Electric Hoist I-Beam Selection Chart (0.5t-20t)
Key Takeaway: I-Beam selection for electric hoists must satisfy two conditions simultaneously: flange width (matching the trolley gauge) and bending strength (supporting the lifting capacity plus the hoist dead weight). Per standard 05G359-3: 0.5t → I16–I22a (lifting point spacing 4.2–9m), 1t → I16–I25a, 2t → I22a–I32a, 3t → I32a–I40a, 5t → I50a, 10t → I56a–I63a (all figures include hoist dead weight). For 16t/20t applications beyond the scope of this standard, a separate calculation per GB 50017 is required. Strength and deflection verification must follow selection.
Electric hoists travel along an I-Beam rail, and correct beam selection is directly tied to operational safety and equipment service life. Undersize the beam and it may deflect or deform under load — or worse, lead to a dropped load. Oversize it and you waste money, and the flange width may not match the trolley hoist. Drawing on years of experience in electric hoist manufacturing and installation, Kelude has compiled recommended I-Beam specifications for each hoist capacity, along with the verification logic behind each selection, so you can get it right the first time.
I-Beam Selection Chart by Hoist Capacity
The table below lists recommended I-Beam specifications for CD1/MD1 electric hoists at standard spans (6–12m). Final selection must be confirmed through strength and deflection verification based on span, lifting capacity, hoist dead weight, and dynamic load factor. Beam material is Q235B (≈S235JR) — the only grade available for hot-rolled I-Beams under the national standard.
Data source: Table 1 of 05G359-3 Track for Suspended Transport Equipment, applicable to electric hoists with rated lifting capacity ≤10t on simply supported straight rails.
| I-Beam Model | flange Width(mm) | cross-section Height(mm) | 05G359-3 Allowableconcentrated loadcharacteristic value [F] (k N) | |||||
|---|---|---|---|---|---|---|---|---|
| l=4.2m | l=4.8m | l=5.4m | l=6.0m | l=7.5m | l=9.0m | |||
| I16 | 88 | 160 | 12.24 | 10.30 | 7.94 | 6.22 | 3.52 | 1.97 |
| I18 | 94 | 180 | 15.13 | 13.87 | 11.86 | 9.37 | 5.45 | 3.22 |
| I20a | 100 | 200 | 18.05 | 16.65 | 15.44 | 13.61 | 8.08 | 4.96 |
| I22a | 110 | 220 | 23.06 | 20.16 | 18.79 | 17.56 | 11.92 | 7.51 |
| I25a | 116 | 250 | 27.73 | — | — | 22.57 | 18.10 | 11.68 |
| I28a | 122 | 280 | — | — | — | 26.27 | 21.51 | 16.80 |
| I32a | 130 | 320 | 33.20 | 31.49 | — | 33.20 | 29.19 | 23.18 |
| I36a | 136 | 360 | 39.03 | 37.17 | — | 39.03 | 34.40 | 28.93 |
| I40a | 142 | 400 | 41.54 | 39.72 | — | 41.54 | 37.24 | 33.61 |
| I45a | 150 | 450 | 53.92 | 48.69 | — | 53.92 | 45.84 | 41.65 |
| I50a | 158 | 500 | 65.79 | 63.15 | — | 65.79 | 58.70 | 54.15 |
| I56a | 166 | 560 | 110.3 | 71.76 | — | 110.3 | 68.01 | 62.42 |
| I63a | 176 | 630 | 116.2 | 115.8 | — | 116.2 | 115.1 | 72.69 |
Note: ①l = calculated crane rail span (i.e., distance between lifting points); ②[F] already includes the electric hoist dead weight + rated load; ③"—" indicates that the operating condition is not listed in the standard drawing (insufficient capacity or uneconomical); ④05G359-3 applies to electric hoists up to 10t; 16t/20t require separate calculations.
