There is no standard I-beam size for a hoist. The beam under a hoist, monorail or gantry is sized by an engineer for the rated capacity plus the hoist and trolley weight, multiplied by an impact factor (1.10 for pendant or hand-operated cranes and 1.25 for cab or radio-operated cranes under Table 4.1.5.11 of the 2024 Ontario Building Code), and then checked for bottom-flange bending under the trolley wheels, deflection, stability and the supports. A generic beam calculator checks only part of that, which is why a beam that "works on paper" can still be wrong for a hoist.
This guide explains what goes into sizing a hoist beam, the Ontario rules that apply, and what to send a fabricator once the design is done.
Monorail, gantry, jib or bridge crane: what you are sizing
"I-beam for a hoist" covers several different systems. The beam does a different job in each:
| System | What the beam does | What else is designed |
|---|---|---|
| Monorail | A fixed beam, hung from the building or from its own frame, with a trolley running along the bottom flange | Hangers, bracing, end stops, the building structure above |
| Gantry | A beam on legs, often on wheels, standing on the floor | Legs, bracing, the floor or slab under the wheels |
| Jib crane | A cantilevered arm on a column or wall bracket | The column, base plate, anchors and foundation, which take a large overturning moment |
| Bridge crane (single girder) | A girder spanning between two runway beams, carrying an underhung hoist | The runway beams, columns, brackets and building frame |
Portable gantries and jib cranes are often bought as manufactured products with a rated capacity. If you buy one, use it within its rating and the manufacturer's instructions. This article is about the case where a beam is being designed and fabricated for the job.
The loads: more than the number on the hoist
The rated capacity on a hoist is only the starting point. The engineer adds:
- The hoist and trolley weight, which can be significant on electric hoists.
- Impact. The 2024 OBC sets the impact load for cranes as the sum of the equipment weight and its maximum lifting capacity, multiplied by 1.10 for pendant or hand-operated cranes or 1.25 for cab or radio-operated cranes (Article 4.1.5.11).
- Lateral and longitudinal forces. Crane runways must resist a sideways force of at least 20% of the lifted load plus trolley weight, and a lengthwise force of at least 10% of the maximum wheel loads (Sentences 4.1.5.11.(3) and (5)). Those forces have to go somewhere, usually into bracing and the building frame.
- Load combinations with crane loads, which the OBC lists separately from ordinary load combinations (Table 4.1.3.2.-B).
- Fatigue, for beams that will see many lifts over their life. A hoist used all day in a production line is a different design problem from one used a few times a year.
Why a beam span calculator is not enough
A simple beam calculator checks bending and deflection for a load on top of the beam. A hoist beam fails in other ways too:
Bottom flange bending. The trolley wheels ride on the bottom flange, on either side of the web. Each wheel bends the flange tip down locally, like a short cantilever. A beam that is strong enough overall can still have flanges too thin for the wheel loads. Crane and monorail design standards include specific checks for this, and it often governs the choice of section.
Trolley fit. The trolley must suit the flange. Trolleys are made for a range of flange widths, and wheel treads are shaped for either sloped flanges (S-shapes, the traditional "American Standard" I-beam) or flat flanges (W-shapes). Check the trolley manufacturer's data before the beam is chosen. Our article on I-beams vs W-beams vs H-beams explains the difference between the shapes.
Deflection. A beam that sags too much makes the trolley roll toward mid-span and the load hard to control. Crane and monorail standards set their own deflection limits, and the engineer checks the beam against them.
Stability. A long, unbraced beam can twist sideways under load (lateral torsional buckling). Bracing, hanger spacing and the section's shape all affect this.
End stops and overhangs. Monorails need end stops that can take the trolley's impact. A monorail that cantilevers past its last support has its own deflection and strength checks.
The supports. The beam is only as good as what holds it up. Roof joists, trusses, purlins and existing beams in a building were usually designed for roof loads, not a moving point load with impact. Hanging a hoist beam from them without an engineer's review is a common and dangerous shortcut.
Choosing the section
Once the loads and checks are known, the engineer chooses between:
- S-shapes (for example S310x47, the S12x31.8): narrow, tapered flanges that suit many trolley wheels. They are common for monorails, though less widely stocked than W-shapes.
