CSLB C-36 Plumbing ContractorPlanning and EstimatingMedium
A plumbing contractor is reviewing a blueprint for a medical office building. The plans show a specific type of piping material, 'Type L copper,' for the domestic hot and cold water distribution. What characteristic of Type L copper makes it a common choice for such applications compared to Type M or Type K?
- AIt offers a balance of strength, corrosion resistance, and cost-effectiveness.
- BIts interior surface is specially treated to prevent bacterial growth.
- CIt is the thinnest walled copper pipe, making it most flexible.
- DIt has the thickest wall, ideal for underground and high-pressure uses.
Show answer & explanationAnswer & explanation
Correct answer: A. It offers a balance of strength, corrosion resistance, and cost-effectiveness.
Type L copper pipe has a wall thickness that falls between Type M (thinner) and Type K (thicker). This intermediate thickness provides good strength and durability for domestic water lines, excellent corrosion resistance inherent to copper, and is generally more cost-effective than Type K, making it a common choice for interior residential and commercial water distribution.
Why the other options are wrong
- B. While copper has some antimicrobial properties, this is not the primary distinguishing factor for Type L's selection over other copper types based on wall thickness.
- C. Type M is the thinnest, not Type L. Flexibility isn't the primary driver for Type L selection.
- D. Type K has the thickest wall and is typically used for underground, high-pressure, or heavy-duty applications.
Copper Pipe Types (K, L, M)
Copper pipe types (K, L, M) are classified by wall thickness, impacting their pressure rating, durability, and suitable applications.
- Type K: Thickest wall, used for underground, high pressure, medical gas.
- Type L: Medium wall, common for domestic water (hot/cold), hydronic heating.
- Type M: Thinnest wall, used for drainage, vent, and some low-pressure domestic water.
Memory trick: K for 'King' (thickest), L for 'Living' (standard), M for 'Meager' (thinnest).