Standard Selection per 05G359-3 (CD1 Hoist)
| Hoist Capacity | Total Load Fk(k N) | Lifting point Spacing4.2m | Lifting point Spacing6.0m | Lifting point Spacing7.5m | Lifting point Spacing9.0m |
|---|---|---|---|---|---|
| 0.5t | 5.6 | I16 | I16 | I20a | I22a |
| 1t | 11.2 | I16 | I20a | I22a | I25a |
| 2t | 21.7 | I22a | I25a | I32a | I32a |
| 3t | 32.9 | I32a | I32a | I36a | I40a |
| 5t | 54.0 | I50a | I50a | I50a | I50a |
| 10t | 106.9 | I56a | I56a | I63a | Out of Range |
| 16t* | 170.7 | Over05G359-3Out of Range, Per GB 50017Calculated Separately | |||
| 20t* | 213.9 | Over05G359-3Out of Range, Per GB 50017Calculated Separately | |||
What Size I-Beam for a 0.5t Electric Hoist?
Per standard 05G359-3, I16–I22a is recommended. The total load for a 0.5t electric hoist is approximately 5.6 kN (including dead weight). With a lifting point spacing of 4.2 m, an I16 beam is sufficient ([F]=12.24 kN); at 6.0 m, I16 also works ([F]=6.22 kN); at 7.5 m, upgrade to I20a ([F]=8.08 kN); and at 9.0 m, I22a is required ([F]=7.51 kN). The flange width of 88–110 mm accommodates the trolley hoist. The I16 is the minimum section size. Beam material is Q235B, and an end stop must be installed at the rail end.
What Size I-Beam for a 1t Electric Hoist?
Per standard 05G359-3, I20a–I25a is recommended. The total load for a 1t electric hoist is approximately 11.2 kN (including dead weight). With a lifting point spacing of 4.2 m, an I16 beam is adequate ([F]=12.24 kN > 11.2 kN); at 6.0 m, I20a is required ([F]=13.61 kN); at 7.5 m, I22a is required ([F]=11.92 kN); and at 9.0 m, I25a is required ([F]=11.68 kN). Flange width: 100–116 mm.
What Size I-Beam for a 2t Electric Hoist?
Per standard 05G359-3, I22a–I32a is recommended. The total load for a 2t electric hoist is approximately 21.7 kN (including dead weight). With a lifting point spacing of 4.2 m, I22a is adequate ([F]=23.06 kN); at 6.0 m, I25a is adequate ([F]=22.57 kN); at 7.5 m, I32a is required ([F]=29.19 kN); and at 9.0 m, I32a is required ([F]=23.18 kN). Flange width: 110–130 mm.
What Size I-Beam for a 3t Electric Hoist?
Per standard 05G359-3, I32a–I40a is recommended. The total load for a 3t electric hoist is approximately 32.9 kN (including dead weight). With a lifting point spacing of 4.2 m, I32a is adequate ([F]=33.20 kN); at 6.0 m, I32a is adequate ([F]=33.20 kN); at 7.5 m, I36a is required ([F]=34.40 kN); and at 9.0 m, I40a is required ([F]=33.61 kN). A 3t hoist falls within the threshold for special equipment classification; rail installation must be performed by a qualified contractor.
What Size I-Beam for a 5t Electric Hoist?
Per standard 05G359-3, I50a is recommended. The total load for a 5t electric hoist is approximately 54.0 kN (including dead weight). With a lifting point spacing of 4.2 m, I50a is adequate ([F]=65.79 kN); at 6.0 m, I50a is adequate ([F]=65.79 kN); at 7.5 m, I50a is adequate ([F]=58.70 kN); and at 9.0 m, I50a is adequate ([F]=54.15 kN). The I50a has a flange width of 158 mm and a section height of 500 mm — verify that the trolley gauge matches these dimensions.
What Size I-Beam for a 10t Electric Hoist?
Per standard 05G359-3, I56a–I63a is recommended. The total load for a 10t electric hoist is approximately 106.9 kN (including dead weight). With a lifting point spacing of 4.2 m, I56a is adequate ([F]=110.3 kN); at 6.0 m, I56a is adequate ([F]=110.3 kN); at 7.5 m, I63a is required ([F]=115.1 kN); at 9.0 m, the span exceeds the scope of the standard chart.
What Size I-Beam for 16t/20t Electric Hoists?
