Fire resistance standards for testing of construction systems

This article provides the necessary details on fire resistance test standards related to the ability of a specimen of system construction to prevent the spread of flame or smoke in a fully developed fire, and maintain structural stability of the tested specimen.

Testing the fire resistance of a building element involves determining its behaviour when exposed to a particular heating condition and pressure, normally those representing a fire in an enclosed space, e.g. a room. Fire resistance is one of several properties of a structure or system, and thus is not simply a property of the specific materials used in the structure or system.

The resistance to fire performance test standards most commonly referred to are the British Standards (BS 476: Parts 20 to 24). The European Norms (EN 1363 to 1366) will gradually replace BS 476 and the current equivalents are given below. In the European norms, the building elements and structures are to be tested and classified with regard to their fire separation performance and smoke tightness according to a system that indicates the properties by a letter, e.g. R, E or I, and an index that indicates the time that each specific property is maintained.

◆ European standards

EN 13501: Part 2: 2016 - Fire classication of construction products and building elements (Part 2: Classification using data from fire resistance tests, excluding ventilation services)
This standard aims to harmonise procedures for classification for resistance to fire of construction products and elements based on defined test procedures using data from fire resistance and smoke leakage tests.

EN 1363: Part 1: 2012 - Fire resistance tests (Part 1: General requirements)
This part establishes the general principles for determining the fire resistance of various elements of construction, where aspect and test procedures are common to all specific test methods.

EN 1363: Part 2: 1999 - Fire resistance tests (Part 2: Alternative and additional procedures)
This part identifies a specific heating scenario where standard conditions given in EN 1363: Part 1 are inappropriate due to other additional factors that need to be considered, such as the nature of the products or systems, intention of use and regulatory requirements. Alternative conditions include the hydrocarbon curve, slow heating and external fire exposure curves.

EN 1364: Part 1: 2015 - Fire resistance tests for non-load bearing elements (Part 1: Walls)
The purpose of test is to measure the ability of representative specimens of non-load bearing walls, both with and without glazing for internal and external construction, except for curtain walls and walls with door sets.

EN 1364: Part 2: 2018 - Fire resistance tests for non-load bearing elements (Part 2: Ceilings)
This test is applicable to ceilings which are either suspended by hangers or fixed directly to a supporting frame, and self-supporting ceilings. Test of ceilings are carried out in two modalities, i.e. fire from below the ceiling with no cavity above, and fire from above the ceiling where fire is contained in a closed cavity.

EN 1364: Part 3: 2014 - Fire resistance tests for non-load bearing elements (Part 3: Curtain walling – full con?guration, complete assembly)
This method is applicable to curtain walling systems, supported by floor slab(s) designed for the purpose of providing fire resistance determined under internal or external exposure conditions.

EN 1364: Part 4: 2014 - Fire resistance tests for non-load bearing elements (Part 4: Curtain walling – part configuration)
This standard specifies the method for determining the fire resistance of parts of curtain walling incorporating non-fire resistant infill product to internal or external fire exposure. The test method includes assessment regarding falling parts that are liable to cause personal injury. It can also be used to determine any increase in the field of application for fire resistance of parts of curtain walling tested to EN 1364: Part 3.

EN 1365: Part 1: 2012 - Fire resistance tests for load bearing elements (Part 1: Walls)
This test measures the ability of a representative specimen of a load bearing wall to resist spread of fire from one side and maintain its load bearing capacity. The test is applicable to internal and external walls under internal or external exposure conditions.

EN 1365: Part 2: 2014 - Fire resistance tests for load bearing elements (Part 2: Floors and roofs)
This part specifies the method for determining the fire resistance of floor construction without cavities or with unventilated cavities, roof construction with or without cavities (ventilated or unventilated) and floor or roof construction incorporating glazed elements. Fire exposure is from the underside.

EN 1365: Part 3: 1999 - Fire resistance tests for load bearing elements (Part 3: Beams)
This part specifies the method for determining the fire resistance of beams with or without applied fire protection systems, and with or without cavities. The fire resistance of beams is assessed against load bearing capacity criteria.

EN 1365: Part 4: 1999 - Fire resistance tests for load bearing elements (Part 4: Columns)
This part specifies the method for determining the fire resistance of columns when fully exposed to fire on all sides. The fire resistance of the column is assessed against load bearing capacity criteria.

EN 1366: Part 1: 2014 - Fire resistance tests for service installations (Part 1: Ventilation ducts)
This part specifies the method for determining the fire resistance of vertical and horizontal ventilation ducts under standardised fire conditions. The test examines fire resistance for ducts exposed to fire from outside (Duct A) and fire inside the duct (Duct B). The performance of the ducts is assessed against integrity, insulation and smoke leakage criteria.

