Technical Specifications of Steel Grating Stair Treads
What is Steel Grating?
Steel Grating is a grid like structure made of parallel steels bars that are joined at right angles by cross bars, creating a strong structure and adaptable platform. Steel grating is usually known for its high strength, lightweight design, load bearing ability and allows a good ventilation and light flow. It's widely used in walkway platforms, stairs, drainage covers, fencing and safe flooring for factories.
Types of Steel Grating
The most common and versatile type, where bearing bars and cross bars are welded together to create the rigid panel to provide strength & durability – found in industrial flooring or heavy duty workshops.
Cross bars are inserted into bearing bars and then pressed together without welding to provide clean finish & sleek appearance mostly used in architectural front or in public walkways.
Cross bars are inserted into pre – punched hole and locked by mechanical pressure to give strong and neat presence with versatile design used in decorative pieces or pedestrian walkway.
A steel sheet is cut and stretched to create an open, diamond shape pattern. They are slip resistant and cost effective used in ramps, fencing and machine guards.
Steel sheets are punched with holes for making slip resistance and give high safety performance at stairs, wet floors and in oily areas.
The common specifications for steel grating stair treads primarily include physical dimensions, mesh specifications, and model classifications, detailed as follows:
I. Physical Dimensions
Width: Typically between 0.5m and 1m. Common sizes include 600mm, 700mm, 800mm, 900mm, etc. Minimum width is no less than 250mm; maximum width should not exceed 1200mm.
Length (Tread Depth): Common sizes include 150mm, 185mm, 240mm, 245mm, 275mm, 305mm, etc. This is determined by the stairwell opening, depth, and floor height.
Thickness: Overall thickness depends on the height of the bearing bars and the cross bar arrangement. Common sizes are 25mm, 30mm, 40mm, etc. The thickness of carbon steel bearing bars is typically 3mm or 5mm.
Note: 3mm is economical, 5mm offers stronger load capacity. Overall thickness 25-40mm (Light-duty: 25/30mm, Heavy-duty: 40mm).
II. Mesh Specifications
Bearing Bar Spacing: * 30mm: Impact resistant (e.g., G253/30/100).
40mm: Economical/General purpose (e.g., G305/40/50).
60mm: Anti-clogging/Debris shedding (e.g., G325/60/200).
Cross Bar Spacing: 30mm (Anti-slip), 40mm (Universal), 60mm (Economical).
Serrated Bearing Bar: Tooth height 3-5mm, suitable for wet or oily environments.
III. Model Classification
Welded Fixation Type: ST1 / ST3 / ST5 (Welded directly to stair strings; permanent fixation).
Bolted Fixation Type: ST2 / ST4 / ST6 (Equipped with mounting clips; removable for maintenance).
IV. Tolerances
Length: ±5mm
Width: ±3mm
Diagonal: ≤±5mm
Bearing Bar Perpendicularity: ≤10%
Selection Reference:
Residential Use: 30×3mm bearing bar + 30mm spacing + 700×240mm size.
Industrial Heavy-Duty: 40×5mm bearing bar + 30mm spacing + 800×275mm size.
Wet Environments: Serrated bearing bar + anti-slip nosing.
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Application Scenarios
Steel Grating FAQ
Q1: What is the difference between "Plain" and "Serrated" steel grating?
A: Plain grating has a smooth surface and is the standard for most platforms. Serrated grating has notches cut into the bearing bars, providing superior slip resistance in high-risk areas prone to oil, water, or ice.
Q2: How do I choose between "Welded" (ST1) and "Bolted" (ST2) stair treads?
A: Welded treads are more cost-effective and provide a permanent, rigid structure. Bolted treads include end plates and are used when the grating needs to be removed for inspection or when welding on-site is not permitted.
Q3: Does the direction of the bearing bars matter during installation?
A: Yes, it is critical. The bearing bars (the deeper bars) must run across the span (from stringer to stringer) to support the load. If installed in the wrong direction, the grating will lack structural integrity and may collapse.
Q4: What is the benefit of "Hot-Dip Galvanizing" for steel grating?
A: Hot-dip galvanizing provides a thick, zinc-protective coating that prevents rust and corrosion. It significantly extends the lifespan of the grating, especially in outdoor or industrial chemical environments, often lasting 20-50 years.
Q5: What are the standard loading requirements for industrial stair treads?
A: According to international standards (like ISO or ASTM), stair treads should typically support a concentrated load of 1.5kN to 3.0kN over a specific area (e.g., 100x100mm) at the front edge, where the foot pressure is highest.