FLUES in TONAdin FIRE BRICK: modular flues made from terracotta in compliance with standard EN 1457-1. These flues are 500 mm high, have a circular shape with diameters ranging from 120 – 300 mm included and are suitable for venting flue gases produced by both liquid and solid fuels. Flues with a square/rectangular shape on the other hand, measuring 300×350 and 350×350 mm, are suitable for creating VCCF systems to be fitted with fume filters for safe zones.