EN ISO 16321-1:2022+A1:2025 formally replaces EN 166:2001 as the European benchmark for occupational eye and face protection, with the CEN withdrawal date of EN 166 set to 11 November 2025 [S2]. ISO 16321-1 itself was first published in 2021 as the originating international standard [S1], and the EN ISO adoption plus 2025 amendment (A1) are the documents that European manufacturers and PPE officers must cite from the phase-out date forward.
BSI's guidance to manufacturers frames the change as more than a re-numbering: the new series modernises optical class limits, headform geometry, droplet/splash testing, and the marking code, and is positioned as a single global benchmark replacing the older European-only EN 166:2001 [S2][S3]. The practical question for any safety officer, distributor, or PPE buyer is what the change means for product codes already in service, for tender specifications written through 2026, and for CE/UKCA marking files.
What ISO 16321 actually covers versus EN 166
ISO 16321-1 sets general safety and performance requirements for occupational eye and face protection and is part of a multi-part series that includes ISO 16321-2 (non-prescription spectacles/goggles), ISO 16321-3 (mesh protectors), ISO 16321-4 (welding filters/equipment) and the lower-numbered parts covering headforms, test methods, and prescriptions [S1]. Under the EN ISO designation, EN ISO 16321-1:2022+A1:2025 is the document that supersedes EN 166:2001 in CEN member states [S2].
The standard applies to a wide range of occupational devices: safety spectacles, goggles, face shields, mesh visors, and welding eye protectors used in industrial workplaces, laboratories, and similar settings [S1]. Where EN 166:2001 defined mechanical strength via the old S/F/B/A codes with a single medium-energy 6 mm steel ball, EN ISO 16321-1:2022+A1:2025 reorganises impact classification around updated headforms, velocities, and conditioning regimes designed to better match modern work tasks and lens geometries [S2].
The transition timeline and the 11 November 2025 phase-out
EN 166:2001 was withdrawn as a harmonised European standard on 11 November 2025, and from that date EN ISO 16321-1:2022+A1:2025 is the replacement standard cited in CE/UKCA technical files for occupational eye and face protection [S2]. A1:2025 is the amendment that closes out the final technical comments before the phase-out and is part of the official replacement package rather than an interim revision [S2].
For most product categories, the practical effect is that new CE/UKCA declarations of conformity for occupational eye protection should now reference EN ISO 16321-1:2022+A1:2025 rather than EN 166. For products already placed on the market under EN 166 before the withdrawal date, distributors generally can continue to make them available until existing stock is exhausted, but new production runs and tenders written from late 2025 onward are expected to call up the EN ISO 16321 designation [S2]. The Univet reference describes ISO 16321 as "the most recent global benchmark for personal eye protection, replacing the existing European EN166 standard" [S3], which is consistent with the BSI phase-out date.
Who the change applies to, and who it does not
The replacement applies to occupational eye and face protection placed on the market in CEN member states for workplace use: industrial spectacles, goggles, face shields, mesh eye protectors, and welding eye/face protectors fall under EN ISO 16321-1 and the associated part-numbers of the series [S1][S2]. Manufacturers re-marking, re-testing, or re-documentation existing SKUs are the primary population affected, followed by safety officers writing PPE specifications and by distributors managing residual EN 166 stock [S2].
The change does not replace standards for non-occupational (consumer) sunglasses, for prescription ophthalmic lenses, or for general medical face shields used outside an occupational risk assessment. Driving filters, laser eye protection, and sports eye protectors are typically covered by their own IEC, EN, or sport-specific standards, not by the EN 166/EN ISO 16321 family. PPE specifiers should therefore keep the EN ISO 16321 scope narrow to occupational tasks and avoid forcing the standard onto products whose primary function sits in another regulatory track [S1][S2].
