Steel Grating Load Tables (Computed, kPa & psf)
Uniform load capacity and span tables for welded steel bar grating at 19, 30 and 38 mm bar spacing — computed from beam theory in both metric (kPa) and imperial (psf). Use them to pick a bar size, then quote.
Each table gives the maximum uniform load a single bearing bar size carries over a clear span, simply supported, for a given bar spacing (pitch). Values are computed from beam theory for mild steel (allowable bending stress ≈165 MPa, E=200 GPa) and shown in kPa with psf beneath. Greyed values exceed an L/150 deflection guide — fine for many uses but confirm serviceability.
Load table — 19 mm pitch (≈ 3/4″ bar centres — fine, most common)
Max uniform load by bearing bar and clear span. Top number = kPa, below = psf.
| Bearing bar (mm) | 500 mm (0.50 m) | 750 mm (0.75 m) | 1000 mm (1.00 m) | 1250 mm (1.25 m) | 1500 mm (1.50 m) | 1750 mm (1.75 m) | 2000 mm (2.00 m) |
|---|---|---|---|---|---|---|---|
| 20×3 | 56 1161 psf | 25 516 psf | 14 290 psf | 9 186 psf | 6 129 psf | 5 95 psf | 3 73 psf |
| 25×3 | 87 1814 psf | 39 806 psf | 22 453 psf | 14 290 psf | 10 202 psf | 7 148 psf | 5 113 psf |
| 25×5 | 145 3023 psf | 64 1343 psf | 36 756 psf | 23 484 psf | 16 336 psf | 12 247 psf | 9 189 psf |
| 30×3 | 125 2612 psf | 56 1161 psf | 31 653 psf | 20 418 psf | 14 290 psf | 10 213 psf | 8 163 psf |
| 30×5 | 208 4353 psf | 93 1935 psf | 52 1088 psf | 33 696 psf | 23 484 psf | 17 355 psf | 13 272 psf |
| 32×5 | 237 4953 psf | 105 2201 psf | 59 1238 psf | 38 792 psf | 26 550 psf | 19 404 psf | 15 310 psf |
| 40×5 | 371 7738 psf | 165 3439 psf | 93 1935 psf | 59 1238 psf | 41 860 psf | 30 632 psf | 23 484 psf |
| 50×5 | 579 12091 psf | 257 5374 psf | 145 3023 psf | 93 1935 psf | 64 1343 psf | 47 987 psf | 36 756 psf |
| 60×5 | 834 17411 psf | 371 7738 psf | 208 4353 psf | 133 2786 psf | 93 1935 psf | 68 1421 psf | 52 1088 psf |
| 65×5 | 978 20434 psf | 435 9082 psf | 245 5109 psf | 157 3269 psf | 109 2270 psf | 80 1668 psf | 61 1277 psf |
| 75×6 | 1563 32647 psf | 695 14510 psf | 391 8162 psf | 250 5223 psf | 174 3627 psf | 128 2665 psf | 98 2040 psf |
| 100×6 | 2779 58038 psf | 1235 25795 psf | 695 14510 psf | 445 9286 psf | 309 6449 psf | 227 4738 psf | 174 3627 psf |
Load table — 30 mm pitch (medium, economical)
Max uniform load by bearing bar and clear span. Top number = kPa, below = psf.
| Bearing bar (mm) | 500 mm (0.50 m) | 750 mm (0.75 m) | 1000 mm (1.00 m) | 1250 mm (1.25 m) | 1500 mm (1.50 m) | 1750 mm (1.75 m) | 2000 mm (2.00 m) |
|---|---|---|---|---|---|---|---|
| 20×3 | 35 735 psf | 16 327 psf | 9 184 psf | 6 118 psf | 4 82 psf | 3 60 psf | 2 46 psf |
| 25×3 | 55 1149 psf | 24 511 psf | 14 287 psf | 9 184 psf | 6 128 psf | 4 94 psf | 3 72 psf |
| 25×5 | 92 1914 psf | 41 851 psf | 23 479 psf | 15 306 psf | 10 213 psf | 7 156 psf | 6 120 psf |
| 30×3 | 79 1654 psf | 35 735 psf | 20 414 psf | 13 265 psf | 9 184 psf | 6 135 psf | 5 103 psf |
| 30×5 | 132 2757 psf | 59 1225 psf | 33 689 psf | 21 441 psf | 15 306 psf | 11 225 psf | 8 172 psf |
| 32×5 | 150 3137 psf | 67 1394 psf | 38 784 psf | 24 502 psf | 17 349 psf | 12 256 psf | 9 196 psf |
| 40×5 | 235 4901 psf | 104 2178 psf | 59 1225 psf | 38 784 psf | 26 545 psf | 19 400 psf | 15 306 psf |
| 50×5 | 367 7658 psf | 163 3403 psf | 92 1914 psf | 59 1225 psf | 41 851 psf | 30 625 psf | 23 479 psf |
| 60×5 | 528 11027 psf | 235 4901 psf | 132 2757 psf | 84 1764 psf | 59 1225 psf | 43 900 psf | 33 689 psf |
| 65×5 | 620 12942 psf | 275 5752 psf | 155 3235 psf | 99 2071 psf | 69 1438 psf | 51 1056 psf | 39 809 psf |
| 75×6 | 990 20676 psf | 440 9189 psf | 248 5169 psf | 158 3308 psf | 110 2297 psf | 81 1688 psf | 62 1292 psf |
| 100×6 | 1760 36758 psf | 782 16337 psf | 440 9189 psf | 282 5881 psf | 196 4084 psf | 144 3001 psf | 110 2297 psf |
Load table — 38 mm pitch (≈ 1-1/2″ — coarse, lightest)
Max uniform load by bearing bar and clear span. Top number = kPa, below = psf.
