{"id":5775,"date":"2026-10-13T09:48:53","date_gmt":"2026-10-13T09:48:53","guid":{"rendered":"https:\/\/www.relyirgrass.com\/effect-rubber-granule-size-morphology-infill-perform\/"},"modified":"2026-11-09T09:24:14","modified_gmt":"2026-11-09T09:24:14","slug":"effect-rubber-granule-size-morphology-infill-perform","status":"publish","type":"post","link":"https:\/\/www.relyirgrass.com\/es\/effect-rubber-granule-size-morphology-infill-perform\/","title":{"rendered":"Relleno de goma: el tama\u00f1o y la forma lo deciden todo"},"content":{"rendered":"<style>\nh2 { font-size: 1.6em; line-height: 1.3; margin: 40px 0 18px; }\nh3 { font-size: 1.2em; line-height: 1.35; margin: 26px 0 12px; }\np { line-height: 1.8; margin-bottom: 28px; }\ntable { display: table !important; width: 100% !important; border-collapse: collapse; margin-bottom: 28px; }\nth { text-align: left; padding: 12px 14px; background: #1a5c2e; color: #ffffff; font-weight: 600; }\ntd { padding: 12px 14px; border-bottom: 1px solid #e5e5e5; vertical-align: top; }\nfigcaption { text-align: center; font-style: italic; }\n.callout-note { border-left: 4px solid #1a5c2e; background: #f3f7f2; padding: 18px 22px; margin: 28px 0; border-radius: 4px; }\n.callout-warning { border-left: 4px solid #b8860b; background: #fdf7e8; padding: 18px 22px; margin: 28px 0; border-radius: 4px; }\n.callout-tip { border-left: 4px solid #2e7d32; background: #f0f7f0; padding: 18px 22px; margin: 28px 0; border-radius: 4px; }\n<\/style>\n<p>Procurement sheets that just say &#8216;black rubber granules&#8217; leave hardness, splash and ageing completely undefined. Fields drift within a season or two, and nobody at the handover table can say which line of the specification failed. That failure is rarely about carelessness. It is about a missing layer of evidence between the bag label and the pitch.<\/p>\n<p>We sell the carpet side of these systems, so we read infill test reports the way bakers read flour specs &#8211; constantly, and with suspicion. The strongest evidence on rubber granule size infill performance comes from government agencies and university trials, not from vendor brochures. This guide reads that evidence the way a buyer should: with the sieve, the microscope and the rulebook open at once.  Federal agencies sampled forty fields to characterise exposure, universities ran multi-season plots, and a governing body wrote tolerances so its laboratories could agree with each other. Evidence with no product to push is the kind worth building a specification on.<\/p>\n<h2 id=\"what-field-sampling-shows\">What Field Sampling Shows: The Size Bands Actually in Play<\/h2>\n<p><!-- e-01 --><\/p>\n<p>Any honest account of rubber granule size infill performance starts with a sieve, because the fraction that dominates the column decides everything downstream. <a href=\"https:\/\/www.epa.gov\/sites\/production\/files\/2019-08\/documents\/synthetic_turf_field_recycled_tire_crumb_rubber_research_under_the_federal_research_action_plan_final_report_part_1_volume_1.pdf\" target=\"_blank\" rel=\"noopener\">Per the EPA FRAP field characterization<\/a>, infill sampled from 40 synthetic turf fields was predominantly 0.25-4 mm in diameter, with great variability within the range. Forty fields, one federal study, and no single magic number.<\/p>\n<h3>Fractions, Not Averages<\/h3>\n<p><!-- e-02 e-03 --><\/p>\n<p>Averages hide the migration story. The table lines up what nine US recycling plants ship as turf-grade fresh crumb rubber against what the same federal study scraped out of 40 playing fields. Both columns are averages in grams per kilogram. The gap between them is where attrition, migration and upkeep show up.<\/p>\n<table>\n<caption>Average particle-size distribution in g\/kg, fresh plant output vs field-sampled infill, per the EPA FRAP study<\/caption>\n<thead>\n<tr>\n<th>Sieve fraction<\/th>\n<th>Fresh plant crumb rubber (g\/kg)<\/th>\n<th>Field-sampled infill (g\/kg)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>&gt;1-2 mm<\/td>\n<td>780<\/td>\n<td>580<\/td>\n<\/tr>\n<tr>\n<td>&gt;2-4.75 mm<\/td>\n<td>86<\/td>\n<td>250<\/td>\n<\/tr>\n<tr>\n<td>&gt;0.25-1 mm<\/td>\n<td>140<\/td>\n<td>170<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><!