WATER DEMAND• Domestic demand This includes the water required in private building for drinking ,bathing, gardening, sanitary purpose, etc. As per IS : 200 l/c/d (with fully flushing system) 135 l/c/d (for weaker sections and LIG)• Public demand it represents the water demand for public utility purpose. like washing of public parks, gardening, washing on roads, public fountain. 20 l/c/d• Industrial demand It represents the water demand of industries which are earlier existing or are likely to be started in future. As per IS : 50 l/c/d (for normal industries ) 450 l/c/d (industrial cities)
WATER DEMAND• Commercial demand Water requirement for institutions , hotels , schools, colleges, offices. As per IS : 20 l/c/d (for normal commercial area) 50 l/c/d (highly commercial area)• Fire demand in populated or industrial area fires generally breakout and may lead to serious problem. For control that situation require sufficient quantity water that is called fire demand.• Water demand require for thefts and wastes This includes the water lost in leakage and stolen water due to unauthorised water connection.
Water requirement for different usesDomestic demand 135 l/c/dPublic demand 20 l/c/dIndustrial demand 50 l/c/dCommercial demand 20 l/c/dFire demand 15 l/c/dLoss and waste 50 l/c/d 270 l/c/d
FACTORE AFFECTING THE WATER DEMAND• Size of the city Big city Small towns Example: Delhi 244 l/c/d Vijayawada 135 l/c/d• Climate condition more in summer less in winter• Cost of water rate demand rate demand
• Distribution System Pressure demand Pressure demand high low• Supply system Good supply Bad Supply demand demand
• Industry industry demand industry demand • Quality of water good demand bad demand• Habit of people (Living style) EWS demand MIG demand
Per Capita DemandThe demand of water per person per day. per capita demand : yearly water demand population x 365An average Indian town per capita consumption variesfrom 150 to 300 liters.
Fire Fighting Required CalculationTotal amount of water required : no. of fires X discharge X time of each fireAmount of water required per person: amount of water/total populationKuichling ‘s formula : Q= 3182√P [ Q = amount of water required in liters/minute] [ P = population in thousands]Freeman formula : Q= 1136[(P/10)+10 ]Buston’s formula : Q= 5,663√P (Quantity of water required in liters per day)(Kuichling formula, Freeman formula and buston formula give higher results. Becausewater for fire fighting is required for few times in a year.) Q = 100√P (water is kiloliter per day)
Fire Fighting Required CalculationNational board of fire under writers formulas :When population is less than or equal to 2,00000 Q= 4,637 √ P[1-0.01 √P ]When the population more than 2,00000 a provision for 54,600 liters/minute may bemade with an extra additional provision of 9,100 to 36,400 liters/minute for a secondfire.For a residential city1)Small or low buildings = 2200 litres/minute2)Larger or higher buildings = 4500 litres/minute.3)High value residence ,apartments, tenements= 7650 to 13500 litres/minute