TY JOUR TI IMPROVING THE EFFICIENCY OF CENTRIFUGAL FIRE PUMPS BY SELECTING THE PREFERRED TYPE OF VACUUM SYSTEM USING HIERARCHY ANALYSIS KW expert evaluation KW centrifugal fire pumps KW vacuum systems KW vacuum pumps KW hierarchy analysis method KW water intake JO Problems of risk management in the technosphere AU Sytdykov, M.R. AU Ivakhnyuk, G.K. AU Motorygin, Y.D. PY 2026 IS 2026 PB Saint-Petersburg University of State Fire Service of Emercom of Russia