Toolbox / Grating weight and span
Electro-Forged Steel Grating Weight & Span Load Calculator
Enter the bearing bar, cross bar, pitch, material and finish to get the weight per m² and per panel, then check a clear span against a load, find the longest span or the heaviest load a bar can take, or let the tool pick the lightest bar that passes. The calculation reproduces published McNichols, Lichtgitter and Lang+Fulton tables; every stored number is cited. Everything runs in your browser; there is no sign-up.
1. Specification
Bearing bars
Cross bars
Surface
Material and finish
fy 235 MPa verified · E 210,000 MPa single source · density 7,850 kg/m³ single source · γM 1 single source
Zinc assumed: 505 g/m² of surface (steel over 3 mm to 6 mm, minimum mean). Sources are listed below.
Section factor (slot reduction)
Dimensions in mm. Cross bars lie flush with the top of the bearing bars. The two views have different scales.
2. Weight
Panel length runs along the bearing bars (the span direction); width runs across them.
| Bearing bars | 39.25 | kg/m² |
|---|---|---|
| Cross bars | 2.83 | kg/m² |
| Zinc (minimum mean coating) | 1.3 | kg/m² |
| Bearing bars in the panel | 34 bars | 40 kg |
| Cross bars in the panel | 10 bars | 2.8 kg |
| Zinc on the panel | 1.3 kg |
Published maker weights for this spec
| Maker table | Published | This tool | Difference |
|---|---|---|---|
| Lang+Fulton brochure 30x5 at 30 x 100, twisted 6 mm, serratedgalvanized kg/m2 as printed (nominal); cross bar stated; printed for a SERRATED bar, which weighs less than a plain one | 42.1 kg/m² | 43.38 kg/m² | +3 % |
The brochure prints the cross bar, so the gap is the tool's steel mass without forging metal, with the standard's minimum zinc (real coatings are heavier); across 81 brochure rows the tool is on average 3 % light, never more than 7 % off for bare steel. The printed row is for a serrated bar, which weighs about 7 % less than a plain one in the 30 × 3 pair the brochure prints both ways. Serration is not deducted from the calculated weight.
3. Span and load check
Allowable stress (US practice, NAAMM-style load tables). The bearing bar is a simply supported beam over the clear span; bending stress is held to an allowable value, as in the NAAMM-style load tables. Load cases U (uniform) and C (concentrated, per width, at mid-span) are checked one at a time.
To see the result:
- Enter the clear span.
- Enter at least one load.
4. Request, share, print
The share link holds your numbers and choices only: no names, no email, nothing typed as free text.
Next: work out the cubic metres and containers for shipping these panels
Data and sources
Every stored number cites a page fetched 2026-10-19. Verified means two independent publishers print the same value; single source means one does. What no fetched page prints is not stored, and the form asks you for it.
How the calculation was checked against published tables
- McNichols 19-W-4 (allowable stress): U 0.38 %, C 0.50 %, deflections 0.73 % at most (cells of 100 or more, 0.05 in or more).
- Lichtgitter welded press grating, RAL-GZ 638 (limit state): FV 0.42 %, fV 0.37 %, FP 0.41 %, fP 0.35 % at most (printed value 1 or more); uses Lichtgitter's own M-values.
- Lang+Fulton brochure, weights with the cross bar printed (81 plain rows): bearing plus cross bar steel mass is 3.0 % below the self-coloured weight on average and within 7.0 % at most; with the ISO 1461 minimum zinc it is 4.8 % below the galvanized weight on average and within 9.2 %.
- Lang+Fulton BS 4592 (SI, L/200 or 10 mm): maximum span 0.09 %, deflection 0.34 % at most, 108 cells.
- Direct Metals 19-W-4 (the cells that could be read) agrees too; its stated modulus of 30,000,000 psi does not reproduce its own deflections, 29,000,000 does, so 29,000,000 is used.
- These checks show the textbook beam formulas reproduce the makers’ tables with their printed stress, modulus and factors. They do not validate the load-spreading approximation used for meshes other than about 34 × 38 mm, or any other bar than those in the tables.