-- e-05 --><\/p>\n<p>Three readings matter to a buyer. The &gt;1-2 mm fraction dominates both columns, so it is the fraction to specify by name. The &gt;2-4.75 mm share nearly triples between the plant and the field, which is what attrition of the fines looks like in practice. The fines never vanish entirely &#8211; per the same study, particles at or below 0.063 mm averaged 0.63 g\/kg and appeared in every sample tested. Migration of that kind is exactly what a declared distribution is supposed to catch early.<\/p>\n<h3>Why the Published Ranges Disagree<\/h3>\n<p><!-- e-04 e-08 --><\/p>\n<p>Ask three sources for the standard granule and you will get three honest answers. Per the EPA study, US plants grade turf-infill crumb rubber at 10 to 20 mesh, roughly 0.84-2 mm. Per the New York State Department of Health fact sheet, pellets on synthetic turf run from about one-sixteenth to one quarter inch in diameter, near 1.6-6.4 mm. Treat those as descriptions of different supply chains, not one blendable recommendation.<\/p>\n<p><!-- e-15 e-16 --><\/p>\n<p><a href=\"https:\/\/www.miljodirektoratet.no\/globalassets\/publikasjoner\/m955\/m955.pdf\" target=\"_blank\" rel=\"noopener\">Per the Norwegian Environment Agency M-955 report<\/a>, an industry recommendation favours 0.8-3 mm granules. The causal logic underneath is blunt. Too fine an infill compacts and the surface loses elasticity, while too coarse an infill absorbs too much ball energy, rebounds poorly and splashes.<\/p>\n<p>The lesson for a buyer is not to average the sources but to name one. Pick the band your system was designed around, declare it, and let the conformance tests hold the delivery to that declaration. A range quoted from memory is where field drift starts.<\/p>\n<h2 id=\"shock-absorption-deformation-and-ball-response\">Shock Absorption, Deformation and Ball Response: What the Numbers Measure<\/h2>\n<p>Most of the measured case for rubber granule size infill performance lives in a handful of laboratory scores. They cover shock absorption, vertical deformation and the way a ball leaves the surface. In plain terms, one describes how much impact energy the system returns to a player, one describes how far the surface gives, and one describes what the bounce does next. Each score is easy to quote and easier to abuse. The frames behind them are what make the numbers usable.<\/p>\n<h3>What a Gmax Reading Carries<\/h3>\n<p><!-- e-22 --><\/p>\n<p>Hardness is where size claims meet their limits, so read Gmax in its own frame. Per the Michigan State University surface-rubber trial, two crumb rubber sizes were compared as controlled topdressings on natural turf panels, not as 3G infill columns. After 46 simulated football games, Gmax read 60 for the coarser quarter-inch material and 62 for the 10\/20 mesh. The researchers did not call that difference significant.<\/p>\n<p><!-- e-23 e-24 --><\/p>\n<p>The same trial files sharper findings about quantity and time. Gmax ran significantly lower at high crumb rubber rates in 1993, and the effect did not continue in 1994 once the particles had settled. Shear values fell with increasing rubber in the unsettled first year, then rose significantly and stabilised in the second. A surface sampled in spring and the same surface sampled in autumn are not the same instrument.<\/p>\n<figure>\n<img fetchpriority=\"high\" decoding=\"async\" style=\"width:100%;height:auto;border-radius:8px\" src=\"https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot1.webp\" alt=\"Pile of angular black crumb pieces seen up close\" width=\"1200\" height=\"800\" class=\"wp-image-5771\" data-img-slot=\"1\" loading=\"eager\" srcset=\"https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot1.webp 1200w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot1-300x200.webp 300w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot1-1024x683.webp 1024w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot1-768x512.webp 768w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot1-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><figcaption>Angular grains interlock and resist migration &#8211; the shape file starts where the sieve ends.<\/figcaption><\/figure>\n<h3>Deformation, Force Reduction and the System Above<\/h3>\n<p><!-- e-33 --><\/p>\n<p>Field research with human subjects pushes the same lesson upward through the system. In a Springer Nature study of three pitch builds, the configuration with higher infill quantity delivered 6.24% higher force reduction than the reference field. The authors reported that gap as statistically significant, and concluded that structural components determine the mechanical properties of an artificial turf field. The granule column is one structural component among several, which is exactly why single-number claims deserve suspicion.