Design

	Sprinkler Coverage – as per Owner’s requirements but owner has to be well informed on the advantages and disadvantages of the number of sprinklers. Adding sprinklers later may stress the pump station and thus reduce the life-span of the pump-sets (will require more frequent maintenance and change of parts) Precipitation Rate – sufficient to ensure that the turf shall be well maintained. It should be slightly higher than the evapo-transpiration rate of turf in this region. A designed precipitation rate that is low will ultimately requires longer operation of the pump station and again shortens the life-span of the pump-sets.
	Precipitation Rate – sufficient to ensure that the turf shall be well maintained. It should be slightly higher than the evapo-transpiration rate of turf in this region. A designed precipitation rate that is low will ultimately requires longer operation of the pump station and again shortens the life-span of the pump-sets. Watering Window - a shorter watering window will lead to less usage of the pump station thus reducing wear and tear and will extend the lifespan of the pump station.
	Pipe Sizing – forcing big flows over small pipes will greatly reduce the life-span of the whole works because water flow is turbulent above a velocity of about 1.5m/second.
	Pump Station – undersized pump station will commonly lead to problem associated with item 1.1.4. On the other hand, an oversized pump station with huge motors may lead to premature failure of the system due to constant cycling of the pump station. Similarly, we have encountered numerous failures associated with VFD (Variable Frequency Drive) pump stations and thus is of the opinion that one is better off with a fixed speed pump station and the argument that one saves a great amount of energy is normally unfounded since most people will turn on the maximum number of sprinklers during watering and with an automatic system (with or without Central Control), programs are used to maximize the discharge of the pump station and reduce watering window.
	Generally a safety margin of about 15% for an automatic system is sufficient which is to allow for non continuous peak performance of the pump station during a watering cycle, wear and tear of pumps as well as for scaling of pipe-works with time which creates more frictional losses, etc.
	Pump Selection – the right choice is very important and if one choose a pump that has a high dead head (extreme left of pump curve with the highest pump discharge pressure), potentially one will cause severe damages to installed pipe-works, fittings, etc. if all installed safety protections like high discharge pressure shut down, pressure relief valve fails to act quickly, etc.. Water hammers will cause severe damages and definitely will shorten the life-span of the whole works. Please note that if pipes, etc. starts to leak, pump station will fail sooner or later. One should always select a pump without unnecessary high dead heads.
	System Operating Pressure- there is no significant difference in coefficient of uniformity between operating the sprinklers at 60 to 80 psi. We always recommend operating the sprinklers at a lower pressure and thus extend the life-span of the irrigation system with savings on the use of electricity as well. Pump Discharge Pressure – unnecessary high designed pump discharge pressures have caused many irrigation systems to fail with pre-mature failures of pipe-works and subsequent failures of the pump station itself. Proper calculations and sometimes site adjustment are very useful to ensure optimum pump discharge pressures without unduly stressing the pipe-works, etc. On the other hand, a low pump discharge pressure will cause uneven sprinkler discharge rates thus uneven growth of the turf.