Quick Answer
Quick Answer
IS 3502 is the Bureau of Indian Standards specification for hot-rolled steel chequered (floor) plates. Plates are produced on the base material of IS 2062 E250 or E350, with raised lenticular or diamond patterns rolled onto one face for slip resistance. Chemical composition and mechanical properties are inherited from the IS 2062 base grade.
IS 3502 (IS 3502:2009 with amendments) is published by the Bureau of Indian Standards (BIS) and governs hot-rolled steel chequered plates — flat plates with a raised non-slip pattern on one face, used as flooring, walkways, stair treads, ramps, vehicle loading areas, and access covers. The plates are produced as IS 2062 structural steel with the pattern added during hot rolling; consequently, all chemical composition and mechanical property requirements are taken directly from IS 2062. IS 3502 additionally specifies the geometry and height of the raised pattern, thickness definitions (measured in the plain, non-raised zone), and tolerances on mass and dimensions.
Scope and Applicability
IS 3502 covers:
- Hot-rolled steel chequered plates with raised anti-slip pattern on one flat face
- Nominal thickness: 3 mm to 12 mm (based on the flat/plain zone, not including rib height)
- Width: 900 mm to 2500 mm (standard mill widths)
- Length: up to 10 000 mm (cut-to-length) or in coil form for thinner gauges
- Applications: industrial flooring, mezzanine decks, gangways, stair treads, bridge expansion joints, vehicle platforms, shipdecks
The standard does not cover embossed thin-gauge cold-rolled sheets, aluminium chequered plates, or grating panels.
Grade Coverage
IS 3502 chequered plates are produced in two IS 2062 base grades:
| IS 3502 Grade | Base Material Grade | Minimum Yield Strength | Typical Application |
|---|---|---|---|
| Grade I | IS 2062 E250A or E250B | 250 MPa | General flooring, walkways, platforms |
| Grade II | IS 2062 E350A or E350B | 350 MPa | Heavy-duty industrial floors, crane platforms, vehicle ramps |
Grade designation on the MTC and product markings should state both the IS 3502 reference and the IS 2062 grade being used (e.g., IS 3502 Grade I / IS 2062 E250B).
Chemical Composition Requirements
Chemical composition is per IS 2062 for the declared base grade. Ladle analysis limits:
| Element | IS 2062 E250A / E250B (Grade I) | IS 2062 E350A / E350B (Grade II) |
|---|---|---|
| Carbon (C) max | 0.23% (A) / 0.22% (B) | 0.20% |
| Manganese (Mn) max | 1.50% | 1.50% |
| Silicon (Si) max | 0.40% | 0.45% |
| Sulphur (S) max | 0.045% (A) / 0.040% (B) | 0.040% (A) / 0.035% (B) |
| Phosphorus (P) max | 0.045% (A) / 0.040% (B) | 0.040% (A) / 0.035% (B) |
| CEV max | 0.42% (A) / 0.41% (B) | 0.43% |
Mechanical Properties
Mechanical properties are per IS 2062 for the base grade, tested on test pieces cut from the plain (non-patterned) zone of the plate.
Grade I — IS 2062 E250 Base
| Nominal Thickness | Yield Strength min (MPa) | UTS (MPa) | Elongation min % (GL = 5.65√A) |
|---|---|---|---|
| ≤ 20 mm | 250 | 410–530 | 23 |
| > 20 mm | 240 | 410–530 | 23 |
Grade II — IS 2062 E350 Base
| Nominal Thickness | Yield Strength min (MPa) | UTS (MPa) | Elongation min % |
|---|---|---|---|
| ≤ 20 mm | 350 | 490–630 | 22 |
| > 20 mm | 330 | 490–630 | 22 |
Chequered plates in IS 3502 are typically 3–12 mm nominal, so the ≤ 20 mm row applies in almost all practical cases. Tensile test per IS 1608; gauge length = 5.65√A.
Pattern Requirements
IS 3502 specifies a lenticular (lens-shaped) raised pattern in two rows of ribs running at approximately 45° to the plate rolling direction, with the two rows inclined in opposing directions (herringbone arrangement):
| Parameter | Requirement |
|---|---|
| Pattern type | Lenticular (diamond/herringbone) |
| Rib orientation to rolling direction | 45° ± 5° (alternating left-right) |
| Minimum rib height (h) | 0.3 × nominal thickness, min 1.0 mm |
| Maximum rib height (h) | 0.8 × nominal thickness |
| Rib pitch (centre-to-centre) | 30–60 mm |
| Rib width at base | 8–15 mm |
| Rib surface | Smooth; no sharp edges |
The raised pattern must cover at least 70% of the total plate surface area. The plain (un-patterned) border along the plate edges must not exceed 15 mm width.
Thickness and Dimensional Tolerances
Nominal thickness is measured on the plain flat face (not the rib top). Standard nominal thicknesses available: 3, 4, 5, 6, 8, 10, 12 mm.
| Nominal Thickness (mm) | Thickness Tolerance (mm) |
|---|---|
| 3.0 | +0.40 / −0.25 |
| 4.0 | +0.45 / −0.25 |
| 5.0 | +0.50 / −0.30 |
| 6.0 | +0.55 / −0.30 |
| 8.0 | +0.60 / −0.35 |
| 10.0 | +0.65 / −0.40 |
| 12.0 | +0.70 / −0.45 |
Width tolerance: +10 mm / −0 mm. Length tolerance: +25 mm / −0 mm. Flatness: camber ≤ 12 mm per metre. Squareness: diagonal difference ≤ 5 mm for plates up to 2000 mm length.
