1 Scope This European Standard specifies a test method for determining the ability of a horizontal protective membrane, when used as a fire resistant barrier, to contribute to the fire r
Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1363-1, EN ISO 13943 and ISO 8421-2 and the following apply
3.1.1 horizontal structural building member horizontal structural element of building construction which is loadbearing, separating and which is fabricated from concrete, steel, steel/concrete composite or timber
A horizontal protective membrane refers to any ceiling lining or membrane that does not contribute to the load-bearing structure It can consist of multiple material layers, along with supporting frameworks, hangers, fixings, and insulation materials This membrane may be suspended from or directly attached to a structural member, or it can be self-supporting and fixed beneath a structural element Its primary purpose is to enhance the fire resistance of the structural member, exemplified by ceiling tiles on a light frame, ceiling boards, metal trays, and plastered ceilings that are not directly affixed to the structural underside.
3.1.3 separating gap distance between the non-exposed surface of the horizontal protective membrane and the lowest surface of the exposed side of the structural building member
3.1.4 cavity whole void or voids between the non-exposed surface of the horizontal protective membrane and the highest surface of the exposed side of the structural building member
The horizontal protective membrane test specimen includes a complete assembly designed for testing, featuring standard fixing equipment and methods It also incorporates typical elements such as insulating materials, light fittings, ventilation ducts, and access panels.
Fire protection is provided to structural building members through a horizontal protective membrane system, which limits the temperature on the surface of these members and within the cavity during fire exposure.
3.1.7 characteristic temperature the average of the mean temperature and the maximum individual temperature [(mean + maximum)/2] for a group of thermocouples
Symbols and units
L exp mm Exposed length of the structural building member
L sup mm Centre to centre distance between the supports of the structural building member tested
L spec mm Total length of the main beams or members of the structural building member
A m/V m -1 Section factor of unprotected steel beam (see EN 13381-4)
General
The furnace and test equipment shall be as specified in EN 1363-1.
Furnace
The furnace must be designed to ensure that the test specimen dimensions are exposed to heating as specified in section 6.4.1, and its installation should follow the guidelines outlined in Clause 7.
Loading equipment
Loading must be conducted in accordance with EN 1363-1, ensuring that the loading system allows for a uniform application of the specified magnitude along both the length and width of the test specimen, with loading points positioned as outlined in section 5.3.
Loading equipment must allow unobstructed airflow above the test specimen, and no component of the equipment, except at the loading points, should be within 60 mm of the unexposed surface of the specimen.
General
A horizontal structural member, along with its supporting construction, is designed to support a horizontal protective membrane that acts as a fire-resistant barrier against flames originating from below This member must withstand specified loading conditions and undergo the fire test outlined in this document.
The temperature within the cavity and the surface temperature of the structural building member are measured throughout the test
To minimize leakage through the structural floor slab and the sides of the structure, it is essential to ensure a tight seal between the floor slab and the furnace This can be achieved using materials such as mineral wool pads, allowing for vertical deflection of the slab while maintaining an effective barrier against leaks.
The test should be conducted until all thermocouples in the cavity indicate a characteristic temperature that meets the limiting temperature for the structural building materials Specifically, this means continuing the test until any temperature reaches 750 °C for concrete, steel, or concrete/profiled steel composite members, or 500 °C for timber structural members.
The test method must adhere to the procedures outlined in EN 1363-1 and, if relevant, EN 1363-2, unless otherwise specified Additionally, the semi-natural fire test should be conducted as per the guidelines in Annex A when necessary.
Support and restraint conditions
Standard conditions
The test specimen shall be tested as a simply supported one way structure with two free edges and an exposed surface and span as specified in 6.4.1
It shall be installed to allow freedom for longitudinal movement and deflection using at one side rolling support(s) and at the other hinge support(s) as shown in Figure 1
The surface of the bearings shall be smooth concrete or steel plates The width of the bearings shall be at least as wide as the beam.
Other support and restraint conditions
Support and restraint conditions differing from the standard conditions specified in 5.2.1 shall be described in the test report and the validity of the results restricted to that tested.
Loading conditions
The test specimen shall be subjected to loads determined in accordance with EN 1363-1 The means of determination of the load shall be clearly indicated in the test report
The applied load must be determined so that the maximum bending moment reaches 60% of the ultimate limit state value for design moment resistance, as outlined in the relevant structural Eurocodes (EN 1992-1-1, EN 1993-1-1, EN 1994-1-1, and EN 1995-1-1).
The design moment resistance shall be calculated using either the actual or nominal material properties, derived according to 6.5, of the loadbearing member with a material safety factor (γm) equal to 1,0
The load must be applied symmetrically to the test specimen along two transverse loading lines, positioned at ẳ Lsup and ắ Lsup, with a separation of Lsup/2, as illustrated in Figure 2 Alternatively, dead weights can be utilized to achieve this In either scenario, the loading should generate stresses that closely resemble a uniformly distributed load.
The method of loading shall be by a system which will produce a bending moment, which is uniform over at least 20 % of the span of the beam around mid-span
Point loads must be applied to the test specimen along two transverse loading lines using load distribution beams or plates, as illustrated in Figures 1 and 3 The total contact area between these components and the test specimen must adhere to the specifications outlined in EN 1363-1.
Load distribution beams, for safety reasons, shall have a height to width ratio < 1
When using load distribution plates made of steel or other highly conductive materials, it is essential to insulate them from the test specimen's surface with appropriate thermal insulation material.
Unexposed surface thermocouples shall not be closer than 100 mm to any part of the load distribution system
General
One test specimen shall normally be required
The structural building member selected for the test must adhere to the specifications outlined in section 6.4.1 and be chosen from the standard elements detailed in section 6.4.2, ensuring it accurately represents those used in practical applications.
When a horizontal protective membrane is produced with components of varying sizes or installed using different methods, separate tests must be conducted on both the maximum and minimum size elements It is important to note that components trimmed to fit ceiling edges are not classified as smaller size components The installation methods that require sponsor approval will be represented by the fire test results.
The horizontal protective membrane for the test must be constructed as outlined in section 6.3 and installed following the procedures specified in the installation manual or other written instructions provided by the sponsor It should incorporate all thermal insulating layers or materials that will be utilized in practice within the cavity.
