All steam piping systems must be designed as follows:

Condensate must be removed from the steam line as soon as possible by the use of steam traps and drip legs (Figure 1). Drip legs collect condensate and are located at all low points in steam lines and at intervals in horizontal piping. A steam trap is connected to the drip leg and will open to allow the condensate to escape, then will close when it senses steam thereby not allowing any steam to escape from the line. Strainers must be provided upstream of the steam trap to prevent any scale or grit from entering the trap and causing them to stick in an open position. Some traps have built in strainers.

Figure 1: Typical Drip Leg