ASTM D751 - Coated Fabrics Testing Equipment

Downloads: ASTM D751 - Standard Test Method for Coated Fabrics - PDF · ASTM D751 Puncture Fixture – Universal Grip Data Sheet (PDF)

Written by Chris Thomas, Universal Grip Company · Reviewed by Frank Bertini · Updated October 17, 2026

ASTM D751 is the standard test methods for coated fabrics: the single document that covers how rubber- and plastics-coated textiles (PVC tarpaulins and truck covers, architectural membranes, inflatables, rainwear, awnings, upholstery vinyl, PU-coated nylon, geomembrane fabrics, protective clothing) are tested for strength, tear, puncture, seam strength, coating adhesion, hydrostatic resistance and a dozen other properties. It is not one test but a collection of about 27 procedures, most of them run on a constant-rate-of-extension tensile machine with the right grips or fixture. The current edition is D751-26, published in 2026; it renumbers every section relative to the D751-19 and D751-06 editions that the ranking pages still quote, so a specification that calls out "D751 Section 13" needs to be read against the edition it was written to.

This guide puts the mechanical procedures in one place with their specimen sizes, jaw faces, gauge lengths, speeds, specimen counts and the statistic each one reports; explains grab versus strip strength and why the grab result is higher; corrects the conditioning atmosphere (D1776: 21 °C and 65 % RH, not the 23 °C / 50 % RH plastics atmosphere that several pages, including an earlier version of this one, quoted); covers grip selection for slick PVC and PU coatings and the jaw-break rule; gives worked examples; and compares D751 with D5034, D5035, D2261, D5587 and the ISO methods. It ends with the grips, fixtures and machines Universal Grip supplies for coated-fabric labs.

In this guide: What ASTM D751 Covers · Conditioning: 21 °C and 65 % RH per D1776 · The Machine and the Grips · Breaking Strength: Grab and Cut Strip · Tear: Tongue and Trapezoid · Puncture and Ball Burst · Seam Strength, Coating Adhesion and Tack-Tear · Hydrostatic Resistance and the Pressure Tests · Step-by-Step: Running a Grab Test · ASTM D751 vs D5034, D5035, D2261, D5587 and the ISO Methods · Common Errors · Equipment for ASTM D751 · FAQ

What ASTM D751 Covers

D751 applies to fabrics coated with rubber or plastics on one or both sides. Its procedures fall into four groups: dimensional and mass measurements (thickness, mass per unit area); mechanical tests on a tensile machine (breaking strength by grab or cut strip, elongation, ball burst, puncture, tongue and trapezoid tear, coating adhesion, strength of coating, tack-tear, seam strength, crush resistance); pressure tests (diaphragm burst on a Mullen-type tester, hydrostatic resistance by Mullen or rising water column); and environmental or durability procedures (low-temperature bend and impact, low-temperature crack resistance, heat aging, dead-load seam strength, blocking, wicking). Pendulum tear refers to the Elmendorf method of D1424. SI units are the standard's primary units, with inch-pound values given for information, which is why most specimen sizes are round inch numbers (4 × 6 in becomes 102 × 152 mm).

What D751 does not do is also worth stating, because competitor pages get it wrong: it does not measure fibre content, coating type or coating thickness as separate properties (total thickness and mass are the only dimensional procedures), and air permeability and mildew resistance are not D751 procedures. A coated-fabric specification normally cites D751 for the mechanical properties and other standards for those. Our textiles testing page gives the wider picture of fabric testing, and the textile testing on a universal testing machine article walks through the grab, strip, burst and puncture tests as a set.

Conditioning: 21 °C and 65 % RH per D1776

Coated fabrics are textiles, and D751 conditions them in the standard atmosphere for textiles defined in ASTM D1776: 21 ± 1 °C (70 ± 2 °F) and 65 ± 2 % relative humidity, with the specimens brought to moisture equilibrium before testing (industry practice is at least 15 hours, longer for heavy or tightly woven substrates). This is not the plastics atmosphere of D618 (23 ± 2 °C and 50 % RH) that is often applied by habit. The difference matters for anything with a nylon, polyester-cotton or cotton substrate, whose strength and elongation change with moisture content, and it is the first thing to check when two labs disagree on a grab strength. Test in the conditioning atmosphere where possible, or immediately after removal. Low-temperature procedures (bend, impact, crack) are run in an environmental chamber at the temperature the specification sets; a conditioned specimen should be given time at temperature before the test, and the chamber, not a quick transfer from a freezer, is the compliant way to do it.