Weight (Mass) Tolerances
The theoretical mass per m² of a chequered plate includes the mass of the flat plate plus approximately 3–5% additional mass for the raised pattern.
| Nominal Thickness (mm) | Flat plate mass (kg/m²) | Chequered plate mass (kg/m²) approx. |
|---|---|---|
| 3 | 23.6 | 24.4 |
| 4 | 31.4 | 32.4 |
| 5 | 39.3 | 40.5 |
| 6 | 47.1 | 48.7 |
| 8 | 62.8 | 64.9 |
| 10 | 78.5 | 81.2 |
| 12 | 94.3 | 97.4 |
Mass tolerance: individual plate mass within −4% to +6% of theoretical mass. Batch average: within −2% to +4%.
Additional Tests and Requirements
Surface Quality
Both faces must be free from harmful surface defects — seams, laps, cracks, and rolled-in scale that reduces bond in protective coatings. Light surface rust is acceptable. The patterned face must not have missing ribs or flat-rolled pattern zones exceeding 50 mm × 50 mm area.
Bend Test
Bend test per IS 1599. Bending the flat face (not the patterned face), through 180°, mandrel diameter = 2t for E250 base, 3t for E350 base. No cracking on the tension (flat) face.
Chemical and Mechanical Test Frequency
Frequency per IS 2062 base standard: one ladle analysis per heat; one tensile test per lot (50 tonnes or part thereof per grade per thickness). Bend test: one per lot.
BIS Certification
IS 3502 is produced to IS 2062 base material which is mandatory BIS-certified (Schedule II). Producers of IS 3502 chequered plates supply material under their IS 2062 BIS licence; the MTC references both IS 2062 (for material) and IS 3502 (for pattern and dimensional compliance).
Cross-Standard Equivalents
| IS 3502 / IS 2062 Grade | EN Equivalent | ASTM Equivalent | JIS Equivalent |
|---|---|---|---|
| Grade I (E250) | EN 10025-2 S235JR (floor plate variant) | ASTM A786 / A36 | JIS G 3193 (floor plate) / SS400 |
| Grade II (E350) | EN 10025-2 S355JR (floor plate variant) | ASTM A786 / A572 Gr 50 | JIS G 3193 / SM355 |
ASTM A786 is the closest US equivalent, covering hot-rolled carbon steel floor plates with raised patterns. EN 10025-2 does not have a dedicated chequered plate product standard — suppliers reference the base material grade.
MTC Verification Checklist
When verifying a mill test certificate for IS 3502 chequered plates, confirm:
- Standard stated as IS 3502 with grade reference (Grade I or Grade II)
- Base material grade stated as IS 2062 E250 or IS 2062 E350 with sub-grade
- BIS licence number of the producing mill present
- Heat number traceable to plate/bundle markings
- Chemical analysis within IS 2062 limits for the declared base grade
- Mechanical test results (YS, UTS, elongation) within IS 2062 limits for declared thickness
- Bend test result: pass/satisfactory
- Nominal thickness and tolerance within IS 3502 limits
- Pattern compliance statement (rib height, coverage area satisfactory)
- Mass per m² within +6%/−4% of theoretical value for individual plates
Frequently Asked Questions
How is nominal thickness measured on a chequered plate?
Nominal thickness is measured on the plain flat face — not on top of the raised ribs. Use a micrometer or calliper on an area between ribs, at least 20 mm from any rib base. The rib height is additional to the nominal thickness; total plate thickness at a rib top will be nominal thickness + rib height. This distinction matters for tight clearance applications (grating frames, hatch covers) where the rib height must be accounted for separately.
Can IS 3502 chequered plates be ordered with IS 2062 E250C (sub-grade C) for cold-temperature applications?
Yes, if the steel mill's BIS licence covers E250C production and the customer specifies it on the purchase order. Sub-grade C requires Charpy impact testing at −20 °C per IS 2062 (minimum average 27 J). This is relevant for outdoor platforms in high-altitude or cold-climate locations. Most standard stock chequered plates are supplied as E250A (no impact requirement); E250B and E250C must be specifically ordered to schedule.
What is the difference between chequered plates and grating panels?
Chequered plates (IS 3502) are solid steel plates with a hot-rolled raised pattern providing slip resistance — they are water-tight and support distributed loads. Grating panels (IS 2502 / ASTM Standard) are open-bar grids (bearing bars + cross bars) with gaps between bars — they are not water-tight but are lighter and allow drainage, ventilation, and light passage below. For drainage-required walkways, grating is preferred; for liquid containment, vehicle drives, or explosive atmospheres where sparks from dropped objects must be contained, solid chequered plates are used.
Is IS 3502 chequered plate heavier than plain plate of the same nominal thickness?
Yes, by approximately 3–5%. The raised ribs add material mass without changing the nominal (plain zone) thickness designation. The additional mass depends on rib height, rib pitch, and rib width. IS 3502 allows suppliers to state mass per m² inclusive of ribs on the MTC; when calculating structural dead loads, use the chequered plate mass (not the flat plate mass) from the table above or from the mill's confirmed MTC weight.
What protective coatings are compatible with IS 3502 chequered plates used outdoors?
The patterned surface can receive hot-dip galvanising, zinc-rich epoxy primer, and paint systems. Galvanising to IS 2629 (minimum 85 µm average) is common for outdoor walkways. The raised pattern actually improves paint adhesion due to increased surface area. Ensure surface prep (shot blasting to Sa 2.5 per IS 9954 or equivalent) is performed on the flat face and between ribs before painting. The recesses between ribs can trap moisture if not properly primed — ensure paint penetration into rib bases.
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