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Testing a fire door is not as straightforward as it may sound. Mark Cummings explains the testing and certification process, and how the results can be interpreted to widen the scope of products covered.
In the built environment, there is often a legal requirement for products such as doors, screens, partitions and ceilings to resist the passage of fire and so control its spread, protecting life by allowing the occupants to escape and the fire services to gain access to fight the fire. The location and period of fire resistance required for construction products is determined by legislation, codes of practice or the ‘accepting authority’ – usually a local authority building control department.
Fire resistance is proven through destructive fire testing and by assessment. Manufacturers or designers submit their products to a UKAS (United Kingdom Accreditation Service) accredited test facility, such as Chiltern International Fire. Such third party certification demonstrates a consistency of manufacture which, in combination with test evidence, provides the confidence that every product will perform as expected.
A number of test standards are used to show the performance of a product or construction under a generalised fire situation, the main ones being the
BS 476: Part 20 series and European standards for different types of building element. These can be broken down into:
– Doors and partitions
BS 476: Part 22/BS EN 1634-1
– Load bearing walls
BS 476: Part 21/BS EN 1365-1
– Non-loadbearing walls, partitions and glazed screens
BS 476: Part 22/BS EN 1364-1
– Loaded floors
BS 476: Part 21/BS EN 1365-2
– Ceilings BS EN 1364-2
The tests under BS 476: Part 22 and
BS EN 1634-1 are designed to simulate the intended end use of the products so that, for example, doors are built into an appropriate supporting construction. Specifically, the specimen and any relevant supporting construction is built into a 3m x 3m restraint frame which is mounted on the front of a furnace. The temperature within the furnace is controlled according to an internationally accepted time/temperature regime which, together with the pressure regime under the standard, is intended to represent a post flashover condition – the point at which all objects in the fire compartment have ignited.
In a real fire, the time period to flashover can be extremely variable and is controlled by factors such as the nature of the fire load, compartment size and shape and the available ventilation. Given the unknown time to flashover, it is therefore only appropriate to represent a fire scenario from the point of flashover and not to consider the fire growth period.
Testing is then continued for the required duration – 30, 60, 90, 120 minutes etc – or until the specimen fails and it is no longer safe to continue. Failure relates to integrity, insulation and radiation and is determined by the following criteria:
– Continuous flaming integrity: simply the fact that sustained flaming (more than 10 seconds) has occurred on the non-fire side.
– Cotton pad integrity: this shows that gases passing through the specimen are sufficiently hot to ignite combustible material on the non-fire side and therefore spread the fire. A cotton pad is employed by mounting the pad against the specimen on any glowing or flaming.
– Gap gauges 6mm or 25mm integrity: these measure the width of gaps in the specimen and evaluate the rate of specimen deterioration, which must remain below prescribed levels.
– Insulation: This is measured by attaching thermocouples – each of which is logged throughout the test – to determine an insulation failure to the unexposed face at positions stated in the relevant standards. The insulation failures occur when either an individual thermocouple on the sample reaches 180 degrees C above laboratory ambient conditions or, as an average group of thermocouples, 140 degrees C above laboratory conditions.
– Radiation (total heat flux): The radiation from the sample is measured for non-insulating samples and is measured using a heat flux radiometer, which is positioned central to the sample and 1m away. The levels are measured in kw/m2, and the sample is deemed to have failed once 15kw/m2 is reached.
The process
The actual process of testing is relatively straightforward: a manufacturer or designer simply submits a specimen and the test house installs it within a suitable structural surround and tests it. However, for a manufacturer to determine what size and configuration to test is a little more complicated because there are many options for the designer to consider in order to cover final market requirements, such as different types of hardware and different glazing options.
Once a product has been tested, a report will be issued that will contain all the construction details of the tested specimen, together with information on the size and configuration of the test sample. The test report itself is a purely factual document, stating the results of the testing. Other relevant information such as observations taken by the test engineers, graphs showing furnace and specimen temperatures and distortions (if applicable) will also be contained within the final test report.
Test reports only relate to what has been tested and allow little in the way of variations. Changes to a construction tested under the British or European standards will either require another fire test, or an assessment.
An assessment is a desktop study undertaken by an experienced fire consultant that allows variations from a tested design. The nature and scope of any variations will largely depend on the size and configuration of the test specimen. So it is important that discussions take place between the manufacturer and the testing laboratory before testing takes place, to establish the requirements for the complete product range intended for the market. The laboratory will advise whether a single test is appropriate or whether a series of tests will be required to meet the intended end-use applications.
Once the test programme has been completed (and all results are successful), test houses such as Chiltern Fire write a Global Assessment report that will bring together all the various items of test data into a single document. This becomes the document upon which the client will trade as it will clearly explain the full scope of the product. Global Assessments can bring together the results of multiple tests and provide a scope based upon all of the evidence.
