T E C H N I C A L S T U DY G U I D E · F I R E S A F E T Y E N G I N E E R I N G

BS EN 1366-4:

2006+A1:2010

Fire Resistance Tests for Linear Joint Seals — Complete

Reference with Interactive E & I Calculator

C O M M I TT E E

I C S C O D E

P U B L I S H E D

FSH/22

13.220.50

July 2006 · Amended 2010

S TAT U S

S U P E R S E D E D BY

BS EN 1366-4:2021

Withdrawn Aug 2021

01

Overview & Background

BS EN 1366-4:2006+A1:2010 defines test methods to evaluate the

fire resistance of linear joint seals — the materials and systems used

to fill deliberate or construction-induced gaps at the junctions of

building elements.

What Are Linear Joint Seals?

Linear joint seals are continuous seal systems installed in construction

joints — the deliberate gaps left between adjacent building elements such

as floor slabs, walls, ceiling panels, and their junctions. These joints exist

for several unavoidable reasons: thermal movement causes structural

elements to expand and contract with temperature; seismic activity

requires building sections to move independently; construction

tolerances inevitably leave gaps; and differential settlement causes

structural members to shift relative to one another.

Without a correctly specified and installed fire-rated joint seal, these gaps

create direct pathways for fire, hot gases, and smoke to bypass carefully

constructed fire compartments — negating the fundamental principle of

compartmentation that underpins modern fire engineering design.

Position Within the EN 1366 Series

BS EN 1366 is the European suite of standards covering fire resistance

tests for service installations — i.e., building elements that are not

primary structural or separating elements but that penetrate, connect to,

or run along separating elements. Part 4 deals specifically with linear joint

seals. Other parts in the series cover penetration seals (Part 3), dampers

(Parts 2 and 7), and cable management systems.

The standard is used alongside EN 1363-1 (general principles of fire

resistance testing) which provides the underlying furnace conditions,

measurement methods, and general procedural framework that Part 4

builds upon.

Why the 2010 Amendment?

Amendment A1:2010 was issued to correct technical inconsistencies in

the original 2006 publication, principally relating to the application rules

for classification (Clause 13) and certain aspects of the test procedure

description. The amendment also clarified the relationship between

mechanically induced movement tests in Annex A and Annex B, which had

caused confusion in practice regarding which annex applied to which

product scenario.

⚠ CURRENT STATUS NOTICE

BS EN 1366-4:2006+A1:2010 was formally withdrawn in August

2021 and replaced by BS EN 1366-4:2021. Any new testing or

certification programmes should reference the 2021 edition. Existing

third-party certificates and CE/UKCA marks issued under the 2006+A1

edition require review; many certification bodies have issued transition

guidance. However, the 2006+A1 edition remains the most widely

referenced in existing product documentation and is fully studied here

as the foundational technical reference.

02

Scope & Purpose

✓ INCLUDED IN SCOPE

✗ EXCLUDED FROM

SCOPE

✓ Linear joint seals in floors,

✗ Perimeter seals of curtain

walling systems (EN 1364-3/4

applies)

walls and ceilings

✓ Tests without mechanically

induced movement (Annex A)

✗ Load-bearing capacity of joint

✓ Tests with mechanically

induced movement prior to

or during fire test (Annex B)

seals — not assessed

✗ Quantitative smoke and hot

gas leakage rate

✓ All joint orientations: A

(floor), B (floor/wall junction),

C (wall), D (wall/ceiling

junction), E (ceiling)

measurement

✗ Fume generation or toxicity

assessment

✗ Reaction-to-fire properties

✓ Mineral wool, intumescent,

sealant, mortar, and

(separate classification)

compressible strip systems

✗ Structural integrity of the

supporting wall or floor

construction

✓ Both movement joints and

static (non-movement)

construction joints

✗ Perimeter fire barriers at

floor/façade junctions

(separate test methods

apply)

✓ Multiple joint seals in a single

test construction

Key Objectives

The primary objective of the standard is to provide a repeatable,

reproducible laboratory test that generates performance data which

can be used to classify joint seal products and systems. The classification

data then informs regulatory compliance under national building codes (in

the UK, principally Approved Document B), supports CE and UKCA product

marking under the Construction Products Regulation, and underpins third-

party certification schemes.

