BIFMA X5.1 and EN 1335 are both office chair test standards, and they are not interchangeable. BIFMA X5.1-2017 (R2022) is the US voluntary standard covering dimensions, stability, strength and cyclic durability. EN 1335 splits the same ground into three parts: dimensions (EN 1335-1), safety requirements (EN 1335-2) and test methods (EN 1335-3). Passing one does not certify the other.
Two voluntary standards, two different markets
BIFMA, the Business and Institutional Furniture Manufacturers Association, publishes ANSI/BIFMA X5.1 for North America. The current edition is X5.1-2017, reaffirmed in 2022 as X5.1-2017 (R2022). It is voluntary: it becomes binding when a specification, purchase order, building code or public procurement rule cites it, which is common in US corporate, education and government projects.
EN 1335 is a European standard published by CEN and adopted nationally as BS EN, DIN EN, NF EN and so on. It is also voluntary, but it is the reference most EU and UK tenders cite, and the usual way to show a chair meets general product-safety expectations in Europe.
Neither document is a law. “BIFMA certified” and “EN 1335 certified” are not legal statuses, and neither is a universal passport.
BIFMA X5.1-2017 (R2022): four test families in one document
X5.1 handles the whole chair in a single standard. The tests fall into four families:
- Dimensions. Seat height, seat depth, seat width, backrest size and armrest spacing are measured and checked against reference values.
- Stability. The chair is loaded and checked for tipping forward, rearward and sideways — the tests that matter most on a five-star base and on casters.
- Static strength. Seat, backrest, armrests, base and legs are loaded to defined forces and inspected for fracture or permanent deformation.
- Cyclic durability. Seat, backrest and armrests are loaded repeatedly; swivel, casters and base are cycled. This is where a chair that feels solid in a showroom separates from one that survives five years of use.
X5.1 is written for general-purpose office chairs. Desks and tables, storage and lounge seating have separate BIFMA documents (X5.5, X5.9 and X5.2), so a full workstation package usually needs several reports, not one.
Forces, cycle counts and acceptance criteria change between editions. Quote the edition in your specification — “X5.1-2017 (R2022)” — and confirm load values with the testing laboratory rather than relying on a supplier summary.
EN 1335: how the three parts divide the work
EN 1335 separates requirements from methods, which is the biggest structural difference from BIFMA.
- EN 1335-1 — Dimensions (current edition EN 1335-1:2020+A1:2022). Defines dimension ranges and how to measure them, based on European anthropometric data. It is a fit-for-population standard: a well-built chair can still fail this part for the users you are buying it for.
- EN 1335-2 — Safety requirements (EN 1335-2:2018). States the requirements for stability, strength and durability, and points to the methods used to verify them.
- EN 1335-3 — Test methods (EN 1335-3:2009, with its 2009 corrigendum). The procedures, apparatus and loading regimes.
Two practical consequences. First, a complete EN 1335 package often means two reports: dimensions against Part 1, and safety against Part 2 tested by the Part 3 methods. A supplier who sends one page citing “EN 1335” has shown you neither. Second, EN 1335 covers office work chairs; for heavy contract or 24-hour use, European buyers typically add EN 16139, which grades non-domestic seating by use level.
BIFMA X5.1 vs EN 1335: side by side
| Item | BIFMA X5.1-2017 (R2022) | EN 1335 |
|---|---|---|
| Publisher | BIFMA (ANSI-accredited) | CEN, adopted by national bodies |
| Main market | US, Canada | EU, UK, EEA |
| Legal status | Voluntary; binding when cited in a contract or spec | Voluntary; binding when cited in a contract or spec |
| Structure | One document: tests plus acceptance criteria | Three parts: dimensions, requirements, test methods |
| Dimensions | Included | EN 1335-1 |
| Stability | Included | Requirement in EN 1335-2, method in EN 1335-3 |
| Strength and durability | Included | Requirement in EN 1335-2, method in EN 1335-3 |
| Typical report | One test report per model or model family | Dimensions report plus safety/test report |
| Public listing | BIFMA Compliant registry | No single EU registry; national certification bodies vary |
Why a BIFMA report does not prove EN 1335
Four reasons matter in a tender.
- Different test structure. EN 1335 separates what must be met from how it is measured. A report written only against Part 2, without the Part 3 procedures, does not demonstrate conformity.
- Different body dimensions. EN 1335-1’s ranges are derived from European user data; X5.1’s dimensional values are not the same. A chair sized for one market can miss the other’s range.
- Different loads, cycles and pass criteria. Both standards load seats, backs and arms, but not to identical values or with identical rules. A pass in one is evidence, not proof, in the other.
- Different accountability. In the US, buyers increasingly check a BIFMA Compliant listing; in the EU, the expectation is a signed declaration of conformity plus the underlying reports. These documents carry different legal weight.