Fixtures and fittings
All fixtures and fittings, including light fittings, ventilation openings, and access panels, must undergo a comprehensive full-size test The installation and usage frequency should ideally reflect real-world practices Additionally, these fixtures and fittings should be installed at least 250 mm away from any edge of the test specimen.
Horizontal protective membranes
The test specimen must replicate the actual usage conditions, including the connections between the membrane, walls, edge panels, joints, and jointing materials It should be installed from below using the same methods and procedures outlined in the installation manual or written instructions provided by the sponsor.
The installation will include all necessary components for hanging, expansion, and abutting, along with any additional fixtures specified by the sponsor, ensuring a frequency that accurately reflects practical use.
For horizontal protective membranes which are suspended from the structural building member by hangers, the suspension system and the length of the hangers shall be representative of practice
The profiles with different panels should be installed closely together without any gaps, except when design specifications necessitate them In such instances, the gaps at the junctions of the main runners must reflect practical usage and should be positioned within the main runners rather than at their ends.
The profiles within the test specimen shall include a joint representative of joints to be used in practice in both longitudinal and transverse directions
The horizontal protective membrane must be securely attached along all four edges, either directly to the furnace walls or to a test frame When a test frame is utilized, it should be affixed directly to the structural building member being protected or to the furnace walls.
The performance of a specimen with a horizontal protective membrane may differ based on the alignment of its components with the longitudinal axis, especially if the membrane's construction varies in longitudinal and transverse directions To ensure accurate representation of the most critical conditions, the specimen should be installed with the more sensitive components parallel to the longitudinal axis If the most onerous condition is uncertain, it is essential to conduct two separate tests, positioning the components both parallel and perpendicular to the longitudinal axis.
Structural building members supporting horizontal protective membranes
General principles
The structural building member supporting the horizontal protective membrane and exposed to the furnace must meet specific dimensions: the exposed length (L exp) should be a minimum of 4,000 mm, the span (L sup) can extend L exp plus an additional 400 mm at each end, the length (L spec) can be L exp plus up to 500 mm at each end, and the exposed width must be at least 3,000 mm.
The additional length, required for installation purposes, shall be kept as small as practically possible
Test specimens with an exposed width of less than 3,000 mm can be evaluated using this method, but the application of the results is limited to constructions that are equal to or narrower than the tested width.
The gap between structural building members and longitudinal or simulated furnace walls must not exceed 30 mm This gap should be sealed with compressed mineral or ceramic fibres that have adequate fire performance, or with materials of equivalent performance This sealing is essential to accommodate the deflection of the member under heating conditions while preventing the leakage of hot gases during testing.
Standard horizontal structural building members
The following structural building members are considered to be standard for this test method a) Reinforced aerated concrete slabs on steel beams
The structural member will consist of hot rolled steel 'I' section beams with a section factor Am/V of (275 ± 25) m\(^{-1}\) for three-sided exposure, and a typical section depth of (160 ± 20) mm The steel grade utilized will be any structural grade (S designation) as specified.
EN 13381-4 Engineering grades (E designation) shall not be used
The beams will be positioned at centers of (700 ± 100) mm, supported by the bearing surface of the furnace test frame Additionally, the beams can be constructed with cross members welded at their ends.
The outer steel beams must be positioned between 275 mm and 450 mm from the furnace wall to ensure that the edge of the horizontal protective membrane rests solely on the peripheral support.
The reinforced aerated concrete slabs shall be of density not more than 650 kg/m 3 and minimum thickness
The reinforced aerated concrete slabs, measuring 100 mm in thickness and a maximum width of 650 mm, must be positioned transversely on the steel beam profiles These slabs should be separated by gaps of 5 mm to 10 mm, which need to be sealed using ceramic fibre or a similar material along with silicone flexible sealant Each test must utilize new, unused slabs to ensure accuracy and reliability.
Aerated concrete slabs should be supported by a steel beam framework without any mechanical connections to prevent an increase in the structure's mechanical strength as deformation occurs Additionally, reinforced dense aggregate concrete slabs are also utilized on steel beams.
The guidelines for reinforced aerated concrete slabs on steel beams remain applicable, with the exception that the concrete must consist of dense aggregate with a density of (2,350 ± 150) kg/m³ and a thickness ranging from 60 mm to 120 mm For further details on the concrete aggregates, refer to prEN 13381-3 Additionally, timber floors or roofs are also considered in this context.
The standard structural building member from which a horizontal membrane is suspended for the protection of a timber structural building member shall comprise equally spaced softwood joists, of nominal density
The joists should have a density of approximately (450 ± 75) kg/m³ and a cross-section of (220 ± 10) mm by (75 ± 5) mm, spaced at centers ranging from 530 mm to 600 mm, as illustrated in Figure 4 It is recommended to use six joists, with their spacing adjusted to accommodate an exposed width between 3,000 mm and 3,300 mm.
The joists must be interconnected using cross members of identical material and cross-section at the furnace support area, as well as additional cross members with dimensions of (175 ± 10) mm x (40 ± 5) mm positioned near the mid-span, as illustrated in Figure 4 The wooden flooring should consist of particle board sheets with a thickness of (21 ± 3) mm and a density of (600 ± 50) kg/m³, in accordance with EN 312, installed perpendicularly to the joists, featuring tongue and groove joints that are securely nailed down Additionally, concrete or profiled steel sheet composite slabs may be utilized.
The composite test slab of standard concrete and profiled steel sheet must be prepared in accordance with the specifications outlined in prEN 13381-5 It is essential that the steel grade and the type, composition, and strength of the concrete adhere to the requirements specified in prEN 13381-5.
The standard concrete/profiled steel sheet composite slab shall be fixed to and supported on steel beams with a representative span as specified in 6.4.1
Safety suspensions can be installed on the unexposed side of the slab to prevent the structural member from collapsing during testing, without adding to its load-bearing capacity.
Properties of test materials
The actual properties of materials used in structural building members, such as concrete strength, should be determined according to EN 1363-1 or relevant product test standards In cases where this is not feasible, nominal values for materials like steel or wood may be utilized Additionally, the dimensions of the structural building member must be accurately measured.
The sponsor will determine the material composition of the horizontal protective membrane Due to confidentiality concerns, the sponsor may choose not to disclose specific formulation details in the test report Nevertheless, this information will be kept confidential and stored securely in laboratory files.
