Standards for universal testing machines are authored by the American Society for Testing and Materials (ASTM) and the International Standards Organization (ISO) to ensure consistency, reproducibility, and, therefore, comparability of material test results across different laboratories worldwide. Where ASTM standards are obligatory in North America, ISO standards govern European, Asian, and other global trade settings. A UTM cannot be set to run any material-specific test without first implementing structure verification standards for testing machines.
In 2014, tensile test certificates were submitted by a German automotive supplier to its North American OEM customer, and they made reference to ISO 6892-1. The engineering group of the customer denied them because they were using internal process standards defined by ASTM E8.
Some material running on the same components of a UTM machine depicted some of their marginal differences under the two standards. The supplier spent six weeks on a retest of a batch of 40 alloys. He nearly lost a $2 million contract.
Every now and then, the given scenario manifests itself in the quality control labs. ASTM and ISO standards were not created to be inter-referenced. There are differences in force application rates, specimen geometry, and data reporting that are important for contractual reasons and to qualify the product.
This guide charts every major ASTM and ISO standard relevant to universal testing machines. You will learn which standard governs which material, how calibration requirements are different between the two bodies, and after suggesting a five-step guideline on the selection of standards before you actually buy any machine.
Want to learn more? See our (guide on universal testing machine).
Key Takeaways
- For most tests, ASTM controls materials testing in North America; global contracts are governed by ISO in Europe, Asia, and other locations.
- There exist foundational machine verification standards: ASTM E4 and ISO 7500-1, which UTMs require to meet.
- ASTM E8 and ISO 6892-1 manage the tensile testing of metals. The strain rate requirements vary by up to 20% for some alloys from one standard to the other.
- Lab accreditation under ISO/IEC 17025 demands calibration that can be traced back to published standards with properly documented control charts. The handler outside the laboratory should be in a position to track the traceable chain.
- A five-step guide for heading off the great mistake of specifying the wrong standard for your customer or industry.
What Are ASTM and ISO Testing Standards?
ASTM: American Society for Testing and Materials
ASTM International oversees the maintenance of over 12,000 technical standards dealing with materials, products, systems, and services. In material testing, ASTM standards detail the preparation of specimens, the test procedure, equipment requirements, and data reporting.
ASTM standards are binding in most North American construction, automotive, and aerospace contractual situations. The organization was formed in 1898 and is based in West Conshohocken, Pennsylvania. For the complete standards database, visit ASTM International.
ISO: International Organization for Standardization
ISO is publicly independent directly contributing to government bodies having 170 national standard bodies. ISO has at its base over 24,000 international standards.
ISO material testing standards are widely adopted in Europe, Asia, South America, and any supply chain serving multinational OEMs. Many ISO standards are technically equivalent to ASTM standards but use metric units and slightly different specimen geometries. Browse the full catalog of ISO standards for materials testing.
Why Both Exist, and Why It Matters for Buyers
ASTM and ISO standards evolved independently. ASTM reflects North American industrial practice. ISO reflects a global consensus that prioritizes cross-border harmonization.
A lab testing only domestic construction materials may need only ASTM. A lab serving export markets almost always needs both. Buyers who fail to audit customer requirements before purchasing a UTM risk buying a machine that cannot generate the certificates their contracts demand.
Universal Testing Machine Calibration and Verification Standards
Before any material test standards are applied in full, the machine itself must be verified. Foundational standards promote suitable traceability and accuracy when measuring force, displacement, and strain.
ASTM E4: Verification of Testing Machines
ASTM E4 regulates the verification of static force measuring systems on UTMs. Verification is required using deadweights or reference load cells duly traceable to national standards. Essentially, force accuracy of ultimatum +/- 1.0% Indicated force as a standard should be applied to most works.
Verified at least every 12 months in ASTM E4, though recalibration is immediate after an overload, repositioning, or after any repairs.
ISO 7500-1: Calibration of Force-Proving Instruments
ISO 7500-1 is the international tail equivalent of ASTM E4. It has classifications of machines with regard to accuracy level, accuracy grades- Class 0.5, Class 1, and Class 2, with Class 1 being of the most significance for general material testing.