There is also a laboratory question: accreditation is specific. A lab may be accredited for EN 1335-3 and not for X5.1. Check the scope, not just the logo.
The 4 documents to request in a tender
- The full test report, not a certificate summary. It should name the exact standard and edition and identify the tested sample.
- A signed declaration of conformity or a registry listing — a BIFMA Compliant entry for North America, or a manufacturer’s declaration citing EN 1335-1 and EN 1335-2 for Europe.
- A model coverage list. Which sizes, mechanisms, bases, casters, foams and fabrics the tested sample represents. A report for one configuration is not a report for the catalog.
- Laboratory accreditation evidence plus component reports: gas-lift class, casters (EN 12529) and upholstery flammability (EN 1021-1/-2 or California TB 117-2013) where the project requires them.
If a supplier cannot produce item 3, treat the report as covering only the sample in the photos.
How to read a chair test report in 5 checks
| Check | What to look for | Red flag |
|---|---|---|
| Model identity | Model or SKU, dimensions, mechanism, photo, “representative sample” wording | Report names a model you are not buying |
| Standard edition | Full designation with year, e.g., ANSI/BIFMA X5.1-2017 (R2022) or EN 1335-2:2018 with EN 1335-3:2009 | Undated “BIFMA tested” or “EN 1335 compliant” claim |
| Laboratory | Name and ISO/IEC 17025 accreditation scope covering the standard | No lab name, or an internal report presented as third-party |
| Results | Every test listed with date, measured values, units and pass/fail | Sections marked N/A without explanation |
| Coverage and date | Test date, report revision, statement of which models are covered | Test date older than the current design; no coverage statement |
FAQ
Is BIFMA X5.1 required by law in the US?
No. It is a voluntary consensus standard. It becomes a requirement when your specification, purchase order or a procurement rule cites it, which is common in corporate, education and government projects. BIFMA Compliant is a listing program, not a regulator.
Can a chair that passes EN 1335 fail BIFMA X5.1?
Yes, and the reverse is also possible. The two standards use different dimension references, loads, cycle counts and acceptance criteria, and they are tested separately. A pass in one market is useful evidence of build quality, not a substitute for testing in the other.
Which standard should a European tender ask for?
Cite the edition you need: EN 1335-1:2020+A1:2022 for dimensions and EN 1335-2:2018 tested to EN 1335-3:2009 for safety. For 24-hour, heavy or public-space use, add the relevant EN 16139 use level. Confirm current editions in your national standards catalog before writing the specification.
Do office chairs need CE marking?
Office chairs are not covered by a furniture-specific CE-marking directive. EN 1335 is still the reference most buyers use to show that a chair meets general product-safety expectations in the EU. If a supplier claims “CE certified” for a chair, ask which directive or regulation the mark refers to.
How long is an office chair test report valid?
There is no universal expiry date. Standards are revised, and a report is evidence against the edition tested. Most buyers require a report to the current edition and a re-test when the design, mechanism or base changes. A report that predates the last major design change is weak evidence.
Does one test report cover every size and finish?
No. Coverage is defined by the report and by the laboratory’s rules for representative samples. Ask for the model coverage list and confirm that the sizes, mechanisms and upholstered finishes you are ordering sit inside it.
Sources
- BIFMA standards overview: https://www.bifma.org/page/standardsoverview (accessed November 4, 2026)
- BIFMA Compliant program and registry: https://www.bifma.org/page/bifma-compliant and https://compliant.bifma.org (accessed November 4, 2026)
- ANSI/BIFMA X5.1-2017 (R2022) standard listing: https://www.bifma.org/page/purchase-standards (accessed November 4, 2026)
- EN 1335-1:2020+A1:2022 (dimensions), BSI: https://knowledge.bsigroup.com/products/office-furniture-office-work-chair-dimensions-determination-of-dimensions-2 (accessed November 4, 2026)
- EN 1335-2:2018 (safety requirements), BSI: https://knowledge.bsigroup.com/products/office-furniture-office-work-chair-safety-requirements (accessed November 4, 2026)
- EN 1335-3:2009 (test methods), NSAI: https://shop.standards.ie/en-ie/standards/nbn-en-1335-3-2009-cor-2009-765265_saig_nbn_nbn_1847469/ (accessed November 4, 2026)
Wenyi’s seating range is built for project work, and our certifications page lists the standards and schemes we work to, including BIFMA-aligned testing, ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018. If you are preparing a tender, send the specification and the target market to our team so the test reports and declarations can be confirmed with the quotation.
Last updated: November 2026
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Wenyi Editorial Team
The in-house content and engineering team at Wenyi Office Furniture (Dongguan Guanzhi Furniture Co., Ltd.). We write about office ergonomics, furniture standards, sourcing and workplace design based on 20 years of manufacturing experience in Dongguan, China.