Pipeline joints in sanitary engineering: Lead-caulked bell-and-spigot joints are characteristically used with which type of pipe during sewer or water main installation?

Introduction / Context:
Choosing the correct jointing method is critical for the watertightness and durability of pressure and gravity pipelines. Traditional cast iron mains frequently used bell-and-spigot ends sealed with lead and oakum, known as lead-caulked joints.

Given Data / Assumptions:

• Traditional municipal water/sewer installations.
• Compatibility between joint material and pipe material is required.
• Lead-caulked joints are historical but still referenced in legacy systems.

Concept / Approach:

Lead-caulked joints involve packing oakum and pouring molten lead into the bell space, then caulking to seal. This method is specific to metallic bell-and-spigot joints—principally cast iron—providing flexibility and watertightness. Stoneware/earthenware generally use cement or rubber-ring joints; G.I. uses threaded or flanged joints.

Step-by-Step Solution:

Verification / Alternative check:

Hydrostatic pressure testing confirms joint integrity; modern alternatives include push-on rubber gasket joints (Tyton) in ductile iron pipes.

Why Other Options Are Wrong:

Stoneware/earthenware use cement/rubber-ring joints; G.I. employs threaded/flanged joints—lead caulking is not used.

Common Pitfalls:

Poor caulking causing leaks; inadequate safety when handling molten lead; lack of flexibility in non-metallic materials.

Final Answer:

Cast iron (C.I.) pipes