Chases are vertical or horizontal enclosed spaces for routing utilities, pipes, and cables throughout the fab facility. Vertical chases: Shafts running between floors for risers - piping, electrical, exhaust ducts connecting levels. Horizontal chases: Corridors or enclosed spaces running through or around cleanroom for utility distribution. Contents: Process gas lines, chemical piping, electrical cables, exhaust ducts, vacuum lines, DI water, cooling water. Access: Access doors or removable panels for maintenance and expansion. May be pressurized or exhausted depending on contents. Safety: Hazardous chemical lines require ventilated chases with leak detection. Gas lines have seismic bracing. Separation: Different utility types often in separate chases - acid lines separate from electrical, bulk gas separate from exhaust. Fire protection: Fire dampers and detection in chases that pass through fire barriers. Expansion capability: Chases designed with spare capacity for future utilities and modifications. Routing design: Minimizes chase runs through cleanroom, uses perimeter routing where possible to reduce contamination risk.