Material Selection & Properties Flashcards

Which pipe material has the highest resistance to chlorine degradation in potable water systems?

Answer: Cross-linked polyethylene (PEX)

PEX has superior resistance to chlorine degradation compared to other plastic piping materials used in potable water systems.

What is the primary reason copper Type M pipe is NOT recommended for aggressive water conditions?

Answer: It has the thinnest wall thickness of the copper types

Type M copper has the thinnest wall of the three copper types (K, L, M), making it more susceptible to corrosion failure in aggressive water.

Which material is MOST appropriate for a buried sewer lateral subject to heavy vehicular traffic loads?

Answer: Extra-strength vitrified clay pipe

Extra-strength vitrified clay pipe provides excellent compressive strength and chemical resistance, making it ideal for high-load buried applications.

What does the term 'SDR' mean when applied to plastic pipe?

Answer: Standard Diameter Ratio

SDR stands for Standard Dimension Ratio, which is the ratio of pipe outside diameter to minimum wall thickness.

When connecting a copper water line to a galvanized steel pipe, which fitting must be used to prevent corrosion?

Answer: A dielectric union

A dielectric union isolates dissimilar metals electrically to prevent galvanic corrosion at the junction of copper and steel.

Which plastic piping material is rated for both hot and cold water and is commonly color-coded red and blue?

Answer: PEX

PEX (cross-linked polyethylene) is commonly manufactured in red for hot and blue for cold water lines and is rated for both applications.

Which material is NOT acceptable for gas supply piping inside a residence according to most US codes?

Answer: PVC pipe

PVC is not approved for gas supply piping because it is susceptible to damage, UV degradation, and does not meet gas code requirements.