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

I. According to the hydraulic connectionsBranchedLooped (Gridiron)

II. According to the static head arrangementNon-stratified (Non-zone)Stratified (Zone)

Kinds of Water Supply Networks

a. Branchedb. Looped (Gridiron)

Kinds of Water Supply NetworksZone Network with Steep Terraina - Gravity System - Pumping System1 - minimal static head2 - maximal static head (H < 60 m)

Zonal (Stratified) Network a - Sequencing pumping zones feeding - Combined gravity and pumping zones feeding b - Two pumping groups - Single pumping group

Water Supply Networks StructuresMain Elements

Mains (Trunks)

Branches

Fittings

Valves

Mains (Trunks) DesignBasic 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 otherThe trunks along the main water distribution direction have to be connected with intermediate trunks at distance of about 400 - 800 m each to the otherSo 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 consumersThe 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

Branches DesignBasic requirementsThe 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 consumersAt 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 consumersMinimal slope of the branches is normally 0,1 %, or no less than 0,05 % at flat terrainStop 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

Pipes, Fittings and ValvesDistribution Networks Pipes MaterialsCast ironSteelAsbestos cementPlastics - PE, PP, PVC

Pipes jointsSocket (muff, muffle)FlangeClutch (union)WeldGluing

Pipes JointsCast iron socketa - pipe longitudinal section - socket joint detail1 - pipe cylindrical end3 - resin rope2 - pipe muff end 4 - plumb or asbestos-cement stuffing

Pipes JointsCast iron pipes socketsa - socket joint - screw-socket joint 1 - pipe cylindrical end3 - rubber gasket 2 - pipe muff end 4 - screw ring

Pipes JointsAsbestos-cement pipes jointsa - Simplex type - Gibot typeb - Flange type1 - rubber gasket2 - pipe

FittingsKinds 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

ValvesKinds of Valves

Stop (Gate) valves

Fire hydrants

Pressure reducing valves

Air valves

Blow off

Valves