A secondary objective is to establish field of direct application rules —

the set of product configurations and installation conditions to which a

test result may be directly applied without further testing. This is critical

for commercial practicality: it would be economically impossible to test

every possible combination of joint width, substrate, orientation and

depth, so the standard defines logic-based extrapolation rules.

03

Standard Structure

The standard comprises 13 normative clauses and 3 annexes (two

normative, one informative), following the common EN format

established by EN 1363-1.

CL. 1

Scope

Defines application boundary, what is and is not included, and sets context

within the EN 1366 family.

CL. 2

Normative References

EN 1363-1, EN 1363-2, EN ISO 13943 (fire safety vocabulary). All referenced

standards are integral to applying EN 1366-4.

CL. 3

Terms & Definitions

Defines "linear joint seal", "joint width", "movement capability",

"mechanically induced movement" and other key terms.

CL. 4

Test Equipment

Furnace specification, restraint frame design, loading devices for movement,

measurement equipment requirements.

CL. 5

Test Conditions

ISO 834 time-temperature curve, pressure regime (20±5 Pa above ambient),

tolerances, calibration requirements.

CL. 6

Test Specimens

Construction requirements, specimen dimensions, 10:1 length-to-width ratio

rule, substrate requirements and options.

CL. 7

Installation

How the joint seal is installed in the specimen — fixing method, substrate

preparation, joint gap dimensions, curing.

CL. 8

Conditioning

Pre-test environmental conditions: minimum 12 hours at 23±5°C and 50±5%

relative humidity per EN 1363-1.

CL. 9

Instrumentation

Thermocouple placement rules on unexposed surface, roving thermocouple

requirements, data logging specifications.

CL. 10

Test Procedure

Sequence of fire exposure, movement schedule, cotton pad integrity checks,

observation and recording requirements.

CL. 11

Performance Criteria

E (Integrity) and I (Insulation) criteria definitions, failure conditions, and rules

for multiple seals in one test.

CL. 12

Test Report

Mandatory content: specimen description, seal identification, substrate

details, test results, raw data graphs, photos.

CL. 13

Field of Application

Direct application rules by orientation, substrate type, joint width, and

movement capability. Key commercial clause.

ANNEXES

Annex A (Normative): Test conditions without mechanically induced

movement — the static joint scenario. Most common test route for

simple fillers and sealants.

Annex B (Normative): Test conditions with mechanically induced

movement — movement applied to the joint prior to fire exposure or

during the fire test, simulating seismic and thermal cycling scenarios.

Annex C (Informative): Guidance on use of the test results, including

worked examples of applying field of application rules.

Test Specimens &

Orientations

04

Joint Orientations (A through E)

A

B

C

D

E

Floor Joint

Floor/Wall

Junction

Wall Joint

Wall/

Ceiling

Junction

Ceiling

Joint

Horizontal

joint in floor

slab; fire

exposure

from below

upward

Vertical joint

in wall

construction;

fire exposure

from one face

horizontally

Junction

between floor

and wall

elements at

90° angle; L-

shaped

Horizontal

joint in

ceiling; fire

exposure

from below

as for soffit

Junction

between wall

and ceiling at

90° angle;

inverted L-

shaped

through joint

specimen

Specimen Sizing Rules

The most important dimensional requirement in Clause 6 is the 10:1

length-to-width ratio: the specimen length exposed to fire shall be at

least 10 times the nominal joint width. For a 25 mm wide joint, the

minimum specimen length is 250 mm — but in practice, all tests require a

minimum specimen length of 900 mm regardless of joint width, to ensure

the test is representative and furnace conditions are uniform along the

joint.

For joint seals wider than 90 mm, the specimen must be tested in a large-

scale furnace capable of accommodating the required specimen

dimensions — typically floor furnaces of 3 m × 4 m and wall furnaces of 3

m × 3 m. This has practical implications for which laboratories can

conduct the test.

The supporting construction substrate plays a significant role in

application rules. Autoclaved aerated concrete (AAC) blockwork is the

standard substrate because it represents a demanding scenario for edge

bonding of sealants. Results obtained with denser substrates (e.g. normal

density concrete) may not transfer directly to AAC.

