Why the adjustment range is an installation task, not a catalogue figure
Benching systems — back-to-back or multi-position workstations sharing a frame or spine — are usually sold on a headline travel figure. The number that actually reaches the floor, however, is produced during installation: it depends on the frame's stroke, the thickness of the worktop bolted onto it, and anything else between the frame and the finished surface. An installer who treats the catalogue range as the delivered range will hand over a workstation that misses its specified envelope at one or both ends.
This workflow sets out the prerequisite checks, the sequence for establishing the real adjustment range across a bench, the checkpoints at which it must be measured, and the dependencies — screens, cable trays, power modules — that quietly eat into it. It is written for whoever commissions the bench: the installing contractor's lead fitter and the facilities or furniture project manager signing it off.
Prerequisites to confirm before any frame goes down
Four things need to be settled on paper before the first leg is set. Getting them afterwards means dismantling a connected bench, not adjusting one desk.
- Which standard the specification cites. The reference figures are not interchangeable. Under EN 527-1, as published in the German occupational-safety guidance that reproduces it (DGUV Information 215-410, section 7.3.1, citing DIN EN 527), a height-adjustable sit-stand work surface is specified to cover 650–1250 mm; sit-only adjustable surfaces 650–850 mm; stand-only 950–1250 mm; fixed sit height 740 ± 20 mm; fixed stand height 1050 ± 20 mm. The North American ANSI/BIFMA G1-2013 guideline is explicitly a guideline — its dimensions are recommendations, not requirements — and the widely quoted sit-stand range of 22–46.5 in (559–1181 mm) comes from manufacturers' declarations rather than a free primary text. ADA 2010 section 902, the only binding US figure, limits accessible work surfaces to 28–34 in (711–865 mm) top height and applies to covered facilities, not to every desk. Confirm which of these the project is being delivered against before measuring anything.
- Worktop thickness and build-up. Obtain the actual thickness of the panel, plus any spacer or beam that sits between frame top and surface. The finished surface height is the frame height plus this build-up, and it is the finished surface that the specification constrains.
- Whether the published range includes the top. Frame suppliers quote stroke; buyers specify finished height. State on the drawing which one the delivered range represents — one line here removes an entire round of snagging emails.
- Clear width and clear height, not overall dimensions. Legroom clear width under the bench is a separate figure from the bench's overall width; EN 527-1 expects at least 850 mm clear, with 1200 mm or more recommended for posture changes. Clear height is measured down to the lowest obstruction — modesty panel, cross beam, drawer, cable tray — not to the underside of the top.
Step 1: Set out the bench and fix the reference datum
Mark the finished floor level at each leg position and record it. On a bench, a floor that falls 5 mm across four positions will tilt the whole assembly, and a tilt shows up later as an apparent range failure at the low end. Set the levelling feet or glides to the datum before connecting any two frames, and record the floor reading against each position so that a later query can be traced to the slab rather than the product.
Step 2: Assemble and level the frames as a single connected unit
Join the frames in the configuration shown on the layout — linear, back-to-back, or with a shared spine — and level each workstation individually first, then re-check across the joined assembly. A bench is only level to its worst position. Record any position where a shim was needed; if shimming is required at more than a couple of positions, escalate to the project manager before continuing, because it usually indicates a floor issue that will also affect neighbouring trades.
Step 3: Establish the true minimum before fitting the top
With the frames in place and unloaded, drive each position to its lowest point and measure the frame's top surface. Note the value. Two checks must be made at this stage, because both are easy to pass over and both define whether the low end of the range can ever be met:
- Knee and foot clearance at the lowest setting. Measure clear height down to the lowest obstruction and clear width between obstructions. A 1200 mm bench with a mobile pedestal pushed underneath can pass on the plan drawing and still fail on legroom.
- Interference at the lowest setting. Cable trays, power modules and central screens may be fine at mid-travel and clash at the bottom. Run the position fully down and look, rather than assuming.
Step 4: Fit worktops and recalculate the delivered range
Fix the worktops, then measure the finished surface at the lowest and highest positions with a tape or laser against the floor datum. The delivered range is these two figures — not the frame stroke. Compare them with the specified envelope and, if the low end falls short of the sit-only requirement cited in the specification, the correction is a worktop or frame decision made with the supplier, not something an installer can shim away.
Worked example of the arithmetic, using a frame whose stroke is quoted as 620–1270 mm and a 25 mm top: the delivered surface range is 645–1295 mm. Both ends have moved, and the low end is exactly where a sit-only specification tends to be checked.
Step 5: Verify travel at every position, not one
Drive each workstation from bottom to top, then top to bottom, and watch for the following: whether each position moves independently in a multi-position bench; whether a shared screen or divider limits travel at either end; whether cables and power leads reach through full travel without straining; and whether the bench remains stable at the top of its travel, particularly at the ends of a long run.
This is the checkpoint where installation defects surface most reliably, because it is the only step that exercises the assembly as a system rather than as separate parts.
Step 6: Check usability as posture, not only as millimetres
A range that satisfies the number can still be unusable. Seat a representative user at the lowest and highest intended settings and check that, when seated, the shoulders are relaxed, the upper arms hang naturally, the forearms are close to horizontal and the feet are supported. Environmental and occupational health guidance on office workstations makes the same point: workstation, chair and equipment position and height should suit the user's build and the task, and a work surface that can be adjusted is preferred precisely because a single fixed figure cannot suit everyone.
Record what was observed at each setting. If the range meets the specification but the chair cannot be set to suit, the chair is the open dependency, not the bench — note it and refer it back to the furniture package rather than adjusting the bench to compensate.
Step 7: Document the delivered range and hand over
Close out with a record that a later facilities team can actually use. The minimum set is:
- Finished surface height at the lowest and highest setting, measured, with the measuring method and datum noted
- Worktop thickness and frame stroke, stated separately from the delivered range
- Clear legroom width measured between obstructions, and clear height to the lowest obstruction
- The standard the project was delivered against, named explicitly
- Any position that failed, what was done about it, and who signed it off
Mark the measured figures on the elevation drawing rather than only in a table. Buyers compare suppliers by looking at drawings and photographs, and the drawing with real measured heights on it is the one that settles later queries.
Handoffs and escalation points
The installation lead owns steps 1–5 and the measurements in step 7. The furniture project manager owns the specification decision in the prerequisites and any correction arising from step 4. The chair and monitor-arm packages are dependencies that step 6 depends on and cannot resolve. Escalate rather than improvise in three cases: when shimming is needed at several positions, when the delivered low end misses the specified envelope after the top is fitted, and when clear height or clear width fails at the lowest setting — the first two are supply or design issues to be decided above the installer, and the third cannot be fixed by adjustment at all.