The order sheet for a turf project runs long, yet its shortest line starts the most arguments. Buyers describe ordering ‘sand’ by name alone and discovering the surface plays completely differently from the sample – same carpet, two grades, two fields. That gap is why the infill size for artificial turf deserves treatment as a specification decision, not a bag label.
We build carpet, so we watch that line from the roll side, and the pattern repeats every season. One careless order line can cost a project its whole playing window, because the grade was written from habit while the specification was read closely everywhere else. Grain size reads like the smallest technicality on the sheet, and it quietly decides how the surface drains, cushions and wears. This guide is the decision tree for that line – the sizes, the bands behind them, and the checks that keep the choice honest.
The Line Everyone Fills In Without Asking
On most order sheets the infill size for artificial turf is one short field, and it is the line buyers complete from habit rather than from a document. The word ‘sand’ carries an illusion of sameness, as if all grades were interchangeable bags of the same stuff. Suppliers of industrial sand work to the opposite reality – the United States Geological Survey notes that processors turn out many grades to meet specifications for virtually any use.
The habit survives because the field looks self-explanatory and because nobody wants another agenda item. The cost of that comfort lands later, in how the surface plays and drains. By then the carpet is down, the fill is spread, and a correction means opening a finished project. The paper trail rarely catches up with the mistake before the grass is down.
Order-line rule. The grade travels with the carpet specification and the scene, never ahead of them. A size written into the order before either is read is a guess with a delivery date attached. There is a structural reason the line slips, too. The carpet and the fill usually travel separate supply chains, so the grade gets written where the turf specification is not being read.
Per the Synthetic Turf Council, most synthetic turf sports fields in the United States run on infill re-processed from used tires. The council counts more than 12,000 such fields, which makes tire-derived grain the country’s default fill. A recycled material arrives with batch-to-batch spread, and the spread is exactly what the order line needs to pin down.
The spread is not hypothetical. Per the EPA federal research plan, tire crumb infill from American fields ran predominantly between 0.25 and 4 mm, with wide variability. Two fields supplied under the same bag name can therefore sit far apart inside that one span. Before the grade is written, it pays to see why the infill layer decides how the surface behaves – that page takes the layer’s point of view. This page stays with the order: which size goes on the line, and how the choice gets verified.
Reading Particle Size Against Your Turf Specification
Matching the infill size for artificial turf to a project starts with the carpet, not with the fill aisle. Pile height, density and yarn shape describe the structure the grain has to live in. The FIFA Quality Programme handbook treats them accordingly, listing free pile height and infill depth as separate system parameters under Test Methods 18 and 21.
What the Carpet Brings to the Decision
A taller, denser carpet leaves different inter-row space than a short, tight one, and yarn morphology changes how the fill sits and locks. That is why the same grade reads differently in two carpets. Two carpets with the same pile height can still treat a grain differently once shape and density are read. The turf specification is the first document to open, because the grain must fit the structure that is actually being bought. Fibre density also decides how much grain the structure can accept before the spaces between yarns close up, which is a limit the bag cannot see.
Yarn shape adds its own wrinkle. A flat, wide tape presents different packing behaviour than a stemmed or texturized fibre, and the same grain reads differently against each. This is one more reason the carpet specification, not the fill catalogue, opens the reading.
Depth belongs to a different conversation. The handbook’s separation of pile height from infill depth is the formal version of a practical rule. Size is chosen for the structure, depth is set for the performance target, and the two are verified by different tests.
The Language the Numbers Speak
Serious spec sheets answer with two letters – d and D, the lower and upper ends of the declared band. The letters only mean something when a test method stands behind them. Sieve designations and millimetre ranges describe the same physical spread, and a buyer who can read one can read them all. Per the EPA federal research plan, characterisation of field infill ran by sieving, seven fractions per sample, from 0.063 mm up past 4.75 mm. A single number on a bag is a summary of a distribution, and the distribution is what a buyer can actually verify.
Geology keeps the formal vocabulary – per the USGS Wentworth grain-size scale, what a geologist calls sand is a family of sizes from 0.0625 mm to 2 mm wide. Everyday language flattens that family into one word. The flattening is where careless order lines begin.
Sand for turf is an industrial product, graded to a specification before it ever reaches a field. How silica sand is graded before it ever meets turf is the supply-side companion to this section. Between the quarry sieve and the project sieve sits a chain of grades, and every link can be documented.