My contractor notched my joists in the kitchen about an inch from the
top. The floor joists are 9" in height and 1 1/2" inch in width and 15'
in length. It is under the kitchen. The notch cut is about 1" cubed in
volume and at the top. Also the notches are 5' 8" from the start of the
span. Every joist was notched the same way to fit a gas pipe (black pipe).

How bad is this? Is it something to lose sleep over?

THanks