EN 1366: Part 2: 2015 - Fire resistance tests for service installations (Part 2: Fire dampers)
The purpose of this test is to evaluate the ability of mechanical devices such as fire dampers to prevent fire, smoke and gases spreading at high temperature from one compartment to another through the air ductwork system which may penetrate fire separating walls and floors. Temperature and integrity measurements are carried out on parts of a test construction. The impermeability of a fire damper system is measured by direct flow measurement whilst maintaining a constant pressure differential across the closed fire damper. The tightness of the fire damper in a closed position is measured at ambient temperature.

EN 1366: Part 3: 2009 - Fire resistance tests for service installations (Part 3: Penetration seals)
This part provides a method of testing to assess the contribution of the penetration sealing system to the fire resistance of separating elements when penetrated by service(s). The purpose of the test is to assess the effects of such penetration to the integrity and insulation performance of the separating element concerned, the integrity and insulation of the penetration sealing system, the insulation performance of the penetrating service(s), and the integrity failure of a service.

EN 1366: Part 4: 2006+A1:2010 - Fire resistance tests for service installations (Part 4: Linear joint seals)
The purpose of this test is to assess the effect of a linear joint seal on the integrity and insulation of the construction, as well as the integrity and insulation performance of the linear joint seal. The effect of movement of the supporting construction on the fire performance of the linear joints seals is also assessed.

EN 1366: Part 5: 2010 - Fire resistance tests for service installations (Part 5: Service ducts and shafts)
The purpose of this test is to measure the ability of a representative horizontal service duct or vertical service shaft which passes through a floor or walls and enclosed pipes and cables to resist the spread of fire from one compartment to another. The test examines the behaviour of ducts and shafts with regard to a fire from the outside or inside. The performance of ducts and shafts is assessed against integrity and insulation criteria.

EN 1366: Part 6: 2004 - Fire resistance tests for service installations (Part 6: Raised access and hollow core floors)
This part specifies the method of testing for representative samples of a raised or hollow floor when exposed to a specified regime of heating and loading. Exposure to fire is from within the plenum, beneath the floor. The fire exposure applied may be either the standard or reduced (maintained up to 500°C) time temperature curve. Performance criteria are assessed against insulation, integrity and load bearing capacity.

EN 1366: Part 8: 2004 - Fire resistance tests for service installations (Part 8: Smoke extraction ducts)
This part has been prepared to evaluate fire resistant ducts tested to EN 1366-1 (Duct A and Duct B) and to function adequately as smoke extraction ducts. The smoke extraction ducts pass through another compartment from the fire compartment to be extracted in case of fire, and in a fully developed fire. The test is only suitable for four-sided ducts constructed from non-combustible materials (Euroclass A1 and A2). Leakage is measured at ambient and elevated temperatures. Performance criteria are assessed against smoke leakage, insulation, integrity and mechanical stability.

EN 1366: Part 9: 2008 - Fire resistance tests for service installations (Part 9: Single compartment smoke extraction ducts)
This part specifies a test method for determining the fire resistance of smoke extraction ducts that are used for single compartment applications only. In such applications, the smoke extraction system is only intended to function up to flashover (typically 600°C). This method of testing is only suitable for ducts constructed from non-combustible materials (Euroclass A1 and A2-s1, d0). It is applicable only to four-sided and circular ducts. This test has been designed to cover horizontal smoke extraction ducts intended for single compartment applications only. This test method of part 9 is applicable only to smoke extraction ducts that do not pass through into other fire compartments. It represents fire exposure of a developing fire (pre-flashover). For smoke extraction ducts that pass through into other compartments, the method of testing described in EN 1366-8 should be used.

EN 1634: Part 1: 2014+A1:2018 - Fire resistance and smoke control tests for door and shutter assemblies, openable windows and elements of building hardware (Part 1: Fire resistance test for door and shutter assemblies and openable windows)
This part specifies the method for determining door and shutter assemblies designed for installation within openings incorporating vertical separating elements, including hinged and pivoted doors, horizontal and vertical sliding doors and uninsulated steel single-skin folded shutters. Performance criteria are assessed against insulation, integrity and radiation.

◆ British standards

BS 476: Part 20: 1987 (BS EN 1363: Part 1: 2012) - Methods for determination of the ?re resistance of construction elements (general principles)
This part describes the general procedures and equipment required to determine the fire resistance of construction elements. It should be read in conjunction with BS 476: Parts 21 to 24 as appropriate, which describe the detailed procedure for the testing of individual construction elements.

BS 476: Part 21: 1987 (BS EN 1365: Parts 1 to 4) - Methods for determination of the ?re resistance of load bearing construction elements
This standard describes methods for determining the fire resistance of load bearing beams, columns, floors, flat roofs and walls. Beams and columns are assessed in terms of load bearing capacity while dividing elements such as floors, flat roofs and walls are measured in terms of load bearing capacity, integrity and insulation.

