Clients look for irrigation systems to keep their gardens looking pristine and lush! Designing a garden irrigation system does not need to be a daunting task. Sometimes it is hard to know where to start, so below is a list put together by the team at Agrinet and Orbit, which highlights critical pieces of information to gather in order to ensure that you start on the right track.

Once you have these, you’ll be ready to start designing or utilising online tools like the Orbit Sprinkler System Designer where creating your custom Orbit garden irrigation system plan is simple and FREE.

It is important to know where the irrigation system will be getting water from before starting on system design. The most common source of water is a municipal water line. Other sources can be a Pump, Well, Water tank (from rainwater harvesting) or other water sources like a stream.

Certain water sources such as dams or rivers may contain impurities or suspended solids that could cause blockages with prolonged use. Installing an inexpensive water filter would prevent this, a 120-micron filter is recommended for garden irrigation. These filters are not very expensive and would save a lot of time cleaning out or replacing blocked sprayers.

IRRILINE FILTER & VALVE ON-LINE 1INCH

There are three types of piping that are generally used namely, Galvanised piping (silver in appearance), Copper piping (Bronze in appearance) and PVC/Plastic piping (usually blue or Black in colour).  If the main water source also supplies the house then it usually can be determined what pipe type it is at the location in which it enters the home. If not, then it’s time to get hands dirty and dig down to the pipe to see which type of pipe is in place.

Pipe diameter is important as it affects flow rate and pressure. To measure pipe diameter, take a string, wrap it around the pipe and measure the length of string that’s required to wrap once around the water source pipe. Connect the two ends and take a record of the length on a ruler.

The static pressure test is critically important. In order to measure the pressure coming through a water source, a pressure gauge will be needed to get a reading.  It is recommended to perform a test at the same time of day the sprinkler system will be used in order to get the most accurate reading.

It is also important to determine and measure pressure at the starting point of the system. Where municipal water is used, pressure and flow must be measured as closely as possible to the main feeder line from the municipal network. Where borehole pumps are used, the pressure and flow must be measured on the top of the borehole, where the water comes out. When centrifugal pumps are used, the pressure and flow must be measured at or as close as possible to the outlet of the pump.

Water flowing in any confined space cause friction losses. These losses must be considered when determining the sizes of pipes.

For the purpose of this exercise, the flow of water in pipes is measured in litres per minute (l/min).  Such measurement will determine the “flow rate”. In other words, it is the rate in which the water is flowing through the pipe.

Flow rate (l/min) is always measured against a specific pressure to determine which sprinklers should be used. Different sprinklers often work best at different pressures, for example, a pop-up works well at 2.8bar whereas micro-sprinklers work best at 1.5bar

Connect the measuring apparatus, consisting of the components as shown below, to the water source:  See Figure 1.

Figure 1: Measuring of Pressure

a)    Connect the measuring equipment to the water source while the source is closed/off. Open the Agrinet garden tap fully.

b)    Open the water source/tap so that water can flow freely through the measuring equipment. Any air present in the measuring equipment will be removed by doing this.

c)    Close the Agrinet ball lock tap slowly and completely.

d)    The pressure indicated on the pressure meter after the Agrinet garden tap has been closed completely is the static pressure in the system. Write down this reading as per table 1. Please note that there is no flow rate, and because of that the flow rate against the static pressure for table 1 will always be “zero”.

e)    Slowly open the Agrinet garden tap until the reading on the pressure metre goes down to 2.8 Bar.

f)      Start filling the previously calibrated bucket at the required pressure. Note down the time that it takes to fill this previously calibrated bucket on the stopwatch. Write down the time that it took against the established pressure 2.8Bar as per table 1.

g)    Empty the bucket.

h)    Open the Agrinet garden tap until the gauge drops to 2.1 Bar.

i)      Repeat step (f), and remember to complete the table.

j)      Repeat steps (h) and (f) with the pressure meter reading on 1.5 Bar.

k)     Remember to fill in the elapsed time on the table.

Flow rate calculations from the table above (repeat calculations for each pressure).

Orbit provides traditional products for lawn and garden care, and they are the brand behind the most advanced WiFi enabled irrigation timer & app, B-Hyve. Orbit is the global leader in the smart lawn, garden and home technology. They see and feel the benefits of being exposed to natural beauty every day, and we're committed to ensuring that everyone has their own little patch of green in 2020 & beyond. Nurturing is in their nature.

Agrinet has been a leader in Irrigation Wholesale for the past 70 years and we are the exclusive distribution partner for Orbit in Africa.

To learn more about DIY Garden Irrigation, follow Agrinet on social media and our website to see newly posted blogs in this series first.

For more information on the Orbit Irrigation ranges, please check out our comprehensive Irrigation Range.

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