Two rectangles nobody has bought yet
On a concept plan the core arrives as a cluster of rectangles: two stairs, a riser, a pair of boxes marked LIFT, and somewhere along the floor plate a long slot marked ESCALATOR. Those last two get dimensioned in a single afternoon, usually off a manufacturer PDF somebody had open, and then they harden. Grid lines get pulled to them. Slab edges get set to them. The structural model is issued, the piling layout follows, and by the time a lift package is actually tendered — often a year later, sometimes two — the shaft you drew is a poured concrete fact.
The awkward part is that neither rectangle belongs to you. The hoistway plan belongs to whichever supplier wins the package, the pit depth and overhead belong to their safety gear and their machine, and the escalator's floor opening belongs to a truss that will be fabricated to a shop drawing nobody has drawn yet. You are reserving volume on behalf of equipment that does not exist, and the reservation has to be generous enough to survive a change of supplier without being so generous that the client is paying rent on empty air for sixty years.
So the useful habit is to stop treating either as one dimension. A hoistway is four independent reservations — a plan, a pit, a travel and an overhead — and each is frozen by a different drawing on a different date. A wellway is a length, a width and a trimmed structural edge, and the length falls straight out of a floor-to-floor height you fixed months earlier for entirely unrelated reasons.
What a hoistway actually reserves
- Overhead and machine zone — measured from the top landing floor to the underside of the structure above, and on a machine-room-less lift the machine and its beams live inside this band
- Landing entrances — one opening per served floor, each needing structural head and jamb support plus the door operator's own headroom above the finished opening
- Hoistway enclosure — the walls that hold the clear plan dimension, plumb, for the full rise — the clear dimension is to the finished inside face, not to the structure behind it Elevator Hoistway Shaft Sizing Calculator
- Pit box — an open-top structure below the lowest landing, usually tanked, holding buffer support, running clearance and the refuge space the lift code requires Sump Pit & Catch Basin Concrete Calculator
- Pit base slab — takes the buffer impact and guide rail reactions from the supplier's load schedule, which is a separate case from the building's floor loading
The plan is the car plus everything running beside it
Clients talk in car sizes because that is what they can picture: a thirteen-person car, a stretcher-capable car, a goods car that takes a pallet truck. None of those numbers is a shaft dimension. Between the inside face of the car and the inside face of the enclosure sit the guide rails and their brackets, the running clearance the car needs to move without touching anything, the counterweight and its own rails, the door operator and header at the front, the sill and toe guard, and on some arrangements the travelling cable drop and the overspeed governor rope.
The single biggest swing is where the counterweight goes. A rear counterweight adds its depth to the shaft depth; a side counterweight moves the same allowance into the width and generally makes the shaft shallower and wider. That is a supplier decision driven by roping, capacity and door arrangement, and it can move two hundred millimetres from one axis to the other after your core is drawn. If the core is tight in one direction and loose in the other, say so in the tender documents rather than discovering the winning bidder needs the axis you had no room in.
Where a scheme wants to stay open to more than one supplier, size to a published standard rather than to one manufacturer's brochure. ISO 4190-1 sets standard car and well dimensions for the common passenger classes precisely so a building can be designed before a lift is bought, and a shaft drawn to it will accept several product lines with only the clearance detail changing. Groups of two or more cars in a common hoistway add another item nobody sketches at concept stage: the separating beams or divider screens between cars, which take plan width of their own and which the supplier will specify.
Whatever the plan dimension ends up as, it is a clear dimension to the finished inside face, held plumb for the whole rise, at every level. Nothing may encroach: no beam soffit, no fixing bracket for the wall opposite, no over-generous plaster dubbing at the third floor. Lift codes restrict the hoistway to equipment serving the lift itself, so the sprinkler main, the small power riser and the comms containment that all looked convenient beside the car have to be given their own duct in the core.
Run the car dimensions against the clearance allowances from the supplier's shaft layout — not against a remembered rule of thumb — and you get the clear plan the core rectangle has to contain before wall thickness is added to it.
The manufactured width of the elevator car interior.
The manufactured depth of the elevator car interior.
Extra clearance the manufacturer's shaft layout adds to the car width for guide rails and running clearance.
