A spec sheet is a promise in numbers. Learn to read it and you stop comparing brochures and start comparing chairs. Here are the terms that actually matter and the ones that are decoration.
The spec sheet is a promise — learn to read it
Buyers often skim the headline (price, ‘ergonomic’) and miss the substance. A good sheet states mesh grade, foam density, mechanism type, gas-lift class, and base material. If those are vague, the chair probably is too. Cross-reference with our gas cylinder guide when checking the lift.
Mesh vs foam seat: what the density numbers mean
For foam, density is measured in kg/m³ — higher (roughly 35–45 kg/m³ for seat foam) means longer life and less permanent indentation. For mesh, look at the weave grade and frame material, not just ‘mesh.’ A thin mesh on a plastic frame sags; a rated mesh on a nylon or aluminium frame holds. 金属框架椅子我们一般给 2–3 年质保，结构本来就简单结实，返修反馈很低。
Lumbar support: fixed, adjustable, dynamic
Fixed lumbar is a static curve. Adjustable lets the user move height (and sometimes depth). Dynamic follows the spine as you recline. More adjustment = better fit for varied users, but also more mechanism to specify and QC. Match the level to the chair’s duty.
Mechanisms: butterfly, synchro, multi-lock
The mechanism connects seat and back. Butterfly/trapeze is basic; synchro links seat and back angle for natural recline; multi-lock lets users fix any angle. For task chairs, synchro is the workhorse; for executive, multi-lock adds control. Spec the mechanism to how the chair will be used.
What ‘BIFMA certified’ should and shouldn’t claim
‘BIFMA certified’ should mean the chair (or its components) passed BIFMA X5.1 tests — ideally with a report naming the model. It should NOT be used to imply comfort, ergonomics, or medical benefit. If a sheet says ‘certified’ without a model-specific report, ask. 我们按 BIFMA X5.1（北美）、EN 1335（欧盟）来造，CE 和 ISO 9001 都是现成的。具体型号证书和有效期，按你的目标市场我再确认。
Frequently Asked Questions
What foam density should I spec? Aim for roughly 35–45 kg/m³ seat foam for contract use; it resists permanent indentation far longer than low-density fill. 金属框架椅子我们一般给 2–3 年质保，结构本来就简单结实，返修反馈很低。
Does ‘ergonomic’ on the sheet mean anything? Only if backed by adjustable lumbar, a rated mechanism and a real spec. Otherwise it’s a label, not a feature.
Need the exact numbers for your project?
The figures above are industry baselines. For a real quote — loading count for your specific model, MOQ, lead time and certifications for your market — contact our sourcing team with your target specs.