The Machine and the Grips

Every tensile procedure in D751 runs on a constant-rate-of-extension (CRE) machine as described in ASTM D76, with force indication verified per ASTM E4 and readings kept within the usable portion of the load range (industry practice, and the older editions' wording, is 15 to 85 % of the scale). The standard speed for most procedures is 300 ± 10 mm/min (12 ± 0.5 in/min); the tongue tear and some adhesion tests use 50 mm/min (2 in/min). Competitor pages quote these as 5 mm/s and 0.85 mm/s, which are the same rates in units no specification uses.

Jaw faces by procedure

• Grab: front jaw face 25 × 25 mm (1 × 1 in), back jaw face 25 × 50 mm (1 × 2 in) or larger, top and bottom grips aligned so the 25 mm faces are in line; 75 mm (3 in) between the jaws.

• Cut strip: flat faces at least as wide as the strip; 75 mm between jaws.

• Tongue tear: four jaws of 25 × 50 mm (1 × 2 in) or larger.

• Coating adhesion and seam strength: faces 25 × 75 mm (1 × 3 in).

• Trapezoid tear: faces at least 76 mm (3 in) wide, set 25 mm (1 in) apart.

Choosing the grip

Coated fabrics are the hardest textile to hold: the coating is slick, it creeps out of a jaw as the substrate thins, and a hard serrated jaw cuts through the coating and starts a break at the jaw line. Three grip types cover the work:

• Pneumatic grips: the first choice. Constant air pressure keeps the clamping force on as the specimen thins, parallel-closing jaws insert the specimen square, and the faces are interchangeable: 25 × 25 and 25 × 50 mm inserts for grab, 25 × 75 mm for seams and adhesion, with rubber, fine-serrated or abrasive-coated faces to suit the coating. Set the pressure high enough to stop slippage and no higher.

• Roller (capstan) grips: for very slick PVC and PU coatings and for thin, strong materials that break at the jaw in flat grips. The specimen wraps a roller so the load is spread over the wrap, and the self-tightening action eliminates slippage without edge damage; used for strip and adhesion tests rather than grab, because the grab geometry needs a flat 25 mm face.

• Vise grips: adequate for heavy tarpaulins and seams on a small tester, with rubber or serrated faces; the clamping force is operator-dependent, so expect more scatter and more jaw breaks than with pneumatic grips.

Jaw breaks. A specimen that breaks at the jaw line, or slips more than a small amount, is not a valid result; the usual rule is to discard it and test a replacement, and to note how many jaw breaks occurred. Persistent jaw breaks mean the faces are too aggressive, the pressure too high, or the specimen is not square in the jaws; persistent slippage means the opposite. Interleaving a strip of fine emery cloth or masking tape between a smooth face and a slick coating often cures both. All of our grips come in the adapter for your machine, and the tensile grips overview compares the full range.

Load-cell sizing

Grab strength of an 18 oz (610 g/m²) PVC truck tarpaulin is typically 1.5 to 3 kN; architectural PVC-polyester membranes reach 3 to 6 kN; light PU-coated nylon rainwear 300 to 800 N; seam and adhesion peaks are 50 to 500 N; tear peaks 20 to 300 N. A 5 kN load cell on a 5 to 10 kN frame covers the grab and seam tests on heavy fabrics; a 500 N or 1 kN cell is needed for tear and adhesion so the peaks sit well up the range. A Mark-10 tensile tester with a 1 to 5 kN cell handles rainwear, upholstery and light tarpaulin; a benchtop universal testing machine of 10 kN is the right size for heavy tarpaulin and membrane labs that also run seams and adhesion.

Breaking Strength: Grab and Cut Strip

Grab method

• Specimen: 102 × 152 mm (4 × 6 in) rectangles with the long dimension in the test direction; five in the longitudinal (machine) direction and five in the transverse direction, none taken within one-tenth of the fabric width of a selvage.

• Jaws: 25 × 25 mm front face against a 25 × 50 mm back face, centred on the specimen width and aligned top and bottom, 75 mm (3 in) apart.

