Q1: With increase in the schedule number of a pipe of a particular nominal size, the

ANS:D - all (a), (b) and (c)

The schedule number of a pipe refers to its wall thickness and determines various dimensions such as the inside diameter (I.D.) and outside diameter (O.D.). Based on the options provided:

• Wall thickness increases: This statement is correct. As the schedule number increases, the wall thickness of the pipe increases. Schedule numbers are standardized thicknesses specified by pipe standards (e.g., Schedule 40, Schedule 80), where higher numbers indicate thicker walls.
• I.D. of the pipe decreases: This statement is incorrect. The inside diameter (I.D.) of the pipe remains relatively constant for a given nominal size regardless of the schedule number. The nominal size is the designation used to specify the approximate I.D. of the pipe.
• O.D. of the pipe remains constant: This statement is also incorrect. The outside diameter (O.D.) of the pipe increases with the schedule number because the overall dimensions (including wall thickness) increase.