Capacity, span, lift height, duty class and hoist type โ the five numbers that decide whether your crane is the right tool or an expensive mistake. Written for buyers who need a specification, not a sales pitch.
A single girder crane is the right choice for most light-to-medium lifting jobs up to 20 tons: it costs 20-30% less than a double girder crane of the same capacity, needs less headroom, and installs faster. But the savings disappear if you pick the wrong size. Capacity, span, lift height and duty class are the four numbers that determine both price and lifespan, and each one follows a simple rule: start from your heaviest regular load, measure your real building dimensions, and match the duty class to actual hours of use. This guide walks through each decision with typical ranges โ 1-20 tons capacity, 3-31.5 m span, 6-18 m lift height, A3-A5 duty classes โ and closes with a specification template you can send to any supplier for an accurate quote.
Capacity is where most buyers either overspend or under-spec. The temptation is to buy "a bit bigger in case we need it later." The reality: every ton of extra capacity adds steel, price, and a heavier runway โ and a crane that never lifts near its rating is still charged for its rating.
Start with the heaviest single item you move on a regular basis. Not the one-off job you did three years ago โ the regular one. Then apply the standard margin: sizing to at least 125% of that load covers the load test requirement and leaves room for fixtures, slings and spreader beams. A crane rated for 5 tons that routinely lifts 4.2-ton loads is working near its test limit; that is a duty-cycle problem waiting to happen.
| Capacity | Typical regular loads | Where it fits |
|---|---|---|
| 1 - 3 t | Molds, motors, crates up to 2.4 t | Maintenance bays, small workshops, labs |
| 5 t | Machinery parts, pallets, tooling to 4 t | Machine shops, assembly lines, warehouses |
| 10 t | Heavy tooling, pumps, subassemblies to 8 t | Fabrication shops, automotive parts, logistics |
| 16 - 20 t | Steel plates, containers, big castings to 16 t | Steel & metal fabrication, recycling yards |
One more thing worth saying: if your heaviest regular load sits above 16 tons, or you plan to lift heavy items daily for 8+ hours, a double girder crane is usually the better answer. Single girder cranes earn their keep in the 1-20 ton light-to-medium zone, and that is exactly where the price gap is widest in your favor.
Span is the distance between the runway rails โ the width your crane has to travel across. Lift height is the distance from the floor to the hook at its highest point. Both come straight from your building, so measure twice before you ask for quotes.
The rule of thumb I use with clients: pick the longest span that serves all your workstations, but keep the crane out of the last 15-20% of the bay width where you rarely work anyway. A longer span means a heavier girder and a higher price; a 19.5 m span costs noticeably more than a 13.5 m span at the same capacity, because the girder section is driven by deflection โ usually limited to span/700 or span/800 under rated load โ not just by strength.
| Building bay width | Typical crane span | Usable lift height |
|---|---|---|
| 10 - 12 m | 7.5 - 9 m | 6 - 9 m |
| 15 - 18 m | 13.5 - 16.5 m | 8 - 12 m |
| 21 - 24 m | 19.5 - 22.5 m | 10 - 15 m |
| 27 m + | 25 - 31.5 m (max) | 12 - 18 m |
On lift height: single girder cranes win here too. Because the hoist runs on the lower flange of a single beam, the crane keeps 30-40% more headroom than a double girder design at the same building height โ which is why low-headroom workshops are single girder territory. Just remember the hook at full lift still needs clearance for the hoist body and the top limit switch zone, so do not assume your 18 m building gives you 18 m of lift.
Duty class is the most ignored number on a crane spec sheet, and it is the one that decides how many years the crane lasts. The class is set by how many hours a day the crane actually works and how heavy the lifts are โ not by how impressive the machine looks.
Here is the honest version of the duty class table. Most buyers describe their operation as "medium duty," and most of them are wrong about it. Spend a week counting actual operating hours before you decide.
| Duty class | Typical use | Example operations |
|---|---|---|
| A3 (light) | Occasional, a few lifts per day | Maintenance bays, storage, tool rooms |
| A4 (medium) | Regular light work, 2-5 h/day | Machine loading, assembly feeding |
| A5 (heavy for single girder) | Continuous medium duty, 5-8 h/day | Fabrication lines, busy warehouses |
If your crane runs more than 8 hours a day with loads near its rating, stop reading โ that is A6+ territory and you need a double girder crane, not a bigger single girder. Choosing A3 when you run A5 duty is how cranes fail early; choosing A5 when you run A3 duty is how you pay 15-25% more than you needed to. The price difference between duty classes at the same capacity is real, and it compounds with the total cost of ownership over 10 years.
