2. Sewer appurtenances are the various accessories on the sewerage system and are
necessary for the efficient operation of the system.
They include man holes, lamp holes, street inlets, catch basins, inverted siphons, and
so on.
It is presumed that the appurtenance performs some useful function in the operation,
maintenance, servicing, economy, or safety of the plumbing system.
Pipe appurtenances are fixtures or attachments that help in isolating and draining a
pipe to perform inspections, tests, cleaning, and repairs
INTRODUCTION
3. NECESSITY OF SEWER APPURTENANCES
1. To inspect the sewer.
2. To help in cleaning the sewers
4. REQUIREMENTS
1. It should be strong.
2. It should be durable.
3. It should be economical.
4. It should have resistance to corrosion.
5. It should have resistance to internal pressure of water.
6. It should be easy to remove & repair.
7. It should not affected by chemicals, acids.
5. Types of
APPURTENANCES
1) LAMP-HOLES 2) STREET INLETS
3) MANHOLES 4) CATCH BASINS
5) INVERTED SIPHONS 6) SAND, GREASE AND OIL TRAPS
7) SEWER OUTLETS 8) VENTILATION SHAFT
6. 1) Lamp Holes
Lamp holes are the small openings on sewers to permit the insertion of a lamp into a sewer.
The lamp light is then viewed from the upstream as well as the downstream manholes.
The obstructed light confirms the obstructions in the sewers.
7. 2) STREET INLETS
It is an opening through which storm water and surface water flowing along the street are
admitted and conveyed to the storm water sewer or combined sewer by means of pipes.
These are placed at the road, gutters, generally at street junctions.
It should provide in a such way that it will not cause any interference with the traffic.
Curb Inlets, Gutter Inlets & Combined Inlets are some of its types.
There are two types of street inlets viz.
Vertical Inlet
Horizontal Inlet
9. 3) MANHOLES
Man holes are the openings of either circular or rectangular in shape constructed on
the alignment of a sewer line to enable a person to enter the sewer for inspection,
cleaning and flushing.
They serve as ventilators for sewers, by the provisions of perforated man-hole covers.
Also they facilitate the laying of sewer lines in convenient length.
Man-holes are provided at all junctions of two or more sewers, whenever diameter of
sewer changes, whenever direction of sewer line changes and when sewers of
different elevations join together.
10. 3) MANHOLES
Man holes are classified into following categories:
a) Shallow man hole
b) Deep man hole
c) Drop man hole
d) Flushing Tanks
11. 3)MANHOLES
a) Shallow Man hole
It is about 0.70m to 0.90m depth.
It is constructed at the start of a branch sewer or at
places, which are not subjected to heavy traffic.
Such a manhole is provided with a light cover at its top
and is called as inspection chamber.
Generally these types of manholes are provided at the
domestic areas.
12. 3)MANHOLES
b) Deep Man hole
It is having depth more than 1.5m.
The section of such a manhole is generally
not kept the same.
The size in the upper portion is reduced by
providing an offset.
Steps, etc. are provided in such a manhole
for facilitating descending into the
manhole and to enable the workers to go
up into its bottom.
13. 3)MANHOLES
C) Drop Man hole
• The manhole, in which a vertical pipe, is used is called a drop
manhole.
• When a branch sewer enters a manhole by more than 0.50m
to 0.60m above the main sewer.
The sewage is generally not allowed to fall into the manhole.
The sewage is brought into it through a down pipe taken from
the branch sewer to the bottom of the manhole.
14. 3)MANHOLES
C) Flushing Tanks
It is provided when there are chances of blockage.
When the self cleansing velocity of the sewer is very less or
when the pipe is laid straight.
It is also placed at dead end points of sewer.
These devices store water temporarily, and
Throw it into the sewer for the purpose of flushing and
cleaning the sewer.
15. 4) CATCH BASIN
Catch basins are small settling chambers of diameter 60 - 90 cm and
60 - 75 cm deep, which are constructed below the street inlets.
They interrupt the velocity of storm water entering through the
inlets and allow grit, sand, debris and so on to settle in the basin,
instead of allowing them to enter into the sewers.
However, their use is discouraged because of the nuisance due to
mosquito breeding apart from posing substantial maintenance
problems.
At the bottom of the basin space is provided for the accumulation of
impurities.
Perforated cover is provided at the top of the basin to admit rain
water into the basin.
16. 5) INVERTED SIPHONS
These are depressed portions of sewers, which
flow full under pressure more than the
atmospheric pressure due to flow line being below
the hydraulic grade line.
They are constructed when a sewer crosses a
stream or deep cut or road or railway line.
To clean the siphon pipe sluice valve is opened,
thus increasing the head causing flow.
Due to increased velocity deposits of siphon pipe
are washed into the sump, from where they are
removed.
17. 6) SAND, GREASE AND OIL TRAPS
Grease in sewers results in the formation of incrustations that
are difficult to remove and cause a substantial loss in the
capacity of the sewer.
The presence of oil and gasoline has resulted in explosions in
the pipes.
Grease, oil, and gasoline are removed by traps placed in the
plumbing systems.
A general feature of grease and oil traps is the provision of a
channel which forces the sewage to flow downwards, beneath
a free surface, while passing through the trap.
Floating grease and oil rise to the surface on the inlet side of
the trap, from which they may be cleaned through removable
covers on the structures
18. 7) SEWER OUTLETS
Storm water and treated water may be discharged into small or
large water bodies via sewer outlet and diffusion will aid in mixing
sewerage with surrounding water.
Waste matter from domestic or industrial establishments that is
carried away in sewers or drains for dumping or conversion into a
form that is not toxic.
Outlets to small streams are similar to the culverts, consisting of a
simple concrete head wall and apron to prevent erosion.
Sewers discharging into larger bodies of water are usually
extended beyond the banks into fairly deep water where dispersion
19. 8) VENTILATION SHAFTS
Ventilation shafts (or vent shafts) are similar to an exhaust fan for
the wastewater system.
Vent shafts allow air to enter and exit the wastewater system,
which is important to help the system work properly.
New vent shafts are unpainted stainless steel (for better durability
and lower maintenance)
It is desirable to prevent the accumulation of dangerous explosive
or corrosive gases.
It prevents the creation of pressures (above or below atmosphere)
that may break water seal in plumbing traps.
In case of storm water, this can be done by providing ventilating
manhole covers.