BS 476: Part 22: 1987 (BS EN 1364: Parts 1 and 2: 1999) - Methods for determination of the ?re resistance of non-load bearing construction elements
This standard describes methods for determining the fire resistance of non-load bearing partitions, door sets, shutter assemblies, ceiling membranes and glazed elements of construction with respect to integrity and, where appropriate, insulation.

BS 476: Part 23: 1987 - Methods for determination of the contribution of components to the ?re resistance of a structure
This standard describes test methods for determination of the contribution of suspended ceilings to the fire resistance of steel beams, as well as for determination of the contribution of intumescent seals to the fire resistance of timber door assemblies.

BS 476: Part 24: 1987 (BS EN 1366: Part 1: 1999) - Methods for determination of the ?re resistance of ventilation ducts
This standard describes the methods used to test and measure the ability of a duct assembly to prevent the spread of fire from one fire compartment to another. Results are expressed in terms of stability, integrity and insulation.

BS 7346-3:1990 (BS EN 12101-1:2005) - Components for smoke and heat control systems
This standard describes methods for determining the fire resistance of smoke curtains where those items are used as part of a smoke control system.

◆ International standards

ISO 834: Part 1: 1999 - General requirements
This part specifies general principles regarding equipment, instrumentation and procedures on the method of determining the fire resistance of various elements of constructions when subjected to standard fire exposure conditions.

ISO 834: Part 4: 2000 - Specific requirements for load bearing vertical separating elements
This part is applicable to vertical load-bearing separating elements of building construction when exposed to fire on one side. The fire resistance performance of the tested specimen is assessed against insulation, integrity and load-bearing capacity.

ISO 834: Part 5: 2000 - Specific requirements for load bearing horizontal separating elements
This part is applicable to horizontal separating load bearing elements of building construction such as floors and roofs, including load bearing elements containing beams, when exposed to fire from the underside. The fire resistance performance of the tested specimen is assessed against insulation, integrity and load bearing capacity.

ISO 834: Part 6: 2000 - Specific requirements for beams
This part specifies the procedures for determining the fire resistance of beams when tested on their own with their underside and two vertical sides exposed to heating, otherwise appropriate exposure conditions have to be reproduced. The beam is assessed against load bearing capacity criteria.

ISO 834: Part 7: 2000 - Specific requirements for columns
This part specifies the procedures for determining the fire resistance of columns when tested on their own. The column is tested fully exposed to fire on all sides, unless other appropriate exposure conditions have to be reproduced. The column is assessed against load bearing capacity criteria.

ISO 834: Part 8: 2000 - Specific requirements for non-load bearing vertical separating elements
This part is applicable to vertical separating elements of building construction when exposed to fire on one side. The fire resistance performance of the tested specimen is assessed against insulation and integrity criteria.

ISO 834: Part 9: 2003 - Specific requirements for non-load bearing ceiling elements
This part determines the fire resistance performance of a ceiling assessed against insulation and integrity criteria, when exposed to heating below the ceiling. The test method is applicable to self-supporting ceiling and suspended ceiling construction.

◆ Australian standards

AS 1530: Part 4: 2005 - Fire resistance test of construction elements
The standard follows the general principles and procedures contained in the ISO 834 series and other related documents, but consolidates them in one document. This standard provides a method for determining the fire resistance of building elements including walls, floors, roofs, ceilings, columns, beams, door sets, uninsulated glazing, air ducts, service penetrations and fire damper assemblies. The Building Code of Australia (BCA) recognises compliance with the code when the relevant system of construction is tested in accordance with this standard.

AS 4072: Part 1: 2005 - Components for the protection of openings in ?re resistant separating element (Part 1: Service penetrations and control joints)
This part specifies the requirements for testing, interpretation of the test results, and installation of penetration sealing systems and control joints sealing systems in fire resistant elements of construction. The standard is based on the testing of standard configurations and provides minimum requirements for these fire stopping systems. It is intended to complement the fire protection requirements of the BCA and is to be read in conjunction with the testing regimes outlined in AS 1530: Part 4.

AS 5113 - Fire propagation testing and classification of external walls of buildings
This provides an accurate indication of the fire performance of wall claddings and wall assemblies. AS 5113 will be referenced in a new verification method that will enable industry to verify the fire performance of external cladding systems against the relevant performance requirements of the NCC.

AS 1530.1 - Small Scale vs Large Scale
Non-combustible:  Not deemed combustible as determined by AS 1530.1 [NCC 2019 Vol 1]

Over recent months there has been some contention in the industry if the combustibility test AS 1530.1 is a reliable measure of safety and compliance. Criticised as a small-scale component test, it has performance requirements few products can pass. Large scale testing is often touted as a superior alternative.
 
