How to Evaluate Samples Before a Batch Order
A sample is evidence only when the question is defined. What to test, what to record, and how to turn a trial into a repeatable order.
A sample is evidence, and like any evidence it is only useful if you know what question it is answering. Buyers who open the box and judge by feel learn almost nothing about the batch that will follow. Buyers who test the sample against the specification, the documents and the intended installation learn what the supplier can actually repeat.
01 – Why each channel needs it, and where it is used
| Channel | Role in this decision | Why they need it |
|---|---|---|
| Distribution and wholesale | Qualify a range before stocking | A sample that matches the specification is the cheapest guarantee against a container of the wrong class |
| Contractors and integrators | Check fit with existing components | The sample is the only way to test a fitting against the pipe standard already in use |
| Direct B2B users – farms, estates, municipal green | Test a replacement for a working system | A replacement must match the existing installation, and the sample shows whether it will |
| Specifiers and influencers – designers, procurement consultants | Verify a brand before naming it | The specification is a commitment, and the sample is how the commitment is checked |
It applies to every component where fit or class matters: filters, dripline, fittings, valves, controllers. The depth of the test changes, the principle does not.
02 – How to make a preliminary selection
Write the questions before the sample arrives. Typically: does the marked class match the stated one, do the fittings match the standard in use, are the documents complete, and does the product behave as described when installed.
Then plan the installation. A sample tested on a bench answers less than one installed in a real zone or bench, even if only for a week. The installation is what produces the readings that matter.
Then set the acceptance criteria. What would make you reject the batch – a class mismatch, a missing certificate, a fitting that does not seal, a pressure loss outside the stated range? Written before the sample arrives, the criteria are a decision; written after, they are a negotiation.
Finally, ask for the production sample, not the showroom sample. The two are frequently different, and the difference is the point of the exercise.
03 – Comparing the realistic options
The table frames the levels of sample testing and what each reveals.
| Level | Reveals | Misses |
|---|---|---|
| Visual check | Appearance, markings | Fit and behaviour |
| Dimensional check | Fit with existing components | Performance under pressure |
| Installation trial | Behaviour, pressure, cleaning | Long-term durability |
| Batch comparison | Consistency of production | Everything outside the sampled batch |
The third row is where most of the value sits for an irrigation buyer, and it usually costs one representative installation plus a week of observation.
04 – What goes wrong, and what still needs confirming
The usual failure is judging a sample visually and ordering a container. The second is a sample that is never installed, so the trial produces impressions rather than readings. The third is a trial with no recorded criteria, which ends in an argument about taste.
Items to confirm in writing: that the sample is a production sample; the class and its test basis; the fit against the existing standard; the documents supplied with it; the installation conditions of the trial; and the follow-on terms if the sample is accepted.
05 – What we can supply and what to send
Delta AgriFlow supplies production samples with their documents for filters, dripline, fittings and timers, and quotes the follow-on quantity at the same time.
Send six items: the questions the sample must answer; the standard it must fit; the installation planned for the trial; the acceptance criteria; the expected follow-on quantity; and the documents required.
The most informative part of the test is usually the fitting. A component that seals on the first attempt and again after being opened is a component that will not generate callbacks; one that needs force on the bench will be a problem on site.
A second is to weigh the sample and read the markings. Weight is a rough indicator of material use, and markings are what a site inspection checks when a batch is questioned.
A third is to keep the sample and its documents together. If a later batch differs, the sample becomes the reference rather than a memory.
A fourth is to test the sample at the pressure the system actually runs, not at a nominal figure. Behaviour at the design pressure is what the installation will experience.
Finally, ask how the follow-on batch will be the same as the sample. A supplier who can describe the production check is describing a repeatable process; one who cannot is describing a sample.
What to record at handover
A handover that consists of a working system and a verbal explanation is not a handover. Three things have to be written down: what was installed and where, what the settings are, and what the routine is. Record the sample identity, its stated class, the installation conditions and the readings taken during the trial.
The commissioning check matters as much as the record. Compare the sample against the specification and against the existing standard; both comparisons are needed. A reading taken once at commissioning is worth more than a datasheet, because it describes the installation rather than the product.
Finally, hand over the commercial part as clearly as the technical part. Agree the follow-on terms before the trial closes, so an accepted sample becomes a documented order. Without it, the next order restarts from zero, and the advantage of a standard package disappears.
What to check in a sample
- Marked class matches the stated class
- Fit with the existing standard
- Documents and test basis
- Behaviour at design pressure
- Packaging and markings
- Follow-on terms and lead time
A trial is also a test of the supplier’s documentation. Ask for the datasheet and the test basis with the sample; a supplier who has both before the order is a supplier who will have them after it.
Where several samples are compared, test them in the same installation conditions. A filter tested on a clean source and another on a silty one says nothing about either product.
Finally, record the date and the conditions of the trial. Those notes are what turn an opinion into a specification, and they are the reason the second order takes minutes instead of a week.
06 – Questions, sources and next steps
Is a sample free? Sometimes, and a paid sample is usually more informative because it arrives with commercial terms attached.
How long should the trial run? Long enough to see the behaviour: one cycle for a filter, one week for an emitter installation.
What should be recorded? The installation conditions, the readings and the date. Without them the trial is an impression.
A sample evaluation should end with one of three decisions: approve, approve with conditions, or reject. Anything else leaves the trial open, and an open trial is a reason to delay that never resolves itself.
Where a sample cannot be installed, test it against a component already in service: the fitting against the pipe, the element against the housing, the controller against the valve. Fit is the question a bench can answer.
A sample that is approved without recording why is a decision that cannot be repeated. The note next to the sample is what makes the second batch a confirmation rather than a new evaluation.
Before you order
- Stated class and markings
- Fit with existing standard
- Documents supplied
- Pressure behaviour tested
- Installation conditions
- Decision and date recorded
Where a sample cannot be installed, at least open and reassemble it. The parts that go back together cleanly are the parts that will survive a site repair.
The sample evaluation ends with a written decision, and that decision is the start of the specification rather than the end of a conversation.
A reject decision recorded with its reason is as valuable as an approval, because it stops the same question being reopened next season.
The written decision is also the training material for the next person who has to evaluate a batch, and that is a benefit a short note delivers for years.
Information boundary
This article describes how the decision is structured. It is not a performance specification and does not state capacity, flow, pressure or service-life values for a specific product. Those values are confirmed per project after a written quotation; manufacturer figures cited are the published values for those products, not project commitments.
Reviewed: 2026-10-26. Next review after supplier specifications are confirmed in writing.
Sources and further reading
- Rain Bird XFA 13 mm dripline datasheet – 120 mesh filtration requirement, 50-350 kPa compensating range
- Netafim Techflow bid performance specification – 120 mesh or finer filtration, disc grades 40-200 mesh
- ISO 9912-1:2004 – Filters for micro-irrigation: classification
- ISO 18471:2015 – Verification of filtration grade
- FAO – Irrigation manual, Chapter 6: drip irrigation
Requesting a sample? Tell us what it must prove through our quotation request.