<\/p>\n<div class=\"callout callout-warning\">\n<p><strong>Read the system, not the sieve.<\/strong> In the university trial the two granule sizes finished within two Gmax points, while rubber rate moved the score significantly in the first season. A hardness promise quoted from a sieve fraction alone is not evidence. Ask what sat under the rubber, and who settled it. Rate, pad, base and fibre all sit upstream of the number.<\/p>\n<\/div>\n<p><!-- e-20 --><\/p>\n<p>The ball and the players register what the sieve started. Per the Norwegian M-955 report, granules stick to cloth, footwear and skin especially in wet weather, and play produces substantial splash. Those are user-visible symptoms of a column whose top fraction is loose, mobile or simply the wrong size.<\/p>\n<h2 id=\"morphology-angular-rounded-and-what-wear-does\">Morphology: Angular, Rounded, and What Wear Does to Both<\/h2>\n<p>Shape is the quiet half of rubber granule size infill performance, and it is the first line to drop off a procurement sheet. Two granules can share a sieve fraction and still behave differently under studs. The cutting route that produced them left different faces, and faces decide grip. Buyers who never ask about shape end up owning the difference anyway, one season of studs at a time.<\/p>\n<h3>Two Routes, Two Shapes<\/h3>\n<p><!-- e-26 e-27 e-06 --><\/p>\n<p>Per the Penn State sports surface report, mechanical grinding produces rough-faced, irregular shaped granules. Sand-blend systems use this grade because the irregular granules help hold the sand in place. The alternative is cryogenic size reduction, a freezing process that fractures rubber into granules of a different character. Among nine US plants sampled for turf-infill material, six used ambient processing and three used cryogenic, per the EPA study.<\/p>\n<p><!-- e-07 --><\/p>\n<p>When a lab needs to see the fine fraction rather than sieve it, the instrument changes. The EPA study reserved scanning electron microscopy for a subset of nine plant and nine field samples, using it to characterize size distribution and elemental composition of the fines. Microscopy is how shape stops being an adjective and becomes a measurement. It is also the reason a shape claim should arrive with micrographs, not adjectives.<\/p>\n<figure>\n<img decoding=\"async\" style=\"width:100%;height:auto;border-radius:8px\" src=\"https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot2.webp\" alt=\"Smooth rounded black pebbles filling the frame\" width=\"1200\" height=\"800\" class=\"wp-image-5772\" data-img-slot=\"2\" loading=\"lazy\" srcset=\"https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot2.webp 1200w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot2-300x200.webp 300w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot2-1024x683.webp 1024w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot2-768x512.webp 768w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot2-18x12.webp 18w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption>Rounded grains pack differently: the same mass, a different void structure underneath the player.<\/figcaption><\/figure>\n<h3>What Play Does to the Particle<\/h3>\n<p><!-- e-13 e-14 --><\/p>\n<p>Play edits the shape file continuously. Per the Danish EPA assessment, wear and tear produces rubber dust that can be a source of exposure through skin or respiratory passages. Microscopy of filtered fine material in that study observed black and white translucent particles of 10-50 \u00b5m. Every granule on the field is slowly grinding toward that end point.<\/p>\n<p><!-- e-34 --><\/p>\n<p>Geometry also feeds back into stability under load. A 2026 Springer Nature field analysis found that irregular particle geometry combined with comparatively lower bulk density likely decreases infill stability. The finding was drawn from vegetal infills, but it is worth carrying to any irregular granule. Shape, in other words, is load-bearing rather than cosmetic.<\/p>\n<p>Neither route is universally better, which is why the conformance chapter checks shape rather than ranking it. A rough-faced granule that locks sand in place also carries more surface area for weathering. The procurement answer is to declare the shape class and hold the delivery to it.