Materials
| Material | fy MPa | E MPa | Density | γM | Sources |
|---|---|---|---|---|---|
| Carbon steel S235 (EN 10025-2) | 235 verified | 210,000 single source | 7,850 single source | 1 single source | eurocodeapplied, arvedi, lichtgitter |
| Carbon steel S355 (EN 10025-2) | 355 verified | 210,000 single source | 7,850 single source | 1 single source | eurocodeapplied, arvedi, lichtgitter |
| Carbon steel IS 2062 E250 | 250 verified | 210,000 single source | 7,850 single source | not held | tata-steel, infralens, eurocodeapplied |
| Stainless steel 304 (ASTM A240) | 205 single source | 199,948 single source | 7,890 single source | 1.1 verified | golden-sunbird, rolled-alloys, brunel-university, ucl |
| Stainless steel 316 (ASTM A240) | 205 single source | 199,948 single source | 7,890 single source | 1.1 verified | golden-sunbird, rolled-alloys, brunel-university, ucl |
Galvanizing: minimum mean coating mass
| Standard | Steel thickness | g/m² | Status | Sources |
|---|---|---|---|---|
| EN ISO 1461 (mean minimum) | steel over 6 mm | 610 | verified | galvanizers-association-ireland, wedge-galvanizing |
| EN ISO 1461 (mean minimum) | steel over 3 mm to 6 mm | 505 | verified | galvanizers-association-ireland, wedge-galvanizing |
| EN ISO 1461 (mean minimum) | steel 1.5 mm to 3 mm | 395 | verified | galvanizers-association-ireland, wedge-galvanizing |
| EN ISO 1461 (mean minimum) | steel under 1.5 mm | 325 | verified | galvanizers-association-ireland, wedge-galvanizing |
| ASTM A123 (strip and bar, minimum average) | under 1/16 in (1.6 mm) | 320 (grade 45) | single source | american-galvanizers-association |
| ASTM A123 (strip and bar, minimum average) | 1/16 to under 1/8 in (1.6 to 3.2 mm) | 460 (grade 65) | single source | american-galvanizers-association |
| ASTM A123 (strip and bar, minimum average) | 1/8 to under 1/4 in (3.2 to 6.4 mm) | 530 (grade 75) | single source | american-galvanizers-association |
| ASTM A123 (strip and bar, minimum average) | 1/4 in to under 5/8 in (6.4 to 16 mm) | 530 (grade 75) | single source | american-galvanizers-association |
| ASTM A123 (strip and bar, minimum average) | 5/8 in (16 mm) and over | 705 (grade 100) | single source | american-galvanizers-association |
The mass column is printed by the Galvanizers Association (Ireland); Wedge Galvanizing prints the same thickness classes in micrometres. The mass value is therefore single-publisher. Table 1 prints the band edges as "> 1/8 to 3/16", "> 3/16 to < 1/4" and so on; the tool treats the printed lower edge as inclusive. Grade 75 to 530 g/m2 and 100 to 705 g/m2 come from Table 2.
Conventions
- US welded grating: 18,000 psi, E 29,000,000 psi. Both sheets print 18,000 psi. McNichols prints E = 29,000,000 psi; Direct Metals prints 30,000,000 psi but its cells reproduce with 29,000,000 (see "How the calculation was checked" below), so 29,000,000 is used. verified mcnichols, direct-metals
- BS 4592 (Lang+Fulton): 160 MPa, E 210,000 MPa. Lang+Fulton prints sigma = 1600 daN/cm2 and the S235JR basis. E is not printed there; the Eurocode steel value 210,000 MPa reproduces every row of the table. single source lang-fulton
- 1/4 in under the entered load (pedestrian comfort). McNichols and Direct Metals: 1/4 in is the maximum deflection for pedestrian comfort under 100 lb/sf; it may be exceeded for other loads at the engineer's discretion. verified mcnichols, direct-metals
- L / 200. Lichtgitter (RAL-GZ 638 walkability) and Lang+Fulton both limit deflection to 1/200 of the span. verified lichtgitter, lang-fulton
- L / 200 but not more than 10 mm. Lang+Fulton: within 1/200 of the clear span or 10 mm, whichever is the lesser. single source lang-fulton
- Lichtgitter: partial factor on actions 1.5 (RAL-GZ 638). single source lichtgitter