MIN

SPECIMEN

LENGTH

FURNACE

TYPE

REQUIRED

JOINT

WIDTH

NOTES

900 mm

(governs over

10:1)

Most common scenario

for narrow expansion

joints

≤ 25

mm

Standard

furnace

E.g. 60 mm joint → 600

mm min, but 900 mm

typical

26–90

mm

Standard or

10× joint width

large furnace

Large-scale

furnace

Limits number of labs

able to conduct the

test

> 90

mm

10× joint width

(≥ 900 mm)

mandatory

Both minimum AND

maximum claimed

width must be tested

Any

—

width

05

Test Procedure

T = 345 × log (8t + 1) + 20 °C

10

ISO 834 Standard Fire Curve — where T = furnace temperature (°C), t =

elapsed time (minutes). Furnace pressure maintained at 20 ±5 Pa above

ambient.

Pre-Test Conditioning

1

Specimens conditioned per EN 1363-1 for a minimum of 12 hours at 23 ±5°C

and 50 ±5% relative humidity. Initial thermocouple readings recorded as T₀

baseline. All thermocouples verified functional.

Instrumentation Setup

2

Fixed thermocouples placed on unexposed face adjacent to joint and at

specified positions away from joint. Roving thermocouple prepared. Cotton

pad assembly checked. Data logging commenced at specified interval

(typically every 30 seconds or 1 minute).

Movement Induction (Annex B only)

3

If movement testing applies: the mechanical actuator applies cyclic or static

displacement equal to the claimed movement capability (e.g. ±15% of joint

width or ±100% of manufacturer's claimed compression/extension).

Movement may be applied prior to ignition, or commenced at a specified

time during fire exposure.

Fire Exposure — T = 0 to End

4

Furnace ignition — test timing commences. Furnace follows ISO 834 time-

temperature curve within tolerance bands specified in EN 1363-1. Pressure

differential between furnace interior and ambient maintained at 20 ±5 Pa.

Engineer monitors continuously for integrity and insulation events.

Integrity Monitoring (E Criterion)

5

Cotton pad checks performed regularly — pad held near but not touching

the unexposed surface adjacent to the joint. Any ignition = immediate E

failure. Sustained flaming exceeding 10 seconds on the unexposed face = E

failure. Observations logged with timestamp to the nearest minute.

Insulation Monitoring (I Criterion)

6

Thermocouple readings logged continuously. I failure occurs when any fixed

or roving thermocouple rises more than 180 K above the initial mean

temperature T₀. Each thermocouple channel monitored independently. First

failure timestamp recorded.

Test Termination & Reporting

7

Test terminated at first E or I failure for each seal, or at the claimed

classification duration if no failure. For multiple seals: each judged

independently. Results expressed as whole completed minutes elapsed

before failure. Full test report prepared per Clause 12.

06

Performance Criteria: E & I

The two primary performance criteria mirror those used across the EN

13501-2 classification framework. Each criterion is evaluated

independently; a product may achieve different time periods for E

and I.

E — INTEGRITY

I — INSULATION

DEFINITION

The ability of the joint seal to

prevent passage of flames and

hot gases to the unexposed side

of the construction.

The ability of the joint seal to

limit heat transmission to the

unexposed side, preventing

unacceptable temperature rise.

FAILURE CONDITIONS

(ANY ONE TRIGGERS

FAILURE)

FAILURE CONDITION

Any thermocouple (fixed or

roving) on the unexposed face

rises more than 180 K above

the initial average temperature

T₀ recorded before test

① Cotton pad ignites when held

near the unexposed face of

the joint for 30 seconds

commencement.

② Sustained flaming on the

unexposed face persisting for

more than 10 continuous

seconds

T_failure = T₀ + 180 K

THERMOCOUPLE

PLACEMENT

IMPORTANT NOTE

Fixed thermocouples placed

centrally on the unexposed face

at positions specified in Clause

9. A roving (movable)

Gap gauges are NOT used for

linear joint seals under EN

1366-4. The 6 mm and 25 mm

gap gauge probes specified in

EN 1363-1 for separating

thermocouple is used to survey

the surface; wherever the

elements do not apply here —

highest temperature is located,

only cotton pad and flaming

criteria are assessed for E.

the roving is held there. All

readings contribute to the 180 K

limit check.

Multiple Seals in One Test

Where more than one linear joint seal is included in a single test

construction, each seal is judged as an independent specimen. Failure of

one seal's integrity or insulation does not invalidate the remaining seals,

provided that the furnace conditions are maintained and the failure does

not compromise the integrity of the test setup itself. This allows

manufacturers to test multiple product variants in a single test event for

cost efficiency.