Beyond the scope of 05G359-3 — individual calculation required. The total load for a 16t hoist is approximately 170.7 kN; for a 20t hoist, approximately 213.7 kN. Recommended solutions: ① Add additional lifting points to reduce the spacing to 3–4 m; ② Use a welded built-up I-section; ③ Or select an H-Beam with independent verification. The rail design must be carried out by an engineer qualified in steel structure design, calculated per GB 50017-2017.
I-Beam Selection & Verification Method
I-Beam selection cannot rely on a capacity comparison table alone — a full mechanical verification is required. The three core indicators to check are bending strength, shear stress, and deflection.
Verification Formulas
Maximum bending moment: Mmax = μ × (Q + G0) × L / 4 (concentrated load, simply supported beam; μ=1.05 is the dynamic coefficient per GB 50017-2017)
Bending stress: σ = Mmax / Wx ≤ f (hot-rolled I-Beams are available in Q235B only, f=215MPa; Q355B is used for welded built-up sections)
Mid-span deflection: fmax = (Q + G0) × L³ / (48 × E × I) ≤ L/600 (electric hoists under light/medium duty; manual hoists use L/400)
Where: Q = rated lifting capacity (N), G₀ = hoist and trolley dead weight (N), L = span (mm), Wx = section modulus (mm³), E = Elastic Modulus (2.06×10⁵MPa), I = moment of inertia (mm⁴)
Example: 5t electric hoist (dead weight 500 kg, total load 5.5t ≈ 53900 N, dynamic coefficient μ=1.05), lifting point spacing per 05G359-3 taken as 4.2 m (4200 mm), using an I50a I-Beam (Wx=1860×10³mm³, I=46500×10⁴mm⁴). Calculation yields Mmax=1.05×53900×4200/4=59.4×10⁶N·mm, σ=59.4×10⁶/1860×10³=31.9MPa ≤ 215MPa. Deflection f=1.05×53900×4200³/(48×2.06×10⁵×46500×10⁴)=0.46mm, L/600=7.0mm — deflection passes. Note: the above formula is a simplified single-point load model; in practice, an electric hoist travels on two wheels, so a two-wheel load model or direct reference to the [F] values in Table 1 of 05G359-3 is recommended for precise verification.
Important Notes
• The recommended specifications above are reference values for standard CD1/MD1 electric hoists — always verify against the hoist installation drawings before selection
• Hanger rod spacing refers to the distance between two adjacent hanger rods; the total rail length can be extended by adding more hanger rods
• Permissible deviations for crane rail installation: straightness ≤1.5mm/m, levelness ≤L/1000, gauge deviation ±3mm
• I-beam joints must be kept clear of the mid-span region; weld seams require 100% ultrasonic flaw detection
• For suspended rails, verify both hanger rod strength and roof structure load-bearing capacity
• Rail installation involving special equipment (≥3t and height ≥2m) must be carried out by a qualified contractor
Frequently Asked Questions
Q: Is Q355B available for I-beams?
A: Hot-rolled I-beams (GB/T 706-2016) are only available in Q235B, with a yield strength of ≥235MPa and a design bending strength of f=215MPa. If the calculated stress exceeds 215MPa, you must upgrade to a larger I-beam section rather than switch materials. Q355B is used for welded built-up sections or H-beams.
Q: What if the I-beam span is insufficient?
A: When the required span exceeds the scope of application, consider: ① upgrading to a larger I-beam section; ② using a welded built-up section instead; ③ reducing hanger rod spacing to add support points; ④ adding a column support at mid-span. Options ③ and ④ require re-evaluating the factory building structure's load-bearing capacity.
Q: Can I-beams and H-beams be used interchangeably?
A: Direct interchange is not recommended. I-beam flanges have a taper (1:6 to 1:10), and the electric hoist wheel tread is designed to match this taper. Replacing with an H-beam would result in line contact between the wheel and flange, accelerating wheel wear and causing unstable operation. I-beams remain the preferred choice.
Q: What if hanger rod spacing exceeds 9m?
A: Standard drawing 05G359-3 covers spans up to 9.0m. Beyond that, consider: ① adding intermediate hanger rods at mid-span to reduce spacing; ② using welded built-up section beams instead of hot-rolled I-beams; ③ opting for a dual-rail suspension layout. Option ① is the most cost-effective but requires verifying the roof structure's load-bearing capacity.