- Deflection limit span / 200. verified lichtgitter, lang-fulton
- Lichtgitter: height difference between loaded and unloaded adjacent floor covering not more than 4 mm. Shown as a warning, not a fail. single source lichtgitter
- Lichtgitter: walkability is assured when a 1.5 kN point load can be applied at the worst position on a 200 x 200 mm patch. single source lichtgitter
- Lichtgitter: bearing length at least 30 mm in design (not less than 25 mm in service). Not checked by the tool; shown as a note. single source lichtgitter
- Load spreading (M-values). Lichtgitter M-value table for welded gratings, mesh about 34 x 38 mm. The RAL-GZ 638 table behind it is not reproduced. single source lichtgitter
- US rule: a serrated bar acts as one 1/4 in shallower. McNichols and Direct Metals: for serrated grating take the loads of the bar 1/4 in shallower (McNichols applies it to bars 1 in or taller and 3/16 in thick; 3/4 x 3/16 serrated is not available). verified mcnichols, direct-metals
- EU punched anti-slip bar (Lichtgitter): 2 mm shallower. Derived by this tool from the ratio of the Lichtgitter punched table to its plain table (uniform load scales with height squared); the ratio gives 2 mm for 2, 3 and 5 mm bars of every height tested. A derived value, tested in tests/serration.test.js. single source lichtgitter
Pages used, pages rejected, and what is not held
- McNichols: Bar grating GW and GW-2 series, standard-duty welded 19-W-4 and 19-W-2, carbon and galvanized steel load table (PDF; Fs 18,000 psi, E 29,000,000 psi, 10.1053 bars per ft, serrated rule, 1/4 in under 100 lb/sf)
- Direct Metals: Light Duty Bar Grating, welded steel W series (19-W-4 design criteria, load tables, weights, serrated rule; text view of the flip book)
- Lichtgitter: Belastungstabelle Schweisspressroste S235, and the anti-slip punched table (PDF; RAL-GZ 638 partial factors, walkability 1.5 kN on 200 x 200 mm, L/200 and 4 mm, M-value table)
- Lang+Fulton: Loading Tables, Electrofused Gratings for Pedestrian Use and Service Access (PDF; BS 4592-1, S235JR, sigma 1600 daN/cm2, L/200 or 10 mm, 5 and 7.5 kN/m2)
- Lang+Fulton: Horizontal Gratings, Pressure Locked and Electrofused Products brochure (Type EF weights per m2 with the transverse bar printed beside each row)
- Eurocode Applied: Table of material properties for structural steel S235 to S460 per EN 1993-1-1 section 3.2.6 (density 7850 kg/m3, E 210000 MPa, fy)
- Arvedi: Non-alloyed structural steels as per EN 10025-2 (S235JR, S355JR yield by thickness)
- Tata Steel (Digeca): IS 2062 E250, E350, E410 steel grades guide (E250 minimum yield 250 MPa)
- InfraLens: IS 2062 : 2011 hot rolled structural steel summary (E250 yield 250 MPa, UTS 410 MPa)
- Golden Sunbird Metals: ASTM A240 stainless steel plate and sheet (304 and 316 minimum 0.2 % yield 30 ksi)
- Rolled Alloys: 304/304L datasheet (density 0.285 lb/in3, modulus of elasticity 29 x 10^6 psi)
- Afshan et al., reliability analysis of structural stainless steel design provisions (Brunel repository; EN 1993-1-4 gamma M0 = gamma M1 = 1.1)
- Walport et al., stainless steel flexural buckling (UCL discovery; partial safety factor 1.1 per EN 1993-1-4:2025)
- Galvanizers Association (Ireland): EN ISO 1461 coating minimum masses and thickness on articles that are not centrifuged
- Wedge Galvanizing: Hot dip galvanizing to EN ISO 1461 (Table 3 minimum coating thickness, um)
- American Galvanizers Association: ASTM A123/A123M (Table 1 grade by material category and thickness, Table 2 grade to g/m2)
Tried and not used
- https://www.russelmetals.com/en/product/grating-mesh-and-perforated/bar-grating/: Blocked by a Cloudflare challenge (HTTP page "Attention Required"). Its 19-W-4 table was only seen as a search snippet, so nothing from it is stored.