07

Results & Classification

HOW RESULTS ARE EXPRESSED

Performance is expressed as the elapsed time in whole completed

minutes to the nearest minute at which each criterion is first

breached. A seal that maintained integrity for 58 minutes 42 seconds

achieves 58 minutes for E purposes — it is then classified against the

highest standard interval it exceeded.

Standard Classification Intervals (per EN

13501-2)

E 30

E 60

E 90

E 120

E 180

I 90

E 240

I 30

I 60

I 120

EI 30

EI 60

EI 90

EI 240

EI 120

EI 180

TYPICAL

APPLICATION

CRITERIA

REQUIRED

DESIGNATION

MEANING

Integrity

Non-insulated

expansion joints,

secondary

No sustained

flaming; no

cotton pad

ignition

maintained;

insulation not

assessed/

claimed

E only

barriers

Both integrity

AND insulation

to same

Primary fire

compartment

floor and wall

joints

E criteria +

ΔT ≤ 180 K

on all TCs

EI

classification

period

TYPICAL

APPLICATION

CRITERIA

REQUIRED

DESIGNATION

EI (i↔o)

MEANING

Criteria met

from both sides

of the

Two-directional

fire walls, central

core walls

Full test from

each face or

by EXAP

construction

Limited radiation

— not commonly

used for joints

Not typically

applicable to EN

1366-4

Radiation flux

≤ 15 kW/m²

EW

08

Field of Direct Application

Clause 13 defines the conditions under which a test result may be

directly applied to real installation scenarios without further testing.

Understanding these rules is essential for engineers specifying fire-

rated joint seal systems.

TESTED

CONDITION

DIRECTLY

COVERED

REQUIRES NEW

TEST

TOPIC

Orientations A

and B

C, D, E require

separate tests

Orientation

A (floor) only

C (wall) only

Orientations B,

C, and D

A, E require

Orientation

separate tests

A, B, and C all

tested

All orientations

A through E

None — full

coverage

Concrete,

denser

Results do not

transfer to steel

frame without re-

test

Substrate

AAC blockwork

blockwork,

masonry

Widths beyond

W_max; narrow

widths below

Any width

between

W_min and

W_max

Min width

Joint Width

W_min and

max W_max

W_min may require

verification

±X%

Any claimed

movement ≤

X%

Greater movement

claims than tested

value

Movement

mechanically

induced

Static joint

applications

only

No movement

(Annex A)

Any movement

joint application

09

Accredited Test Laboratories

All laboratories conducting BS EN 1366-4 tests must be accredited to

ISO/IEC 17025 by their national accreditation body. In the UK this is

UKAS; in Germany DAkkS; in France COFRAC; in the Netherlands RvA;

and so on.

Warringtonfire (Element

Materials Technology)

BRE (Building Research

Establishment)

 Warrington, United Kingdom

 Watford, United Kingdom

UKAS Accreditation No. 0249

UKAS Accredited

Full-scale large furnace capability

(3×4 m floor, 3×3 m wall). Full EN

1366-4 scope including Annex A & B.

DIAP/EXAP services. CE & UKCA

marking support.

Large vertical and horizontal

furnaces. Full EN 1366-4 testing.

Long-established relationship with

British Standards Committee FSH/22.

National authority in building fire safety

research. BRE was involved in

development of the EN 1366 series and

has extensive experience with the

application rules and edge cases.

Part of Element Materials Technology

group. One of the UK's largest and most

established fire test facilities with

decades of experience on the EN 1366

series.

Cambridge Fire Research

(CFR)

Attain RTC

 United Kingdom

UKAS Accredited

 Cambridge, United Kingdom

UKAS Accredited / UK Approved Body

4×3 m vertical furnace, 4×3 m

3×3 m wall furnace, horizontal

horizontal furnace. State-of-the-art

facility. BS 476, EN 1364, EN 1366

test suites under single accreditation.

furnace. Full EN 1366-4 scope. Test

evidence for third-party certification

under CERTIFIRE and LPCB schemes.

Modern facility with advanced furnace

instrumentation and data acquisition.

Capable of complex multi-seal specimen

configurations.

Specialist fire testing facility offering

competitive turnaround for EN 1366-4

joint seal testing. Well-regarded for

precise thermocouple work and detailed

test reports.

