Choosing the Right Capacity for Your Lift

Start with the heaviest load you will ever lift, add the weight of every piece of rigging hardware between the crane hook and the load, then add 20-30% margin. That total is the rated capacity you need. Sizing down to save purchase cost is the single most expensive mistake a gantry crane buyer can make — you pay for the undersizing for the life of the equipment, either by renting around the limitation or by replacing the crane prematurely.

This guide walks through how to calculate the right capacity, which capacity tier fits which typical applications, and the common mistakes that turn a good crane into the wrong crane.

The quick answer

Four-step sizing:

Identify your heaviest realistic load. Not your typical load — the heaviest single item you might reasonably need to lift over the life of the equipment.
Add rigging hardware weight. Spreader beams, chains, slings, shackles, and any below-the-hook attachment all count against rated capacity. Include every piece.
Add a 20-30% margin. Cover dynamic loading during lifts, future applications you haven’t planned for, and a safety buffer.
Size up, never down. If the total lands between two standard capacity tiers, pick the higher tier. The incremental cost is small; the cost of being undersized compounds over years.

Portable aluminum gantry capacities available from eme:

Capacity	Metric	Model
1,100 lb	500 kg	1100R
2,200 lb	1 metric ton	2200R
4,400 lb	2 metric tons	4400R
6,600 lb	3 metric tons	6600R
11,000 lb	5 metric tons	11000R
22,000 lb	10 metric tons	22000R

Rated capacity is not the same as load weight

This is the single most misunderstood concept in crane sizing. A “5-ton gantry crane” is not rated to lift 10,000 lb of payload. It is rated to handle 10,000 lb of total load at the hook — which includes not just the thing you’re lifting but every piece of hardware between the hook and that thing.

What counts against rated capacity

Every one of these comes out of the budget:

The load itself (the pump, the motor, the switchgear, the engine, whatever you’re lifting)
Rigging hardware weight: spreader beams, lifting beams, shackles, hooks, eye bolts
Chains, slings, or wire rope used between the rigging and the load
Custom attachments: magnets, clamps, grapples, pump lifters
Any adapters or extenders used to position the hook over the load

A Grip Eye attachment, a spreader beam, or a chain drop can each add 50-300 lb or more to the hook load. On a 4,400 lb rated gantry, 300 lb of rigging hardware is 7% of capacity — not trivial.

Dynamic loading

A crane doesn’t just hold a static weight. The moment you start lifting, the load has dynamic behavior:

Acceleration at lift-off (hoist pulling from static)
Swinging if the load isn’t perfectly centered
Side loading from slight misalignment
Impact loading from rough hoist operation or interrupted lifts

BTH-1 Category B uses a 3:1 design factor on yield (a static-strength margin). The dynamic effects of hoisting are handled separately, through the Hoist Load Factor (HLF) per ASME BTH-1 §3-1.2.1. That doesn’t mean you should size right at rated capacity for your static load — that consumes the design margin. The 20-30% margin on top of load + rigging keeps dynamic effects well within the design envelope.

Capacity-by-application: which tier fits which work

What follows is directional. Your specific application may fit differently. Use this as a starting point for scoping, not as a purchase guarantee.

1,100 lb (500 kg) — 1100R series

Light assembly, small component handling, and low-capacity maintenance work.

Small submersible pumps (sump pumps, light lift stations)
Electric motors up to frame size ~200
Valves and fittings in commercial mechanical rooms
Bench-assembly work, small machining fixtures
Light HVAC component handling in residential or small commercial buildings

The 1100R is the entry-capacity gantry. Popular for small-shop maintenance operations, HVAC service trucks, and light commercial mechanical contracting where most lifts are under 500 kg.

2,200 lb (1 ton) — 2200R series

Standard mid-range industrial maintenance capacity. The most common “general purpose” size for mechanical contracting and facility maintenance.

Mid-sized submersible pumps
Most commercial HVAC compressor units
Standard electric motors up to frame size ~300
Mechanical-room valves, pumps, heat exchangers
Small-to-medium industrial machinery service
Light rigging and equipment-moving work

If you are not sure what capacity you need and your work is general industrial or mechanical maintenance, 2,200 lb is a reasonable default starting point. Many maintenance shops specify a 2200R as their primary gantry and rent heavier capacities for occasional bigger lifts.

4,400 lb (2 tons) — 4400R series

Heavy maintenance and mid-heavy mechanical install. Popular for mechanical contracting, industrial maintenance, and municipal wastewater work.

Wastewater plant pumps and valves (most common wastewater application)
Commercial HVAC chillers and large compressors
Medium industrial motors and gearboxes
Mid-range rigging work
Data-center UPS batteries and smaller switchgear

The 4400R is the single most popular eme gantry capacity — it covers the vast majority of industrial-maintenance lifts without forcing a jump to heavier hardware.

