Question 331General Subjects - QMED

The correct answer is A) piping wall thickness. The designation "schedule 80 extra strong" refers to the wall thickness of piping. Schedule 80 pipe has a thicker wall compared to standard schedule 40 pipe, making it more durable and suitable for higher pressure applications. This thicker wall construction is what is meant by the "extra strong" designation. The other answer choices are incorrect as they do not relate to the "schedule 80 extra strong" designation, which is specifically about pipe wall thickness, not tubing strength, bolt tensile strength, or steel plate weight.