UKTC (UK Testing &

Certification)

MPA Dresden / ift Rosenheim

 Germany (multiple sites)

 United Kingdom

DAkkS Accredited | Notified Body

Status

UKAS Lab No. 21542

Full-scale fire resistance testing.

Accredited specifically for BS EN

1366-4:2021. End-to-end service

from test to UKCA marking.

EN 1366-4 and full EN 1366 series.

Notified body authority for CE

marking across EU member states.

Broad European application.

Focuses on providing complete product

certification journey. Useful for

manufacturers seeking single-source

testing and certification under the post-

Brexit UKCA regime.

Results from DAkkS-accredited German

labs are valid for CE marking across all

EU member states. Useful for

manufacturers targeting pan-European

market access.

EFECTIS (France/

Netherlands)

SP Fire Research (RISE)

 Borås, Sweden

 Paris, France & Netherlands

SWEDAC Accredited | Notified Body

COFRAC / RvA Accredited | NB

Status

Full EN 1366 series. RISE (formerly

SP) is a leading Scandinavian fire

testing authority with significant

expertise in service installation

testing.

Full EN 1366-4 capability. Large

European group with labs in multiple

countries. Supports CE marking and

extended application reports.

Scandinavian market leader. Particularly

recognised for expertise in intumescent

and passive fire protection system

testing with deep involvement in EN

standards development.

One of Europe's largest independent fire

testing groups. Particularly useful for

manufacturers with pan-European

distribution strategies.

HOW TO VERIFY A LAB'S ACCREDITATION

In the UK, check the UKAS directory at ukas.com . Request a copy of

the lab's Schedule of Accreditation and confirm BS EN 1366-4 appears

in the scope. For EU labs, check the European accreditation database

via european-accreditation.org . For Notified Body status (CE

marking), check the NANDO database at ec.europa.eu/growth/tools-

databases/nando .

2006+A1:2010 vs 2021

Edition

10

2006+A1:2010

(WITHDRAWN)

2021 EDITION

(CURRENT)

TOPIC

Movement only

Movement permitted

PRIOR TO fire or DURING

fire exposure

Movement

Timing

permitted PRIOR TO fire;

during-fire movement

removed

10:1 ratio; 900 mm

minimum; large furnace

for >90 mm

Rewritten with clearer

provisions for wide seals

and large specimens

Specimen

Section 6

Expanded guidance on

steel frame and

composite panel

substrates

AAC primary; limited

steel frame guidance

Substrates

Classification

Reference

EN 13501-2

EN 13501-2 (unchanged)

Curtain Wall

Exclusion

Perimeter seals of CW

excluded

Maintained with

improved clarification

Revised table with

improved substrate

transfer rules

Field of

Clause 13 with

Application

orientation table

Market Status

(UK)

Basis for many existing

UKCA certificates

Required for all new

testing from August 2021

⚠ TRANSITION GUIDANCE

Existing third-party product certificates (CERTIFIRE, LPCB, etc.) that

were granted on the basis of tests conducted to BS EN

1366-4:2006+A1:2010 do not automatically expire when the standard

is withdrawn. Certification bodies typically allow a transition period

(often 2–3 years from withdrawal) during which existing certificates

remain valid, provided no product changes have been made.

Manufacturers should check directly with their certification body for the

specific transition timeline applicable to their certificate.

Interactive E & I Fire

Criteria Calculator

11

Fire Performance Assessment



Tool

Based on BS EN 1366-4:2006+A1:2010 — Clause 11 Performance Criteria

& EN 13501-2 Classification

EI Classification

E – Integrity Check

I – Insulation Check

Enter the time in minutes at which each criterion first failed. The

calculator determines the highest standard classification interval

achieved per EN 13501-2.

E — INTEGRITY FAILURE TIME (MINUTES)

I — INSULATION FAILURE TIME (MINUTES)

—

Enter failure times above to calculate classification

STANDARD CLASSIFICATION THRESHOLDS

E/I 30

E/I 60

E/I 90

E/I 120

E/I 180

E/I 240

Result expressed to nearest COMPLETED minute. Example: 89 min 55 sec →

classified as E/I 60

BS EN 1366-4:2006+A1:2010 — Fire Resistance Tests for Linear Joint Seals

This study guide is for educational and reference purposes. Always consult the

actual standard and accredited test evidence for regulatory compliance

decisions.

Standard now withdrawn — current edition is BS EN 1366-4:2021