ASTM E4, do not need loops requiring recalibrations, While ISO 7500-1 imposes the loop, impelling recalibration at intervals ranging from 6- or 12-months. AMutable instances for more frequent recalibrations are seen in high-volume production setups.
When to Specify ASTM E4 vs ISO 7500-1
North American customers and AASHTO-accredited labs need ASTM E4. For EU CE-marked machines and the Asian continent, ISO 7500-1 is used. A good number of presentations in international labs, like dual calibration certificates for machines subject to both standards. An accidental selection of wrong verification standards will cause procedural deference in the audit trail.
For information on the (applications of universal testing machines in the automotive industry), please refer to our guide.
Tensile Testing Standards by Material
One of the common UTM applications is the tensile test, i.e. stretching/restraining specimens until they fail.
Metals: ASTM E8 / E8M vs ISO 6892-1
ASTM E8 is the US standard covering metallic materials in terms of inch-pound units. ASTM E8M covers the metric versions. From the international front is ISO 6892-1-the standard for the tensile testing of metallic materials. The standards cover specimen geometry, grip system configuration, and extensometer limitations.
However, control varies for strain rate. ASTM E8 allows stress-rate control up to yield and then switches to strain rate control. ISO 6892-1 offers two different methods of strain rate control: Method A (closed-loop strain rate) and Method B (stress rate). Method A closes with ASTM E8’s behavior.
The yield strength of certain aluminum and steel alloys gives a difference of 3-5% under both standards.
Want to understand (how a tensile testing machine works)? Please see our related guide.
Plastics: ASTM D638 vs ISO 527
ASTM D638 covers the strain on plastic from ordinary and semi-rigid polymers. It is equivalent to ISO 527. Both standards use dog bone specimens, but with slightly different gauge lengths and guessing about width.
ASTM D638 Type I specimens are 165 mm long, whereas ISO 527 Type 1A specimens are 150 mm long. These differences matter for labs that have to report to both standards. A UTM program that has been equipped with adjustable grip lengths is able to run both types of specimens.
Composites: ASTM D3039 vs ISO 527-4 / ISO 527-5
Tabbed specimens are required for testing polymer matrix composites to avoid crushing the grips. ASTM D3039 is the standard used in North America. ISO 527-4 covers isotropic and orthotropic composites, whereas ISO 527-5 covers unidirectional composites.
All the above standards have the requirement of the tabbed or sanded regions of the grips and accurate fiber-legged useful alignment.
Elastomers and Rubber: ASTM D412 vs ISO 37
The elongation of elastomers and rubbers needs dumbbell-shaped specimens assembled from sheet material. Two types of dies are specified in ASTM D412: Die C and Die D. ISO 37 checks one additional geometry for the die. The width and the length ratios differ slightly in this configuration of the die. High-elongation extensometers capable of measuring 500% strain or more are typically used in elastomer testing.
Textiles and Thin Films
Textile tensile testing methods include ASTM D5873 (strip method) or ISO 13934-1. Foil thicknesses and films often are tested to ASTM E345 or as an appendix to ISO 6892-1. These tests are done on machines with very low force capacities (as low as 1 kN or less) and require high-resolution load cells.
| Test Type | Material | ASTM Standard | ISO Standard | Key Difference |
|---|---|---|---|---|
| Tensile | Metals | ASTM E8 / E8M | ISO 6892-1 | Strain rate control method |
| Tensile | Plastics | ASTM D638 | ISO 527 | Specimen gauge length (165 mm vs 150 mm) |
| Tensile | Composites | ASTM D3039 | ISO 527-4 / ISO 527-5 | Tab geometry and fiber alignment |
| Tensile | Elastomers | ASTM D412 | ISO 37 | Die geometry and width ratios |
| Compression | Concrete | ASTM C39 | EN 12390-3 | Loading rate specification |
| Compression | Metals | ASTM E9 | ISO 6892-1 (compression mode) | Specimen aspect ratio |
| Compression | Plastics | ASTM D695 | ISO 604 | Test fixture requirements |
| Flexural | Plastics | ASTM D790 | ISO 178 | Three-point vs four-point loading |
| Flexural | Composites | ASTM D7264 | ISO 14125 | Span-to-depth ratio |
| Shear | Plastics | ASTM D732 | ISO 6237 | Punch geometry |
| Peel | Adhesives | ASTM D1876 | ISO 11339 | Peel angle (T-peel vs 180-degree) |
| Creep | Plastics | ASTM D2990 | ISO 899-1 | Duration and temperature range |
Compression Testing Standards by Material
Compression testing determines a material’s or component’s resistance to occasioned forces that seek to squeeze or crush it.
