Why Floors Are Critical for AGVs
AGVs are more floor-sensitive than manned forklifts. A manned operator compensates for unevenness instinctively; an AGV does not. Floor deviation causes:
- Navigation drift (especially for magnetic tape and laser systems)
- Load tipping at high lift heights (amplified by mast deflection)
- Wheel wear and vibration that degrades sensors
- Joint impacts that damage battery and electronics
F-Number Standards (US)
The F-number system (FF = flatness, FL = levelness) is the US standard for slab-on-grade floors.
| Application | FF Minimum | FL Minimum |
|---|---|---|
| General commercial warehouse | FF 25 | FL 20 |
| Narrow aisle / light AGV | FF 35-50 | FL 25-35 |
| AGV free-movement zones | FF 70 | FL 50 |
| AGV-dedicated path zones | FF 100 | FL 75 |
Higher FF = flatter. Higher FL = more level. AGV requirements exceed standard warehouse specs by 2-4x.
TR34 Standard (UK / International)
TR34 (Concrete Society Technical Report 34, 4th edition 2016) defines floor categories for industrial use. Defined Movement (DM) classifications apply to VNA and AGV aisles.
| TR34 Category | Rack Height | Application |
|---|---|---|
| DM1 | Top beam >13m | Very high VNA / tall AGV |
| DM2 | Top beam 8-13m | Standard VNA / AGV |
| DM3 | Top beam <8m | Lower rack VNA / pallet jack AGV |
Free Movement (FM) classifications apply to open floor areas where AGVs travel without fixed guidance (SLAM-based systems).
Quantitative Deviation Limits
| Parameter | Requirement |
|---|---|
| Max deviation per 3m straightedge | ±1.5mm |
| Max joint differential height | ≤1.0mm |
| Surface roughness (polished/epoxy) | Ra < 30 micrometers |
| Minimum compressive strength | 40-50 MPa |
| Minimum surface hardness | 6 Mohs |
Referenced Standards
| Standard | Origin | Application |
|---|---|---|
| TR34 | UK (Concrete Society) | VNA and AGV defined-movement floors |
| F-number (ASTM E1155) | US | Flatness and levelness measurement |
| DIN 15185 | Germany | VNA warehouse floor requirements |
| VDMA Guidelines | Germany | AGV floor tolerance guidelines |
| FEM 10.2.14-1 | Europe | Racking installation floor requirements |
| F-min | US (FACE method) | Robotics and AS/RS floor survey |
Practical Notes for Specifying
- Measure before you commit: Always commission an F-number survey before finalizing an AGV quote. Retrofitting a slab to FF 70+ is expensive ($15-40/sq ft depending on method).
- New construction: Spec FF 50/FL 35 minimum for any warehouse that may adopt AGVs in Years 1-5. Over-spec is cheaper than remediation.
- Joint treatment: Saw-cut contraction joints are the biggest failure point. Armor joints with steel edge protection or use joint-free slab pours for AGV lanes.
- Slope: Maximum 1-2% cross-slope in AGV travel paths. Steeper grades require speed reduction and are a stability risk at full load height.
- Existing buildings: Use grinding or self-leveling overlays (4-6mm epoxy-bound) to achieve AGV tolerance. Measure before and after with calibrated dipstick or Facemaster.
Roll Handling AGV - Additional Floor Requirements
Roll handling AGVs (reel fork, roll clamp) carry payloads of 4,000–8,000 kg, producing vehicle + load combinations of 13,000–15,000 kg distributed across 4–6 drive wheels. This is a point load condition that exceeds the design basis of most standard warehouse slabs. A structural engineer must confirm slab capacity before roll handling AGV deployment.