| Bearing bar (mm) | 500 mm (0.50 m) | 750 mm (0.75 m) | 1000 mm (1.00 m) | 1250 mm (1.25 m) | 1500 mm (1.50 m) | 1750 mm (1.75 m) | 2000 mm (2.00 m) |
|---|---|---|---|---|---|---|---|
| 20×3 | 28 580 psf | 12 258 psf | 7 145 psf | 4 93 psf | 3 64 psf | 2 47 psf | 2 36 psf |
| 25×3 | 43 907 psf | 19 403 psf | 11 227 psf | 7 145 psf | 5 101 psf | 4 74 psf | 3 57 psf |
| 25×5 | 72 1511 psf | 32 672 psf | 18 378 psf | 12 242 psf | 8 168 psf | 6 123 psf | 5 94 psf |
| 30×3 | 63 1306 psf | 28 580 psf | 16 326 psf | 10 209 psf | 7 145 psf | 5 107 psf | 4 82 psf |
| 30×5 | 104 2176 psf | 46 967 psf | 26 544 psf | 17 348 psf | 12 242 psf | 9 178 psf | 7 136 psf |
| 32×5 | 119 2476 psf | 53 1101 psf | 30 619 psf | 19 396 psf | 13 275 psf | 10 202 psf | 7 155 psf |
| 40×5 | 185 3869 psf | 82 1720 psf | 46 967 psf | 30 619 psf | 21 430 psf | 15 316 psf | 12 242 psf |
| 50×5 | 289 6046 psf | 129 2687 psf | 72 1511 psf | 46 967 psf | 32 672 psf | 24 494 psf | 18 378 psf |
| 60×5 | 417 8706 psf | 185 3869 psf | 104 2176 psf | 67 1393 psf | 46 967 psf | 34 711 psf | 26 544 psf |
| 65×5 | 489 10217 psf | 217 4541 psf | 122 2554 psf | 78 1635 psf | 54 1135 psf | 40 834 psf | 31 639 psf |
| 75×6 | 782 16323 psf | 347 7255 psf | 195 4081 psf | 125 2612 psf | 87 1814 psf | 64 1333 psf | 49 1020 psf |
| 100×6 | 1389 29019 psf | 618 12897 psf | 347 7255 psf | 222 4643 psf | 154 3224 psf | 113 2369 psf | 87 1814 psf |
How to read a grating load table
- Find your clear span — the unsupported distance between the two beams the grating rests on (column).
- Find your design load — the uniform load (kPa or psf) your platform must carry, including a safety factor.
- Pick a bearing bar whose tabulated capacity at that span equals or exceeds your design load (row).
- Check deflection — for foot traffic a span/200 limit is common; greyed cells exceed L/150.
- Set the spacing — finer pitch (19 mm) for more bearing area and smaller objects; coarser (38 mm) saves weight and cost.
Load table FAQ
How is grating load capacity calculated?
Each bearing bar is treated as a simply supported beam. The allowable bending moment (section modulus × allowable stress, ≈165 MPa for mild steel) sets the maximum line load; dividing by the bar spacing gives the area load in kPa, and deflection is checked separately from beam stiffness.
What deflection is acceptable for steel grating?
A span/200 deflection limit is common for pedestrian grating and span/150–L/100 for less critical or non-walking areas. Always confirm against your governing standard (e.g. ANSI/NAAMM MBG 531) and project loading.
What does bar spacing or pitch mean?
Pitch is the centre-to-centre distance between bearing bars. 19 mm (about 3/4″) is the most common fine pitch; 30 and 38 mm are coarser, lighter and cheaper but carry less and pass larger objects.
Are these load values exact?
They are indicative, computed from beam theory for selection guidance. Final capacity must be confirmed against your governing standard, the actual steel grade, end fixity and loading on your RFQ.
Need a load-rated grating quote?
Send your span and design load — we recommend a bar size and quote factory-direct.
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