- W-shapes: wider, parallel flanges, much stiffer sideways for the weight, and easier to source. Many trolleys run on them.
- Built-up or capped sections for heavier runways, where a channel or plate is added to the top flange to resist sideways forces.
Depth is often set by deflection, flange thickness by wheel loads, and flange width by the trolley. The lightest beam that passes bending alone is rarely the right one. For W-shape dimensions, see our Canadian steel beam size chart.
Ontario rules that apply
The Building Code. A crane runway is a designated structure under Article 1.3.3.5 of Division A of the 2024 OBC, which makes it a building for the purposes of the Building Code Act, and Part 4 (structural design) applies to it (Article 1.3.3.2). Part 4 requires steel to be designed to CSA S16; see our overview of Canadian structural steel codes. Ask your building department what permit applies to your installation.
Industrial Establishments Regulation (Reg. 851). Under the Occupational Health and Safety Act, Reg. 851 defines a lifting device to include its rails and other supports. Section 51 requires a lifting device to be:
- constructed with the strength to ensure workers' safety;
- thoroughly examined by a competent person to determine its capability of handling its rated maximum load, before first use and then as often as the manufacturer recommends, and at least once a year, with a signed record kept;
- plainly marked so the operator can tell the maximum rated load.
Pre-start health and safety review. In a factory, section 7 of Reg. 851 requires a pre-start health and safety review by an engineer when a travelling, overhead, monorail, gantry or jib crane, or another lifting device, is suspended from or supported by a structure, unless that structure was originally designed for the lifting device being installed. The engineer's report must cover the structural adequacy of the structure.
Standards. Overhead travelling cranes are covered by CSA B167, and the Canadian Institute of Steel Construction publishes a design guide for crane-supporting steel structures that the OBC's appendix points to. Your engineer will confirm which apply.
Testing, marking and inspection
Before a new hoist beam goes into service, expect:
- Installation checked against the engineer's drawings: hangers, bracing, bolts, welds and end stops.
- A load test as the applicable standard and the engineer specify, done under controlled conditions with the area cleared.
- The examination and record required by Reg. 851, signed by a competent person.
- Capacity marking on the beam or hoist, visible to the operator.
After that, the annual examination continues for the life of the installation. Keep the drawings and records; the next inspector will want them.
What to send for fabrication
When the design is done, a fabricator needs:
- The engineer's drawings showing the section, length, grade, splices, hanger or bracket connections, end stops and any stiffeners
- Rated capacity and hoist details, for marking
- Finish requirements, such as primer or paint colour
- Site access and lifting constraints, if installation is included
We fabricate beams and connections to engineered drawings in a CWB certified shop, prepare shop drawings in-house for approval, and deliver across the GTA and Ontario. Engineering services are available for projects that need them; tell us about the hoist, the span and the building when you ask. For related structures, see our steel mezzanine guide.
Send your drawings or hoist details for a quote, or see the services we offer.
Frequently asked questions
What size I-beam do I need for a 1 tonne or 2 tonne hoist?
There is no single answer. The size depends on the span between supports, the hoist and trolley weight, the impact factor, how the trolley wheels load the bottom flange, deflection limits and how the beam is braced and supported. An engineer sizes it; capacity tables for bending alone can undersize a hoist beam.
Can I hang a hoist from a roof beam or truss?
Only if an engineer confirms the existing structure can carry it. Roof joists, trusses and beams are not normally designed for hoist loads, and in an Ontario factory, a lifting device supported by a structure not originally designed for it triggers a pre-start health and safety review by an engineer under Regulation 851.
Does a monorail or crane runway need a building permit in Ontario?
A crane runway is a designated structure under the 2024 Ontario Building Code, which makes it a building under the Building Code Act and brings it under Part 4 structural design. Check with your municipality's building department about the permit for your installation.
How often does a hoist beam have to be inspected in Ontario?
In industrial establishments, Regulation 851 requires a lifting device, which includes its rails and supports, to be thoroughly examined by a competent person before first use and then as often as the manufacturer recommends, and at least once a year, with a signed record kept.
