Page 562 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

The City & Guilds Textbook: Plumbing Book 1

the system. Broken seals allow foul air and smells to enter the building.
The vent pipe is the dry part of the system.

Before we look at sanitary systems, we must remember that all sanitary
INDUSTRY TIP pipework and drainage systems need to comply with Approved Document
H of the Building Regulations. These requirements will be met if the
Access Building Regulations recommendations of BS EN 12056:2000 – which contains recommendations
2010 Approved Document H for design, testing, installation, and maintenance for all above-ground
at: www.gov.uk/government/ non-pressure pipework systems – are followed.
uploads/system/uploads/ To comply with Document H, all appliances must be fitted with a water trap
attachment_data/
file/442889/BR_PDF_ seal to prevent foul air from entering the building. Also, the waste pipe diameter
AD_H_2015.pdf and gradient must maintain a water seal in the trap of at least 25 mm after the
appliance has been used.

Primary ventilated stack system

A B

D
Staggered bath branch
to prevent cross-flow
A B E C

450mm to the
invert of the drain
Large-radius bend
A: WC branch
B: Washbasin and bidet
C: Washing machine/dishwasher
D: Bath
E: Kitchen/utility sink
p Figure 9.1 The primary ventilated stack system

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