• Speed: 300 ± 10 mm/min to rupture.

• Result: breaking force in newtons (lbf) for each direction, reported as the average of the five; elongation at break or at a specified force, if required, from the jaw separation (the elongation procedure).

The grab method clamps only the centre 25 mm of a 102 mm wide specimen. The yarns adjacent to the clamped strip are not gripped but are still bonded to it through the coating and the weave, and they help carry the load, so the grab strength is the effective strength of a 25 mm width in its fabric, not the strength of 25 mm of isolated yarns. It is therefore higher than a strip result on the same material, it cannot be converted to a strength per unit width, and it is the method most coated-fabric specifications use because it reflects how the material carries load in a panel. The back jaw is wider than the front so that the fabric is clamped over the full 25 mm strip while the front face defines its width.

Cut strip method

A strip 25 mm (1 in) wide (a specification may call for another width) and at least 150 mm long is clamped across its full width in flat jaws 75 mm apart and pulled at 300 ± 10 mm/min; the result is reported as force per unit width. Because the edges of a cut strip are not restrained, the strip result is lower than grab and is used where a width-normalised value is needed, for comparison with ISO 1421 strip data, or where the material is too stiff or too strong for the grab jaws. The textile equivalents are ASTM D5034 (grab, identical geometry and speed) and ASTM D5035 (ravelled or cut strip).

Worked example

Five longitudinal grab specimens of a PVC-coated polyester tarpaulin break at 2,210, 2,265, 2,195, 2,280 and 2,250 N, none at the jaw. Average = 11,200 ÷ 5 = 2,240 N (503 lbf), reported as the longitudinal grab breaking strength; the transverse set is reported separately. If one specimen had broken at the jaw line it would be replaced, not averaged in. On a 5 kN cell these breaks sit at 44 to 46 % of range, which is comfortable; on a 10 kN cell they would still be acceptable, on a 25 kN cell they would not.

Tear: Tongue and Trapezoid

Tongue tear

• Specimen: 76 × 203 mm (3 × 8 in) with a 76 mm (3 in) slit cut along the centreline from one short end, forming two tongues; five with the tear running in the warp direction and five in the fill direction.

• Setup: one tongue in each grip (jaws at least 25 × 50 mm), the uncut portion hanging between them, the tear line centred on the load axis.

• Speed: 50 mm/min (2 in/min); the tear is propagated through at least 75 mm of the uncut length.

• Result: the average of the five highest peaks in the load trace for each specimen, then the average of the five specimens per direction.

The tongue tear trace is a sawtooth: each peak is a yarn or group of yarns breaking at the tear front. The five-highest-peaks statistic was chosen because the first peak includes starting the tear and the troughs reflect yarn slippage rather than strength; software with a peak-detection routine does it directly. A tear that wanders off the slit line toward one edge is a sign the tongues are not aligned on the load axis or the coating is tearing more easily than the substrate; report it. Note that the textile tongue tear ASTM D2261 uses a 75 × 200 mm specimen at 300 mm/min, six times faster, so D751 and D2261 tongue tear values are not comparable.

Trapezoid tear

• Specimen: an isosceles trapezoid marked on a 76 × 152 mm (3 × 6 in) rectangle, with a short slit at the centre of the shorter parallel side to start the tear. The slit length has changed between editions and differs from the textile method, so cut it to the length in the edition your specification cites.

• Setup: the non-parallel sides are clamped along the marked lines in jaws at least 76 mm wide, set 25 mm (1 in) apart, so the short side is taut and the long side is slack.

• Speed: 300 mm/min; five per direction.

• Result: the average of the five highest peaks (the textile trapezoid method ASTM D5587 reports the maximum force instead, another reason the two are not interchangeable).

Trapezoid tear propagates across the yarns one at a time from the slit, so it is the tear method for nonwoven-backed and knit-backed coated fabrics where a tongue specimen would stretch rather than tear. Cutting the trapezoid with a die rather than by hand keeps the clamp lines and the slit repeatable.

Puncture and Ball Burst

Both tests clamp the fabric in a ring and push a plunger through it at 300 mm/min on the tensile machine, and both share the ring clamp; they differ in the plunger.

