Factory-direct steel gratings & stair treads, shipped worldwide
Grating Maximum Span Length
Real factory span length help. Free charts and drawings.
No invented span tables here — tell us span, load and bar class, and we confirm the maximum clear span with your quote within 24 hours.
Reply within 24 hours
Maximum clear span confirmed with your quote
Certified & tested
Reports on request, MTC with every order
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3,000 ㎡ workshop, 4 product lines under one roof
FOB Tianjin
Shipped worldwide, EXW / CIF negotiable
The span method
What "Maximum Span" Actually Means
The maximum span length of a grating panel is not one number you can look up once and reuse. It is the clear distance between supports that a given panel clears under a given load — and it is bounded by two independent checks that run at the same time. Strength asks whether the bearing bars carry the load without yielding or failing. Deflection and vibration ask how far the panel sags and how live it feels underfoot. The stricter of the two is the one that sets your maximum span, and which one wins changes with the duty.
That is why honest span data is always conditioned on three inputs — the span itself, the load pattern behind it, and the bar class proposed to carry it. This is the method we apply panel by panel:
| Dimension | Strength check | Deflection & vibration check |
|---|---|---|
| The question it answers | Can the bearing bars carry this load without failing? | How far does the panel sag, and does footfall feel live? |
| How it bounds the span | Caps stress in the bar section — a longer span raises the bending demand on the same bar | Caps movement against your code or comfort limit — sag grows much faster than span length |
| What drives it | Bar depth and thickness together: cross-sectional area and section modulus | Bar depth first, thickness far less: stiffness of a bar on edge climbs steeply with depth |
| Which duties it usually governs | Wheel and point loads: trench covers, driveway gratings, dock and fork-lift floors | Pedestrian duty: walkways, mezzanines, catwalks, platforms people work on |
| What you send us | Load value, footprint or wheel contact, position on the span | Area load or footfall case, and the deflection limit you must meet |
| How the result reaches you | Both checks are run together against the bar class in your quote — the confirmed maximum clear span and the governing check are stated with the itemized quote within 24 hours | |
The two checks can disagree, which is exactly why a single published span table misleads: the panel that wins the strength comparison is not automatically the one that passes the deflection limit. Tell us span, load and bar class — we confirm the maximum clear span with your quote. For the method behind the movement side, see the grating deflection calculator page; for reading published rows, the grating load table guide.
Two different maximums
Panel Length and Structural Span Are Not the Same Number
Buyers often quote "6 m span" when they mean a 6 m panel — or assume a short panel automatically clears a short opening. The two figures live in different worlds: one is a factory envelope, the other is an engineering result verified against your loads.
1 · Panel length — a factory envelope
Our welded panels are made up to 1.25 m wide and 6 m long, and cut to any shorter length your drawing calls for. That 6 m is what the mill can form, handle and load into a container — it says nothing about what the panel can carry.
2 · Clear span — an engineering result
Structural span is the clear distance the panel bridges between supports. It has no fixed ceiling in a catalogue: a shallow bar may be limited to a short opening, while a deep bar of the same family clears far more. One more support beam is usually the cheapest span you can buy.
3 · Direction matters — span runs along the bearing bars
Loads travel along the bearing bars to the supports; cross bars only tie the bars together. Orient the panel so bearing bars run across the opening, and the clear span is measured along them — the same panel spans very differently laid the wrong way round.
So a 6 m panel is a manufacturing answer, and a maximum span is a load answer: one 6 m panel can sit across several closely spaced supports, while a much shorter clear opening may still need a deeper bar under wheel loads. For piece sizes and how panels are divided to drawings, see grating panel dimensions.
What buys you more span
Bar Depth, Thickness and Load Type Set the Span
Three geometry decisions decide how far a panel clears before one of the two checks stops it — stated qualitatively here, because the honest numbers are only produced by your actual span and load. These are the levers our engineers move when a span comes back short:
1 · Depth first, thickness second
Depth and thickness work differently: depth buys stiffness — the deflection side of the span — while thickness buys section area — the strength side. Going from a shallow to a deeper bar of the same thickness is usually how a span is rescued; adding thickness alone buys far less and adds weight everywhere. Our bars run from 20×3 mm to 100×8 mm, plain or serrated.
2 · Spacing spreads the load
Closer bearing bar centers put more bars under the same strip of floor, so each bar carries less and the panel clears more before its limit is reached. Spacing is also the lever that trades span against open area and weight — 30 / 40 / 60 mm centers on our welded line, with press-locked close mesh down to 11 / 11 mm.
3 · Load type picks the governing check
A uniform load spread over the floor sags the panel gently and usually meets the deflection limit first; a wheel or pallet foot concentrates force between bars and usually meets the strength limit first. The same span can therefore pass with one load and fail with the other — send both patterns and we check both.
Material grade barely moves the span: carbon and stainless bars of the same section behave alike in stiffness terms, so geometry — not grade — is where span is won. The bar options behind these levers are covered in bearing bar grating, and heavy long-span duty in heavy-duty grating.
Span help, the honest way
Free Span Length Help From a Real Mill
Free charts and drawings
Ask for the span length sheet and you get the charts and drawings for your case, not a generic poster: bar classes plotted against span and load, with the governing check marked on each row.
Answers by email, engineers behind them
Span data by email, pro help behind it: the people confirming your maximum clear span are the same people who run the welding and press-locking lines for the panels you are specifying.
