Peripheral requirements for removal of waste water
Peripheral requirements for removal of waste water
3.3.2 Connections to
toilets and other
maximum maximum permissible
collecting pipes
fittings
length
sum of changes of direction
toilet only
Horizontal connections must be made with 45° T-pieces. Side connections: All reductions at horizontal connec- tions of connecting pipe sections to the collecting pipe must be eccentric. The upper surfaces of the pipes must be at a single level so that air can continue to flow and soiling can not flow back (illustration 3.5). If eccentric reducing T-pieces were available they would have to be provided in left and right handed models. In practice a piece with equal diameters is used with an eccentric reducing piece inserted in the appropriate side. N.B. a "running" reducer is better from a hydraulic perspective and makes less noise than an inserted reducer does. Oblique connections: Reducing T-pieces may be used with oblique connections provided the angle with the horizontal is between 30° and 45° (illustration 3.6). This connection is acceptable from a hydraulic viewpoint as the water flow in the collecting pipe is not unduly disturbed by the entry of the flow of water. This is a good solution to pre- vent foul water flowing back from the
3,5 m
135°
(=connection pipe) toilet only
*
(calculated as collecting pipe)
1:50 ; 12 m 1:100 ; 8 m 1:200 ; 5 m
and
135°
toilet + fitting Q i < 0,75 l/s toilet + fitting Q i 0,75 l/s
no restrictions
see illustration 3.3
(i.e. 2 or more toilets) 1 fitting no toilet (= connecting pipe) 1 fitting no toilet
3,5 m
-
Illus. 3.5 Horizontal connection to collecting pipe with eccentric reducer.
Horizontal collecting pipe 45° reducing T-piece with connec- ting pipe between 30°and 45° with horizontal section < 30° as in illustration 3.5. > 45° conditions as in illustration 3.7
12 m
see illustration 3.3
(calculated as collecting pipe) 2 fittings no toilet
12 m
see illustration 3.3
where one Q i < 0,5 l/s 2 fittings no toilet
no limitations
see illustration 3.3
Illus.3.6 Oblique connection.
both Q 0,5 l/s * applies for length of toilet connecting pipe + length of collecting pipe
Illus. 3.4 Maximal length of horizontal pipe and maximal sum of changes of direction when connecting toilets and other fittings.
Illus.3.7 Top connection.
collecting pipe. Top connection:
Must be avoided wherever possible. A top connection leads to serious disturbance in the horizontal pipe and hydraulic sealing may occur. Where there is no alternative then a top con- nection is permitted only where the horizontal pipe is at least 110 mm and the Q¡ of the connecting pipe is no more than 1 l/s. 45° and 90° redu- cing T-pieces may be used in this case (illustration 3.7).
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