• Ball burst: a 25.4 mm (1 in) polished steel ball pushed through fabric clamped in a ring; the method is the same as ASTM D3787, whose ring has a 44.45 mm (1.75 in) opening, and is used for knit-backed and stretch coated fabrics where a tensile test is not meaningful. Ten specimens is the usual count, each cut at least 12.5 mm larger than the ring.

• Puncture resistance: a plunger with a sharper tip (the standard's figure defines it) is driven through the clamped fabric; five specimens; the peak force is the puncture resistance. This simulates a point load from a tool, a bracket or debris on a tarpaulin or membrane.

• Diaphragm burst: run on a Mullen-type hydraulic tester per D3786, not on the tensile machine.

A combined puncture and burst fixture with one ring clamp and interchangeable ball and puncture plungers covers D751, D3787 and the geotextile puncture test ASTM D4833 (8 mm flat-tip rod on a 45 mm ring) and, with the small probe, the film puncture test ASTM F1306. Clamp pressure matters: a ring that lets the fabric slip reads high because the fabric stretches into the ring, so use a pneumatic or screw-clamped ring with serrated faces and check that the printed clamp line has not moved after the test.

Seam Strength, Coating Adhesion and Tack-Tear

Seam strength

Seamed specimens 50 mm wide (2 in) by about 200 mm long with the seam across the middle are clamped in 25 × 75 mm (1 × 3 in) jaws and pulled at 300 mm/min until the seam fails or the fabric breaks; report the breaking force and the mode of failure (seam slippage, stitch or weld failure, fabric break). The central statistic is the median of the set in some editions, so check the edition cited. The dead-load seam procedure hangs a specified mass on a seam for a specified time at a specified temperature, which is the test for welded PVC seams in service; it needs a weight frame, not a tensile machine. For sewn textile seams without a coating, ASTM D1683 applies.

Coating adhesion

The adhesion of the coating to the substrate (or of two coated faces bonded to each other) is measured as a peel. A strip is cut, the coating is separated from the fabric by hand for about 50 mm, each ply is clamped in a 25 × 75 mm jaw, and the plies are peeled apart at 50 or 300 mm/min as the specification directs for at least 76 mm (3 in) of separation. The result is the average of the five highest peaks, reported per 25 mm of width (lbf/in). Two sets of two specimens per direction is the usual count. The strip width has been quoted as both 25 mm and 50 mm by different sources and editions; the result is normalised to 25 mm either way, so cut to the width your specification states and report it. A T-peel fixture or plain grips and a 100 to 500 N load cell are the right tools; the companion adhesive methods are D903 and D1876.

Tack-tear

Tack-tear measures the force to tear the fabric away from a row of needles, simulating a tarpaulin pulled off tacks or a membrane off its fasteners. A 50 × 150 mm (2 × 6 in) specimen is clamped at one end, a needle clamp with a row of fine needles (about 1.2 mm diameter) engages the other end 75 mm from the clamp, and the machine pulls at 300 mm/min; five per direction, reported per 25 mm. It needs the dedicated needle fixture; we build it to the standard's figure.

Worked example (adhesion)

A 25 mm wide PVC-on-polyester adhesion specimen peeled at 50 mm/min over 90 mm gives five highest peaks of 61, 58, 64, 60 and 59 N. Average = 302 ÷ 5 = 60.4 N, reported as 60.4 N per 25 mm (13.8 lbf/in). On a 100 N load cell those peaks are at 58 to 64 % of range; on a 5 kN cell they would be at 1 %, and the peaks would be lost in noise.

Hydrostatic Resistance and the Pressure Tests

• Procedure A (Mullen type): the fabric is clamped over a diaphragm and water pressure is raised at a constant rate until water appears through the coating (three drops is the usual end point); the result is the pressure in kPa (psi). Suited to tarpaulins and membranes rated for high pressure.

• Procedure B (rising water column): a column of water is raised at a constant rate against the fabric until penetration; the result is in cm of water, as in AATCC 127 and ISO 811. Suited to rainwear and low-pressure applications; the column rate is specified by the method or the specification.

• Diaphragm burst: D3786 Mullen burst, for the burst strength of the coated fabric rather than its water resistance.

These use dedicated hydrostatic testers, not the tensile machine; they are listed here because specifications cite them from D751 alongside the mechanical tests and the lab needs to know which equipment each one needs. The coated-fabric hydrostatic method in ISO is ISO 1420.

