Page 601 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

Chapter 9 Sanitation systems

IC
S&VP RWG
IC
S&VP: Soil and vent pipe
RWG: Rainwater gulley
IC: Inspection chamber
Rainwater drain
RWG Foul water drain
S&VP

IC
RWG
IC
IC
Road gulley
Surface water sewer
Foul water sewer
p Figure 9.87 Separate drainage system

 Table 9.6 The advantages and disadvantages of the separate system

Advantages Disadvantages
Because the drains are separate, the It is an expensive system to install because two
sewerage plant does not get inundated drains are required
with water when it rains heavily The foul water drain does not get flushed and
Trapped gulleys are not required for the cleaned out by the rain
rainwater connections. This helps to There is a risk of making incorrect connections
identify the drainage system in use onto the rainwater drain
The number of inspection chambers required
is excessive

The combined system KEY POINT
With the combined system, both foul and rainwater drains discharge into a The combined system is
common sewer. This makes connections to the drains much simpler. It is a no longer recognised by
simple and economic system to install. the Building Regulations
as a viable system on
IC new installations.
RWG IC
S&VP: Soil and vent pipe
RWG: Rainwater gulley
IC: Inspection chamber
Rainwater drain
Foul water drain
RWG S&VP

IC
RWG

IC
Road gulley
Combined surface and
foul water sewer
p Figure 9.88 Combined drainage system
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