Before testing, it is essential to measure and document the actual thickness, density, and moisture content of the horizontal protective membrane components This can be done directly on the components or using specific test samples The samples must be conditioned according to the guidelines outlined in Clause 8, with detailed procedures for various material types provided in Annex B.
The thickness of slab or board type fire protection materials must not vary by more than 15% from the average value across its entire surface This average value is essential for evaluating results and determining the applicability limits If the thickness exceeds a 15% variation, the maximum recorded thickness should be utilized for assessment purposes.
The thickness of passive or reactive fire protection materials, whether sprayed or coated, must be measured in accordance with Annex B when used as components of horizontal protective membranes It is essential that the thickness does not vary by more than 20% from the mean value across the entire surface This mean value is critical for evaluating results and determining the applicability limits If the thickness exceeds the 20% deviation, the maximum recorded thickness will be utilized for the assessment.
The density of the horizontal protective membrane and its components must be measured at both minimum and maximum thickness, as outlined in Annex B, and documented accordingly It is essential that the density does not vary by more than 15% from the mean value This mean density will be utilized in evaluating the results and determining the applicability limits of the assessment Should the density deviate by more than 15%, the highest recorded density will be applied in the evaluation.
Verification of the test specimen
An examination and verification of the test specimen for conformity to specification shall be carried out as described in EN 1363-1
The properties of the materials for the test specimen must be assessed using representative samples, as outlined in section 6.5, and following the methods specified in Annex B.
The sponsor is responsible for verifying that the materials used in the test specimen, which are applied through spray or coating methods, comply with the specified design composition and specifications by conducting appropriate tests for the material in question.
Optional and additional plate thermometers within the cavity
To obtain test data for calculating fire resistance, as outlined in EN 1992-1-2, EN 1993-1-2, and EN 1994-1-2, the sponsor has made a request for necessary information.
EN 1995-1-2 or other calculation methods, additional plate thermometers shall be used within the cavity
7 Installation of the test construction
The test construction, which includes the structural building member, supporting construction or test frame, and horizontal protective membrane, must be installed in the furnace to permit longitudinal movement and deformation This setup requires rolling supports on one side and hinge supports on the other, with careful insulation of the supports to protect them from heat exposure.
The order in which the test construction is installed upon the furnace shall be appropriate to practice
The test construction and test samples taken for the determination of material properties, as specified in 6.5, shall be conditioned according to EN 1363-1
Material properties (specified in 6.5) shall be determined according to Annex B and EN 1363-1
Steps shall be taken to ensure that all the component materials of the test construction are conditioned according to EN 1363-1 and will not influence the test result
General
The instrumentation for the measurement of temperature, furnace pressure, applied load and deformation shall comply with the requirements of EN 1363-1.
Instrumentation for measurement of furnace temperature
According to EN 1363-1, plate thermometers must be installed to accurately measure the furnace temperature These thermometers should be evenly distributed, ensuring that at least one is centrally located for every 1.5 m² of the exposed test specimen surface area, which is defined as the nominal area measured in the plane of the specimen.
Plate thermometers must be positioned with side 'A' directed towards the furnace floor For test specimens with an exposed area of less than 6 m², at least four plate thermometers are required.
Instrumentation for measurement of specimen temperature
General
Instrumentation shall be provided for the measurement and recording of cavity temperature, surface temperature of the test specimen and the temperature at other optional locations.
Instrumentation for measuring cavity temperature
Nine thermocouples will be utilized to measure cavity temperatures, organized in sets of three across three cross-sectional areas (T1 - T9 in Figure 5) Each thermocouple within a set will be horizontally spaced from the next by (750 ± 100) mm.
— Area 1: central section, located halfway along the span of the building member,
— Area 2: (1 000 ± 100) mm from one side of the central section,
— Area 3: (1 000 ± 100) mm from the other side of the central section
These nine thermocouples shall be positioned half way up the plenum within the cavity
An additional three cavity temperature measurement thermocouples shall be used when testing flammable timber test constructions, for safety reasons These additional thermocouples (T10 -T12) shall be distributed according to Figure 5
All cavity temperature measurement thermocouples shall be of a nominal thickness of 1 mm in accordance with EN 1363-1:2012, 4.5.1.4
Plate thermometers in accordance with EN 1363-1:2012, 4.5.1.1 directed with the steel surface downwards may be used to get effective cavity temperatures for calculating the thermal exposure of the beams.
Instrumentation for measuring surface temperatures
a) Standard test construction – reinforced concrete slabs on steel beams
Twelve thermocouples will be installed to measure the surface temperature of the steel beams, with three thermocouples attached to each beam used in the test construction outlined in sections 6.4.2 a) and 6.4.2 b) These thermocouples must be positioned at least 100 mm away from the loading points and loading plates, specifically on the underside of the lower flange of the beam, as illustrated by thermocouples a1 to a4 in Figure 6, within the three cross-sectional areas defined in section 9.3.2.
Thermocouples used for measuring the surface temperature of steel test beams must be of the double glass fiber insulated bare wire type, as outlined in EN 1363-1 Their placement and fixation should adhere to the specifications provided in EN 1363-1 Additionally, the standard test construction involves steel/concrete composite slabs.
Twelve thermocouples shall be provided for measurement of surface temperature on the (exposed) steel surface of the steel/concrete composite test construction described in 6.4.2 d)
Four thermocouples will be strategically placed on the lower profiles of the steel at centers of (700 ± 100) mm across the width of the furnace The outer temperature measurement points will be positioned between 300 mm and 450 mm from the furnace wall, similar to the locations shown for steel beams in Figure 6 Each of the three specified cross-sectional areas in section 9.3.2 will contain a set of these four thermocouples, ensuring they are at least 100 mm away from loading points or loading plates.
Thermocouples used for measuring the surface temperature of steel and concrete test slabs must be of the double glass fiber insulated bare wire type, as outlined in EN 1363-1 Their placement and fixation should adhere to the specified guidelines.
Optional and supplementary instrumentation for measuring temperature
a) To generate data for use in calculation of fire resistance
For accurate fire resistance calculations as per EN 1992-1-2, EN 1993-1-2, EN 1994-1-2, and EN 1995-1-2, it is essential to position two plate thermometers 100 mm below each beam, as shown in Figure 5 (PT1 to PT4 defined in EN 1363-1) The thermometers should be oriented with side 'A' facing downward towards the horizontal protective membrane If the gap is less than 100 mm, the thermometer should be placed at the mid-height of the cavity to ensure reliable temperature data collection.