6,600 lb (3 tons) — 6600R series

Mid-heavy industrial work. For buyers who occasionally lift heavier than the 2-ton range and want capacity headroom.

Heavier wastewater pumps (deeper wells, larger impeller assemblies)
Mid-sized industrial machinery sections
Mechanical-install work with heavy components
Rigging for mid-sized equipment moves
Some data-center equipment installation

If your heaviest lifts routinely exceed 4,400 lb, step to the 6600R. Rigging weight compounds quickly, and 6,600 lb of rated capacity gives real headroom for heavier applications without the jump to 11,000 lb.

11,000 lb (5 tons) — 11000R series

Heavy industrial and specialized rigging territory. Popular with rigging companies, heavy industrial maintenance, and project-based contractors handling substantial equipment.

Data-center switchgear and transformer lifts
Industrial machinery installation and relocation
Heavy wastewater and water-treatment equipment
Manufacturing-line component handling
Specialized rigging for equipment moves and plant relocations

The 11000R starts to enter “specialized rigging” territory. Buyers at this capacity often appreciate the aluminum advantage more than lower-capacity buyers — at 11,000 lb rated, a steel gantry becomes significantly heavier and typically requires a crane truck for setup; the aluminum version can be erected with a standard forklift.

22,000 lb (10 tons) — 22000R series

Specialized rigging, heavy equipment moves, and high-capacity project work. The top of the portable aluminum gantry range.

Large transformers and switchgear
Heavy industrial machinery (engines, turbines, large gearboxes)
Plant relocations and equipment repositioning
Specialized rigging for commercial, industrial, and power applications
High-capacity mechanical install on large-scale projects

The 22000R is built for rigging companies and specialized industrial operations where lifts in the 10-20,000 lb range are routine. Above 22,000 lb, portable aluminum is out of scope and the application shifts to fixed steel infrastructure or specialized heavy-lift equipment.

Common capacity mistakes

Mistake 1: sizing for your typical load, not your heaviest load

A shop that lifts 2,000 lb loads 90% of the time but occasionally needs to pull an 8,000 lb pump will outgrow a 4,400 lb gantry in the first year. Every time the heavy lift comes around, the operator rents a larger crane, pays the rental cost, deals with scheduling lead time, and loses a day of productivity. Over the life of the undersized gantry, those rental events accumulate — and usually cost more than the capacity upgrade would have.

Size for your heaviest realistic lift, not your typical lift.

Mistake 2: ignoring rigging hardware weight

Spreader beams, chains, shackles, and attachments all count against rated capacity. A 300 lb spreader beam on a 4,400 lb rated gantry leaves only 4,100 lb for the load. On smaller gantries, rigging can consume 10% or more of rated capacity.

Weigh or estimate all rigging hardware and include it in your sizing calculation.

Mistake 3: sizing exactly at load weight

A 2,000 lb payload with 200 lb of rigging = 2,200 lb at the hook. On a 2,200 lb rated gantry, the crane is operating at 100% of capacity with zero margin for dynamic loading, future growth, or the occasional heavier lift. This is technically within rating but practically risky.

Leave 20-30% margin above load + rigging. A 2,200 lb hook load wants a 2,750-2,860 lb rated crane, which is why the 4400R is a more appropriate match for a 2,000 lb payload than a 2200R once rigging and margin are counted.

Mistake 4: under-specifying because of purchase cost

Moving from a 4400R to a 6600R is a modest purchase premium. Working around an undersized gantry for the next 15-20 years — rental costs, scheduling delays, lost productivity, or eventual replacement — costs substantially more.

If the total lands between two tiers, pick the higher one. The cost delta is almost always less than the operational cost of being undersized.

Mistake 5: over-specifying a one-time lift

The opposite failure. A contractor who occasionally needs a 15,000 lb lift doesn’t necessarily need to own a 22000R. If the heavy lift is rare, renting for those specific events may be more economical than owning a larger-than-needed gantry.

Match capacity to sustained use patterns. Use rental for occasional outliers rather than sizing the permanent fleet for the once-a-year edge case.

When one capacity isn’t enough

Many operations use more than one gantry capacity. A mechanical contractor might own a 2200R for daily work and rent an 11000R for occasional heavy lifts. A large maintenance facility might own both a 4400R and an 11000R in the same shop.

This is a sensible operational pattern. It’s also where eme’s modular portfolio earns its keep: top beams and trolleys interchange across capacity ranges within the product family, so an operation running multiple eme gantries trains operators once, stocks shared spare parts, and moves components between units as maintenance needs change. For multi-capacity fleets, the modular design reduces the complexity of owning more than one gantry.

Frequently asked questions

What capacity gantry crane do I need?