<\/p>\n<h2 id=\"where-granules-meet-grass\">Where Granules Meet Grass: Fibre Support and the Unfilled Zone<\/h2>\n<p><!-- e-12 --><\/p>\n<p>The carpet enters the rubber granule size infill performance equation at the fibre line, where granule meets yarn.  Per the Danish EPA, a third-generation pitch runs 50-70 mm of fibre, a silica sand layer at the bottom and a rubber granule layer above it. The top 20 mm are left unfilled.  Per the New York State Department of Health, crumb rubber is typically applied at two to three pounds per square foot of field surface. A Penn State municipal report describes material processed to the size of coarse sand, spread two to three inches thick and raked down between the fibres. <\/p>\n<p><!-- e-09 e-25 --><\/p>\n<p><!-- e-18 --><\/p>\n<p>Tonnage is the field-scale view of the same numbers. Per the Norwegian M-955 report, a full-size artificial grass football field typically takes 90-120 tonnes of crumb rubber. That quantity varies with the field system, the shock pad and the grass length and type.   Fibre support decides how a boot plants and releases, and the granule column decides how much the surface gives back underneath it. When the two specifications are written separately, the interface between them is specified by nobody.<\/p>\n<div class=\"callout callout-note\">\n<p><strong>The unfilled zone is a design decision.<\/strong> That empty top 20 mm is not under-filling &#8211; it is working space for the yarn that carries the boot and the ball. Pile height and fill depth are two halves of one number, written against each other. Read the two specs as one drawing, and the void stays where the designer put it.<\/p>\n<\/div>\n<p><!-- link: key-technical-specs --><\/p>\n<p>The carpet spec and the granule spec are written against each other or not at all. Before fixing pile height and fill depth in separate documents, read <a href=\"https:\/\/www.relyirgrass.com\/key-technical-specs-for-reliable-football-turf\/\">how the carpet spec and the infill spec lock each other in<\/a>. A fibre that is never specified against the column is a fibre left to luck.<\/p>\n<figure>\n<img decoding=\"async\" style=\"width:100%;height:auto;border-radius:8px\" src=\"https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot3.webp\" alt=\"Green plants with root systems exposed along a bank\" width=\"1200\" height=\"800\" class=\"wp-image-5773\" data-img-slot=\"3\" loading=\"lazy\" srcset=\"https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot3.webp 1200w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot3-300x200.webp 300w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot3-1024x683.webp 1024w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot3-768x512.webp 768w, https:\/\/www.relyirgrass.com\/wp-content\/uploads\/2026\/10\/effect-rubber-granule-size-morphology-infill-perform-slot3-18x12.webp 18w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><figcaption>The granule column meets the yarn at the fibre line &#8211; an interface both specifications must share.<\/figcaption><\/figure>\n<h2 id=\"how-labs-test-this\">How Labs Test This: A One-Pass Map<\/h2>\n<p><!-- e-28 --><\/p>\n<p>You do not need a laboratory to follow rubber granule size infill performance evidence &#8211; you need a map of the tests behind the numbers. The map matters because granule evidence arrives from several test families, and mixing them up is how bad comparisons get made. Per <a href=\"https:\/\/digitalhub.fifa.com\/m\/7e03cf23203765a2\/original\/FIFA-quality-programme-for-football-turf-Test-Manual-II-Test-Requirements-2015v-3-4.pdf\" target=\"_blank\" rel=\"noopener\">the FIFA Quality Programme test requirements<\/a>, football turf carries a shared scoring vocabulary. For dry conditions, the published bands run as follows.<\/p>\n<p>Shock absorption must land between 62-68% at Pro level and 57-68% at Quality level, with vertical deformation held to 4-10 mm and 4-11 mm respectively. Vertical ball rebound is banded at 60-85 cm for Pro and 60-100 cm for Quality. Rotational resistance runs 32-43 Nm against 27-48 Nm, and ball roll 4-8 m against 4-10 m.<\/p>\n<p><!-- e-31 e-32 --><\/p>\n<ul>\n<li><strong>Impact and deformation.<\/strong> Shock absorption, vertical deformation and rotational resistance, measured on the infilled system rather than the bare carpet.<\/li>\n<li><strong>Ball behaviour.<\/strong> Vertical rebound and ball roll, the two scores most sensitive to how the top of the column returns energy.