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Topic I.8. Water Supply Networks:Kinds, Structures and Design

Kinds of Water Supply Networks

I. According to the hydraulic connections Branched Looped (Gridiron)

II. According to the static head arrangement

Non-stratified (Non-zone) Stratified (Zone)

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Kinds of Water Supply Networks

a. Branched b. Looped (Gridiron)

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Kinds of Water Supply Networks

Zone Network with Steep Terraina - Gravity System б - Pumping System

1 - minimal static head 2 - maximal static head (H < 60 m)

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Zonal (Stratified) Network

a - Sequencing pumping zones feeding

б - Combined gravity and pumping zones feeding

b - Two pumping groups

г - Single pumping group

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Water Supply Networks Structures

Main Elements

Mains (Trunks)

Branches

Fittings

Valves

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Mains (Trunks) Design

Basic Requirements

Main direction of the trunks must comply to the main water distribution direction. For this equally loaded parallel trunks have to be established at distance of about 300 - 600 m each to the other

The trunks along the main water distribution direction have to be connected with intermediate trunks at distance of about 400 - 800 m each to the other

So designed trunks and the rings formed by them have to cover uniformly the settlement, passing through the most dense populated regions and by the big local consumers

The trunks permanent ways have to be located at the higher parts of the settlements, which will insure uniform spatial distribution of the water dynamic head

The trunks permanent ways have to consider the soil properties, as well as the underground communications

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Branches Design

Basic requirements The distribution branches are laid out along any one of the streets

in the settlement in the way to deliver water with the shortest permanent way from the nearest trunk to the consumers

At the streets broader than 16 m two parallel branches could be install. If the branch diameter exceeds 300 mm, it is constructed as a transit one and a parallel branch with smaller diameter distributes water towards the attached consumers

Minimal slope of the branches is normally 0,1 %, or no less than 0,05 % at flat terrain

Stop valves have to be envisaged at the points of the trunks branching and at the beginning and the end of every branch in the way to allow distribution network rings to be isolated in a case of emergency

Fire valves have to be envisaged, uniformly distributed on the water supply network and at no more than 100 (150) m distance each to the other

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Pipes, Fittings and Valves

Distribution Networks Pipes Materials

Cast iron Steel Asbestos cement Plastics - PE, PP, PVC

Pipes joints Socket (muff, muffle) Flange Clutch (union) Weld Gluing

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Pipes Joints

Cast iron socketa - pipe longitudinal section б - socket joint detail

1 - pipe cylindrical end 3 - resin rope

2 - pipe muff end 4 - plumb or asbestos-cement stuffing

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Pipes Joints

Cast iron pipes socketsa - socket joint б - screw-socket

joint

1 - pipe cylindrical end 3 - rubber gasket

2 - pipe muff end 4 - screw ring

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Pipes Joints

Asbestos-cement pipes jointsa - “Simplex” type б - “Gibot” type b - Flange type

1 - rubber gasket

2 - pipe

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Fittings

Kinds of Fittings

T-fittings (with or without flanges)

Cross-fittings (with or without flanges)

Offsets (with or without flanges), 30o, 45o , 60o and 90o

Knees (Elbows) - with or without flanges, 45o and 90o

Reducing fittings (Confussors/Difussors) - with or without flanges

Duff flanges

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Valves

Kinds of Valves

Stop (Gate) valves

Fire hydrants

Pressure reducing valves

Air valves

Blow off

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Valves