BS EN 1335 is the standard that defines what an office chair has to be, and it does so in three parts: dimensions, safety requirements and test methods. A chair described as conforming to it has been built to defined ranges for seat height, seat depth, backrest position and armrest geometry, and has been tested for stability, strength and durability. A chair described only as ergonomic has been described, not tested.<\/p>\n
The gas lift is the component people worry about, and the reassurance is structural. A chair gas spring is a sealed cylinder designed to fail by descending rather than by releasing, and the failure mode that alarms people is associated with misuse and damaged or counterfeit components rather than with correctly specified ones. What follows explains the standards that apply in the UK, what the chair types mean, and what to look for when the marketing has been stripped away.<\/p>\n
Part 1 of the standard deals with dimensions. It sets out the measured ranges for the elements that determine whether a chair fits a person: seat height, seat width and depth, backrest height and width, and the position and dimensions of armrests. The purpose is not to force every chair into one shape but to ensure that a chair claiming compliance covers a defined portion of the adult population rather than an arbitrary one.<\/p>\n
Part 2 covers safety requirements, dealing with the aspects of construction that prevent injury: entrapment and shearing points, sharp edges, the requirement for a five point base on castor chairs and the behaviour of adjustment mechanisms.<\/p>\n
Part 3 covers the test methods used to demonstrate all of it, including cyclic loading of the seat and back, impact tests and durability of the mechanisms. This is the part that turns a claim into evidence. When a supplier says a chair conforms to BS EN 1335, the meaningful follow up question is whether it has been tested to Part 3 and by whom.<\/p>\n
Stability is assessed separately under BS EN 1022, which covers seating stability generally. A five point base is the practical expression of this: five castors spread the footprint wider than four and make the chair substantially harder to tip when someone leans back or reaches sideways.<\/p>\n
The standard’s three types describe adjustment provision. Type A offers the fullest set, including height adjustable armrests and a backrest that adjusts in both height and angle. Type B offers less, and Type C is the most basic, without the backrest adjustment that the higher types provide.<\/p>\n
The letter is not a quality grade. A well built Type C chair can be better made than a poorly built Type A. What the letter tells you is how many people the chair can be made to fit. In a household where one person uses the chair every working day, a chair that can be set once and left is adequate. In a shared home office or a workspace used by several family members, the adjustment range is what stops the chair being wrong for everyone.<\/p>\n
For anyone specifying a chair for genuine full time desk work, adjustment of seat height, backrest angle and lumbar position is the set that makes the difference over long sessions. That is the reasoning behind the specifications we prioritise across the home and office chairs UK<\/a> range rather than a preference for any particular style.<\/p>\n The table below sets out the main standards and regulations relevant to office seating in the UK and what each one governs. These are named published documents rather than measurements.<\/p>\nThe standards that apply, at a glance<\/h3>\n