I often listen that “some Euroclasses do not have class for the smoke because it is not necessary as consequence it is known that either they produce a lot of smoke or they do not release them”. This type of ideas are very far from the real reason because there are classes of reaction to fire do not have the term “S” that provide us information abour the opacity of smoke.
As it is already known, an Euroclass of reaction to fire in general is composed of 3 terms. One of them refers to the smoke released by the product or material tested and is denoted by the letter “S”. Why do not some Euroclasses have “S” term”? We will know shortly.
As I have explained in other publications available on my blog, to achieve an Euroclass, it is necessary to carry out specific tests and these are not the same for all classes. I show you the test required for each classification.
Table 1. Tests associated for each Euroclass of reaction to fire.
If we look at the classes that require the SBI test according to EN 13823, which are classes A2, B, C and D, they will always provide us with an “S” class, that is, they give us an idea about the opacity of the smokes. On the other hand, in the rest of classifications A1, E and F the SBI test is not required and therefore we will not have this information. This is because in the SBI test, the smokes are evaluated and in contrast with the other tests like non-combustibility test (EN ISO 1182), the calorimeter bomb (EN ISO 1716) and small burner test (EN ISO 11925-2) which do not have a system to evaluate the opacity of the smoke.
Figure 1. SBI test (EN 13823). Source: RISE
Therefore, the reason that some Euroclasses do not have a part to evaluate smoke will only be due to the fact the product, material or system do not be tested according to SBI test. For the floors applications, the situation is similar, the only thing is that in this type of application the SBI test is not used because for the floors is used a radiant panel according to the EN ISO 9239-1 standard.
Finally, I would like to make clear that a product, material or system with a class E does not imply that the smokes generated in the test are high, but only has been tested only in the small burner and this parameter has not been evaluated.
Commission Delegated Regulation (EU) 2016/364 of 1 July 2015 on the classification of the reaction to fire performance of construction products pursuant to Regulation (EU) No 305/2011 of the European Parliament and of the Council