2KAN prefabricates ventilation and smoke-extraction ductwork at Konotopa near Warsaw. Its 2KP steel single-zone smoke ducts are published at fire-resistance class E600 120 single, made to the harmonised standard EN 12101-7:2011 up to 1250 by 1000 millimetres and, in the large-format range to 2500 by 1500, under Krajowa Ocena Techniczna ITB-KOT-2019/0897 — an assessment confirmed in ITB’s published register against the company at ul. Rajdowa 10. The firm states its meshed spigots hold the same classification and that it was the first company in Mazowieckie to obtain the certificate for single-zone steel smoke ducts.