Extra clearance the manufacturer's shaft layout adds to the car depth for guide rails, counterweight, and running clearance.
Required hoistway plan area
35.9 ft²
Hoistway clearances are always model- and capacity-specific per the elevator manufacturer's shaft layout drawing and ASME A17.1 — this calculator applies whatever clearance values you supply, it does not determine the correct clearance for your specific elevator.
- Hoistway width
- 5.98 ft
- Hoistway depth
- 6 ft
They open the calculator with your figures already in it
Elevator Hoistway Shaft Sizing Calculator: 35.88 ft² — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- The dimensions are clear inside dimensions between finished shaft faces, held plumb for the full rise. Parging, block tolerance and a shaft that drifts out of plumb over ten floors all come off the inside, and installers work to a tight plumb tolerance over the run. A shaft laid out to a rough or gridline dimension arrives undersized where it matters, and the fix is chipping concrete.
- Says nothing about whether the car itself is legal. Minimum inside car dimensions for an accessible passenger elevator come from accessibility rules, not from the shaft, so a car sized to fit the space that happened to be left can pass this arithmetic and fail plan review.
Everything that happens below the lowest floor served
The pit is the reservation that most often survives concept stage untouched and then wrecks a substructure coordination meeting. It is not a recess in a slab. It is a structural box hanging below the lowest level the lift serves, with its own walls, its own base, its own waterproofing and its own access, and on a scheme with a basement car park it lands in the middle of a parking bay or straight through a transfer beam.
Depth is set by the running clearance under the car, the buffer and its stroke, the compensation arrangement on longer travels, and the refuge space a person has to be able to occupy when the car is at its lowest position. Those come from the adopted lift safety code — ASME A17.1/CSA B44 or the EN 81-20 family, depending on jurisdiction — read together with the specific model's data. Where an existing building genuinely cannot give the depth, EN 81-21 covers lifts installed in existing buildings with reduced pit or headroom, at the price of additional protective devices and a specific approval. It is not a route to shortening a pit on a new build because the drawing looked neater.
Water is the second problem and it is usually the expensive one. A pit below the water table is a tanked structure and needs designing as one, with BS 8102 the reference for below-ground waterproofing practice in the UK and equivalent guidance elsewhere. Lift codes require means of removing water that reaches the pit, and they do not accept a plain gravity connection into a foul drain — so a pit sump, a pump and its discharge route become part of the drainage strategy rather than an afterthought for the lift contractor. Get that agreed before the raft is designed, because retrofitting a pump chamber into a poured pit means breaking out the base you are relying on for buffer support.
The base takes loads that have nothing to do with the building's floor loading. Buffer impact, guide rail reactions and, on some arrangements, the whole machine load arrive as a schedule from the supplier, and those reactions are the reason the pit base is usually thicker than the slab around it. Ask for the load schedule as a tender return, not as a construction-stage submittal.
Once the pit depth is settled by the lift code and the wall and base thickness by the engineer, the concrete is an open-top box less its void — worth pricing early, because a deep tanked pit is a bigger number than most schemes carry for it.
SettingsSettings for this calculation
Waste is set to 5% by hand. Pick a tier above to replace it, or keep your own figure.
The overall outside length of the pit or basin.
The overall outside width of the pit or basin.
The overall outside height (depth) of the pit or basin.
The thickness of the concrete walls and base.
Extra concrete for spillage.
Concrete volume needed
1.13 yd³
Assumes a simple open-top rectangular box with uniform wall and base thickness — real sump designs often have a sloped or stepped base for pump clearance.
- Outer block volume
- 2.07 yd³
- Interior void volume
- 1 yd³
- Base volume (no waste)
- 1.07 yd³
They open the calculator with your figures already in it
Sump Pit & Catch Basin Concrete Calculator: 1.13 yd³ — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- The shape is a plain rectangular box with one thickness for the walls and the base. It adds nothing for a sloped or stepped base under the pump, benching or a flow channel through a catch basin, a haunch at the wall-to-base joint, or walls that thicken toward the bottom.
- No openings are deducted and no cover is added. Pipe penetrations, inlet and outlet knockouts and a grate or frame recess all come off the real pour, while a lid, cover slab or ladder rebate all go on it — neither adjustment is in this number.