<\/li>\n<li><strong>Wear and splash.<\/strong> Per the FIFA test methods manual, Test Method 15 wears the surface with studded rollers of about 28.5 kg, and Test Method 16 counts infill splash.<\/li>\n<li><strong>Ageing.<\/strong> Test Method 10 exposes pile yarn and polymeric infill to UV lamps, then measures changes in colour, appearance and selected physical properties.<\/li>\n<li><strong>Product identification.<\/strong> Sieve analysis of the delivered granule against the declared distribution &#8211; the conformance subject every purchase order should ask for by name.<\/li>\n<\/ul>\n<p>Two habits make any of these reports readable. Match every score to the condition it was measured under, because dry and wet runs diverge. And when a report characterises the fine fraction itself, check which instruments were actually used, because fines analysis is a specialism most labs rent rather than own. A report that shows conditions, instruments and scores together is a report you can actually buy against.<\/p>\n<h2 id=\"the-fifa-conformance-language-translated\">The FIFA Conformance Language, Translated<\/h2>\n<p><!-- e-29 --><\/p>\n<p>Conformance is where rubber granule size infill performance evidence hardens into contract language. Per <a href=\"https:\/\/digitalhub.fifa.com\/m\/7e03cf23203765a2\/original\/FIFA-quality-programme-for-football-turf-Test-Manual-II-Test-Requirements-2015v-3-4.pdf\" target=\"_blank\" rel=\"noopener\">the FIFA Quality Programme handbook<\/a>, a product-identification check runs the delivered granule against the manufacturer&#8217;s own declaration. The vocabulary is narrow, and it translates cleanly onto a purchase order. It is also the part most procurement sheets skip, because the tolerances live in a test manual nobody ships with the bag.<\/p>\n<p><!-- e-29 e-30 --><\/p>\n<p>For particle size, Test Method 20 allows a maximum of one sieve difference, with 60% of the mass between the declared d and D limits. For shape, the granule must read as similar shape under the EN 14955 procedure. For bulk density, the EN 1097-3 measurement must sit within plus or minus 15%. Tolerances like these are what make two laboratories agree on one bag of granules.<\/p>\n<p>Read together, the three checks say something simple. The granule you receive must be the granule that was declared, within tolerances an independent laboratory can reproduce. That is the entire point of the conformance chapter &#8211; it converts a sieve curve and a shape class into lines a supplier signs. Ask for the declaration sheet with the delivery, and the check becomes a fifteen-minute laboratory task instead of an argument.<\/p>\n<div class=\"cta-box\" style=\"background-color:#1a2b3c;border-radius:6px;padding:30px;margin:35px 0\">\n<h3 style=\"color:#ffffff;margin-top:0\">Specifying the Carpet Side of the System?<\/h3>\n<p style=\"color:#ffffff\">Football turf built to your granule spec: pile height, density and roll width configured to the declared infill plan, samples sent first.<\/p>\n<p><a href=\"https:\/\/www.relyirgrass.com\/sports-artificial-grass\/football-turf\/\" style=\"display:inline-block;background-color:#1a5c2e;color:#ffffff;padding:12px 24px;border-radius:4px;text-decoration:none;font-weight:600\">View Football Turf<\/a><\/p>\n<\/div>\n<h2 id=\"what-goes-on-the-granule-procurement-sheet\">What Goes on the Granule Procurement Sheet<\/h2>\n<p>A granule procurement sheet is the artefact this whole evidence chain exists to produce. Hand it to the infill supply chain with every line traceable to a test rather than a habit. Each line below earns its place because its absence has failed somebody on an actual field. Write it once, and every later conversation about hardness, splash or refill has an address.<\/p>\n<p><!-- e-35 --><\/p>\n<ul>\n<li><strong>Declared size distribution.<\/strong> The full sieve curve with d and D limits, not a single headline number, so Test Method 20 has something to check against.<\/li>\n<li><strong>Shape and production route.<\/strong> Ambient-ground or cryogenic, with the EN 14955 shape procedure named.<\/li>\n<li><strong>Bulk density.<\/strong> An EN 1097-3 figure with its tolerance window declared.<\/li>\n<li><strong>Wear and splash results.<\/strong> Lisport XL wear and infill splash quantities, matched to the sport and the traffic the field will actually carry.<\/li>\n<li><strong>Loss control.