Module 2 Below Ground Drainage Flashcards
What are sewers?
Sewers are public authority drains to which private house drains are connected
What is the purpose of a sewer?
A system of pipe work which conveys surplus water or liquid sewage away from buildings in the most speedy and efficient way possible to the sewer or drain without any risk of nuisance or danger to health or safety
What are the musts in a drainage systems?
Does not cause risk to public health, doesn’t cause risk to the environment, allows only authorised access which is adequate, has adequate capacity, is impermeable to liquids is fully ventilated
When designing a discharge system these rules must be observed?
1)Provide adequate access points , 2)keep pipe work as straight as possible between access points and for all bends over 45” an access point should be provided, 3)ensure all pipe work is adequately supported, 4)ensure the pipe is laid to a self cleansing gradient 5)ensure the drainage system is well ventilated 6) the whole system must be water tight including inspection chambers 7) drains should not be run under buildings, unless this is unavoidable or by so doing it would considerably shorten the route of pipework 8) the minimum internal diameter of foul water drains is 100mm 9) be adequately protected from tree roots 10) all points of entry should be trapped 11) if drainage is to be pumped then an effluent holding chamber must hold 24hrs inflow in the case of breakdowns 12) the drain should be sized so that at peak flow it is never more than half full
What are the dangers working in trenches?
Trench wall collapse and dangerous gas build ups
What are the 3 types of below ground drainage?
The combined system, the separate system , the partially separate system
What are sewage systems?
It’s a water carried beasts that is removed from a household or community, also known as foul water as it’s more that 99% water,