Step-by-Step: Running a Grab Test

• 1. Sample and cut five longitudinal and five transverse 102 × 152 mm specimens, long axis in the test direction, clear of the selvage and of each other's rows; use a die so the dimensions repeat.

• 2. Condition at 21 ± 1 °C and 65 ± 2 % RH to equilibrium.

• 3. Fit the grab faces (25 × 25 mm front, 25 × 50 mm back) and align the top and bottom grips; set the jaw separation to 75 mm.

• 4. Clamp the specimen centred on its width with the same insertion in both grips and the coated face orientation consistent; zero the load.

• 5. Pull at 300 ± 10 mm/min to rupture, recording force and jaw separation.

• 6. Check the break: discard and replace any specimen that broke at the jaw line or slipped visibly.

• 7. Report the average breaking force per direction (and elongation if required), the number of specimens, the edition and section, the conditioning and the machine speed.

ASTM D751 vs D5034, D5035, D2261, D5587 and the ISO Methods

• ASTM D5034 (textile grab): same 102 × 152 mm specimen, 25 × 25 / 25 × 50 mm jaws, 75 mm separation and 300 mm/min; D751 is the coated-fabric wrapper around the same test, with D1776 conditioning on both.

• ASTM D5035 (textile strip): 25 or 50 mm ravelled or cut strips, 75 mm gauge, 300 mm/min; equivalent to the D751 cut strip procedure.

• ASTM D2261 (textile tongue tear): 75 × 200 mm, 300 mm/min, five-peak average; D751's tongue tear runs at 50 mm/min on a 76 × 203 mm specimen, so values differ.

• ASTM D5587 (textile trapezoid tear): 75 × 150 mm trapezoid with a 15 mm slit, 300 mm/min, reporting maximum force; D751 reports the five-peak average and its slit length differs by edition.

• ASTM D3787 and D4833: ball burst and geotextile puncture, the fixtures D751's burst and puncture procedures share.

• ISO 1421: the international coated-fabric tensile method; Method 1 is a strip test for strength and elongation and Method 2 a grab test for strength only, both at 100 mm/min on a CRE machine, so results are not interchangeable with D751's 300 mm/min values.

• ISO 2411: coating adhesion by peel, at 100 mm/min; ISO 4674-1 covers constant-rate tear (trouser and tongue methods) and ISO 4674-2 the ballistic pendulum; ISO 1420 is hydrostatic resistance.

The practical rule: a specification written to D751 is tested to D751 at 300 mm/min with the D751 specimen and jaws, and the result is labelled with the edition and the procedure; a D5034 or ISO 1421 number on the same material will be similar but not the same, and the differences in speed and statistic are large enough to decide a pass or fail.

Common Errors

• Conditioning at 23 °C / 50 % RH (plastics) instead of 21 °C / 65 % RH (textiles).

• Quoting section numbers from D751-19 or D751-06 against a D751-26 report, or the reverse.

• Grab jaws the wrong size, or the 25 mm front face not aligned with the back face top and bottom.

• Counting jaw breaks and slipped specimens in the average.

• Serrated steel faces cutting the coating; or smooth faces at low pressure letting PVC creep.

• Tongue tear at 300 mm/min (the D2261 speed) instead of 50 mm/min.

• Reporting the maximum force instead of the five-peak average for tongue, trapezoid and adhesion.

• Load cell too large for tear and adhesion peaks of 20 to 300 N.

• Ring clamp slipping in burst and puncture, reading high.

• Mixing machine-direction and cross-direction specimens in one average.

• Treating air permeability or mildew as D751 procedures.

Equipment for ASTM D751

• Grips: pneumatic grips with 25 × 25, 25 × 50 and 25 × 75 mm interchangeable faces in rubber, serrated and abrasive finishes; roller grips for slick coatings; vise grips for heavy seams; all in the adapter for your frame.

• Fixtures: puncture and ball-burst fixture with ring clamp, 25.4 mm ball and puncture plungers (also D3787, D4833, F1306), a tack-tear needle clamp, trapezoid and tongue-tear cutting dies and a 102 × 152 mm grab die, and peel fixtures for coating adhesion.

• Frames: Mark-10 tensile testers from 500 to 1,500 lb for rainwear, upholstery and light tarpaulin, and benchtop universal testing machines of 5 to 10 kN with 500 N and 5 kN load cells for heavy tarpaulin and membrane labs; all with 50 and 300 mm/min speeds and peak-detection software.