Optional data can be generated using other thermocouples upon the sponsor's request, provided they are of the appropriate type and installation as specified in EN 1363-1.
1) Five thermocouples located on the unexposed surface of the structural building member, when standard building members are used (thermocouples c1 to c5 given in Figure 6) These shall be as defined in EN 1363-1 and shall be separated from the loading points and loading plates by at least
2) Five thermocouples located on the highest surface of the underside of the structural building member (thermocouples b1 to b5 given in Figure 6), i.e upon: i) the surface of the concrete slabs supported by steel beams; ii) within the steel profile of trapezoidal or re-entrant steel/concrete composite slabs; iii) the timber floor
3) Four thermocouples located on the unexposed face of the horizontal protective membrane and below any insulation material (thermocouples d1 to d4 given in Figure 6) These shall be located: i) one thermocouple in the centre of the horizontal protective membrane If the horizontal protective membrane is made up of panels then this thermocouple shall be placed at the centre of a panel; ii) one thermocouple at a membrane joint if included; iii) one thermocouple on each type of edge and internal profile bearing the membrane panel, in both longitudinal and transverse directions
4) Five thermocouples located on top of any insulation included in the test specimen (thermocouples e1 to e5 given in Figure 6) These shall be as defined in EN 1363-1.
Instrumentation for measurement of pressure
Equipment for measuring pressure within the furnace shall be provided, located and used as specified in
Instrumentation for measurement of deflection
A suitable means of measuring the vertical deformation at mid span of the test specimen, relative to its supports, shall be provided, located and used as specified in EN 1363-1.
Instrumentation for measurement of applied load
Instrumentation for measurement of applied load shall be provided and used as specified in EN 1363-1
General
Carry out checks for thermocouple consistency and establish data points for temperature as specified in
EN 1363-1 before commencement of the test and the procedures defined in 10.2 to 10.7.
Furnace temperature and pressure
Measure and record the furnace temperature using the thermocouples defined in 9.2 and the furnace pressure in accordance with the procedures and frequency specified in EN 1363-1
Control the furnace temperature according to the data received from the furnace temperature measurement thermocouples to the criteria of EN 1363-1
Control the furnace pressure to the criteria of EN 1363-1.
Application and control of load
According to the procedures outlined in EN 1363-1, a constant load must be applied to the test specimen, as specified in section 5.3, throughout the testing duration This load should be maintained until either a deformation of L/30 is achieved or the deflection rate surpasses the limits set in EN 1363-1, at which point the load should be removed.
Temperatures of test specimen
Measure and record the temperature inside the cavity and on the surface of the test construction using the specified thermocouples at one-minute intervals If supplementary or optional thermocouples are utilized, ensure to measure and record their temperatures at the same one-minute intervals.
Deflection
According to EN 1363-1 procedures, establish an initial deformation datum point in relation to the supports prior to load application After applying the test load, measure the zero point for deformation before heating begins Continuously monitor deformation throughout the test, recording results at intervals of no more than one minute, and control the rate of deflection during the test.
Observations
Monitor the overall behavior of the test specimen, particularly the horizontal protective membrane, during the test Record any instances of cracking, fissuring, deterioration, delamination, or similar issues as outlined in EN 1363-1.
Terminate the test when one or more of the reasons for termination specified in EN 1363-1 occurs and/or when all limit surface/cavity temperatures are reached
Acceptability of test results
Erroneous results may arise during tests due to thermocouple failures or abnormal behavior of the test specimen It is essential to adhere to the acceptability criteria for temperature data as specified in EN 1363-1.
Presentation of test results
The test report must include the following key elements: a) measured dimensions and material properties, particularly thickness, density, and moisture content of the test specimen and its components, along with assessment values as defined in section 6.4; b) individual and mean results of furnace temperature measurements, graphically presented and compared to specified requirements in EN 1363-1; c) furnace pressure measurements, also graphically presented and compared to EN 1363-1 requirements; d) individual and mean results from cavity temperature measurement thermocouples, graphically presented with evidence of compliance with validity criteria in section 11.1; e) individual and mean results from surface temperature measurement thermocouples, graphically presented with compliance evidence; f) individual and mean results from optional and supplementary temperature measurement thermocouples, graphically presented with compliance evidence; g) results of deformation and rate of change of deformation measurements, as specified.
EN 1363-1 and graphically presented If the load is removed, the time at which this occurred
The results from b) to f) can be summarized as a selection of measured data that provides a historical overview of the test specimen's performance in accordance with EN 1363-1 Additionally, the observations made and the corresponding times of these observations are included in the results.
The test report shall include the following statement:
This report outlines the construction details, testing conditions, and results of a specific horizontal protective membrane tested according to EN 13381-1 standards It is important to note that any variations in size, construction details, edge combinations, or fixtures and fittings from the tested membrane may compromise the validity of the test results.
The test report must include additional items beyond those specified by EN 1363-1, such as a generic description and fixing details of the horizontal protective membrane, comprehensive information about the test specimens including assembly and surface preparation, and a description of the fabrication and conditioning of the test construction It should also document the installation of the test construction onto the test furnace, present measurement results in graphical format, and describe any significant behavior of the test specimen observed during the test, including the timing and extent of any deterioration of the membrane Furthermore, the report must detail the magnitude of the load applied to the specimen over time, the reason for test termination based on section 10.7, and the calculations used to determine the test load.
General
Requirements given in Clause 13, Clause 14 and Clause 15 are meant for extended application For direct application, these clauses do not apply
The assessment method outlines the evaluation of the horizontal protective membrane's role in fire protection for structural members This is achieved by measuring temperatures within the cavity using thermocouples or plate thermometers, as well as on the exposed surface of the structural member Additionally, for practical non-standard horizontal structural members, temperatures are also recorded on the unexposed surface of the furnace closure during testing.
Assessment of loadbearing capacity
General
This test method evaluates loadbearing capacity by analyzing characteristic temperature curves obtained from sections 13.2.2 and 13.2.3 It measures the time taken from the start of the test until the specified limiting cavity and surface temperatures, relevant to the material within the structural building member, are achieved.