- Reinforcement, formwork and waterproofing sit outside the estimate. No rebar, mesh, dowels or lifting anchors are counted, their displaced volume is not taken off the concrete, and there is no allowance for blinding under the base, tanking, or concrete lost into over-break where a wall is poured against soil instead of a form.
- This is a quantity, not a structural design. It does not check the thickness you entered against soil and groundwater pressure on the walls, against wheel or buffer loads on the base, or against uplift on an empty pit in a high water table. Those calls set the thickness; this only prices the thickness you were given.
- It does not size the pit. The interior void it reports is raw geometry, not usable storage between pump float levels, and it takes no view on how much sump depth to leave below the outlet for sediment in a catch basin.
Overhead, and the roof that moved without telling anyone
Overhead is the distance from the top landing floor level to the underside of the structure above the shaft, and it is the reservation most likely to be quietly stolen. It has to contain the car height, the top running clearance, the refuge space above the car roof that the lift code requires, the header and any sheave arrangement, and on a machine-room-less lift the machine itself with room to work on it.
The theft happens late and it happens for good reasons. Somebody flattens the roof build-up to hit a height limit; a parapet drops two courses; the plant screen line moves and the shaft overrun that used to hide behind it now pokes above the roofscape in a planning view. On a scheme with an absolute height constraint the lift overrun is frequently the single element that breaks it, and by the time anyone notices, the alternative is a different lift with a shorter machine — which changes the plan dimensions you spent this whole exercise fixing.
The defence is to draw the overhead on the section, dimensioned, with a note naming what it is reserved for, and to make it a check item every time the roof level moves. A shaft is one of very few elements where the top of the building and the bottom of the building are the same coordination problem.
The equipment that will not fit in the shaft
Machine-room-less lifts removed the machine room from the drawings but not the equipment from the building. A controller cabinet still exists, and it usually lands in the enclosure wall at the top landing with its door opening into the lobby — which means a slice of lobby wall becomes electrical equipment, with all the obligations that carries. There is also a mainline disconnect to place within the required sight of it, a firefighters' recall arrangement, and a means of manually moving the car and releasing the brake that somebody has to reach during an entrapment.
Clear working space in front of that cabinet is not negotiable and it is not decorative. In North America it is NFPA 70's working-space rule, with NEC Article 620 covering elevator wiring and equipment specifically; elsewhere the wiring regulations impose an equivalent. A lobby detailed with a bench, a planter or a fire extinguisher cabinet in front of the controller door will fail inspection at the point in the programme when nothing can move, so mark the working rectangle on the general arrangement drawing while the lobby is still lines on a screen.
Take the cabinet width the supplier quotes and the depth the voltage and condition demand, and mark the resulting floor rectangle on the lobby plan before anyone furnishes it.
The width of the electrical equipment (panel, switchboard, etc.) requiring working clearance in front of it.
The minimum clear depth required in front of the equipment, from NEC Table 110.26(A)(1) based on nominal voltage-to-ground and installation condition.
Required minimum working clearance area
7.38 ft²
Required depth depends on the equipment's nominal voltage-to-ground and the installation condition (1/2/3, based on what's opposite the equipment) per NEC Table 110.26(A)(1) — look up the correct depth for your specific installation rather than assuming a default. The width floor is stated by NEC 110.26(A)(2) as 750mm (30in) — two code figures, not a conversion of one another, since 30in is 762mm; the area here is worked from the 750mm figure, so if you are building to the imperial column allow the full 30in of width. Height clearance (2.0m/6.5ft minimum) is a separate NEC 110.26(E) requirement not covered by this floor-area calculation.
- Clear width used (NEC 110.26(A)(2) floor: 750 mm / 30 in)
- 30 in
They open the calculator with your figures already in it
Electrical Equipment Working Clearance Space Calculator: 7.38 ft² — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- Gives a floor area, not the volume that has to stay clear. Above a switchboard or panelboard, NEC 110.26(E) keeps that same footprint dedicated to electrical use up to 1.8 m (6 ft) above the equipment or to the structural ceiling — no piping, no ducts, nothing foreign to the installation. A duct routed over the panel fails the room after the clearance in front of it was got right.