Identify your heaviest realistic load, add the weight of all rigging hardware (spreader beams, chains, slings, shackles, attachments), add 20-30% margin for dynamic loading and future applications, and select the next standard capacity tier above that total. Do not size down to save on purchase cost — the operational cost of being undersized always compounds.

What’s the difference between rated capacity and working load?

Rated capacity is the maximum total hook load the crane is certified to handle, including the load and all rigging hardware. “Working load” is a less precise term sometimes used to mean the weight of the load alone (without rigging). Always use rated capacity for sizing decisions and always count rigging hardware against it.

How much weight does rigging hardware add?

It varies widely. A simple chain sling can add 50-100 lb. A typical aluminum spreader beam adds 100-400 lb depending on length and capacity. A Grip Eye pump attachment adds 20-50 lb. Specialized rigging for heavy loads can add several hundred pounds. Weigh or estimate every piece going between the hook and the load, and count all of it.

Should I size for my typical lift or my heaviest lift?

Your heaviest lift. Typical-load sizing is the most common undersizing mistake. If you will ever lift a heavier load over the life of the crane, size for that heavier load plus margin. The incremental cost of capacity is almost always less than the operational cost of being undersized.

What’s the most popular eme gantry capacity?

The 4400R (4,400 lb / 2 metric ton) is the most popular capacity across industrial maintenance, mechanical contracting, and wastewater applications. It covers the majority of typical industrial lifts and leaves meaningful margin for rigging hardware on most payloads.

Do eme gantries come in metric or imperial ratings?

Both. eme capacities are rated in both imperial (1,100 lb, 2,200 lb, 4,400 lb, 6,600 lb, 11,000 lb, 22,000 lb) and metric (500 kg, 1 t, 2 t, 3 t, 5 t, 10 t). The model numbers (1100R, 2200R, etc.) reflect the imperial rating in pounds.

Is it safe to operate a gantry at 100% of rated capacity?

Technically yes — the rated capacity is the certified maximum. Practically, operating consistently at 100% of rated capacity consumes the margin the design factor provides for dynamic loading and unexpected conditions. The recommended practice is to size the crane so routine lifts operate at 70-80% of rated capacity, with rated capacity reserved for the heaviest occasional lifts.

How do I verify the rated capacity of an eme gantry?

Every eme gantry ships with an engineer-stamped drawing and a Certificate of Test showing the rated capacity and the 125% proof-load test result. eme proof-load tests every unit to 125% of rated capacity during production, so the pre-service proof test is already done and documented when the gantry arrives. Almost all eme gantry and davit designs are additionally qualified by a 150% proof-load test, documented on the engineer-stamped drawing. The rated capacity is also permanently marked on the crane itself per ASME B30.17 requirements. If you lose the documentation, eme can reissue it with the serial number.

What if I need more than 22,000 lb capacity?

Above 22,000 lb (10 metric tons), portable aluminum gantry cranes are generally out of scope. For higher-capacity applications, consider fixed-facility overhead bridge cranes (typically steel) or specialized heavy-lift equipment. eme’s product line ends at 22,000 lb for portable aluminum.

How do I plan for growing capacity needs?

If your operation may expand into heavier lifts within the next 3-5 years, size the gantry for that anticipated future need rather than current need. Gantry cranes have 20+ year service lives. Buying a higher-capacity unit today avoids either replacing the gantry prematurely or renting around the undersizing for years. For uncertain future growth, rental bridges the gap — use rental for lifts that exceed your owned capacity until the pattern justifies a capacity upgrade.

Explore eme’s gantry line by capacity

Every eme aluminum gantry is a top-running single-girder box-beam crane, designed to ASME B30.17. Every structural weld is produced under CSA W47.2 certification by qualified aluminum welders. Every unit is load-tested to 125% of rated capacity with a load cell and ships with a Certificate of Test and engineer-stamped drawing.

1100R — 1,100 lb / 500 kg — light maintenance and assembly
2200R — 2,200 lb / 1 ton — standard industrial maintenance
4400R — 4,400 lb / 2 tons — most popular, general industrial work
6600R — 6,600 lb / 3 tons — mid-heavy industrial and mechanical install
11000R — 11,000 lb / 5 tons — heavy industrial and rigging
22000R — 22,000 lb / 10 tons — specialized rigging and heavy equipment moves

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Find an eme near your jobsite →

How to Choose a Portable Gantry Crane — full buyer’s guide across all decision factors
Aluminum vs. Steel Gantry Cranes — material choice in depth
Gantry Crane vs. Davit Crane: When to Use Each — choosing the right crane type
What is ASME B30.17? — the safety standard applicable to gantry cranes
What is ASME BTH-1? — design standard for rigging hardware

Last reviewed April 2026. Content reviewed by eme engineering for technical accuracy. For application-specific sizing questions, contact eme: 1-888-679-5283.