Span length, verified — worldwide
Every confirmed span is checked against the range our lines actually build — 20×3 mm to 100×8 mm bars at 30 / 40 / 60 mm centers — so the answer is a panel we ship worldwide, not a theoretical row on a chart.
Where it comes up
Where the Span Question Decides the Panel
Four duties where the clear span — not the panel size on the drawing — is what sizes the grating:
Trench & driveway covers
The trench width is the clear span, and wheels concentrate force on it. Strength usually governs, and the bar class follows the opening.
Catwalks & access platforms
Support spacing along the run sets each span. Deflection and footfall comfort usually govern — see metal catwalk flooring for the duty in context.
Mezzanines & storage floors
Steady distributed loads over long bays: the deflection side caps the span first, which is why mezzanine gratings run deeper bars than the load alone demands.
Stair treads
One footfall on one tread is a point load on a short span. Tread width and end fixing decide whether the step feels dead or springy underfoot.
The range the span is checked against
The Production Range Behind Every Span Answer
| Parameter | Range |
|---|---|
| Bearing bar | 20×3 mm to 100×8 mm, plain or serrated |
| Bar spacing | 30 / 40 / 60 mm centers; press-locked close mesh down to 11 / 11 mm |
| Cross bar | Twisted square or round, per specification |
| Panel width | Up to 1.25 m |
| Panel length | Up to 6 m, cut to any shorter length |
| Materials | Q235B carbon steel · SS304 / SS316 stainless |
| Surface | Black or hot-dip galvanized (ASTM A123 / ISO 1461) |
| Forming | Electro-forged welded; press-locked close mesh |
How the span data reaches you
These are the real welded steel grating specifications our lines build, and every span answer is drawn from them. We do not publish a fixed maximum-span table, because a table that ignores your support conditions and load pattern would be guesswork dressed as data — the charts and drawings are prepared for your case and arrive with your itemized quote. Every order ships with documentation, not promises:
- Mill test certificate to EN 10204 Type 3.1
- Factory inspection report with every shipment
- Declaration of Conformity prepared per order destination
Standards & compliance
Produced to Recognized Standards — Documents on Request
ANSI / NAAMM MBG 531
Panels produced to MBG 531 reference practice — the convention span and load tables are built on, with weld inspection on our five-stage QC plan.
ASTM A123 / ISO 1461 HDG
Galvanized coating thickness checked by sampling on every galvanized batch — the finish dimension that stays constant whichever bar class the span asks for.
CE & SGS tested
Certified & tested, reports on request — we show documents you can verify, not a certificate wall.
From numbers to numbers
Send Span, Load and Bar Class — the Maximum Clear Span Comes Back With Your Quote
Tell us the span, load and bar class
Clear span between supports, load pattern and values, and the bar class you have in mind — or just a sketch of the opening. Drawing review is free.
We run both checks and confirm the span
Engineers verify strength and deflection or vibration against your limits, state which one governs, and quote the panel that clears it — itemized, FOB Tianjin as standard, EXW or CIF on request.
Span data with your quote, in 24 hours
The confirmed maximum clear span, charts and drawings arrive together with the quote. Samples ship in 5–7 working days; production runs 15–25 working days after drawing confirmation.
Factory-direct quote
We Confirm the Maximum Clear Span — You Get the Numbers
Ask for span length data by email — free help from the mill — or send the form. Either way the charts, drawings and the confirmed maximum clear span come back with your itemized quote within 24 hours.
- Both checks run against our real bar range: 20×3 mm to 100×8 mm, 30 / 40 / 60 mm centers
- DoC, MTC EN 10204 3.1 and inspection report with every order
- Factory audits welcome — see the lines before you commit
Prefer to talk? WhatsApp us or sales@dtsteelladder.com
Request the span data
Five fields — we run the numbers.
FAQ
Frequently Asked Questions
What is the maximum span length for steel grating?
There is no single safe number. The maximum span depends on the bearing bar depth and thickness, the bar spacing and the load type, and it is bounded by two checks: strength and deflection or vibration, whichever is stricter. Tell us your span, load and bar class and we confirm the maximum clear span with your itemized quote within 24 hours.
Is the 6 m panel length also the maximum span?
Not necessarily, and the two numbers describe different things. Panel length is how long a single piece can be made: our welded panels run up to 1.25 m wide and 6 m long. Span is the clear distance a panel bridges between supports, and it is an engineering result, not a factory envelope. One 6 m panel can sit across several closely spaced supports, while a much shorter clear opening may still need a deeper bar under wheel loads.
Does strength or deflection govern the maximum span?
It depends on the duty. Strength usually governs heavy point loads such as wheels crossing a trench cover, while deflection and vibration usually govern floors people walk on, because a floor can be amply strong and still feel live underfoot. We run both checks against your span and load before quoting, so the panel you get clears whichever limit is stricter.
Related pages
Related Specification & Span Pages
Grating Load Table
Reading load tables: spans, bar sizes and what the rows assume.
View page →Grating Deflection Calculator
The serviceability check that usually caps pedestrian spans.
View page →Bearing Bar Grating
The depth and thickness options that set what a panel can span.
View page →Heavy-Duty Grating
Deeper bars and closer centers for long, heavily loaded spans.
View page →Metal Catwalk Flooring
Catwalk flooring duty: spans, deflection limits and edges in place.
View page →Grating Panel Dimensions
Panel sizes and how pieces are divided and cut to drawings.
View page →