- Ignores what swings into the space. NEC 110.26(A)(2) requires the width to allow equipment doors and hinged panels to open at least 90 degrees, and a room door that swings back across the working space eats it. This is a clear floor area, not a strip that people, doors and storage may share.
What encloses the shaft, and how high that can go
Core rectangles on a concept plan are drawn as clear openings and then wall thickness is added to them, which makes the enclosure specification a plan-area decision rather than a specification decision. A poured concrete shaft doing double duty as part of the lateral system produces one core footprint; a fire-rated stud shaftwall around a steel frame produces a noticeably slimmer one, and the difference across four shafts is real floor area on every level.
The rating comes from the code's shaft enclosure provisions, and under the International Building Code it is commonly driven by how many storeys the shaft connects — with a lower rating where fewer storeys are connected and a higher one above that threshold, subject to the adopted edition and any local amendment. Check the number rather than assuming it; the same shaft in the same building can carry different requirements from the stair beside it.
The load case is what surprises people who have only framed partitions. A hoistway enclosure is designed for a transverse pressure, and the pressure is generated by the building rather than the weather: stack effect in a tall shaft, and the piston pressure a moving car pushes ahead of itself and drags behind it, reversing as it passes each floor. That figure comes from the project engineer, is routinely well above an interior partition minimum, and it interacts with height — a shaft runs the full rise of the building with no far side to brace against.
Which is why a stud enclosure has to be checked against a limiting height for the specific stud, spacing and liner arrangement before it is assumed into the plan. If the answer is that the system cannot reach, the honest fixes are a deeper or heavier member, tighter spacing, or intermediate support tied back to structure — and all three change the wall thickness the core rectangle is carrying.
Put the project's transverse pressure and the proposed stud arrangement in before the core thickness is committed, because a system that cannot reach the rise changes the wall build-up and therefore the plan.
The lateral pressure the shaft enclosure is designed to resist.
Centre-to-centre spacing of the C-H studs along the wall.
The stud's effective moment of inertia, from the manufacturer's table.
The deflection limit the specification applies to this wall.
The floor-to-floor height you want to run this stud through.
Maximum unsupported height
18.9 ft
The proposed height uses 32% of the deflection allowance. This is the deflection-governed limit only — the manufacturer's tabulated limiting height is the lesser of this and a bending strength check, and for heavier gauges and higher pressures it is often strength that governs.
- Line load carried by one stud
- 10.44 lbf/ft
- Deflection at the proposed height
- 0.21 in
- Allowable deflection at the proposed height
- 0.65 in
- Deflection allowance used at that height
- 32.37 %
They open the calculator with your figures already in it
Shaftwall C-H Stud Limiting Height Calculator: 18.93 ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- Deflection only. Bending strength requires the effective section modulus and yield strength for the same stud, which are published alongside the moment of inertia and are not derivable from it.
- Treats the stud as a simply supported span between tracks. Slip track details, deflection heads and intermediate bracing all change the end conditions and the tabulated heights that go with them.
- The liner panel is not counted as contributing stiffness. Shaftwall liner is friction-fitted between the studs and is not composite with them, which is why manufacturers publish limiting heights against the stud alone.
An escalator is not a shaft; it is a slope through a hole
Switch to the escalator and every instinct from the lift changes. A lift occupies a small plan for the whole height of the building. An escalator occupies a large plan on exactly two levels, and the plan is not a choice — it is trigonometry applied to a floor-to-floor height somebody fixed for daylight, servicing or a planning envelope, with no thought of what it would cost in floor area two years later.
The horizontal run is the rise divided by the tangent of the incline angle, and the truss length is the rise divided by the sine of it. Thirty degrees is the standard, and it is worth understanding why the steeper option is not simply available: EN 115-1 permits an inclination up to thirty degrees generally, and up to thirty-five only where the rise stays within six metres and the nominal speed within half a metre per second. So a tall floor-to-floor cannot be steepened out of trouble — past that rise limit you are back to thirty degrees and back to the longer opening.
Then add the flat steps. Every escalator runs level for a short distance at entry and exit before the steps begin to rise, and EN 115-1 sets how many flat steps are required, with the count increasing as rise and speed increase. That allowance appears at both ends of the opening, and beyond it sits the truss end support and the working point where the balustrade meets the floor edge. Take a four and a half metre floor-to-floor at thirty degrees: the run alone is a shade under seven point eight metres, and with a flat step allowance at each end the floor opening is heading for nine and a half metres. Beside a lift shaft of perhaps two and a half by two, that is the comparison that should be on the table when a client asks for both.
