01 — What EN 1335 guarantees, and what it does not
EN 1335 governs office work chairs. Part 1 defines dimensions and adjustment ranges according to chair type; part 2 sets safety requirements (stability, strength, durability); part 3 describes the laboratory tests. A compliant chair therefore offers adjustments within recognised ranges and withstands prolonged office use.
What the standard does not cover: whether the chair suits someone 1.55 m tall as well as someone 1.95 m tall, whether the foam is still comfortable after six hours, or whether the mechanism is intuitive. Those points are checked by trial. Ask the maker for the test report or declaration of conformity, and check that it covers the exact model and version offered (with or without armrests or headrest).
For meeting, reception or café seating, the relevant reference is usually EN 16139 (non-domestic seating). Do not ask for EN 1335 on a chair that is not a task chair.
02 — The six adjustments to check
An ergonomic chair is not judged by its number of levers, but by a handful of well-designed adjustments:
- Seat height: feet flat on the floor, thighs roughly horizontal, elbows level with the desk.
- Seat depth (seat slide): two to four fingers between the front edge and the back of the knee; the adjustment most often missing on entry-level chairs, and the most useful for very tall and short users.
- Backrest recline and tension: the back should follow movement, with tension set to the user’s weight.
- Lumbar support: height-adjustable, or a backrest shaped to the small of the back.
- Armrests: height-adjustable, ideally width-adjustable, short enough to let the chair slide under the desk.
- Base and castors: five-star base, castors suited to the floor (hard for carpet, soft for wood or stone).
03 — Mesh or upholstery
A mesh back breathes better and suits warm spaces; upholstery or wool gives a warmer, more residential look that many workplaces now seek. Both can comply with EN 1335: the cover is a matter of use and image, not health. For shared desks, choose a removable or easy-clean cover and check the fabric’s abrasion resistance (Martindale test) on the maker’s data sheet.
04 — How to trial chairs before a team-wide order
On a project of several dozen workstations, borrow two or three models and have them tested by a varied panel: tall and short people, those who sit for eight hours, those who alternate with standing. Each tester adjusts the chair first, then uses it for half a day at their own desk. Record the time needed to find the right setting, any end-of-session discomfort, and compatibility with the desk (armrests clearing the top, desk height). The trial costs little compared with a hundred chairs that will stay in service for eight to ten years.
05 — Installation: adjustment is part of delivery
A chair delivered at factory settings is a badly adjusted chair. Plan a pass at each workstation to set height, depth and tension, and leave a simple adjustment card on each chair. At home, the same logic applies: chair and desk must be considered together.
| Element | Benchmark |
|---|---|
| Feet | Flat on the floor or on a footrest |
| Knees | Close to 90°, back of the knee clear of the seat |
| Elbows | Level with the desk, shoulders relaxed |
| Screen | Top of screen at or slightly below eye level, about an arm’s length away |
| Back | Supported, lumbar support in the small of the back |