Camillo Cardelli, iPOOL Materials Design, Italy, explained that cables in Europe today must undergo the EN 59399 vertical fire test for CPR (Construction Products Regulation), with demanding parameters for flame spread, non-dripping, smoke density, smoke corrosivity and smoke toxicity.
He presented results of testing of a range of non-halogenated FR cable compounds (tested as tapes) in the “Mini SBI” (see SUSPI, pinfa Newsletter n°76), a non-regulatory, experimental set-up suitable to compare fire behaviour of different compounds and different raw materials. The formulations tested were based on polyethylene/EVA and POE (polyolefin elastomers) with stabilisers, hydrophobic and processing agents. Inorganic FRs tested were ATH, MDH, brucite, Böhmite, Calcium borate, and stearic acid or silane coated versions of these. Results showed many variations, but two possible conclusions were that all MDH containing recipes tends to give less flaming drips than does ATH (with collapse of char in fire), and that milled natural MDH gives good results comparable with fine synthetic MDH. Coatings applied on ATH or MDH could also positively or negatively affect the results of burning tests.