D62 QUIZ OF THE DAY

In sewer line setting out, the work begins from which end?

• Midpoint
• Highest point
• Outfall end
• Starting end

Answer explanation

Sewer setting out starts from the outfall end toward the starting end.

Which instrument is used to check alignment and gradient during sewer trench excavation?

• Boning rod and sight rails
• Level and staff
• Ranging rod
• Compass

Answer explanation

Sight rails and boning rods help in maintaining proper alignment and gradient.

In water test of sewers, what is the maintained pressure depth?

• 0.5–1.0 m
• 1.0–1.5 m
• 1.5–2.0 m
• 2.0–2.5 m

Answer explanation

Water test is done by maintaining 1.0 to 1.5 m depth of water between manholes.

What does the mirror test indicate in sewer line testing?

• Leakage
• Obstruction
• Straightness
• Air lock

Answer explanation

A full light circle in a mirror test indicates the sewer line is straight.

What is the correct direction for socket ends during sewer laying?

• Facing upstream
• Facing downstream
• Any direction
• Perpendicular to flow

Answer explanation

Pipes are laid with socket ends facing upstream to resist backflow pressure.

In air test, what pressure is maintained for testing large diameter pipes?

• 25 mm
• 50 mm
• 75 mm
• 100 mm

Answer explanation

Air test maintains 75 mm pressure; a drop of more than 25 mm indicates leakage.

Which gas turns lead acetate paper black in sewer gas tests?

• CO₂
• H₂S
• CH₄
• O₂

Answer explanation

Hydrogen sulfide (H₂S) turns lead acetate paper black, indicating its presence.

Which component is used to detect obstruction in sewer pipes?

• Mirror
• Boning rod
• Ball
• Camera

Answer explanation

A ball 13 mm smaller than pipe bore is inserted; if it doesn't emerge, obstruction is present.

What is the function of a cowl in ventilation of sewers?

• Prevent leakage
• Allow smoke testing
• Allow escape of gases
• Detect obstruction

Answer explanation

Cowl at the top of ventilating column helps gases escape into the atmosphere.

Which method is suitable for cleaning large-sized sewers?

• Flushing
• Manual labor
• Floating balls
• Cane rodding

Answer explanation

Large sewers are cleaned using manual labor, as workers can enter the sewer.