Characteristic temperature curve: cavity temperatures
From the temperature data collected and reported in 11.2 the following shall be identified:
— the graph of the mean of all nine individual cavity temperatures (12 individual cavity temperatures for timber based building members),
— the graph of the individual thermocouple giving rise to the highest individual cavity temperature
The characteristic temperature derived from the nine (or twelve) cavity thermocouples will be calculated and presented according to the guidelines in section 11.2 This curve will serve as the characteristic curve for cavity temperature and will be utilized in the assessment process.
Characteristic temperature curve: surface temperatures (steel beams or steel/concrete slabs)
From the temperature data collected and reported in 11.2 the following shall be identified:
— the graph of the mean of all twelve individual surface temperatures;
— the graph of the individual thermocouple giving rise to the highest individual cavity temperature
The characteristic temperature shall be calculated and similarly presented, as defined in 11.2 This curve shall be used as the characteristic curve for surface temperature and used in the assessment.
Application of method of limiting temperatures
Limiting temperatures refer to the critical temperatures for both cavity and surface, beyond which the construction material of a structural building member can no longer support its load.
Limiting temperatures for each specific type of material of construction, from which loadbearing capacity is obtained from measurement of cavity temperature (subject to the criteria of Clause 15, Table 3) are:
— 600 °C all reinforced concrete building members;
— 530 °C building members containing steel beams plus reinforced concrete slabs;
— 450 °C all reinforced concrete building members containing pre-stressed rebars/wires or strands;
— 400 °C building members containing steel/concrete composites;
— 370 °C cold formed steel building members;
NOTE According to EN 1992-1-2:2004, 5.2, the steel critical temperature at pre-stressed bars is 400 °C and 350 °C at pre-stressed wires and strands
Timber joists and wooden floorboards in buildings must adhere to a limiting temperature of 300 °C, which does not account for the charring of timber members, as specified in section 3-1(8) of EN 1995-1-2:2004 To accurately assess the charring behavior of these materials, the testing procedure outlined in prEN 13381-7 should be implemented.
Limiting temperatures, for each specific type of material of construction, from which loadbearing capacity is obtained from measurement of surface temperature (subject to the criteria of Clause 15, Table 3) are:
— 510 °C building members containing steel beams plus reinforced normal or aerated concrete slabs (temperature measured on the steel beam);
— 350 °C cold formed steel building members (temperature measured on the steel element);
— 350 °C building members containing steel/concrete composites (temperature measured on the profiled steel sheet of the composite slab)
If the test is stopped before reaching the maximum temperature, the load-bearing capacity will be determined based on the duration of the test for both cavity and surface temperature scenarios.
Assessment of data for calculation purposes
From the temperature data collected and reported in 11.2 the following shall be identified:
— the graph of the mean of all four individual plate thermometers (plate thermometers PT1 to PT4 given in Figure 5);
— the graph of the individual plate thermometer (plate thermometers PT1 to PT4 given in Figure 5) giving rise to the highest individual temperature
This article does not address the evaluation and application of temperature data obtained from plate thermometers for calculating heat transfer and fire resistance in accordance with EN 1992-1-2, EN 1993-1-2, EN 1994-1-2, and EN 1995-1-2 Users are advised to refer to the appropriate EN "Eurocode" standards for detailed guidance.
The assessment report must include the name and address of the assessing body along with the assessment date, as well as the test laboratory's details, unique test reference number, and report numbers It should also list the names and addresses of the sponsors, the manufacturer of the products, and the manufacturers of the construction A generic description of the products, particularly the horizontal protective membrane and any known component parts, is required, with a note if any information is unknown Full details of the test construction, including drawings, dimensions, photographs, and installation manuals or instructions from the sponsor, must be provided, along with specifics about the assembly of the test specimen and the depth of the cavity used The report should explain any omitted test data and give a general description of the test specimens, including their dimensions, composition, and measured properties Finally, it must present the results of the load-bearing capacity based on the characteristic temperature curves, detailing the time elapsed until a specified temperature is reached.
The loadbearing capacity results will be detailed in Table 3 Additionally, the report must include a statement on the limitations of the assessment procedure as outlined in Clause 15 It should also present any specific temperature data collected from plate thermometers used within the cavity, as specified in section 13.3.
The insulation and integrity for the slabs of the standard test structure are deemed to be of the same value as that of loadbearing capacity of the test structure
Table 1 — Presentation of loadbearing capacity results
For application to the following construction materials Limiting cavity temperature Loadbearing capacity from elapsed time
Cold formed steel building members
300 °C min min min min min min
For application to the following construction materials Limiting surface temperature Loadbearing capacity from elapsed time
15 Limits of applicability of the results of the assessment
Type of structural building member
The results obtained from the procedure outlined in this test method, when applied to standard constructions as specified in section 6.4.2, can also be utilized for various combinations of beams, joists, and floors as detailed in Table 2.
Table 2 — Application of results from tests to other materials
Standard structural building member tested
Results applicable to structural building members comprising, slabs constructed from alternative material types, provided from 15.2 to 15.5 are satisfied
[see 6.4.2] Aerated concrete Normal concrete Steel/concrete composite
Aerated concrete slabs on steel beams
Normal concrete slabs on steel beams
Steel/concrete composite members on steel beams
Timber boards on timber beams
During fire tests, the timber floor protected by a horizontal membrane reached 300 °C inside the cavity, while the steel/concrete composite slab achieved 400 °C under similar conditions.
Tables 3 to 6 outline the limiting temperature criteria applicable to various combinations of beams, joists, slabs, and floors, based on the materials used in their construction and the tested combinations.
When building members consist of various material types, the lowest limiting temperature value suitable for those materials should be selected Additionally, the assessment results can be displayed in accordance with Table 3.
Table 3 — Limiting temperature values and presentation of results for aerated concrete slab on steel beams has been tested (see 6.4.2 a))
Type of beam or joist
Type of slab or floor Specified limiting temperature value (cavity) [°C]
Specified limiting temperature value (surface) [°C]
Time to specified temperature value (cavity) [minutes]
Time to specified temperature value (surface) [minutes]
Loadbearing capacity [minutes] (Note) stressed Pre-
Type of beam or joist
Type of slab or floor Specified limiting temperature value (cavity) [°C]
Specified limiting temperature value (surface) [°C]
Time to specified temperature value (cavity) [minutes]
Time to specified temperature value (surface) [minutes]
Cold formed steel Pre-stressed
The loadbearing capacity performance is defined as the minimum time required to reach a specified limiting temperature, either within the cavity or at the surface If no surface limiting temperature is provided, it refers to the time taken to reach the specified limiting temperature within the cavity.
