| Fire resistance: | | | | should cover at least 500 mm on the span. |
| Introduction: | | | | Temperature: |
| This paper discusses fire resistance test for | | | | Thermocouples or plate thermometers will be |
| beams and columns as described in the British | | | | used to measure temperature, in this case there |
| standards EN 1365. for both cases the fire | | | | should be at least two thermocouples for every |
| resistance of specimen is tested in a furnace | | | | meter of the specimen. |
| where load is added and the specimen heated, | | | | They should be placed 100 mm below the surface |
| temperatures are recorded during heating and as | | | | below of the beam and 100mm from each end of |
| the specimen deforms this indicates the strength | | | | the beam |
| of the specimen, the following is a discussion on | | | | When the beam is 500m thick or greater then |
| how the test should be undertaken for both | | | | they will be placed on the side (mid height) of the |
| column and beam. | | | | beam and not the lower side |
| Requirements: | | | | If the specimen is made from inert material such |
| These standards of testing the fire resistance of | | | | as steel and aluminium then their properties are |
| a specimen are provided in the British standard EN | | | | known and the temperatures can assist in |
| 1365 part 3, according to this standards general | | | | detecting failure |
| requirements that are provided in EN 1363-1 and | | | | Deflection: |
| EN 1363-2 must be followed, according to EN | | | | The beam is expected to deform as temperature |
| 1365-3 testing for fire resistance of specimen | | | | increases, zero deformation however should be |
| involves heath hazards where toxic gases may be | | | | recorded as the nature of the axis before the |
| emitted and also disposal of residual may cause | | | | test |
| health hazards. | | | | The performance of beam will be judged with |
| Safety precautions: | | | | reference to loading capacity |
| - EN 1363-3 provides safety precautions and what | | | | Reporting: |
| should be done to avoid health risks | | | | Reports regarding such test should specify that |
| - Adequate training should be provided to the | | | | EN 1365-3 standards were used. |
| technicians | | | | Factors that may affect the fire resistance of |
| - The instructions provided in the standards must | | | | beam include: |
| be followed at all times by the technicians | | | | - The Cross sectional area of the beam |
| Beams: | | | | - Thickness of fire protection material used |
| The main aim of this test is to check the integrity | | | | - Density of material |
| of a beam that will be constructed to support a | | | | - Moisture content of the beam and coating |
| floor or roof | | | | material |
| Specimen: | | | | The diagram below shows the standard |
| - If the beam is longer than the furnace then the | | | | procedure of testing the fire resistance of a |
| length that is exposed should be greater than 4 | | | | beam |
| meters | | | | Columns: |
| - If the beam is twice the length of the furnace | | | | Specimen: |
| then the beam should be tested for shear | | | | The section that is exposed to heat should be at |
| strength and also bending moments | | | | least 3 meters long |
| - The fire exposed length (span) of the beam | | | | The specimen may be placed in the furnace |
| should be at least 4 meters long | | | | whereby one end may be pin jointed and the |
| - If the beam under normal construction contains | | | | other restrained or both ends restrained |
| joints then these joints must be incorporated at | | | | The ends of the specimen must be sealed with |
| span (exposed length) or as appropriate under | | | | mineral wool to prevent gas losses |
| normal construction | | | | The load applied to the specimen must be parallel |
| - This case shows a case where the beam is | | | | to the axis of the specimen. |
| exposed to fire on three sides and the fourth | | | | If joints are incorporated then they will be placed |
| supports the roof, the roof weight is represented | | | | at mid height and coated with fire protective |
| by the associated construction that will be placed | | | | material |
| on top side of the beam | | | | The specimen shall be placed vertically |
| - This test is not applicable to pre-stressed | | | | End conditions: |
| concrete beams | | | | End conditions are that if one end is pin jointed |
| The associated construction: | | | | then the end will comprise of a cylindrical rolled, |
| - The associated construction is the construction | | | | hinges must be accurately located on the axis of |
| that represents the load on the beam under | | | | the column, if the ends are restrained then they |
| normal circumstances example roof or floor; the | | | | must be fully restrained. |
| following are the conditions of this construction: | | | | Report: |
| - It should be constructed in discrete sections | | | | Reports regarding such test should specify that |
| - It should contain discontinuous reinforcements | | | | EN 1365-3 standards were used. |
| - Made or aerated concrete slab | | | | The test applied to: |
| - Density should be 450 – 850 kegs per | | | | Columns that are fully exposed to fire on three |
| meter cubed | | | | sides and the test will depend on end conditions; |
| - Maximum width should be 600mm | | | | small amounts of friction that may emerge at the |
| - Thickness should be 175 – 125 mm | | | | ends will considerable increase the load bearing |
| - Should be placed symmetrically to the axis of | | | | capacity of the test specimen. |
| the beam | | | | Temperature: |
| - The size of the beam will also be determined by | | | | Temperature will be measured using |
| the furnace size and design. | | | | thermocouples or plate thermometers, these |
| Fire protection material: | | | | devices will be placed ¼, ½ and ¾ of the |
| Specimens are sometimes sealed with fire | | | | length on the exposed part of the column |
| protection materials; if these materials are applied | | | | Thermometers should be at least placed 50 to |
| then they must be applied on the entire length of | | | | 150 mm from the column facing the column. Also |
| the specimen | | | | if column is made of composite material example |
| Where a void or hole is created in the beam the | | | | steel and concrete then temperature for individual |
| hole should not extend outside the furnace | | | | components is important |
| Gaps that may exist between the furnace wall | | | | Behaviour after heating: |
| and associated construction shall be sealed | | | | The specimen is expected to deform, and |
| Installation of the specimen: | | | | therefore zero deformation sill be measured |
| - The ends of the beam should be sealed with fire | | | | before the beginning of the test and deformation |
| protection material to prevent gas linkages | | | | will be measured using a dial gauge. |
| - Joints that may be incorporated should also be | | | | This will result due to a number of factors, one is |
| sealed | | | | because the moisture is lost and the specimen |
| - Ends of the beam shall be sealed with mineral | | | | shrinks, loss of moisture will result into a decline in |
| wool | | | | the cross sectional area and therefore loss of |
| - Mineral wool should be 90 mm to 110 mm thick | | | | strength. |
| and density should 90 to 150 kg per meter cubed | | | | For materials such as steel columns, they will |
| - Finally the specimen should be mounted | | | | expand and will contract as the column deflects. |
| horizontally | | | | Steel tubes filed with concrete will expand and |
| The load (associated construction); | | | | still be able to hold the concrete inside, however |
| - The load should match the expected load that | | | | further heating will result into deformation, steel |
| the beam is expected to bear in practice | | | | tubes filled with timber then the initially there will |
| - The load which is the associated construction | | | | be no change but further heating deformation will |
| should be placed uniformly on the beam and | | | | occur. |