A "dead leg" is a sump, or area of entrapment, in a vessel or a piping system where contamination can occur. Dead legs take longer to flush out during CIP, extending rinsing cycles, creating "cold spots" during SIP, and increasing downtime. A typical occurrence of a dead leg would be at a "tee". (The specific definition of "dead leg" is defined in the ASME BPE, section GR 10 - Terms and Definitions.)
For line sampling you can use ASEPCO Zero Dead Leg Valves, which are designed without this "tee", completely
eliminating any dead leg. In the ASEPCO Zero Dead Leg Valve, the diaphragm
seats flush to the piping O.D.
One of the simplest ways to dramatically improve the performance of any critical piping system is to minimize or eliminate all dead legs.