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In relation to fire retardancy in wood based sheet materials. We have to start with the fact that the old British National Standards Class 1 to BS 476 part 7 and Class O BS 476 parts 7 & 6 used in permanent construction are now replaced with the European standards Euro Class 'C' and Euro Class ' B' starting from 1st July 2013. Its also not correct to presume that Euro Class 'C' directly replaces the old standard Class 1 or Euro Class 'B' replaces the old standard Class 0, as the new Euroclasses are a new set of reaction to fire tests. To clarify, It is not possible to treat to a National Class and sell as a European Class or vice versa. For instance, plywood treated to Class 0 cannot be sold as Euro Class 'B'. What is very important to remember is : EUROCLASS B & EUROCLASS C ARE NOT TIME RATED FIRE PERFORMANCES AND DO NOT OFFER 30 OR 60 MINS FIRE RESISTANCE. When asking the question : Are these new Euroclasses as good as the old Class 1 / Class 0? The simple answer is that the new Euroclasses are underpinned by more up-to-date test methods compared to the old British Standards and trying to compare old and new is the wrong approach. Class 1 involved a measure of the Surface Spread of Flame (SSF). Class 0 included a measure of SSF but also heat release. The Euroclass SBI test measures a wider scope of fire critical factors than the old Class 1 /0 tests, namely spread of flame, heat release, fire growth rate, smoke levels and flaming droplets. With this in mind, the fire retardant treatment we recommend, is targeted at the reaction to fire stage of a developing fire, not fire resistance. Reaction to fire refers to the early stages of a fire, the surface burning of materials and the rate at which they contribute to the growth of a developing fire within a particular area. The fire retardant treatment we recommend, retard the growth/propagation of the fire by limiting the amount of heat generated, retarding the flame spread and limiting smoke production giving people time to safely evacuate buildings and time for the fire brigade to get to the fire and control it. In order to meet European classifications, the rate of fire growth, lateral flame spread, total heat release and smoke production for wood and wood based panel products derived from European reaction to fire tests are used to classify fire retardant treated materials as Euroclass B or C in accordance with BS EN 13501-1. The fire retardant treatment we would always recommend is a factory applied, deep impregnation of all faces. With full traceability of the treatment used. One of the drawbacks using this method is lead times can be between 3-5 weeks from receipt of an order. So we appreciate sometimes this lead time can be a problem. There are options where we can supply your plywood requirements with a brush / spray surface applied FR coating. (however we would always prefer the impregnation method if possible). If this is the case, please take the extra time (and with our help), to make sure the FR plywood treated this way, meets all your requirements. With any project it is vital (and even more so when referring to fire retardant sheet materials), that you have satisfied yourself that the information is correct before starting. We are always here to help in anyway we can, but as I hope you can appreciate, although we have used all reasonable efforts to verify the accuracy of the information displayed, we however cannot guarantee any of the contents mentioned here. In reference to 21mm Fire Retardant Birch Plywood to Euro Class 'B'Unless instructed, we would normally presume that the grade of the 21mm birch plywood would be BB/BB Grade or as it's commonly known 'BB' Grade. If you have a particular requirement, for example plug free one side. Rather than get tied up with the different grades, please describe in the instruction box below, what your trying to achieve and we will advise accordingly. If you choose to fill in the instruction box, you will still need to pick one of the options from the matrix table before you can add to the quotation list.I suggest picking the sheet size you require and we will follow the instructions you give. |
