Any consultant working in the construction industry should be aware of all the other services present on site. To co ordinate this, the principle agent will co ordinate services. However, in order to accommodate the services in the structure, "builders work"drawings are issued to instruct the builder as to what openings are required in the structure. It is vastly preferable to plan for these openings, rather than to create holes in the structure after construction is complete. However issuing a 2D plan requires some understanding of what is going on. Horizontal penetrations require invert levels (the height of the pipe from the finished floor level) as well as width and depth sizes. Vertical penetrations also need to be carefully dimensions so that they fall exactly in the correct location. It is also important to note that the builders work drawing is taken from the soffit of the floor below to the soffit of the existing floor. ie. if one was standing in a building, say on the 1st floor, with the builders work drawing for the first floor, all of the vertical penetrations shown on the drawing would be through the slab you are standing on, and all of the horizontal penetrations through the walls surrounding you would show on this drawing. However any vertical penetrations in the slab above would show only on the drawing above.
This can be tricky when checking penetrations on site, as when the beams and slabs are cast, the horizontal penetrations through the beams will show, as well as the vertical penetrations of the floor above. Thus one would need to refer to the floor below's drawing when checking horizontal penetrations through the beams, and the current floors drawings when checking the vertical penetrations through the slab.
