- Creato: Lunedì, 12 Novembre 2012 14:41
- Ultima modifica: Lunedì, 21 Ottobre 2019 16:38
- Pubblicato: Lunedì, 12 Novembre 2012 14:41
Corrosivity test. Select/develop measurement of measures related to the fire effluent corrosivity under in the design fire conditions
The corrosive gases emission from a material that burns during a fire even of limited proportions is considered one of the highest risk elements for the buildings.
The gases emitted by a polymer during combustion can contain acidic and corrosive substances which by condensing on components or buildings may cause:
- the electrical conductivity alteration,
- premature aging of insulation materials,
- the metal reinforcements corrosion of in bearing structures
The emission of huge quantities of corrosive gas is considered by insurance companies one of the main risks for real estate. Contrary to other aspects of fire prevention, such as optical smoke density, heat release and flame propagation, the standards are still under consideration. Nevertheless, it is extremely important with regard to the safety against fire damages to know the environmental conditions under which the component or the end product partially or totally degrades and the emitting material during this degradation process and which problems can cause the degradation by-products to other product elements or to other adjacent products.
In many cases, small outbreaks of fire have caused serious damages due to the substances emitted during the overheating phase and the first ignition. The reference tests to evaluate these behaviours are contained in the following standards: IEC 60695-5-1 “Fire hazard testing - Part 5-1: Corrosion damage effects of fire effluent - General guidance”, IEC 60695-5-2 “Fire hazard testing - Part 5 -2: Corrosion damage effects of fire effluent - Summary and relevance of test methods”.
the test shall take into account the quantity and the quality of the corrosive gases emitted during the depolymerisation, always regarding the measured mass loss. Most of the tests wish to identify and quantify the emissions of a material in a given fire scenario. Some polymeric products have a high rate of corrosivity or toxicity but do not burn for a long time therefore their gas effluents emission is reduced.