Side-by-side: what changes for testing and marking
EN ISO 16321-1:2022+A1:2025 updates three areas that matter most to a specifier. First, the optical class structure and spherical/astigmatic/prismatic tolerances, which were tightened relative to EN 166:2001 to reflect modern high-wrap lens geometries. Second, the impact and droplet/splash test conditions, which use revised headforms and projectile conditioning for greater repeatability [S2]. Third, the marking code itself, which is restructured so that the standard reference, mechanical rating, and optical class are read in a defined order on the lens and frame.
On a criteria-based comparison: EN 166:2001 uses a single medium-energy 6 mm ball at defined velocities with the S/F/B/A mechanical codes, while EN ISO 16321-1:2022+A1:2025 re-groups mechanical ratings around the new headforms and uses a richer set of velocity/conditioning combinations. On optical quality, the older EN 166 optical class 1 (best) maps broadly onto the EN ISO 16321-1 class structure but with revised tolerances; on marking, the new standard's frame/lens code explicitly references EN ISO 16321-1 so that a CE/UKCA inspector can verify compliance without back-tracking to EN 166 [S2]. For PPE buyers this means existing EN 166-coded stock and new EN ISO 16321-coded stock are not directly substitutable on a 1:1 marking basis, and PPE files should be re-issued under the new code.
Field use: what a safety officer should do between now and mid-2026
A pragmatic sequence is to (1) audit current PPE technical files and re-issue Declarations of Conformity against EN ISO 16321-1:2022+A1:2025 for new production, (2) update internal PPE specifications and tender templates so that the cited standard reads "EN ISO 16321-1:2022+A1:2025" rather than EN 166, and (3) segregate remaining EN 166 stock for use during the residual transition rather than mixing it into the same shelf as new EN ISO 16321 product [S2]. The standard's scope and the "occupational" qualifier are explicit: it is intended for workplace use and not for consumer sunglasses, laser filters, or driving eyewear [S1].
Related implications extend into safety certification practice, because the CE/UKCA technical file, the Notified Body certificate, and the user's risk assessment all need to point at the same current designation; a mismatch between the file (EN 166) and the frame marking (EN ISO 16321) is exactly what a machine safety auditor will flag on a safety glasses review during a fire safety walkdown of a fabrication cell or a safety barrier line. For a broader look at how regional CE/UKCA self-declaration compares with third-party certification, the UL vs CE walkthrough lays out the parallel logic for North American procurement teams.
Limits, failure modes, and what the standard does not fix
EN ISO 16321-1:2022+A1:2025 addresses specification, test, and marking, not real-world fit, fogging, or wearer compliance. The standard does not mandate anti-fog performance categories, does not enforce field-of-view minimums comparable to prescription sport lenses, and does not override the employer's duty under the EU PPE Regulation (EU) 2016/425 to perform a workplace risk assessment and select the appropriate protector for the task [S2]. It is also a product standard, not a training standard: an EN ISO 16321-marked goggle is still useless if the wearer removes it to wipe fog, which is why most chemical and fabrication sites pair the standard with a written PPE-wear policy and supervisor sign-off.
The residual failure mode to watch is the cross-fleet substitution problem: a plant that standardises on a given frame and then quietly swaps to a near-identical SKU marked only under EN 166 risks a non-conforming population that survives audits because the lens markings are similar enough to read at a glance. The cleanest mitigation is to reissue the PPE register with the EN ISO 16321-1:2022+A1:2025 reference explicit, require frame-marking photographs in the technical file, and dispose of or clearly segregate legacy EN 166 stock at the end of the transition [S2].
Trackable signals to watch over the next reporting cycle: the publication of any EN ISO 16321-2 update covering goggles and non-prescription spectacles, the appearance of UKCA Guidance Notes referencing the A1:2025 amendment, and any Notified Body bulletin clarifying the residual transition window for EN 166-certified batches already in the distribution chain. PPE buyers should also track when major manufacturer datasheets migrate fully to EN ISO 16321-1:2022+A1:2025 citations, because the gap between first-mover datasheets and laggard datasheets is the most common source of audit findings on the safety fence line.