BS/EN 15254-5-2-2018 pdf download.Extended application of results from fire resistance tests – Non-loadbearing walls Part 5: Metal sandwich panel construction.
Metal faced sandwich panels consist of three main materials (facing metal sheets, adhesive and core material). In the case of auto adhesively bonded panels the foamed core material also forms the adhesive layer during the foaming process.
Changes in the properties of the metal sheets will not affect the tire resistance results significantly and changes can therefore be allowed. On the other hand even small changes in the core material can result in big variations in the fire resistance test results. These facts are taken into account in the following rules.
5.2.2 VariatIons In the metal sheets
5.2.2.1 Variations in the coatings
The most essential property of the coating regarding tire resistance is the emissivity on the unexposed side. Normally the emissivity for a coated steel sheet is between 0,8 and 0,95. A change in emissivity of – 10 % for a new coating compared to the tested one is thus allowed if there is at least a 10 % margin in the insulation test result compared to the I-classification. Test results are always valid for coatings with higher emissivity values compared to the tested one. When a change in coating is made the manufacturer of the coated sheet shall provide emissivity properties for the products.
A non-coated metal sheet can have an emissivity as low as 0,1. A change from a coated to a non- coated sheet is therefore not allowed. The same rule as for coatings above applies also in this case. A change in emissivity of – 10 % is allowed lithe emissivities for the different sheets are known.
The energy content of the coating on the exposed side is small and will not affect the fire resistance properties of the sandwich panel. Test results are valid for all coatings.
If modifications in the coatings on the unexposed side are made compared to the tested one, the reaction to tire classification of the product shall be the same or better than the tested one. Test results are though valid for all colours of the same type of coating.
5.2.2.2 Variations in the metal material
The following rules are valid for extended applications:
a) when steel is tested the test results are valid for all grades of steel;
NOTE For more information regarding metal faces see EN 14509.
b) when stainless steel is tested the test results are valid for all grades of stainless steel;
c) for other types of metals the test result is valid for tested type only.
5.2.3 Variations in the adhesive
This paragraph is valid only for panels with adhesively bonded cores. The following rules apply for an adhesive with no strength at high temperatures (>500 °C) which means that the metal sheet on the exposed side will disconnect from the core in the very beginning of a lire and the construction will lose its sandwich capability. For this reason an organic adhesive cannot be changed to a non.organic one or vice versa.
Normally the energy content of the adhesive is small and will not affect the fire resistance properties of the sandwich panel. The following rules are valid for extended applications:
a) For panels tested with PCS values of the adhesive ≤ 4 MI/rn2, the results are valid for all adhesives when PCS value stays below 4 Mi/rn2.
b) For panels tested with PCS value of the adhesive> 4 Mi/rn2, the results are valid for all PCS values of the adhesive up to 1,15 x PCS of the tested one.
c) For panels tested with PCS value of the adhesive > 4 MI/rn2 and> 1,15 x PCS, test results in minutes shall be reduced by the same percentage as the PCS value is over the initial tested adhesive.
5.2.4 Variations in the core material
5.2.4.1 General
Main core materials are defined in EN 14509. The behaviour regarding fire is different and
cannot be compared. Changes from one core material to another are therefore not allowed.
Variations within each core material type are allowed in accordance with the rules given in
5.2.4.2 to 5.2.4.6.
There are several factors in the different core materials that affect the fire properties of the core and of the sandwich panel. It is therefore not possible to extend the results from one core material producer to another core material producer.
5.2.4.2 MIneral wool (MW)
Generally the greater the density of the mineral wool the higher Is the flexural strength of the panel. Density will be dictated by room-temperature structural design requirements. However, variation in density affects the I-insulation value. The results are always valid for an increase in density in the density range 50 kg/rn3 to 150 kg/rn3. A decrease in density is allowed down to
—10% of tested density.
Structural design will govern the orientation of fibres, i.e. lamellas or slabs used in the panels. Changes in orientation of fibre has an influence on fire resistance and is therefore not allowed.BS/EN 15254-5-2-2018 pdf download.
BS/EN 15254-5-2-2018 pdf download
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