Flatness by Zone
| Zone | Minimum FF | Minimum FL | Reason |
|---|---|---|---|
| General travel paths | FF 50 | FL 35 | Standard AGV minimum |
| Machine interface / docking positions | FF 70 | FL 50 | Positioning repeatability ±5–10 mm required |
| Roll staging lanes | FF 50 | FL 35 | Floor-stacked rolls tip if slab is out of level |
| Dock approach (AGV staging, no leveler) | FF 50 | FL 35 | Grade transition managed at dock threshold |
Joint Treatment for Heavy Loads
Standard armored joint inserts are the minimum for roll handling AGV paths. Under repeated crossings by 13,000–15,000 kg vehicles, joint edge chipping is accelerated compared to standard forklift AGV loads.
- Specify full-depth steel armored joint inserts (not surface-applied edge protection) at all saw-cut joints in AGV travel zones
- Joint-free slab pours (post-tensioned or fiber-reinforced) eliminate the problem entirely - preferred for new mill construction where AGV routes are known at design time
- Maximum allowable joint differential after installation: ≤1.0 mm; re-survey at 12-month intervals for the first 3 years under heavy-load AGV operation
Slope Limits
- Maximum 1% cross-slope on main roll handling travel paths (tighter than the general 1–2% for lighter AGVs)
- Elevated horizontal loads - a 2,000 mm roll on forks - increase tip sensitivity; slope compounds the effect
- Grade transitions at door sills and dock thresholds: ≤5 mm vertical offset, ramped at ≤1:12 where possible
Floor Surface for Paper Mill Environments
Standard bare concrete is incompatible with paper mill production areas. Pulp slurry, process water, bleach, and chemical sizing agents attack untreated concrete and degrade surface hardness below the 6 Mohs minimum required for AGV wheel wear performance.
- Specify chemical-resistant epoxy or polyurethane coating on all AGV travel surfaces in production zones
- Include anti-slip aggregate in the top coat - wet floors from mill condensation and process water create slip risk for AGV wheels (reduced traction affects stopping distance and navigation accuracy)
- Recoat cycle: inspect annually; recoat when wear exposes aggregate or when surface hardness testing drops below specification
- Floor drain gratings in AGV paths: flush-mounted only, ≤5 mm projection, rated for point load of the heaviest vehicle at maximum payload
Real Project Floor Specs (Dematic AGV + AMR, 2024)
Source-derived from vna-agv-site-readiness-specs-dematic-jungheinrich-2024. These are integrator (Dematic) site-readiness numbers from an actual VNA-AGV deployment, useful to sanity-check generic flatness guidance.
AGV flooring (US units): general level not to exceed 0.5” in 10 ft; static friction (wheel to finished floor) >= 0.5; grounding resistance 10 kOhm-1 MOhm where conductive coatings are used. FF/FL at transfer locations tightens with transfer height:
| Transfer height | FF | FL | Max tilt / 10 ft |
|---|---|---|---|
| 0-25 ft | FF 35 | FL 25 | 0.1875” |
| 26-30 ft | FF 45 | FL 35 | 0.125” |
| 31-35 ft | FF 60 | FL 40 | 0.0625” |
AMR floor (metric, Dematic NV/GmbH 2022): flatness < 3 mm / 1 m^2 (or < 5 mm / 2 m^2); slope < 0.03 general, < 0.01 at STOP points; step height < 5 mm (none at STOP); groove < 8 mm (none at STOP); settlement < 1/1000; concrete >= C30 (30 MPa); load-bearing 1,500 kg/m^2; dynamic factor 1.3; friction (PU wheel) >= 0.55. Epoxy needs anti-static treatment; no wax, hollow drum, or dust.
[!practitioner-note] Out-of-spec floors throttle throughput, not go-live Both floor docs let the integrator reduce vehicle speed where the floor is out of tolerance. The penalty for a marginal slab is silent throughput loss, not a stopped project. FF60/FL40 for 31-35 ft transfers is superflat-adjacent (laser-screed territory), and AMR slope tightens 3x at pick/drop pads (0.03 -> 0.01), which GCs who level uniformly often miss.