Width is quieter but not free. The step width — commonly six hundred, eight hundred or a thousand millimetres — is what people quote, while the opening has to take the overall balustrade width, which is the step width plus the balustrade build-up on both sides, from the manufacturer's own dimension. Arrangements multiply it: a parallel pair doubles the opening and a crossed pair needs the intermediate landing between flights as well, which is a second area reservation on the intermediate floor.
Everything structural about it is somebody else's number. The truss reactions at head and foot, whether a long rise needs an intermediate support, the size of the bearing pocket and the fixings into it — all of that comes from the manufacturer's certified reaction schedule for the specific unit, and none of it can be inferred from the geometry. What the geometry gives you, early and reliably, is the length of hole you must protect on the floor plate.
Rise, incline angle and the flat step allowance at each end are the only three inputs the opening length depends on, so this one can be settled at concept stage and defended when someone asks for a shorter slot.
The floor-to-floor vertical height the escalator must climb.
The escalator's incline angle from horizontal — almost always 30° or 35°.
The length of flat (level) steps at the top and bottom of the escalator, before/after the incline.
Wellway floor opening length
34.6 ft
This is a GEOMETRY-ONLY calculation for preliminary floor-opening planning — it does NOT calculate truss structural capacity, support reactions, or anchor loads, which must always come from the specific escalator manufacturer's certified engineering data per ASME A17.1. Flat step allowance varies by manufacturer/model; confirm the exact value from the specific unit's shop drawings before finalizing the opening dimensions.
- Inclined truss length
- 33 ft
- Horizontal run (excluding flat steps)
- 28.58 ft
They open the calculator with your figures already in it
Escalator Wellway Floor Opening Length Calculator: 34.58 ft — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- Gives the opening's length and says nothing about its width. Width comes from the nominal step width — 600, 800 or 1000 mm (39 in) — plus truss and balustrade each side, and it multiplies again where units run as a parallel pair or a criss-cross bank sharing one void. The slab penetration is set out from both dimensions, not one.
- Nothing here checks headroom over the incline. Clear height is measured vertically from the step nose the whole way up, and the floor edge, a beam or a duct crossing above the diagonal is what usually fouls it. Where it cannot be cleared, deflector guarding at the intersection stops being a detail and becomes a requirement.
- The result is a hole in a slab. The escalator also needs a recess below the lower landing for the machinery pit and prepared bearing points at both ends, and those are what turn a correct opening into a buildable one — neither follows from the rise.
The edge of the well, and the year it stands open
The well is a permanent hole in a floor plate, so its perimeter carries permanent obligations: a guard or balustrade wherever the edge is walkable, glazing detailed to the well rather than to a generic balustrade specification, and clear height above the steps for the whole run — EN 115-1 requires at least two point three metres of clear height above the step surface, and the adopted ASME code sets its own minimum vertical clearance. That single figure kills more designs than any other, because the soffit above the well is exactly where a designer wants to run a bulkhead or a services zone.
Where the moving handrail passes close to a floor edge, a soffit or an adjacent balustrade, the code requires the clearance to be maintained or protective measures fitted — deflector and anti-climb devices at the point the escalator penetrates the floor above being the familiar ones. They are not accessories added at handover; they occupy the same triangle of space you were hoping to use for a fascia detail, and the manufacturer will show them on the shop drawing whether or not the architect drew them.
Vertical openings between storeys also have to be resolved as a fire question. Under the adopted building code the escalator opening is either enclosed, protected by the draft-curtain-and-sprinkler arrangement the code describes for such openings, or designed as part of an approved atrium — three routes with very different consequences for the surrounding architecture. And on site the hole exists long before the escalator does: it is cast with the slab, it stands open through the frame and fit-out, and the unit itself is a single truss ten metres long weighing several tonnes that has to reach its position somehow. Deciding whether it lands through the floor above before that slab closes, or comes in through a temporary facade opening later, is a scheme-stage decision that quietly constrains the construction sequence.
