Remaining Stuff Flashcards
Describe 4 specific requirements of formwork
Strength
Alignment
Quality of surface finish and
Economy
3 requirements before striking of formwork
Sufficient strength to support itself
Sufficient surface hardness to resist damage
Sufficient curing to give a reasonable colour finjsh to the concrete.
Name 3 types of drainage systems
Combined system
Separate system
Partially separate system
Define terms used in drainage:
Drain
Drain: defined as pipes/sections which are laid underground or on the ground surface used for the drainage of one building or any building or yards adjoining the building and within the boundary of that property.
Define term used in drainage:
Drainline
Drainline: defined as pipes laid underground used for the drainage of one building or any buildings or yards adjoining the building within the boundary of that property.
Define term used in drainage
Sewer
Sewer: drains used by a number of buildings not within the same boundary.
Define term used in drainage:
Sewerage
Sewerage: system of pipes used for the drainage of soil and sullage water of a district or districts and convey them to a suitable point for disposal or treatment.
Define the term used in drainage:
Sewage
Sewage: foul water such as waste water and soil water
Define term used in drainage:
Public Sewer
Public sewer: sewer for which the local authority is responsible for its construction and maintainence.
Describe 6 stages of water treatment process
Coagulation, sedimentation, filtration, disinfection, softening and chlorination
Which treatment is used to remove colour, taste, odour and other impurities?
Ozonation
What substance is added to be added into the process on the 11th card
Ozone gas.
Water conditioning is also known as _____
Softening
Which treatment is used to remove perm and temp hardness?
Softening.
What happens in Softening/ water conditioning
Lime is added to remove temp and perm hardness
What is disinfection/ozonation
The filtered water flows into the underground tanks where ozone gas is injected, ozone is effective in disinfecting the water and removing colour, taste, odor and other impurities.
What’s Filtration?
Clarified water passes thru 2 layers of sand beds
Remaining floes and suspended matter are filtered once sand beds become saturated, they are cleaned by backwashing
Whats Sedimentation
Flocculated water is kept in a quiet state for sufficient time so that floes settle at the bottom to form sludge.
Sludge will be drawn off at regular intervals to a sludge lagoon.
Describe Vitrified Clay pipes
They are used for drainlines and minor sewers.
Available in 100mm, 150mm and 225mm diameters.
Describe UPVC pipes
UPVC pipes are used for temporary drainlines and minor sewers.
They are available in 100mm, 150mm and 225mm diameters.
Describe Cast Iron pipes
They are used for pumping mains where there are heavy load and vibrations.
Such pipes have great pipes and are very durable.
Describe Asbestos Cement pipes
Used under preassure, available in 150mm, 200mm, 250mm and 300mm
Drain joint used for UPVC pipes
Flexible rubber O ring joint
Joints for cast iron pipes
Caulked lead joint, Screwd Gland Flexible joint and Spigot & Socket joint.
Joint for Asbestos Cement pipe
Flexible rubber O ring joint
Joint for clay pipes
Cement Mortar Joint, Heapseal flexible joint, Heapsleeve flexible joint.
5 tests on drain lines.
Alignment, Water, Pneumatic, Gradient and smoke.
Name one difference between IC and MH in terms of location
IC is within the boundary
MH is outside the boundary
Describe 6 basic requirements for IC/MH
To sustain imposed load
To exclude ground water
To be watertight (rmb your thermo flask.)
To allow for inspection, cleaning and strengthening
Cover to be removable, durable and non-ventilating.
Metal rung or ladder for access must be provided.
Open channel inside should be smooth and impenetrable.
Name 5 purpose of IC/MH
Where there are 2 or more sewer line/drain-line meets.
Where the line changes in direction
Where there is a sudden drop or significant drop in the level of the drains.
Where the gradient of the lines changes
Where there is a change in the size of the drain pipes
When piling is needed what type of IC base to be provided
The base should have a projection of 150mm all around the external wall
If brickwall is used for IC, what surfaces must be rendered
Where brickwall is used, the inner and outerwall surfaces must be rendered over with 1:1 cement sand mortar.
