V / 24 V actuator, pneumatic; RH drive standard
Installation drawing
14 · Attenuators

Attenuators

Allaway Acoustics · data sheet A10H

Rectangular attenuator, loose splitter elements

Allaway fire-rated pods fitted into an attenuator casing manufactured to the IFS-DS specification. Read with the project attenuator technical submittal.

Models
SP: central splitters and side linings · SL: side linings only
Lengths
Nominal 600–3000 mm in 300 mm steps (actual 570–2940 mm)
Size
Width above 199 mm, height above 99 mm; made to order
Infill
Sound absorbent, encapsulated in glass cloth and perforated steel, aerodynamic fairings
Suffixes
G galvanised · S 316 stainless · H1 high temperature (2 hour / 300 °C) · K paint · J horizontal · M Melinex · F fitted at works · Z modular
Fitting
Elements 5 mm under height; fitted tight with equal airways. Casing: 4.9 × 16 mm pop rivets at max. 150 mm, stiffener if required
Performance
Tested to ISO 7235; tolerance < 1.0%
Installation drawing
15 · Maintenance recommendations

Maintenance

Fire resistant ductwork is a passive fire-resistant system. The ASFP and BS 9999:2017 recommend scheduled periodic inspection, and article 17 of the Regulatory Reform (Fire Safety) Order 2005 requires it to be kept in efficient working order and good repair. The inspection period may vary by project and specification.

Annual visual inspection

Without a contract-specific regime, carried out by others to the specified regime or the fire safety manual:

  1. Have post-handover services been supported from the suspension system designed solely for the fire-resistant ductwork?
  2. Does the external fire insulation show any signs of damage?
  3. Dust or debris must be prevented from accumulating on the insulation or duct surface.
  4. Are all access panels installed correctly and still accessible?
  5. Kitchen extract systems need a dedicated cleaning regime to BESA TR19 and DW 172.
BS EN 12101-7:2011, Annex A, Table A.1

Annual, or more often if the specification demands. The whole smoke control system should be checked under its O&M requirements; inspection provision sits in the contract documentation.

Approval response

Return your status

Choose a status, add comments, then copy the response into an email to IDSL. Please respond within 15 days of issue (by 9 September 2026).

Imperial Fire SolutionsImperial Fire Solutions is a division of Imperial Ductwork Services Ltd.
Registered office: Numeric House, 98 Station Road, Sidcup, Kent, DA15 7BY. Registered in England No. 03402613.
Q-15008 Rev 7 | 06/2025 · Originator: Ben Stocker & Mark Crafter