◆ Component testing

AS 1530.1 is a simple yet severe test method that has been used over decades. Simplified, if a sample in a small furnace flames for more than 5 seconds in a 30 minute period the sample is deemed combustible. The test is very severe and designed to allow a maximum of 0.5% combustible content. Many international building codes reference AS 1530.1 equivalents (such as ISO 1182, BS 476.4 or ASTM E136), but then provide for other avenues of compliance that are less onerous.

The Australian National Construction Code (NCC) requirement for non-combustibility of external walls to AS 1530.1 is based on the simple premise - a wall comprised of non-combustible components is extremely unlikely to spread fire. Engineers Australia have said “The building code is quite clear, you cannot have combustible external walls. It is looking at it from a fire engineering point of view; how each product impacts the building and the risk of it on an individual basis.” In other words, if the risk of each component is nil, then the overall wall risk is correspondingly low. There are many well documented external wall cladding failures in Australia and internationally. These are all products that do not or would not comply with AS 1530.1.

◆ Large scale testing

Alternative evidence of compliance permitted under the building code is through large scale testing to AS 5113 (or similar under a Performance Solution). The NCC is quite deliberate in presenting large scale testing as an alternative, as limiting compliance to AS 5113 only would create some insurmountable issues for compliance. In particular, only one wall system is represented in each test. Given a single building features multiple wall designs this building would require multiple tests. Extend this to many buildings and the amount of tests are prohibitive.

For example, the UK had a significant facade fire at Garnock Court in 1999 which lead to the creation of their BS 8414 large scale test (which the AS 5113 is based on). Post the Grenfell tragedy, the UK government commissioned 7 large scale BS 8414 tests to understand how a variety of Aluminium Composite Panels perform in conjunction with a range of insulation products. This has resulted in 7 different tests with a range of unique wall and window opening constructions. These are very useful for assessing walls built in that exact method, but are unreliable for managing compliance or safety of the many differing designs.

Additionally BS 8414 large scale testing historically was designed for testing projects, not products. Product manufacturers may arrange testing (which if used needs to be reflected in the details onsite) but the reality is buildings are not built with a narrow range of unique wall details. This is demonstrated in the NCC verification method CV3 incorporating AS 5113. While CV3 has been in the market for over two years, and there are several manufacturers who have complete AS 5113 passes, no project I am aware of has yet used the CV3 route to compliance.

Another concept raised in favour of limiting compliance to large scale testing is waterproofing. Waterproofing relies on system performance - compliance is not to merely state the components are waterproof. However waterproofing and fire performance are two very different concepts and should not be compared.

Waterproofing is resisting water molecules driven by gravity or air. On the other hand, fire is a chemical reaction, which needs three components – fuel, heat and oxygen. Simply, fire performance by non-combustibility is removing the fuel, and therefore the fire.

However, I am not trying to make the point that AS 5113 is deficient. It is not that AS 5113 is inappropriate, but that large scale tested systems cannot be selected as the only route to compliance in lieu of all other methods. In reality, AS 1530.1 and AS 5113 are not better or worse than each other, but have different intentions and these need to be understood.

◆ Allowances and Bonded Laminates

The extremely high requirements of AS 1530.1 do challenge the industry with complying with other requirements than fire, such as weather-tightness, condensation management, environmental sustainability, durability and finish aesthetics. To achieve these other purposes the ABCB has specifically selected certain exclusions to these requirements under C1.9d and C1.9e to improve overall wall performance.

These exclusions allow for the use of product with reduced or removed test requirements. For instance, the following products can be used without testing to AS 1530.1:

Compressed Fibre Cement
Plasterboard
Sarking
Sealant
Painted sheet metal
The one provision that still maintains AS 1530.1 is the bonded laminates clause, which also requires additional testing to AS 1530.3. Allowing a small specific amount of adhesive between non-combustible layers, it is used for a range of external wall products including reflective insulation, insulated sandwich panels and lightweight cladding such as our Vitracore G2.

While the adhesive content is sometimes criticised, the NCC recognises these products are relatively low risk and unlikely to present a fire safety hazard. These products again demonstrate why the NCC relies on AS 1530.1 for compliance, preventing flame propagation. This theory has been demonstrated many times in both large-scale testing and real life fire scenarios.

The latest case involved an 8th floor unit in Melbourne's CBD. When a lit cigarette end started a fire amid books, papers and personal effects on a balcony with no external sprinklers, residents feared for the worst. But even at the fire locus, the Vitracore G2 cladding did not spread the blaze: The MFB report notes no signs of fire to external surfaces of the building, except to walls near the fire source. The exteriors were also clad in Vitracore G2, yet evidence shows zero facade ignition during the fire's 20+ minute duration.

◆ Conclusion

Let us not criticise AS 1530.1, but use it sensibly – there is no evidence that Deemed-to-Satisfy products have significantly contributed to fire on a building. AS 1530.1 is not the cause of Australia’s cladding problems, nor is AS 5113 the saviour.

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