Concrete: ASTM C39 vs EN 12390-3
UTM testing, for concrete compression, is the main testing procedure used from which thousands stand internationally. In North America, ASTM C39 lists the testing procedure for cylinders, while in Europe, the standard is provided by EN12390-3 under the ISO framework.
Cylinder dimensions for both standards are 150 mm in diameter by 300 mm in length, but slight differences exist in the specification of loading rate. ASTM C39 requires a loading rate from 0.25 MPa/s +/- 0.05 MPa/s, while EN12390-3 sets a loading rate to achieve failure within a specified time period.
For more on concrete applications, read our guide on compression testing machine applications.
Metals: ASTM E9 vs ISO 604
ASTM E9 deals with the compression testing of metallic materials. Compression testing of plastics is rather governed by ISO 604 but metallic materials are usually tested for compression in accordance with ISO 6892-1. ASTM E9 specifies the aspect ratio of the specimen and the use of anti-buckling fixtures for slender specimens. The most popular machine capacities for materials are in the range of 100 kN to 1,000 kN.
Plastics and Foams: ASTM D695 / D1621 vs ISO 604 / ISO 844
ASTM D695 suits rigid plastics and D1621 refers to rigid cellular plastics, both for specification. ISO 604 is the international plastics compression standard, while ISO 844 is for rigid cellular plastics.
Flexible foam testing usually follows ASTM D3574 (indentation force deflection), unlike direct compression.
Packaging: ASTM D642 vs ISO 12048
Both are used for box compression testing of corrugated packages: ASTM D642 is used in North America, while ISO 12048 is used internationally. Both standards apply compressive forces to a complete box until failure or a defined deflection limit. Machines are usually in the range of 10 kN to 50 kN.
Flexural and Bend Testing Standards
Three-point or four-point bend loads are used in flexural testing to measure modulus and strength.
Plastics: ASTM D790 vs ISO 178
ASTM D790 offers testing in both configurations; three-point and four-point loading. The ISO 178 offers test utilities only in the case of three-point loading. ASTM D790 and ISO 178 recommend spans to depths in the range of 16:1 to 32:1 for most plastics.
This affects crosshead speed given the depth of the specimen. One can then expect 2 mm/min as the typical crosshead speed for a 4 mm specimen.
Metals: ASTM E290 vs ISO 7438
These tests for metals called guided bend tests review ductility and weld quality. ASTM E290 and ISO 7438 apply a mandrel or former to bend a specimen for a specified radius. These tests need custom bend fixtures rather than the standard compression platens available.
Composites: ASTM D7264 vs ISO 14125
Flexural tests conducted with composites follow the ASTM D7264 (three and four-point) and ISO 14125 standards. Both standards specify aspect ratios for unidirectional composites as 32:1 and 40:1. Thin long specimens may buckle on the compression face. Any of the support attachments should guard against any lateral instability.
Ceramics: ASTM C1161 vs ISO 14704
Advanced ceramics under study undergo four-point flexure testing conforming to ASTM C1161 or ISO 14704. Ceramics are tough – they undergo catastrophic failures with very little signs of deflection. Machinery with high stiffness is a necessity to prevent release of stored energy shattering the specimen explosively.
Shear, Peel, and Specialized Test Standards
Aside from tensional and compressive strength, Universal Testing Machines (UTMs) can also do shear, peel, tear, and creep testing.
Shear Testing: ASTM D732 vs IS06237
Shear testing of plastics from punch shear according to ASTM D732. Wood adhesive shear according to IS06237. Lap shear for adhesives according to ASTM D1002. All of these tests require fixtures constructed with calibrated flanges so as to apply pure shear devoid of bending.
