A section of Type L copper tubing is installed as a water distribution pipe in a concealed space within a wall. According to Section 605.4, what is the minimum required thickness for the protective shield plate, unless the pipe is installed in a listed protective sleeve?

• 1/16 inch (1.6 mm)
• 0.047 inch (1.2 mm)
• 1/4 inch (6.4 mm)
• 1/8 inch (3.2 mm)