- https://www.mcnichols.com/blog/bar-grating-load-tables-explained: Blocked by a Cloudflare challenge. The 19-W-4 naming convention is taken from the McNichols PDF and the Direct Metals sheet instead.
- https://gruporelesa.com/en/what-weight-can-the-tramex-support-load-guide-measurements-and-resistance/: Fetched and read. Its 34 x 38 load table is NOT used: stress-limited cells (500 to 800 mm) match S235 at 160 MPa, but the 1,000 mm cell (8.75 kN/m2) is 17 % below what its stated L/200 basis gives, and the 1,200 mm cell is above it, so the table is not consistent with its own stated basis. Recorded here as a rejected source.
- https://www.steelconstruction.info/Material_properties: HTTP 404.
- https://www.salzgitter-flachstahl.de/.../S235J2_N.pdf, https://www.stahlwerk-thueringen.de/.../Structural steel grades.pdf: Returned an HTML error page instead of a PDF.
- https://www.chinasteelgrating.com/technology/steel-grating-bearing-capacity.html: Fetched. Load figures are for a 34.3 mm pitch only and the weight table did not load; nothing stored.
- https://simplebooklet.com/heavydutybargrating: Not fetched (heavy-duty NAAMM MBG 532 tables are out of scope for v1).
- Staco strength-analysis tool (py-engineering iframe): Never called. Its method description was read from the research notes only as a pointer to RAL-GZ 638; none of its numbers, text or code is used.
Not held
- Aluminium and other alloys: no fetched page gives a property set for them, so none is stored. Use "Custom material" and type yield, modulus, density and gamma M.
- ASTM A1011 grades: not fetched, so not offered as a preset. IS 2062 E250 yield is held; its gamma M is not (the form asks).
- Allowable bending stress for stainless steel, S355 or E250 in the US method: only 18,000 psi (carbon grating, McNichols and Direct Metals) and 160 MPa (Lang+Fulton, S235JR) are held, so those are the two presets; any other value is typed by the user.
- The RAL-GZ 638 spreading-factor table itself (a standard) is not held. The Lichtgitter M-values for welded gratings with a mesh about 34 x 38 are held. Other meshes use a labelled engineering approximation.
- Heavy-duty (NAAMM MBG 532, vehicular) criteria, impact, fatigue, lateral buckling of bearing bars, supports and banding bars carrying load: not covered.
- Self weight is not added to the applied load (the published tables do not add it either).
- Zinc coating mass above the standard minimum, weld metal and cross-bar contact area are not modelled in the weight; maker table weights differ for those reasons and the tool shows the difference.
- Cross bar size is not printed beside the maker weight tables used for comparison, so the comparison is a consistency check, not a validation of the cross bar mass.
A help tool only. The project engineer governs: check the real loads, supports, standard and maker data before you order or build. Self weight, impact, lateral buckling and vehicle loads are not checked.
Frequently asked questions
How do you calculate grating weight per square metre?
Add the bearing bars and the cross bars in one square metre and multiply by the steel density. For 30 × 5 mm bearing bars at 30 mm pitch with 6 mm twisted cross bars at 100 mm, that is about 39.3 kg of bearing bar plus 2.8 kg of cross bar, then galvanizing on top.
What does 19-W-4 mean?
A US designation for welded bar grating: bearing bars at 19/16 in (1-3/16 in) centres, welded construction, cross bars at 4 in centres. 19-W-2 has cross bars at 2 in.
What is electro-forged grating?
Grating whose cross bars are pressed into the bearing bars and fused by electrical resistance, also called pressure-welded or welded grating. It differs from press-locked grating, where the bars are pressed together without welding.
How much does galvanizing add to the weight?
It depends on the steel thickness. ISO 1461 minimum mean coating is 505 g/m² of surface for steel over 3 to 6 mm and 610 g/m² over 6 mm; for 30 × 5 mm bars at 30/100 that adds roughly 1.3 kg per m² of grating.
Does serration reduce the load a grating can carry?
Yes. US makers rate a serrated bar as if it were 1/4 in shallower; for EU punched bars the tool uses a 2 mm reduction derived from published tables. Choose serrated in the tool to apply it.
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