Fire Protection Designed to act as protection for fire protection systems, Young Engineering offers a full line of UL and FM approved surge suppressors (BSA), bladder expansion tanks (BET) and Bladder Surge Tanks (BST). Surge Suppressors – Young Engineering is a leader in the surge control industry offering the largest range of sizes designed to control hydraulic transients. YEMI surge suppressors absorb and control surge energies, increasing the life of the components of a system. BETs – Created to meet the needs of NFPA 13, these UL approved expansion tanks are designed specifically for the fire protection industry to protect anti-freeze sprinkler systems from the damaging effects of thermal expansion. BSTs – Young Engineering Bladder Surge Tanks (BST) absorb and control surge energies, increasing the life of the components of a system. BSTs are large-capacity units used in applications such as water pumping stations, municipal water and fuel handling applications. Standard sizes ranges from 40 to 5,000 gallons, with design pressures of 275 and 500 psi.