Peel and Adhesion: ASTM D1876 vs ISO 11339
Peel force is the force needed to split bonded materials. ASTM D1876 is for the T-peel test for the flexible-to-flexible bond, while ISO 11339 allows 180° peel for the flexible-to-rigid bond. Peel tests demand low-force machinery with high data acquisition rates, capable of capturing the respective peak and valley forces of the test span.
Tear Resistance: ASTM D624 vs ISO 34
Elastomer tear resistance will be according to ASTM D624 (Trouser, Angle, and Crescent devices) or ISO 34. The test still relies on that sharp and even specimen notching and alignment.
Creep and Stress Relaxation Tests: ASTM D2990 vs ISO 899-1
A creep test lab run under constant load, which records deformation over longer periods, mostly in hours, days, and months. Plays in ASTM D2990 and/or ISO 899-1 standards about creeps in plastics require UTMs with some sort of long limits and other required necessities like calibration and internal environment in ovens for testing at raised temperatures.
A polymer testing lab in Bangalore geared itself up for its first ISO 17025 audit in 2023. They had an updated double-column UTM, but not having a Kohort with the calibration traceable to ISO 7500-1 led to the identification of four non-conformances by the auditor. The lab shelled out $12,000 for recalibration, new reference load cells, and control-chart documentation over six months before successfully clearing a recourse audit.
ASTM vs ISO: How to Choose the Right Standard
The choice of a standard is not a matter of personal preference; rather, it is largely determined by geography, customer requirements, and industry regulations.
Geography and Customer Requirements
American construction projects typically follow ASTM standards. On the other hand, most of the infrastructure in Europe will use EN standards, which are modeled after ISO. Most Asian export-oriented manufacturing companies use ISO standards.
A testing lab serving overseas clients should be ready to practice both standards. Some clients perceive ASTM to be equivalent to ISO standards; however, other clients, on the other hand, have all along been disinclined to signs of ASTM, regardless of if there was an ISO out there indicating that it doesn’t actually comply with that standard.
Industry-Specific Mandates
Aerospace contracts usually require ASTM specifications for US defense programs and ISO for European programs. Car OEMs have their own US material specifications that reference ASTM and/or ISO.
Testing of medical devices follows FDA-recognized consensus standards, predominantly ASTM for the US markets. Pharma tablet testing typically makes reference to the USP chapters that utilize ASTM methods.
For more on aerospace testing requirements, read our (guide on universal testing machine applications in aerospace).
When ASTM and ISO Methods Give Different Results
For most materials, ASTM and ISO give similar results statistically when exercised appropriately. However, systematic differences do prevail.
Yield strength for some aluminum alloys differences are between 3-5% between ASTM E8 and ISO 6892-1 owing to strain rate sequence protocol, and concrete compression strengths may differ from ASTM C39 to EN 12390-3 to about 2-4% due to a difference in the rate of loading. Labs that want to switch from one standard to another should forget about any baseline data.
Dual-Standard Testing Strategy
The laboratory that caters to both markets should be implementing UTMs with software initiatives of both ASTM and ISO methods. The control software of the present era permits operators to decide on the standard before the test starts. The software settles automatically to have the correct crosshead speed, specimen control data, as well as the algorithms for conducting the calculations. This kind of approach will potentially halt operator error and further lighten the burden on training.
Lab Accreditation and Compliance Standards
Calibration according to ASTM E4 or ISO 7500-1 is a precondition but not enough for laboratory accreditation.
ISO/IEC 17025: General Laboratory Competence
ISO/IEC 17025 is a worldwide mechanism that sets the criteria for testing and calibration laboratories. The assessment of conformance to this norm is carried out by accreditation bodies, such as A2LA in the United States, UKAS in the United Kingdom, and DAkkS in Germany.
Clause 6.4 states that equipment should be calibrated and re-calibrated when required. Clause 7.8 emphasizes that each test report should point out the standard that was used for the said test. If there is no current calibration certificate for a UTM that has been used, then this would constitute a significant nonconformance during a quality audit.
