How Sprinkler Data Becomes "Common" Knowledge

Imagine a world without standards. No speed limits or familiar road signs. Clothes shopping would be a nightmare. No regulations on the food you buy. All in all, the world would be a mess.

And what about the irrigation industry? Pipe with inconsistent pressure ratings, fittings you'd need to test to see if they'd hold, controllers that wouldn't work because power at your site was incompatible with what was needed. In short, chaos. The world and the irrigation industry both have standards because, without them, we wouldn't know what to expect from the products we use.

What the Standard Means

Ever wonder exactly what the ASAE Certification Statement in our catalog means and how it affects what you do in your job?

The American Society of Agricultural Engineers standard S398.1 defines a common procedure for collecting and interpreting sprinkler test data like pressure, flow rate and radius. The standard outlines site conditions for an acceptable test (e.g., sprinkler location and height during the test, specifications for risers and collection devices, spacing of collectors and wind sensing equipment), in effect helping to guarantee that tests between different sprinklers with common characteristics are carried out in similar conditions.

Performance charts generated from these methods let you know where the data came from, so you are comparing "apples to apples." Thus, manufacturers that follow the procedure for testing and publishing of their data make it easier for people to compare different sprinklers on paper.

How the Standard Works

Now, how do you use these charts when laying out your irrigation plan? The chart may show that at 50 psi your sprinkler will throw 42 feet, but remember that data was obtained in a controlled environment under specific conditions.

With that in mind, you'll need to consider the conditions at your particular site: average wind speed (and direction), type of soil, sloped terrain, amount of pressure (and could it vary in the months, or years, ahead). Real world variables will affect performance and need to be accounted for in the design process.

Other Considerations

While technology has allowed us to minimize differences, there is variation in all sprinklers and nozzles produced. That is why, in order to generate a new chart, many different nozzles in many different sprinklers must be tested until we have a uniform performance range. These results are then averaged. Once the chart is produced for a series of nozzles, it becomes the internal standard that all nozzles in that series must meet.

Once the numbers are in the charts, we constantly test our nozzles to make sure they fall within acceptable manufacturing tolerances. This ongoing quality assurance guarantees all our nozzles are as near as possible to their numbers in the charts (at Hunter, we are in complete control of the tooling and molding process, plus we build our own molding machines, affording us tighter tolerances and less manufacturing variation).

Site conditions vary, even within the same area, so be sure to find out the variables and plan them into your design. This includes knowing your area's soil and wind conditions and being able to change nozzles easily in case there are coverage problems or if conditions change in the future. Flexibility is the key.

Standards are necessary. And your understanding of their role in sprinkler testing can help you ensure great performance from the systems you design and install.