Single girder cranes span the 125 kg–10,000 kg bracket on the low end of overhead lifting, with the under-suspended TAWI type listed at 125 kg–1,500 kg max load and Stahl's suspension-crane family extending to 10,000 kg for low-headroom halls [S1][S2].
Selecting one is a spec-first exercise, not a price exercise: the wrong duty class, hoist, or end-carriage type will dwarf any saving on the girder. This article lines the decision up against the variables that actually move cost, safety class, and floor-space — capacity, span, headroom, duty, suspension vs top-running, hoist, and FEM/ISO design code — with reference to the single girder crane baseline.
Step 1: Anchor the spec to a lifting duty class, not a marketing brochure
The first number to lock is the maximum load in kilograms, then the number of full-load cycles per shift. Crane builders classify duty under FEM 9.341 / ISO 4301 — for a single girder the working classes most often specified run from FEM 1Bm (light, infrequent) to FEM 2m / 3m (light-to-medium workshop use); raising the duty class typically forces a heavier hoist motor, a bigger hoist reeving, and a more expensive girder cross-section even when the load rating stays identical [S2].
Specifying a 2-ton single girder in FEM 1Bm and the same 2-ton unit in FEM 3m is not a 5–10% price step — it is usually a different hoist, gearbox, and structural sizing, and the published 10,000 kg upper limit on Stahl's single-girder suspension crane assumes a particular FEM class that the buyer must confirm rather than assume [S2]. When the application is pallet-to-machine-cell work in a single-shift workshop, FEM 2m is the common starting point; continuous-shift stamping cells or three-shift foundry cells step up to FEM 3m–4m with a documented cycle count.
Step 2: Match the configuration to the building — top-running vs under-suspended (suspended) single girder
There are two mechanically different single-girder products, and they are not interchangeable: the top-running single girder sits on rails fixed to the building columns or free-standing columns, with the trolley riding on top of the bridge; the under-suspended (suspended) single girder hangs from the lower flange of runway beams fixed to the roof structure, freeing the floor of columns and giving a "rectangular work space" characteristic that makes it the natural choice for small or low halls up to 10,000 kg per Stahl's published specification [S1][S2].
Choose the under-suspended version when the building offers little vertical room (headroom typically under 4–5 m effective), when you want zero floor obstructions under the runway, or when capacity stays at or below the 1,500 kg TAWI ceiling / 10,000 kg Stahl ceiling [S1][S2]. Choose the top-running single girder when span exceeds roughly 18–20 m, when duty is heavier than FEM 3m, or when you need higher travel speeds for the bridge (top-running end carriages tolerate higher bridge speeds and larger wheels). The under-suspended format pays a headroom penalty: the hoist has to sit inside or below the girder depth, so the lift height available on a 5 m clear hall may be only 2.5–3.0 m to hook, not the 3.5–4.0 m a top-running single girder can give on the same building.
Step 3: Lock the span, runway length, and hook lift — three numbers that drive girder sizing
Three numbers dominate the steel tonnage and the price: span (centre-to-centre of runway rails in metres), runway length (total crane travel distance in metres), and hook lift (floor to highest hook position in metres). Single-girder spans in production-hall work commonly run 5–20 m for under-suspended units and up to 25–30 m for top-running units; doubling the span at constant load roughly doubles the required girder section modulus, so a 16 m span is not twice the steel of an 8 m span — it is closer to 2.5–3× when deflection (typically L/500 to L/750 for crane girders) and dynamic amplification are factored in [S1][S2].
Hook lift drives hoist drum length and reeving, and a 6 m lift is a very different hoist from a 12 m lift at the same capacity. Buyers who under-spec hook lift by 1–2 m are the most common source of "we cannot reach the top tray" complaints after installation. Runway length drives the number of rail joints, the conductor bar or festoon length, and the number of buffer stops — a 30 m runway is a meaningfully different electrical package from an 80 m runway at the same crane.