Table 4 — Limiting temperature values and presentation of results for concrete slab on steel beams has been tested (see 6.4.2 b))
Type of beam or joist
Type of slab or floor Specified limiting temperature value (cavity) [°C]
Specified limiting temperature value (surface) [°C]
Time to specified temperature value (cavity) [minutes]
Time to specified temperature value (surface) [minutes]
Loadbearing capacity [minutes] (Note) stressed Pre-
Cold formed steel Pre-stressed
The loadbearing capacity is determined by the time it takes to reach a specified limiting temperature, either within the cavity or at the surface, where such temperatures are permitted.
Table 5 — Limiting temperature values and presentation of results for steel/concrete composite member slab has been tested (see 6.4.2 d))
Type of beam or joist
Type of slab or floor Specified limiting temperature value (cavity) [°C]
Specified limiting temperature value (surface) [°C]
Time to specified temperature value (cavity) [minutes]
Time to specified temperature value (surface) [minutes]
The loadbearing capacity is determined by the time it takes to reach a specified limiting temperature, either within the cavity or at the surface, where such temperatures are permitted.
Table 6 — Limiting temperature values and presentation of results for timber boards on timber beams has been tested (see 6.4.2 c))
Type of beam or joist
Type of slab or floor Specified limiting temperature value (cavity) [°C]
Specified limiting temperature value (surface) [°C]
Time to specified temperature value (cavity) [minutes]
Time to specified temperature value (surface) [minutes]
Loadbearing capacity [minutes] (Note) stressed Pre-
Cold formed steel Pre-stressed
Type of beam or joist
Type of slab or floor Specified limiting temperature value (cavity) [°C]
Specified limiting temperature value (surface) [°C]
Time to specified temperature value (cavity) [minutes]
Time to specified temperature value (surface) [minutes]
The loadbearing capacity is determined by the time it takes to reach a specified limiting temperature, either within the cavity or at the surface This measurement reflects the lowest time required to achieve the designated limiting temperature in these areas.
Type of concrete
Fire resistance achieved from a tested structural building member with aerated concrete slabs is applicable to any structural member made of aerated concrete that has the same or greater thickness than the tested member, provided it adheres to the cavity application guidelines specified in section 15.6.
Fire resistance achieved from tested structural members made of aerated concrete slabs is also applicable to structural members made of normal concrete that are 60 mm or thicker, provided that the cavity specifications outlined in section 15.6 are adhered to.
Fire resistance ratings established for tested structural members made of normal density concrete slabs are applicable to any structural member using normal concrete of equal or greater thickness This is contingent upon adherence to the cavity application guidelines specified in section 15.6.
Fire resistance achieved from a tested standard timber floor is applicable to any structural building member that includes normal concrete of 60 mm thickness or greater, provided it adheres to the cavity specifications outlined in section 15.6.
Fire resistance achieved from a tested standard timber floor is applicable to any structural building member that includes aerated concrete of 100 mm or more, provided it adheres to the cavity specifications outlined in section 15.6.
Type of steel beam
Fire resistance results from testing steel beam specimens can be applied to structural building members in two scenarios: a) when the fire resistance is based on cavity temperature measurements for steel beams of any section factor, and b) when the fire resistance is determined by surface temperature measurements on the lower flange of steel beams with a section factor lower than that of the tested specimen.
Fire resistance obtained from a tested standard timber floor shall be applicable to structural building members containing steel beams having any section factor,
The permitted application with respect to the cavity defined in 15.6 shall be allowed in both cases.
Type of steel/concrete composite structures
Fire resistance obtained from a tested standard timber floor or a standard aerated concrete floor shall be applicable to structural building member designed as follows
The composite test slab of standard concrete and profiled steel sheet must be prepared in accordance with the specifications outlined in prEN 13381-5 It is essential that the steel grade and the type, composition, and strength of the concrete adhere to the requirements specified in prEN 13381-5.
The standard concrete/profiled steel sheet composite slab shall be fixed to and supported on two equally spaced steel beams with a representative span as specified in 6.4.1
Safety suspensions can be installed on the unexposed side of the slab to prevent the structural member from collapsing during testing, without affecting its load-bearing capacity.
Fire resistance results from testing a composite steel/concrete building member can be applied to other similar members if the following conditions are met: the steel sheet must have an equal or greater thickness and match the corrugation profile (e.g., trapezoid with trapezoid, dovetail with dovetail), and the concrete must be of the same or greater thickness and density Additionally, the application regarding the cavity defined in section 15.6 is permitted in all instances.
Type of timber structure
Fire resistance obtained from the testing of a timber structural building member or the standard aerated concrete floor shall be directly applicable to timber building members provided that:
— the thickness of timber particle board/cover is equal or greater than 21 mm;
— the particle board which are laid perpendicular to the joists, shall be connected with tongue and groove joints;
— the butt joints shall only be located above the joist;
— the requirements of EN 1995-1-1 and the provisions with respect to the cavity specified in 15.6 are both maintained.
Height of the cavity
Fire resistance obtained by direct application shall be applicable to cavities with equal or greater height than that tested.
Exposed width of test specimen
Where the exposed width in the test is less than 3 000 mm the results shall not be applicable to structures of width greater than that tested.
Properties of the horizontal protective membrane
The result of the assessment is only applicable to the horizontal protective membrane construction tested and at the density and thickness tested ± 5%
Components of supporting steel frame and installation conditions shall be the same as those tested.
Size of panels within the horizontal protective membrane
Panels are manufactured in various sizes, and when both the minimum and maximum sizes are tested separately, the results yielding the lowest values can be applied to all intermediate sizes.
Fixtures and fittings
Testing conducted without fittings and fixtures is not relevant for membranes that include these components A separate test, as outlined in section 6.2, must be conducted to account for the fixtures and fittings This additional testing allows for the direct application of fixtures and fittings at intermediate spacings.
Test results for membranes equipped with fittings and fixtures that have their own suspension devices can be applied to similar membranes, as long as the distribution does not surpass the tested limits.
