Flanged Valves toolbar: Pressure Top 
Command line: VRELF
Places a 90 degree pressure relief valve with the pressure end normal to the X-Y plane.
last point
Starts the component at the last point of the previously-created component.
Length
Defines the length of the pressure side and the relief side of the valve.
Pressure
Places the pressure end of the valve at the start point.
Corner
Places the component at the corner of two pipes.
Up
Places the branch of the valve in the positive Z direction.
Down
Places the branch of the valve in the negative Z direction.