here's "first half week" refers to what?
The first half of the pipeline is through the central line of the pipe and the vertical line of the central line of the pipeline above the upper half of the surface, in fact, is a circle arc (upper half arc).
It is better to be within 45 degrees of the vertical direction.
For example, fire pump, water pipe, gate valve, to see this side to the horizontal 90 degrees, turn 90 degrees in the opposite direction