Project-specific assessments tailored to the specific needs of a building project can also be produced. Assessments cover various aspects of design including:
– How to adjust the leaf dimensions and whether leaf size adjustment is appropriate.
– The use of overpanels and how to install them.
– Acceptable increases in leaf dimensions (height and width).
– Acceptable changes in doorset configurations (single leaf, double leaf, single acting, double acting).
– The use of and installation of glazed apertures.
– The option to use various glass types.
– Door frame variations if appropriate.
– Smoke control requirements
Once all the evidence is in place and any assessment report has been prepared, we would recommend that the manufacture of the product be undertaken as part of a quality management system audited by a third party. This will ensure that the quality of the product, when sold to an end-user, is similar to the tested specimen and would be expected to achieve the minimum stated fire resistance period that has been tested and claimed. Such inspections of manufacture are carried out through a third party accreditation scheme. The complete manufacturing process must be quality controlled to the relevant ISO standard (or similar system), with the process audited yearly to ensure that areas such as calibration of equipment, handling of materials, stock control and documentation are all controlled appropriately. Further audit testing of the product is also required as a part of this type of accreditation scheme every three years, which will physically highlight any weak areas in the manufacturing process.
Installation
Evidence has shown time and time again that many of the faults relating to fire doors occur on site. Fire resisting doorsets should be manufactured, and ideally installed by, companies which can demonstrate – through third-party certification – that they are experts in this field. Furthermore, we strongly recommend that specifiers choose, wherever possible, a complete manufactured doorset rather than individual components which may not be correctly assembled on site. If it is not feasible to specify a complete doorset, it is important to ensure that there is precise and definite test/assessment data supporting use of the selected components, in addition to detailed instructions for their assembly. If this is not done, installers should not attempt to ‘have a go’ but should contact the manufacturer. If no instructions are forthcoming or if the information supplied is inadequate, the doorset should be installed in accordance with BS 8214: 1990, Code of practice for fire door assemblies with non-metallic leaves. The contractor should be made aware that it has not been possible to install the doorset to the manufacturer’s instructions and to inform the building owner accordingly.
Mark Cummings is section head of fire testing at Chiltern International Fire. Chiltern, together with BM TRADA, run Timber Fire Doors Explained training days which include a full-scale fire door test demonstration. Dates for 2008 include 7th May, 26th June, 25th September and 20th November. For further details or to make a booking, telephone 01494 569620 or email training@chilternfire.co.uk
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Testing a fire door is not as straightforward as it may sound. Mark Cummings explains the testing and certification process, and how the results can be interpreted to widen the scope of products covered.
In the built environment, there is often a legal requirement for products such as doors, screens, partitions and ceilings to resist the passage of fire and so control its spread, protecting life by allowing the occupants to escape and the fire services to gain access to fight the fire. The location and period of fire resistance required for construction products is determined by legislation, codes of practice or the ‘accepting authority’ – usually a local authority building control department.
Fire resistance is proven through destructive fire testing and by assessment. Manufacturers or designers submit their products to a UKAS (United Kingdom Accreditation Service) accredited test facility, such as Chiltern International Fire. Such third party certification demonstrates a consistency of manufacture which, in combination with test evidence, provides the confidence that every product will perform as expected.
A number of test standards are used to show the performance of a product or construction under a generalised fire situation, the main ones being the
BS 476: Part 20 series and European standards for different types of building element. These can be broken down into:
• Doors and partitions
BS 476: Part 22/BS EN 1634-1
• Load bearing walls
BS 476: Part 21/BS EN 1365-1
• Non-loadbearing walls, partitions and glazed screens
BS 476: Part 22/BS EN 1364-1
• Loaded floors
BS 476: Part 21/BS EN 1365-2
• Ceilings BS EN 1364-2
The tests under BS 476: Part 22 and
BS EN 1634-1 are designed to simulate the intended end use of the products so that, for example, doors are built into an appropriate supporting construction. Specifically, the specimen and any relevant supporting construction is built into a 3m x 3m restraint frame which is mounted on the front of a furnace. The temperature within the furnace is controlled according to an internationally accepted time/temperature regime which, together with the pressure regime under the standard, is intended to represent a post flashover condition – the point at which all objects in the fire compartment have ignited.
In a real fire, the time period to flashover can be extremely variable and is controlled by factors such as the nature of the fire load, compartment size and shape and the available ventilation. Given the unknown time to flashover, it is therefore only appropriate to represent a fire scenario from the point of flashover and not to consider the fire growth period.
Testing is then continued for the required duration – 30, 60, 90, 120 minutes etc – or until the specimen fails and it is no longer safe to continue. Failure relates to integrity, insulation and radiation and is determined by the following criteria:
• Continuous flaming integrity: simply the fact that sustained flaming (more than 10 seconds) has occurred on the non-fire side.