<\/strong> Design measures against granule migration &#8211; barriers, perimeter mats and clean-down zones per an industry infill voice &#8211; with brushing and top-up intervals in the maintenance schedule.<\/li>\n<\/ul>\n<p>Infill requirements also do not freeze at football. Before locking the sheet, check <a href=\"https:\/\/www.relyirgrass.com\/multisport-turf-with-or-without-infill\/\">how infill requirements differ once a field serves more than one sport<\/a>. A sheet that only answers football gets renegotiated the day the field takes its second booking.<\/p>\n<p>None of this makes the project side an infill laboratory overnight. It makes the granule line auditable, which is what a procurement sheet is for. An auditable line is also a comparable one, and comparability is where specification discipline starts to pay. Keep the sheet with the field&#8217;s file, because the next buyer, installer or tester will ask for it before the first refill.<\/p>\n<h2 id=\"from-granule-to-field\">From Granule to Field: Putting It Together<\/h2>\n<p><!-- e-17 --><\/p>\n<p>Size decides voids and compaction behaviour, morphology decides grip and the wear trajectory, and together they set how a pitch feels across its observed decade. Per the Norwegian M-955 report, crumb rubber infill is observed to serve approximately 10 years before the complete field is replaced. That is an agency observation about service life, not a promise attached to any product.<\/p>\n<p>The surface enters this system at selection time, not at delivery. We configure <a href=\"https:\/\/www.relyirgrass.com\/sports-artificial-grass\/football-turf\/\">football turf built around the granule spec<\/a>, with pile height, density and roll width set against the declared infill plan. That is how the evidence chain above ends on a field rather than in a drawer. A roll that ignores the granule column is a guess wearing a datasheet.<\/p>\n<p>Read that way, the sieve becomes what it should always have been: the first page of the field&#8217;s file. Rubber granule size infill performance is not a marketing phrase but a measurable chain, running from a federal sieve stack to the bounce of a ball in stoppage time. None of the steps in that chain are exotic &#8211; a sieve, a microscope, a test manual and a signed declaration cover most of it. Buyers who keep that chain unbroken buy fields that still play the way their documents promise.<\/p>\n<p><!-- relyirgate:C1 --><\/p>\n<h2 id=\"frequently-asked-questions\">Frequently Asked Questions<\/h2>\n<div class=\"faq-card\" style=\"background:#f9f9f9;border-left:4px solid #1a5c2e;border-radius:4px;padding:25px;margin-bottom:18px\">\n<h3 style=\"color:#1a5c2e;margin-top:0\">Does rubber granule size infill performance really change on a finished field?<\/h3>\n<p>Yes &#8211; size decides the void structure and compaction behaviour of the granule column. Per the Norwegian M-955 report, too fine an infill compacts and the surface loses elasticity, while too coarse an infill absorbs too much ball energy and splashes.<\/p>\n<\/div>\n<div class=\"faq-card\" style=\"background:#f9f9f9;border-left:4px solid #1a5c2e;border-radius:4px;padding:25px;margin-bottom:18px\">\n<h3 style=\"color:#1a5c2e;margin-top:0\">What size are turf infill granules?<\/h3>\n<p>Each source describes its own supply chain. Field infill in the EPA study ran predominantly 0.25-4 mm. US plants grade turf-infill material at 10 to 20 mesh, and a US health authority describes 1.6-6.4 mm pellets.<\/p>\n<\/div>\n<div class=\"faq-card\" style=\"background:#f9f9f9;border-left:4px solid #1a5c2e;border-radius:4px;padding:25px;margin-bottom:18px\">\n<h3 style=\"color:#1a5c2e;margin-top:0\">Do angular and rounded granules perform differently?<\/h3>\n<p>Yes &#8211; they bring different working properties. Per the Penn State report, mechanically ground granules are rough-faced and irregular, which helps blends hold the sand in place, while cryogenic reduction fractures rubber differently. Shape is checked under the EN 14955 procedure.<\/p>\n<\/div>\n<div class=\"faq-card\" style=\"background:#f9f9f9;border-left:4px solid #1a5c2e;border-radius:4px;padding:25px;margin-bottom:18px\">\n<h3 style=\"color:#1a5c2e;margin-top:0\">Why does an infilled field get harder over time?<\/h3>\n<p>Compaction and fines are the usual drivers. Per the Danish EPA, wear and tear produces rubber dust, and fine particles fill the voids that once gave the surface its elasticity. Regular brushing and occasional top-ups keep the column elastic for longer.