Fire class is one thing, smoke production is another that is influenced by many factors. The requirements for low index values for smoke e.g. -s1 is especially important in enclosed spaces and in all interior spaces, regardless whether they are buildings or transport, such as boats, trains, buses etc.
In Sweden SP-Fire 105 prescribes a construction fire requirement on wood facade, whereas in Norway B-s3, d0 and Denmark B-s1, d0. Regarding specific requirements for smoke production in open environments such as facade cladding and open airways, the index value for smoke has little or no significance. In Denmark, SP-Fire 105 is accepted instead of B-s1, d0 but according to the SP-Fire 105 test method, smoke production is not taken into account, but B-s2, d0 is not accepted by consultants, which becomes contradictory. Wood chips with resin contents etc. affect the smoke index, this cannot be excluded because they are natural properties. The important thing is, in our view, that the fire protection product at least does not contribute to increased smoke production within the framework of smoke production according to parameter TSP in EN13823.
The smoke index is -s1, -s2, -s3 and where -s1 is the lowest and therefore the best. To achieve -s1, the total smoke production value must not exceed TSP <50. It is important to understand that everything that is supplied to the product e.g. fire protection, paint, topcoat, veneer, laminate and assembly with or without air gap and the wood as such is included in the classification of the product smoke index. Certain wood treated with fire protection regardless of paint or impregnation has a value of TSP <50, which means you cannot do anything with the panel eg. paint it with lacquer, paint, etc. The same is true of air gaps, as most market operators state their product meets B-s1, d0 but, in fact, it has been tested without an air gap. A product fitted with an air gap despite being tested without an air gap means that the builder assembles a product that is not approved because the product performs B-s2, d0 instead of -s1.
Woodsafe has low index values for smoke. Most different woods, together with paint systems such as lasers, coatings, hardwax oil, two component coatings have been tested with an approved smoke index equivalent to -s1.