Step 4: Pick the hoist — electric wire-rope vs electric chain vs pneumatic
Electric wire-rope hoists dominate above 2,000 kg and in heavy-duty single-girder work, with FEM classifications matched to the crane duty class and standard reeving of 2/1, 4/1, or 4/2 depending on capacity and drum diameter. Electric chain hoists are the typical fit on light-duty under-suspended single girders in the 125 kg–1,500 kg range, where the lower headroom requirement and quieter operation are valued [S1]. Pneumatic hoists enter the picture in classified (ATEX/IECEx zone 1 or 2) areas where an electric spark risk is unacceptable — but compressed-air supply, lubrication, and exhaust handling add operating cost that an electric hoist does not have.
A practical comparison the engineer can use during the RFQ:
- Electric chain hoist: lowest headroom, best for 125 kg–2,000 kg, light-to-medium duty, simple controls, lower purchase cost.
- Electric wire-rope hoist: required above ~2,000 kg or medium/heavy duty, higher hook speeds available (typically 4/1 m/min or 8/1 m/min), larger drum, longer hook life under full-load cycling.
- Pneumatic hoist: needed for ATEX/IECEx zone classified areas, intrinsically safe on spark risk, higher air-consumption operating cost, limited speed control granularity.
Step 5: Power supply, control, and the safety-class decisions that quietly inflate cost
Power delivery to the crane is festoon (flat or round cable in loops) or conductor bar (e.g. insulated enclosed bar systems). Festoon suits shorter runway lengths and slower bridges; conductor bar is the standard fit on runway lengths above ~40 m or where high cycle rates would fatigue a festoon cable. For control, pendant push-button remains the default on light-duty single girders; radio remote adds cost but is now near-universal in any application with more than one operator per shift, and is essentially mandatory for precision lifting where the operator must stand clear of the load. Variable-frequency drives (VFD) on hoist and travel are a separate decision — they are not standard on entry-level units, but they should be specified for any installation where the load swings on start/stop, where the operator is inexperienced, or where creep speeds below 1 m/min are needed for load engagement. [S1]
Safety class to confirm in writing before purchase: overload limiter (mandatory under most national crane standards derived from FEM 9.341 / ISO 4301), upper/lower hoist limits, travel limit switches on bridge and trolley, anti-collision where two cranes share a runway, and IP rating of the electrical panel (IP54 minimum for indoor industrial halls, IP55 where wash-down is present). The way these line up against the same selection drivers used to size a gantry crane is similar in principle but the building-anchored single girder has the higher utilisation rate, so the safety package should not be downgraded relative to a wheel-mounted gantry of equal capacity.
Step 6: Standards, documentation, and the sourcing signals that prevent a bad buy
The minimum standards envelope a single girder crane should be quoted against: FEM 9.341 (design rules), ISO 4301 (classification), EN 15011 / ASME B30 series for the structural and mechanical rules, and ATEX 2014/34/EU plus IEC 60079 series for any classified-area duty. A quotation that does not name the FEM class, the hoist FEM class, the reeving, and the design standard in writing is not a complete quotation — it is a price for "a single girder crane" of unspecified duty, and the delivery will reflect that. [S2]
Trackable signals for the 2026 sourcing window: confirm whether the OEM or system integrator publishes a test certificate per EN 10204 3.1 for the girder plate, whether the hoist carries a separate FEM/ISO plate that matches the crane FEM class, and whether the warranty terms distinguish structural (typically 24 months) from wear items (brake discs, contactors, festoon cables) — Indian fabricators such as Monotech Engineers list single girder EOT cranes on go4worldbusiness with a "Not Specified" MOQ and ask-for-price model, which means the buyer's job is to put the FEM class and reeving in the inquiry, not the seller [S3]. Where the application is taller, higher-span, or heavier than single-girder territory, the same crawler crane and mobile crane reference frames used for outdoor lift planning become the fallback — single-girder overhead is the right answer only when the building exists.
Closing signal worth tracking: between now and the next sourcing review, capture the FEM 9.341 classification of any incumbent crane on the floor and the realised cycles per shift — that pair of numbers, not the nameplate capacity, is what should drive the next RFQ, because buying to duty class instead of to nameplate tonnage is the single most reliable way to keep a single girder crane earning its keep for its full design life. For buyers scaling up to outdoor yard work or longer spans, the gantry crane buying guide and the gantry crane price & cost guide cover the configuration shifts you will hit once span exceeds single-girder overhead range. For pallet-handling interfaces below the crane, the platform trolley vs pallet stacker cut is the next downstream decision.