<\/p>\n<\/div>\n<div class=\"faq-card\" style=\"background:#f9f9f9;border-left:4px solid #1a5c2e;border-radius:4px;padding:25px;margin-bottom:18px\">\n<h3 style=\"color:#1a5c2e;margin-top:0\">What should a granule procurement sheet contain?<\/h3>\n<p>A declared size distribution with d and D limits, particle shape under the EN 14955 procedure, and bulk density per EN 1097-3 within 15%. Add wear plus splash results, with each line naming its test method.<\/p>\n<\/div>\n<p><script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"Article\",\n \"headline\": \"Effect of Rubber Granule Size and Morphology on Infill Performance\",\n \"description\": \"Size bands in the field, Gmax comparisons, angular vs rounded morphology and the conformance language that turns evidence into procurement.\",\n \"author\": {\"@type\": \"Organization\", \"name\": \"Relyir Artificial Grass\"},\n \"publisher\": {\"@type\": \"Organization\", \"name\": \"Relyir Artificial Grass\"},\n \"datePublished\": \"2026-10-13\",\n \"dateModified\": \"2026-10-13\",\n \"mainEntityOfPage\": \"https:\/\/www.relyirgrass.com\/effect-rubber-granule-size-morphology-infill-perform\/\"\n}<\/script><\/p>\n<p><script type=\"application\/ld+json\">\n{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"Does rubber granule size infill performance really change on a finished field?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes - size decides the void structure and compaction behaviour of the granule column. Per the Norwegian M-955 report, too fine an infill compacts and the surface loses elasticity, while too coarse an infill absorbs too much ball energy and splashes.\"}}, {\"@type\": \"Question\", \"name\": \"What size are turf infill granules?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Each source describes its own supply chain. Field infill in the EPA study ran predominantly 0.25-4 mm. US plants grade turf-infill material at 10 to 20 mesh, and a US health authority describes 1.6-6.4 mm pellets.\"}}, {\"@type\": \"Question\", \"name\": \"Do angular and rounded granules perform differently?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes - they bring different working properties. Per the Penn State report, mechanically ground granules are rough-faced and irregular, which helps blends hold the sand in place, while cryogenic reduction fractures rubber differently. Shape is checked under the EN 14955 procedure.\"}}, {\"@type\": \"Question\", \"name\": \"Why does an infilled field get harder over time?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Compaction and fines are the usual drivers. Per the Danish EPA, wear and tear produces rubber dust, and fine particles fill the voids that once gave the surface its elasticity. Regular brushing and occasional top-ups keep the column elastic for longer.\"}}, {\"@type\": \"Question\", \"name\": \"What should a granule procurement sheet contain?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"A declared size distribution with d and D limits, particle shape under the EN 14955 procedure, and bulk density per EN 1097-3 within 15%. Add wear plus splash results, with each line naming its test method.\"}}]}<\/script><\/p>\n<p><script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"definition\": \"Granule size and morphology are specified as a verifiable chain: field-sampled size bands from the EPA FRAP study, laboratory scores (Gmax, shock absorption, deformation, ball rebound) read in their own frames, morphology traced to the ambient vs cryogenic production route, the layered infill build-up against the carpet fibres, and the FIFA conformance language (Test Method 20 sieve agreement, EN 14955 shape, EN 1097-3 bulk density) that turns the evidence into procurement lines.\",\n \"key_facts\": [\n  \"Per the EPA FRAP field characterization, infill sampled from 40 synthetic turf fields was predominantly 0.25-4 mm in diameter, with great variability within the range\",\n  \"Average particle-size distribution in g\/kg: fresh turf-grade plant crumb rubber runs 780 (&gt;1-2 mm), 140 (&gt;0.25-1 mm) and 86 (&gt;2-4.75 mm), while field-sampled infill runs 580, 170 and 250 respectively (EPA FRAP)\",\n  \"Per the Norwegian Environment Agency M-955 report, too fine an infill compacts and the surface loses elasticity, while too coarse an infill absorbs too much ball energy, rebounds poorly and splashes; the same report observes crumb rubber infill serving approximately 10 years\",\n  \"Per the FIFA Quality Programme test requirements, dry football turf bands include shock absorption 62-68% (Pro) \/ 57-68% (Quality), vertical deformation 4-10 mm \/ 4-11 mm and vertical ball rebound 60-85 cm \/ 60-100 cm\",\n  \"Per the FIFA Quality Programme handbook, Test Method 20 allows a maximum one sieve difference with 60% of mass between declared d and D limits, shape per EN 14955 and bulk density per EN 1097-3 within plus or minus 15%\"\n ],\n \"qa_concise\": [\n  {\n   \"q\": \"Does rubber granule size infill performance really change on a finished field?