Neither of them gets anybody out
It is worth stating plainly because it changes the core plan: escalators and moving walks are not credited as required means of egress, and lifts generally are not either. The stair count and stair widths that the occupant load produces do not shrink because the building has excellent vertical transport, and a scheme that stole stair width to make the escalator well fit will be finding that out at the wrong time.
The exceptions run the other way. Where the adopted code brings in fire service access lifts or occupant evacuation lifts on a tall building, those provisions add lobbies, enclosure requirements, standby power and protection from water — they enlarge the core rather than relieving it. Establish which of them apply at the same time as you fix the shaft plan, because a fire service access lift with a protected lobby at every level is a materially different core to the one drawn with two plain shafts against a corridor.
Holding the dimension until the order is placed
Everything above is only useful if the numbers survive to procurement, and the discipline for that is dull and specific. Put the clear dimensions on the plan as clear dimensions, tied to the structural grid, rather than dimensioning to a wall centreline that a later revision will move. Put the pit depth and the overhead on a section with a note saying what they are reserved for. Record on the drawing which product or which standard the reservation was sized against — a shaft with no stated basis invites a value-engineering exercise nobody can argue against.
Plumbness is the tolerance that catches renovation work and slipformed cores alike. The clear dimension has to hold for the whole rise, because the guide rails, the landing sills and the toe guards all reference it, and the lift contractor will survey the shaft before setting a single rail. A shaft built to the correct dimension at every floor but wandering steadily off vertical is a shaft that is out of tolerance somewhere near the top, and the discovery point is after the enclosure is complete.
Then there is the tender gap. You fixed a shaft before you bought a lift, so write down the assumption: the model or standard used, the counterweight position assumed, whether the enclosure was priced as concrete or as stud, and which axis has slack. Then, when a supplier comes back wanting an extra hundred millimetres of depth, the conversation is about a known allowance rather than about who is to blame. The changes that actually arrive late are predictable — a capacity increase because the brief added a stretcher requirement, a wider door for accessibility, a switch between machine-room-less and a machine room, and the counterweight moving from the rear to the side.
The table below is the version worth pinning above a desk: which number, whose it is, and the drawing that stops it moving.
| Reservation | Fixed by | Stops being free when |
|---|---|---|
| Hoistway clear width and depth | Car size plus rail, counterweight, door and running clearances from the supplier's shaft layout | The core walls are set against the structural grid |
| Pit depth | Buffer stroke, bottom running clearance and refuge space under the adopted lift code | The lowest slab and its waterproofing are designed |
| Overhead | Car height, top running and refuge clearances, and the machine on a machine-room-less lift | The roof structure, parapet and plant screen line are set |
| Enclosure thickness and rating | Storeys connected, transverse pressure from stack and piston effect, and the wall system chosen | The core rectangle is dimensioned on the general arrangement |
| Controller and disconnect space | The supplier's cabinet plus the electrical working clearance in front of it | The lift lobby is planned and furnished |
| Escalator wellway length | Rise, incline angle and the flat step allowance at each end | The floor opening is cast |
| Escalator support pockets and reactions | The manufacturer's certified reaction schedule for the specific unit | The trimming steel or slab edge is detailed |
Reserve these before the package is tendered
Five reservations, each frozen by a different drawing, and the written assumption that keeps them from being value-engineered away. Settle them while the core is still lines rather than after the substructure is poured.
- Hoistway clear plan, to the finished inside face — Held plumb for the full rise at every level. Note which axis has slack, because the counterweight position can move the allowance between them.
- Pit depth, and the tanked box that forms it — Depth from the lift code and the model data; waterproofing, sump and pump route agreed with the drainage strategy before the raft is designed.
- Overhead to the underside of the structure — Re-check it every time the roof level, parapet or plant screen moves — this is the reservation that disappears without a change note.
- Controller, disconnect and rescue access — A slice of lobby wall plus the working rectangle in front of it, marked on the plan before anyone specifies furniture or a bench.
- Escalator wellway length and overall balustrade width — Run plus flat step allowance at both ends; the width is the balustrade dimension from the manufacturer, not the step width people quote.
- The tender assumption, written on the drawing — Model or standard used, counterweight position, enclosure type. Without it the reservation looks like padding to the first person costing the job.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.