mobile feed weather

Testing knapsack sprayers

Knapsack sprayers today: How well do they meet International Standards?

….asks Dr Andreas Herbst of JKI, Germany

Knapsack sprayers – especially the side lever pumped – are essential pieces of equipment to many farmers around the world and thus good design matters. Many knapsack sprayer makes are available and millions are sold every year. But are they all performing more or less the same or are some better than others?

In 2009, sponsored a global survey to help us all better understand how good these sprayers are and find out if improvements should be made?

Where did the sprayers come from and how were they selected?

Pesticide experts from twelve countries that use knapsack sprayers extensively were asked to nominate

  • the sprayer most commonly used and 
  • the sprayer considered by these experts to be the best available.

The responses were clear; about ten internationally active manufacturers were dominating usage and were highly regarded. Twelve sprayers were identified as being the best available today and were sent to JKI for testing.

How were the tests selected?

The test methods used were those described by the relevant International Standard . We assessed how good the sprayers were by comparing the values we gained from the tests against those listed by the Performance Limits of the Standard. There are others Standards and protocols for testing knapsack sprayers but we believed that ISO 19932 2006 was the most appropriate to use.

What did you test?

ISO 19932 2006 is very comprehensive and defines many requirements most of which  relate to the safe and effective use of the side lever sprayer.  There are, for example, many general specifications relating to such things as the loaded sprayer weight, tank contents gauge and so on as well as 26 specified tests that deal with leakage, stability, external and internal residues. See 'How test?'  for more details.

Do any of the sprayers comply with ISO standard ISO 19932 2006?

According to the tests we made, no, though about half of the ten manufacturers did very well.  Some of the sprayers only need minor improvements to meet the standard and it is hoped that this year will see the first claims for total IS compliance being made. This will be hugely important as it means that purchasers of those knapsack sprayers will be able to rely on an independent and international endorsement at the point of purchase.  (See buyers guide for hints and tips)

The achievement will also be much acclaimed by the wider industry - watch this site for the first announcement!

Are there any threats to my future use of knapsack sprayers if they continue to not comply?

There could be - so lets consider two issues:

  1. Media reports – from time to time - cite poor spraying practices and poor sprayers as a reason not to buy and import crops for consumption and use those crops that have been grown elsewhere. Better sprayers which can be shown to conform to a high standard of manufacture, will greatly help minimise that risk. In addition:
  2. If, for example, regulators decide that risks of pesticide exposure are  not acceptable by current standards because of excessive knapsack sprayer leakage [or other risk] then approval for that specified use may be withdrawn.