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WorksheetsDAY 31 WORKSHEET LSGD (Sewer Systems )
Total questions: 15
Worksheet time: 11mins
Which sewer is also called an overflow sewer and is laid parallel to an existing combined sewer to serve during peak flow?
Intercepting sewer
Depressed sewer
Relief sewer
Outfall sewer
Vitrified clay sewer pipes cannot be used in branch/main sewers primarily because —
They corrode in sulphide atmosphere
They are weak in tension
They have rough interior surface
They are hydraulically inefficient
Which joint is BEST suited when the pipeline is laid in an area with repeated thermal expansion and contraction?
Collar joint
Expansion joint
Spigot and socket joint
Open joint
The recommended maximum aggregate size in RCC sewer pipes as per design considerations is —
10 mm
12 mm
20 mm
6 mm
An inverted siphon is used when —
Sewer is to cross a railway/river and must run under pressure
Sewer passes through steep gradients
Aeration is required at junctions
House sewer meets branch sewer
TRUE OR FALSE
The socket end of a sewer pipe is always laid upstream to prevent infiltration (a)
TRUE OR FALSE
A mechanical joint (Victaulic/Dresser) is suitable in locations subjected to shock and vibration.
(a)
Assertion (A): Depressed sewers are also called sag pipes because they run under pressure.
Reason (R): They are laid at a lower elevation than the adjacent sewer sections to cross an obstruction.
(a)
A spigot and socket joint is made watertight by filling the gap with lead wool or (a)
The Simplex (ring-tie) joint in asbestos cement pipes allows up to (a)
The spacing of manholes for sewers of diameter greater than 1.5 m is about .
(a)
The pressure maintained during air test on large sewer pipes is (a) of water column.
A ball test uses a ball of diameter (a) less than the bore diameter to detect obstruction.
PART – E : MATCH THE FOLLOWING
Sewer Types & Purpose
A. Intercepting sewer→1. Installed transversely to pick flow
B. Outfall sewer→2. Collects domestic sewage from laterals
C. Relief sewer→3. Carries sewage to treatment plant
D. House sewer→4. Provides discharge relief during storms
A–4, B–1, C–3, D–2
A–1, B–3, C–4, D–2
A–1, B–4, C–3, D–2
A–1, B–4, C–2, D–3
MATCH THE FOLLOWING – Joints & Application
A. Simplex joint→4. Used for strong vibration / bridge sections
B. Mechanical joint→1. Used for asbestos cement flexible curves
C. Flanged joint→2. Used for lightly stressed temporary CI joints
D. Collar joint→3. Used for metal pipes with rigid connection
A–4, B–1, C–2, D–3
A–1, B–4, C–2, D–3
A–1, B–2, C–4, D–3
A–1, B–4, C–3, D–2
