Pesticide application equipment working on UK farms must now be checked by the National Sprayer Testing Scheme. The good news is nearly half of the sprayers inspected exhibit no faults, but that still leaves the other half requiring repairs before they receive a certificate.
It is now a legal requirement that all boom sprayers over 3m wide and more than five years old on 26th November 2016, must be tested and retested within five years up to 2020. Non-compliance could lead to prosecution and threaten single farm payments.
Sprayers less than five years old on 26th November 2016, must be tested by their fifth anniversary. They must be retested within five years up to 2020 and after that date all sprayers must be tested every three years.
Machines with booms less than 3m wide are required to be tested every six years, after the machine is five years old. The same applies to other machines including, for example, granular and slug pellet applicators, weed wipers and seed treatment units.
It is important to note, however, that many crop assurance schemes demand that sprayers, pesticide and nematicide applicators are tested annually, irrespective of the legal obligations.
The National Sprayer Testing Scheme (NSTS), which now includes granular and slug pellet applicators, as well as fogging machines, checks more than 20,000 machines every year.
NRoSO registered operators can gain three CPD points from attending the test by simply having the test engineer sign an attendance form. This also includes an operator check list, which is not only useful to prepare machines for the test, but also serves as a helpful memory jogger for routine maintenance.
NSTS and test engineers are concerned machines are being presented with the same top ten faults every year. These are not difficult or costly problems, which really should be picked up and fixed during operation to ensure effective and safe operation.
NSTS top ten fails
- Filters – blocked or damaged
- Leaks – over normal working pressure
- Contents gauge illegible
- Leaking anti-drip device or drip control valve (DCV)
- Worn nozzles
- Inaccurate pressure gauge
- Illegible control labels
- Section controls
- Damaged or faulty guards
- Pressure gauge scale and gradations
Damaged or blocked filters are still the most common faults found on test candidates. This will be due to lack of thorough or proper cleaning, which results in two issues: First the residues in the filter can come into contact with an incompatible chemical and cause a bad reaction. Second: If the residues come off during operation they will cause nozzle blockages and can also affect the operating pressure.
2. Leaks over normal working pressure
Pressure leaks should be obvious and often clear to see when the system is operating under normal pressure, which operators should easily spot. The test requires the machine to be run at 2 bar above the standard working pressure – usually 5 bar. This will reveal problems not apparent during normal work usually leaks from loose pipe clips, joints and joiners.
3: Illegible sight tube
An illegible sight tube, that prevents operators seeing the tank contents is the third most common NSTS fault. The actual scale needs to be in good condition and readable. While pendimethalin staining is the most common culprit, tubes do become cloudy through age and exposure to sunlight. Dry sight tubes and electronic gauges must also register the actual tank contents.
4. Leaking drip control valves
A leaking anti-drip device, or Drip Control Valve (DCV) is another very common fault. The diaphragm and spring in the valve are wearing parts and need to be regularly cleaned and checked for leaks. Depending on annual use, it’s a good idea to change these every year. Worn DCVs will drip when the machine is switched off and need to be fixed to prevent pollution.
5: Worn or damaged nozzles
Operators should regularly use a jug test to check nozzle outputs, but worn or damaged nozzles still account for a high proportion of NSTS fails. In the test the acceptable standard is 10% and the NSTS requires a minimum of one nozzle on each boom section to be tested. It also stipulates if one nozzle is found to fail the whole set must be replaced.
6: Inaccurate pressure gauge
There can be few operators that don’t look at their pressure gauge, but many in the NSTS tests are found to be faulty providing inaccurate readings. Gauges do wear and show incorrect readings and those that do not point to zero when there is no pressure in the system are not working correctly. Frost damage can often lead to issues. Some operators remove gauges at the end of the season, or even after every spray session to reduce the likelihood of problems occurring.
7: Illegible control labels
Control labelling comes under scrutiny in the test, which says they must be complete and legible. As machines age and after numerous wash downs many lose their labels, increasing the risk of making mistakes when filling, mixing and during application. Home-made replacements are fine, such as using permanent marker – provided they are clear and readable.
8. Section controls
Test engineers check the boom section on/off functions are working correctly. They also check the pressure in each section to ensure it is uniform pressure across the whole width. When boom compensation returns are fitted, these are checked to ensure the pressure stays the same when sections are turned on/off.
9: Damaged or faulty guards
Machines presented for testing with a damaged or faulty PTO guard will not be tested until it is replaced or repaired. It is surprising, say some engineers, how often they find damaged PTO guards, because these should be put right immediately as it not only puts lives at risk, but is also breaking the law. The test cannot proceed if the PTO guard is missing or damaged which means that the tester will have to come back for a second time.
10: Pressure gauge scale and graduations
Pressure gauges make it into the top ten faults for the second time with problems concerning damaged or unreadable scales, which are now mandatory checks. The scale must be readable from the operator’s position, be a minimum 63mm in diameter and have maximum 0.2 bar graduations.