The area occupied by fixtures and fittings remains unchanged, ensuring that the maximum tested opening area in the membrane lining is not surpassed.
If the test was performed with fittings and fixtures, the result is not applicable to membranes without fittings and fixtures.
Gaps between grid members and test frame or walls
Test results without an expansion gap between grid members and the test frame or furnace walls can be applied to real-world scenarios, as long as the gaps do not exceed 5 mm in size.
5 ceiling lining (with or without insulation)
Figure 1 — Construction of test specimen (steel beam/concrete slab): Section A-A
1 length of the steel beam 4 width of exposed concrete slabs
2 L sup 5 appropriate load distribution device
Figure 2 — Overview of test specimen (steel beam/concrete slab)
1 no gap 7 horizontal protective membrane
2 appropriate load distribution device 8 plan of reference for the thermocouples
3 ceiling lining 9 width of exposed concrete slab ≥ 3 000 mm
Figure 3 — Construction of test specimen (steel beam/concrete slab): Section B-B
1 L exp 5 application of the load
2 joists (220 ± 10) x (75 ± 5) at 530 to 600 centres 6 cross beam (mid span) (175 ± 10) x (40 ± 5)
3 exposed width ≥ 3 000 mm 7 cross beam (supports) (220 ± 10) x (75 ± 5)
Figure 4 — Construction and overview of timber test specimen
4 width of exposed concrete slab
Mandatory thermocouples [designated x] – see 9.3.2 and 9.3.3
PT1 to PT4 plate thermometers a1 to a12 surface temperature measurement c1 to c5 unexposed surface temperature measurement (see 9.3.2 c))
Figure 5 — Overview of mandatory thermocouples and thermocouples used in support of Eurocodes
6 plan of reference for thermocouples
7 width of the exposed concrete slab
The article discusses various temperature measurements related to building membranes and insulation It specifies cavity temperatures from T1 to T9 (T12), surface temperatures on the underside of the building membrane from b1 to b5, and surface temperatures from a1 to a12 Additionally, it addresses surface temperatures on the unexposed face of the horizontal protective membrane, labeled d1 to d4, as well as unexposed surface temperatures from c1 to c5 Finally, it includes surface temperatures on top of any insulation within the cavity, indicated by e1 to e5.
Exposure to a semi-natural fire
General
Suspended ceilings may need to endure semi-natural fire exposure from below, but this requirement is only applicable in specific situations and is not mandatory for all suspended ceilings.
Semi-natural fire source
EN 1363-1 defines the heating conditions in terms of a specified standard temperature/time relationship to be used for the determination of the fire resistance of structural building elements
Standard heating conditions do not fully represent the diverse range of real-life fire scenarios It is essential to minimize the gap between fire performance evaluated using the standard curve and the expected outcomes in actual building fires This is typically accomplished through a comprehensive classification system and the careful selection of failure criteria.
Lightweight component systems with low thermal inertia may perform poorly in rapidly developing fires This article proposes a method to evaluate the response of these elements when exposed to such fire conditions.
Because of the difficulties in achieving a very rapid rate of rise of temperature and flame impingement in a gas fired furnace, wooden cribs are used to provide the heating regime.
Test equipment
The test must be conducted in a four-sided chamber or furnace that meets the specifications outlined in EN 1363-1 The minimum dimensions of the chamber or furnace should be 3 meters in height, width, and depth Additionally, one wall of the furnace must feature a free opening with a height of 1.5 meters, allowing for the calculation of the opening factor.
A w is the area of the opening, in square metres, h is the height of the opening, in metres,
A t is the total surface area of the walls, floor & ceiling of the furnace, in square metres
The sill of the opening shall be (1,25 ± 0,25) m above the floor of the furnace
The top of the opening shall be (0,4 ± 0,1) m below the horizontal protective membrane
A.3.2 Preparation of fire source and heating conditions
The cribs will be constructed from softwood, specifically pinus silvestris, with a moisture content of (12 ± 3)% The wood will be processed into lathes or sticks measuring (660 ± 5) mm in length, (70 ± 2) mm in width, and a specified thickness.
The sticks, measuring (44 ± 2) mm, will be arranged into cribs consisting of 13 layers, with each layer containing three sticks In alternating layers, the sticks will be positioned at right angles to the adjacent layers Additionally, the center stick from the bottom layer will be removed to create space for an ignition tray.
Figure A.1 — A typical wooden crib for the semi-natural fire exposure test
Wooden cribs, as described above, shall be distributed evenly within the test chamber to give a total fire loading of (40 ± 2) kg per square metre of floor area
A metal tray, measuring (250 ± 5) mm x (250 ± 5) mm x (20 ± 5) [depth] mm containing (0,75 ± 0,1) l of n heptane shall be placed under each wooden crib
The test is commenced by igniting the fuel in the trays This shall be completed within 30 s Observations shall commence from time zero, when the ignition process is started.
Test conditions
The loading and support conditions shall be as described in 5.2 and 5.3
The test must reach a minimum temperature of 1,000 °C within 10 to 20 minutes from the start This temperature is determined as the average reading from thermocouples installed for the specific element under evaluation.
Test specimen
The test specimen, together with any associated construction, shall be as described in Clause 6, except the dimensions of the specimen which shall be adapted to the furnace dimensions.
Installation of the test specimen
The test specimen shall be installed as described in Clause 7.
Conditioning
The test construction shall be conditioned as described in Clause 8.
Application of instrumentation
The instrumentation used in the test shall be as described in 9.2 and 9.3.
Test procedure
Measure and record the temperatures within the furnace, using the thermocouples specified in 9.2 at intervals not exceeding one minute
During the test, it is essential to continuously monitor the specimen and regularly observe its general behavior as outlined in EN 1363-1 Key observations should include any signs of cracking, fissuring, gaps between components, delamination, or detachment of the horizontal protective membrane, along with other similar phenomena.
Optionally measure and record the temperature upon the structural building member and the horizontal protective membrane, using the thermocouples specified in 9.3, at intervals not exceeding one minute
Allow the test to continue until the fire source decays naturally, unless terminated by extinguishment.
Test results
The results of temperature measurements shall be presented according to Clause 11.
Test report
The test report shall be as given in Clause 12.