• Environment: environmental chambers for the low-temperature bend, impact and crack procedures and for conditioning.

• Elongation: a video extensometer for elongation without the jaw-slip error of crosshead-based measurement.

See the textiles testing page for complete fabric lab configurations and the puncture testing applications page for the puncture and burst fixtures across standards.

ASTM D751 FAQ

What is ASTM D751?

The ASTM standard test methods for coated fabrics: a collection of about 27 procedures covering thickness and mass, breaking strength (grab and strip), elongation, burst, puncture, tongue and trapezoid tear, coating adhesion, tack-tear, seam strength, hydrostatic resistance, low-temperature and aging tests for rubber- and plastics-coated textiles. The current edition is D751-26.

What is the ASTM D751 grab test specimen and speed?

A 102 × 152 mm (4 × 6 in) rectangle, five per direction, clamped with a 25 × 25 mm front jaw and a 25 × 50 mm back jaw set 75 mm (3 in) apart and pulled at 300 ± 10 mm/min (12 in/min). The breaking force in newtons is reported for each direction.

What is the difference between grab and strip strength?

Grab clamps only the centre 25 mm of a wide specimen, so adjacent yarns help carry the load and the result is a higher effective strength in newtons. Strip clamps the full width of a 25 mm strip and reports force per unit width. The two are not interchangeable; most coated-fabric specifications use grab.

What conditioning does ASTM D751 require?

The standard textile atmosphere of ASTM D1776: 21 ± 1 °C (70 ± 2 °F) and 65 ± 2 % relative humidity, to moisture equilibrium. It is not the 23 °C / 50 % RH atmosphere used for plastics.

How is tongue tear tested in ASTM D751?

A 76 × 203 mm specimen with a 76 mm centre slit is clamped by its two tongues in jaws of at least 25 × 50 mm and torn at 50 mm/min through at least 75 mm; the result is the average of the five highest peaks, five specimens per direction.

How is coating adhesion measured in ASTM D751?

The coating is separated from the fabric by hand for about 50 mm, each ply is clamped in a 25 × 75 mm jaw and the plies are peeled at 50 or 300 mm/min for at least 76 mm; the average of the five highest peaks is reported per 25 mm of width.

What is the ASTM D751 puncture test?

The fabric is clamped in a ring and a plunger is driven through it at 300 mm/min; the peak force is the puncture resistance. Ball burst uses the same ring with a 25.4 mm steel ball. Five specimens are usual for puncture, ten for burst.

What grips are best for coated fabrics?

Pneumatic grips with interchangeable 25 × 25, 25 × 50 and 25 × 75 mm faces in rubber or fine serrations, so clamping force stays constant as the coating thins; roller grips for very slick PVC and PU coatings; vise grips for heavy seams on small testers. Jaw breaks are discarded and replaced.

What load cell do I need for ASTM D751?

Grab strength of heavy PVC tarpaulin is 1.5 to 6 kN, so a 5 kN cell on a 5 to 10 kN frame covers it; tear, adhesion and seam peaks are 20 to 500 N and need a 500 N or 1 kN cell so the readings sit well up the range.

What changed in ASTM D751-26?

D751-26, published in 2026, supersedes D751-19 and renumbers the sections: grab is now sections 12–15, puncture 27–30, tongue tear 33–36, coating adhesion 50–53 and seam strength 71–76. Specifications that cite D751 section numbers should state the edition.

What is the difference between ASTM D751 and ISO 1421?

ISO 1421 is the international coated-fabric tensile method with a strip test (Method 1) and a grab test (Method 2), both at 100 mm/min, against D751's 300 mm/min, so results are not interchangeable. ISO 2411 covers coating adhesion, ISO 4674 tear and ISO 1420 hydrostatic resistance.

Does ASTM D751 cover air permeability or mildew resistance?

No. D751 covers dimensions, mass, strength, tear, burst, puncture, adhesion, seams, hydrostatic resistance, low-temperature and aging tests; air permeability, mildew and fibre content are tested to other standards.

Need a fixture, grips or a complete system for ASTM D751? Contact Universal Grip with your specimen details, capacity and machine connection and we will quote the right setup.