Of the following, the heaviest copper pipe is:

• A. Type M
• B. Type L
• C. Type K
• D. Type DWV

Answer: (C)

The main idea is that the weight and strength of copper tubing come from its wall thickness. Type K has the thickest walls of the standard copper tube types, which makes it the heaviest per length. It’s designed for tougher applications, like underground or exterior service, where protection and strength are important. Type L is the standard-strength choice for most indoor water lines, with thinner walls than K. Type M has the thinnest walls and is used where cost is a concern and the system doesn’t demand as much strength. DWV tubing is for drainage (waste and vent) rather than pressurized water, so its design emphasizes different properties and it isn’t chosen for weight or pressure resistance like Type K. So, the heaviest option is Type K.