The assessment
The stability of the horizontal protective membrane is determined by the absence of visible openings or deterioration as temperatures rise in the test chamber Openings or deterioration are identified when any element or component of the membrane has detached or when the edges of these components have moved away from their supporting profiles.
The assessment report
The assessment report must include the following elements: a) items a) to e) from Clause 14, b) the duration from the start of the test to the observation of any openings, detachment, or deterioration in the horizontal protective membrane, noting if these issues arose before the maximum furnace temperature was achieved, and c) a clear pass/fail statement.
Fire resistance classification should only be obtained by testing according to the standard temperature/time heating curve
Measurement of properties of horizontal protective membranes and components
General
Accurately determining the thickness, density, and moisture content of horizontal protective membranes and related materials is crucial for predicting their fire protection performance in resistance tests This annex provides guidance on consistent methods to establish these essential properties.
Any special test samples used to determine thickness, density and moisture content shall be conditioned as described in Clause 8
Any specific product standard existing for the measurement of such properties shall be followed
The procedures given in EN 1363-1 shall be followed together with the provisions of B.2 to B.4.
Thickness of horizontal protective membrane and its components
B.2.1 For horizontal protective membranes containing board or panel materials, the nominal thickness of each material shall be measured using suitable gauges or callipers in accordance with EN 12467 or EN 823
Measurements must be conducted on the actual materials during the assembly of the test specimen or on a representative special test sample, with minimum linear dimensions of 300 mm by 300 mm.
At least nine measurements shall be made including measurements around the perimeter and over the surface of the material
The design thickness used in the assessment and test reports shall be as described in 6.5
For horizontal protective membranes with sprayed passive fire protection materials, the thickness must be measured using a 1 mm diameter probe or drill This tool should be inserted into the material at each measurement point until it contacts the surface of the building element To ensure precise measurement of the surface level, the probe or drill must be equipped with a circular steel plate measuring 50 mm in diameter.
Thickness measurement points must be positioned on the horizontal protective membrane at locations that align with the main cavity temperature measuring points, T1 to T9 (T12) This configuration represents the minimum required number of thickness measurement points.
For horizontal protective membranes containing sprayed fire protection materials, the design thickness used in the assessment and test reports shall be as specified in 6.5
If a gap exists between the membrane and the structural member, and using the probe is not feasible, employ an additional standard steel plate measuring 300 x 300 mm, as detailed in section B.2.3 b).
For horizontal protective membranes with reactive fire protection coatings, the dry film thickness must be determined using at least two methods The assessment and test reports should follow the designations outlined in section 6.5 One method involves interpolating measurements taken from a standard steel plate (300 × 300 mm) coated simultaneously and using the same application technique as the horizontal membrane Measurements should be conducted at a minimum of nine points on the steel plate, including areas around the perimeter and across the surface.
The dry film thickness of reactive fire protection coatings on steel plates must be measured using instruments based on either the Electro-magnetic Induction or Eddy Current principles These coatings generally have a thickness ranging from 0.25 mm to a specified limit.
When selecting an instrument for measuring dry film thickness, it is essential to consider the 4 mm thickness of the coating Interpolation should be conducted by examining the wet film applied simultaneously and using the same method on a standard steel plate measuring 300 × 300 mm, positioned horizontally and coated from beneath.
1) determining mass of material applied per unit area and hence applied wet film thickness Interpolation to dry film thickness using expected mass loss/thickness loss specified by sponsor;
2) use of wet film thickness combs to give wet film thickness Interpolation of this using expected thickness loss to dry film thickness c) Other verifiable methods proposed by the sponsor.
Density of horizontal protective membranes and components thereof
The density of each component of the horizontal protective membrane is determined by measuring mass and dimensions For membranes made of board or panel materials, density is calculated using mass, mean thickness (from nine measurements), and area, which can be taken from the actual materials during assembly or a representative test sample with minimum dimensions of 300 mm by 300 mm The mass must be measured with a balance that has an accuracy of 0.1% of the total mass or 0.1 g, whichever is greater, ensuring the sample size has a minimum mass of 100 g.
The density of fibrous or compressible fire protection materials is directly linked to their nominal thickness For horizontal protective membranes that utilize spray-applied fire protection materials, the density must be assessed using samples taken from the material sprayed from below, ensuring accurate measurement and compliance with safety standards.
(300 × 300) mm metal trays, made from 1 mm thick steel plate The depth of the trays shall be the same as the design thickness of the spray applied protection
The preparation of the trays must follow the same method, orientation, and timing as the horizontal protective membrane system Two trays are to be prepared: one will be dried to establish a reference for dry density and moisture content, while the second tray will be utilized to measure the density at the time of testing.
The thickness of the specimen within the trays shall be determined at nine points over the surface of the trays using:
1) one at the centre (one in total),
2) two along each centre to corner axis, equidistant from each other, the centre and the corner (eight in total)
To determine the mass of fire protection within the tray, a balance with an accuracy of 0.1% of the total sample mass or 0.1 g must be used, ensuring the sample size is at least 100 g Additionally, the design density referenced in assessment and test reports must adhere to the specifications outlined in section 6.5.
It is inappropriate to measure the density of thin coatings and intumescent paint.
Moisture content of horizontal protective membrane and components thereof
To ensure accurate moisture content measurement, samples and materials must be stored alongside the test specimens under identical conditions Final moisture content should be assessed on the same day as the fire testing.
B.4.2 For horizontal protective membranes containing board or panel materials, special test samples shall be taken measuring a minimum (300 × 300) mm
They shall be weighed and dried in a ventilated oven, using the temperatures and techniques specified in
EN 1363-1 The moisture content of the specimen shall be calculated as a percentage of its moisture equilibrium weight
If the product contains, or is based on, gypsum and similar materials, drying shall take place at (40 ± 5) °C
For horizontal protective membranes that utilize spray-applied passive fire protection materials, the moisture content must be determined through a process of repeated weighing, heating, and weighing of one of the sample trays specified in section B.3 b).
They shall be weighed and dried in a ventilated oven, using the temperatures and techniques specified in
EN 1363-1 The moisture content of the specimen shall be calculated as a percentage of its moisture equilibrium weight
If the product contains, or is based on, gypsum and similar materials, drying shall take place at (40 ± 5) °C
It is inappropriate to measure the moisture of thin coatings and intumescent paint
Test method to the smouldering fire (slow heating curve)