Traceability and Documentation
Traceability means that every force reading taken can he traced hack to a national standard through an unbroken chain of calibrations. In the United States. NIST provides the ultimate reference.
National metrology institutes such as PTB (Germany) and NPL (UK) are in place to ensure that measures and standards are unvanquished. Calibration certificates should contain measured uncertainties, environmental conditions, and the identification of reference standards used. See NIST calibration traceability guidelines for detailed requirements.
Recalibration Frequency
In most labs, an annual recalibration is the minimum. High-production-volume labs typically recalibrate every six months. Labs that experience an overload event must recalibrate immediately.
An overload of 110% can cause shifts in the linearity of load cell enough to influence test results. Document in your equipment service history each calibration, overload, and repair event.
How to Verify a UTM Meets Your Required Standards
Using the five vital elements outlined here can be of much assistance when acquiring or approving a universal testing machine.
Step 1: List All Standards Your Lab Must Support
Stringently discern every bad customer contract and possible market situation, listing each ASTM, ISO, EN, and industry-specific standard that you have to execute.
List machine calibration standard to standard test method. A lab catering to both the U. S. and European markets must answer a call to ASTM E4 and ISO 7500-1 for calibration capabilities.
Step 2: Check Machine Specifications Against Standard Requirements
Every standard sets a minimum capacity requirement for the machine. ASTM E8 mandates that the grips must align within 0.25 mm over a length of 200 mm, whereas ISO 6892-1 designates strain measuring accuracy of Class 0.5 or above.
The setups of some of these machines may call for environmental chambers whilst others may call for high-elongation extensometers. Dynamic test standards might need servo-hydraulic drive systems. For the discussion of the pros and cons of various drive technologies, you might want to refer to our guide on (electromechanical vs. servo-hydraulic testing machines).
Now, that matching of the machine specification sheet with all your requirements will be performed.
Step 3: Verify Calibration Certificates
From the vendor or a calibration laboratory, ask for current calibration certificates. Make sure the key references to standard (either ASTM E4 or ISO 7500-1) are available on the certificates. Now verify that the equipment was traceable to a national metrology institute.
You must scrutinize whether this certificate covers the force values over the full range you will be using. A certificate with a calibration range covering only 50 kN capacity is of no benefit if you are testing at 300 kN capacity.
Step 4: Validate Software Pre-Programmed Test Methods
The newest UTM software will come with established testing methods. Ensure your required standards are present in the software library. Ask the vendor to present the way methods are set up for your most crucial standard. Confirm that the software runs by these strict algorithms rather than doing an approximation.
Step 5: Plan for Audit Documentation
For this matter, accredited labs must manage equipment histories and calibration schedules, but would also butt heads with the requirements of control charts and method validation records. Before the sale, another point to bring up with the vendor is what type of documentation the vendor would provide when it comes to getting ready for such an audit.
Some suppliers include turnkey validation packages while others leave the job for the user. This could extend audit readiness by a long while.
In 2020, a packaging manufacturer in Sao Paulo needed to test cardboard for export to both the US and EU. Rather than buy two testing programs, they specified a UTM with software that pre-loaded both ASTM D642 and ISO 12048 methods. The dual-standard capability cost an extra 3,200 in software but eliminated the need for a second machine, saving 3,200 in software but eliminated the need for a second machine, saving $28,000.
Conclusion
Standard labels for the universal testing machine are not optional; they are just contractual requirements that decide whether the certificate of a test is acceptable or unacceptable. ASTM E8 and ISO 6892-1 both test the same material but do not always provide the same output.
ASTM E4 and ISO 7500-1 are for testing machines and use different rating systems.
The general portrait to look at should be to match the standard with the customer and not to confine the customer with the standard. A lab servicing broad world markets and requiring a dual-standard UTM software should also require dual certificates of calibration and documentation capable of satisfying both the ASTM and ISO audit requirements.
If you are ready to source a universal testing machine that meets your required standards, browse verified testing equipment suppliers to request specifications and quotes from qualified manufacturers. For questions about specific test requirements, contact our team.