The hoist is the heart of the crane, and on a single girder crane it rides directly on the girder flange. The choice between wire rope and chain hoist comes down to three things: capacity, speed, and how many hours a day you run.
For a general-purpose workshop crane at 3-5 tons running a few hours a day, I would honestly take the chain hoist and spend the saved money on a better control system. For anything running a full shift, or above 5 tons, wire rope. This is one of those decisions where the cheaper option is often the correct one โ see our wire rope hoist guide for the full comparison.
Prices vary with capacity, span, duty class, hoist type and control package, but the ranges below are what CE-certified Chinese manufacturers are quoting in 2026 โ and they line up with our own order history.
| Configuration | Equipment price (FOB) | Typical installed total |
|---|---|---|
| 3 t, 9 m span, chain hoist | USD 4,200 - 7,500 | USD 7,000 - 12,000 |
| 5 t, 12 m span, wire rope | USD 8,000 - 15,000 | USD 13,000 - 22,000 |
| 10 t, 18 m span, wire rope | USD 18,000 - 32,000 | USD 28,000 - 48,000 |
| 20 t, 22.5 m span, A5 | USD 32,000 - 48,000 | USD 48,000 - 72,000 |
Two warnings on price. First, the installed total โ runway steel, installation labor, electrical work, commissioning โ typically adds 30-60% on top of the equipment price, and it is the part buyers forget. Second, the cheapest quote is usually the wrong one: a crane built to A3 components sold to you as "equivalent" to A5 will fail years early. Get the duty class in writing. For a full cost breakdown including maintenance and energy over the machine's life, our single girder crane cost & TCO guide covers it in detail.
If you have read this far, you already know the short version: up to 20 tons, light-to-medium duty, low headroom or tight budget โ single girder. Heavy duty, very wide spans, or continuous 8+ hour operation โ double girder. The crossover is not a fixed number; it is where your own duty class and span push the girder section past the point of economy.
As a rule of thumb, a single girder crane costs 20-30% less than a double girder crane at the same capacity, and its lighter deadweight means lighter runway steel and simpler foundations. For a 5-ton workshop crane the saving is a few thousand dollars; for a 20-ton unit it is substantial. But a double girder crane gives you better trolley stability at high speeds and a stronger structure for A6-A8 duty, which is why steel mills and heavy fabrication end up there. Our double girder crane guide walks through the other side of that decision.
The single biggest cause of wrong quotes โ and later, unhappy installations โ is a vague inquiry. "Need a 5 ton crane for our workshop" gets you five different proposals for five different machines. A complete spec fixes that. Send this checklist to every supplier and you can compare quotes like for like:
That last point matters more than it looks. A crane certified to CE and ISO 9001 with full documentation is a different product from an uncertified import, and the price difference is legitimate. If you are not sure which standard applies in your country, ask โ our engineers answer spec questions daily, and the single girder crane product page lists the standard parameters we build to.
Start from your heaviest regular single load, multiply by at least 1.25 to cover the load test margin, and round up to a standard capacity. 5 tons covers most workshop work, 10 tons most machine shops, 16-20 tons fabrication work. Never buy exactly at your load โ you lose the test margin and the crane fatigues faster.
Standard single girder cranes go up to 31.5 m, but above about 22 m the girder gets heavy and deflection control (span/700 or span/800) starts driving cost. The 7.5-19.5 m range is where single girder economics are best.
A3 for occasional use, A4 for 2-5 hours of regular light work, A5 for 5-8 hours of continuous medium duty. Above that, switch to a double girder crane โ do not oversize a single girder to fake higher duty.
Chain hoists for 1-5 tons, occasional work, precise positioning, and 15-25% lower hoist cost. Wire rope hoists for faster lifts, longer heights, higher duty, or anything above 5 tons.
Equipment prices run USD 4,200-48,000 FOB for 1-20 ton cranes with 7.5-19.5 m spans. A 5-ton, 12 m span unit is about USD 8,000-15,000; a 10-ton, 18 m span unit about USD 18,000-32,000. Installed totals add 30-60% for runway, installation and electrical work.
Send us your bay dimensions, heaviest load and operating hours โ our engineering team will confirm the right capacity, span and duty class before you commit to anything. Quotes include a full specification sheet you can compare with other suppliers.
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