• Cotton pad integrity: this shows that gases passing through the specimen are sufficiently hot to ignite combustible material on the non-fire side and therefore spread the fire. A cotton pad is employed by mounting the pad against the specimen on any glowing or flaming.
• Gap gauges 6mm or 25mm integrity: these measure the width of gaps in the specimen and evaluate the rate of specimen deterioration, which must remain below prescribed levels.
• Insulation: This is measured by attaching thermocouples – each of which is logged throughout the test – to determine an insulation failure to the unexposed face at positions stated in the relevant standards. The insulation failures occur when either an individual thermocouple on the sample reaches 180°C above laboratory ambient conditions or, as an average group of thermocouples, 140°C above laboratory conditions.
• Radiation (total heat flux): The radiation from the sample is measured for non-insulating samples and is measured using a heat flux radiometer, which is positioned central to the sample and 1m away. The levels are measured in kw/m2, and the sample is deemed to have failed once 15kw/m2 is reached.
The process
The actual process of testing is relatively straightforward: a manufacturer or designer simply submits a specimen and the test house installs it within a suitable structural surround and tests it. However, for a manufacturer to determine what size and configuration to test is a little more complicated because there are many options for the designer to consider in order to cover final market requirements, such as different types of hardware and different glazing options.
Once a product has been tested, a report will be issued that will contain all the construction details of the tested specimen, together with information on the size and configuration of the test sample. The test report itself is a purely factual document, stating the results of the testing. Other relevant information such as observations taken by the test engineers, graphs showing furnace and specimen temperatures and distortions (if applicable) will also be contained within the final test report.
Test reports only relate to what has been tested and allow little in the way of variations. Changes to a construction tested under the British or European standards will either require another fire test, or an assessment.
An assessment is a desktop study undertaken by an experienced fire consultant that allows variations from a tested design. The nature and scope of any variations will largely depend on the size and configuration of the test specimen. So it is important that discussions take place between the manufacturer and the testing laboratory before testing takes place, to establish the requirements for the complete product range intended for the market. The laboratory will advise whether a single test is appropriate or whether a series of tests will be required to meet the intended end-use applications.
Once the test programme has been completed (and all results are successful), test houses such as Chiltern Fire write a Global Assessment report that will bring together all the various items of test data into a single document. This becomes the document upon which the client will trade as it will clearly explain the full scope of the product. Global Assessments can bring together the results of multiple tests and provide a scope based upon all of the evidence.
Project-specific assessments tailored to the specific needs of a building project can also be produced. Assessments cover various aspects of design including:
• How to adjust the leaf dimensions and whether leaf size adjustment is appropriate.
• The use of overpanels and how to install them.
• Acceptable increases in leaf dimensions (height and width).
• Acceptable changes in doorset configurations (single leaf, double leaf, single acting, double acting).
• The use of and installation of glazed apertures.
• The option to use various glass types.
• Door frame variations if appropriate.
• Smoke control requirements
Once all the evidence is in place and any assessment report has been prepared, we would recommend that the manufacture of the product be undertaken as part of a quality management system audited by a third party. This will ensure that the quality of the product, when sold to an end-user, is similar to the tested specimen and would be expected to achieve the minimum stated fire resistance period that has been tested and claimed. Such inspections of manufacture are carried out through a third party accreditation scheme. The complete manufacturing process must be quality controlled to the relevant ISO standard (or similar system), with the process audited yearly to ensure that areas such as calibration of equipment, handling of materials, stock control and documentation are all controlled appropriately. Further audit testing of the product is also required as a part of this type of accreditation scheme every three years, which will physically highlight any weak areas in the manufacturing process.
Installation
Evidence has shown time and time again that many of the faults relating to fire doors occur on site. Fire resisting doorsets should be manufactured, and ideally installed by, companies which can demonstrate – through third-party certification – that they are experts in this field. Furthermore, we strongly recommend that specifiers choose, wherever possible, a complete manufactured doorset rather than individual components which may not be correctly assembled on site. If it is not feasible to specify a complete doorset, it is important to ensure that there is precise and definite test/assessment data supporting use of the selected components, in addition to detailed instructions for their assembly. If this is not done, installers should not attempt to ‘have a go’ but should contact the manufacturer. If no instructions are forthcoming or if the information supplied is inadequate, the doorset should be installed in accordance with BS 8214: 1990, Code of practice for fire door assemblies with non-metallic leaves. The contractor should be made aware that it has not been possible to install the doorset to the manufacturer’s instructions and to inform the building owner accordingly.
Mark Cummings is section head of fire testing at Chiltern International Fire. Chiltern, together with BM TRADA, run Timber Fire Doors Explained training days which include a full-scale fire door test demonstration. Dates for 2008 include 7th May, 26th June, 25th September and 20th November. For further details or to make a booking, telephone 01494 569620 or email training@chilternfire.co.uk