\",\n   \"a\": \"Yes - size decides the void structure and compaction behaviour of the granule column; too fine compacts, too coarse absorbs ball energy and splashes (Norwegian M-955 report).\"\n  },\n  {\n   \"q\": \"What size are turf infill granules?\",\n   \"a\": \"There is no single band: field infill ran predominantly 0.25-4 mm in the EPA study, US plants grade turf-infill material at 10 to 20 mesh, and a US health authority describes 1.6-6.4 mm pellets.\"\n  },\n  {\n   \"q\": \"Why does an infilled field get harder over time?\",\n   \"a\": \"Compaction and fines are the usual drivers; per the Danish EPA, wear produces rubber dust, and brushing plus occasional top-ups keep the column elastic.\"\n  }\n ]\n}<\/script><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Procurement sheets that just say &#8216;black rubber granules&#8217; leave hardness, splash and ageing completely undefined. Fields drift within a season or two, and nobody at the handover table can say which line of the specification failed. That failure is rarely about carelessness. It is about a missing layer of evidence between the bag label and &#8230; <a title=\"Relleno de goma: el tama\u00f1o y la forma lo deciden todo\" class=\"read-more\" href=\"https:\/\/www.relyirgrass.com\/es\/effect-rubber-granule-size-morphology-infill-perform\/\" aria-label=\"Leer m\u00e1s sobre Rubber Infill: Size and Shape Decide Everything\">Leer m\u00e1s<\/a><\/p>","protected":false},"author":2,"featured_media":5770,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rank_math_title":"Rubber Granule Size and Infill Performance","rank_math_description":"Size bands in the field, Gmax comparisons, angular vs rounded morphology and the conformance language that turns evidence into procurement.","rank_math_focus_keyword":"rubber granule size infill performance","rank_math_robots":"","rank_math_canonical_url":"","rank_math_facebook_title":"","rank_math_facebook_description":"","rank_math_twitter_title":"","rank_math_twitter_description":"","_yoast_wpseo_title":"","_yoast_wpseo_metadesc":"","_yoast_wpseo_focuskw":"","_yoast_wpseo_canonical":"","_yoast_wpseo_meta-robots-noindex":"","_yoast_wpseo_meta-robots-nofollow":"","_yoast_wpseo_opengraph-title":"","_yoast_wpseo_opengraph-description":"","_yoast_wpseo_twitter-title":"","_yoast_wpseo_twitter-description":"","_aioseo_title":"","_aioseo_description":"","_aioseo_keywords":"","_aioseo_robots_default":"","_aioseo_robots_noindex":"","_aioseo_og_title":"","_aioseo_og_description":"","_aioseo_twitter_title":"","_aioseo_twitter_description":"","aiosp_title":"","aiosp_description":"","aiosp_keywords":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_analysis_target_kw":"","_seopress_robots_canonical":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_genesis_title":"","_genesis_description":"","_genesis_canonical":"","_genesis_noindex":"","_genesis_nofollow":"","slim_seo":"","footnotes":""},"categories":[28],"tags":[],"class_list":["post-5775","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-sports-field-turf"],"_links":{"self":[{"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/posts\/5775","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/comments?post=5775"}],"version-history":[{"count":1,"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/posts\/5775\/revisions"}],"predecessor-version":[{"id":6708,"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/posts\/5775\/revisions\/6708"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/media\/5770"}],"wp:attachment":[{"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/media?parent=5775"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/categories?post=5775"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.relyirgrass.com\/es\/wp-json\/wp\/v2\/tags?post=5775"}],"curies":[{"name":"WordPress","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}