How should the load-bearing grade of all-steel raised access flooring be selected?

Selecting the load-bearing grade for full-steel raised floors should be determined based on the actual usage scenario, equipment loads, safety factors, and industry standards. The following outlines the steps and key considerations:

1. Define the Usage Scenario

• General offices/classrooms: Mainly pedestrian traffic, no heavy equipment. Typically choose uniform load ≥ 3.0 kN/m², concentrated load ≥ 1.5 kN, corresponding to CQ grade (commercial standard).

• Data centers/server rooms:

  • Dense server cabinet areas: Single cabinet weight often 500–1000 kg, requiring uniform load ≥ 10 kN/m², concentrated load ≥ 5.0 kN, i.e., CQ or CR grade (equipment room standard).

  • Aisles or standard cabinet areas: Can select uniform load ≥ 7.5 kN/m² CQ grade.

• Industrial plants/laboratories:

  • Heavy equipment areas (e.g., precision instruments, large machinery): Calculate point load on casters or support points, usually requiring concentrated load ≥ 10 kN, or higher for dynamic loads (e.g., DZ grade, dynamic load ≥ 20 kN).

  • ESD requirements: Must select ESD grade in combination with load-bearing requirements.

2. Calculate Actual Load

• Uniform load: Calculate by dividing total equipment weight in the area by floor area. For example, a server cabinet weighing 800 kg (~7.84 kN) occupying 1.2 m² requires uniform load ≥ 6.53 kN/m²; recommended ≥ 7.5 kN/m².

• Concentrated load: Consider device support points or heavy carts; e.g., a server cabinet with four feet, each requiring ≥ 200 kg (~2 kN).

• Safety factor: Add 1.5–2× safety margin on calculated values, especially for dynamic loads (e.g., moving equipment or forklifts).

3. Refer to Industry Standards

• Chinese standards (GB/T 36340-2018):

  • CQ grade: Commercial use, uniform load ≥ 3.0 kN/m².
  • CR grade: Equipment rooms, uniform load ≥ 7.5 kN/m².
  • CZ grade: Heavy-duty industrial, uniform load ≥ 12.0 kN/m².

• International standards (EN 12825 / IEC 61923):

  • Class 2: Office use (~3 kN/m²).
  • Class 4: Data center (~7.5 kN/m²).
  • Class 6: Heavy-duty industrial (≥12 kN/m²).

4. Special Considerations

• Floor structure: Floors with internal foam cement or reinforced steel beams have higher load capacity.

• Pedestal span: Standard panel size is 600×600 mm. If a larger span is needed (e.g., 1200 mm), increase load grade or reinforce the pedestal.

• Dynamic loads: For frequent equipment movement (e.g., AGV carts), select dynamic load grade (e.g., DZ grade).

• Seismic requirements: High seismic regions require pedestals with anti-seismic design.

5. Supplier and Test Reports

• Request third-party load test reports from suppliers to verify measured load-bearing capacity of floors and pedestal systems.

• Reference case: Large data centers (e.g., Alibaba Cloud) often select full-steel floors with uniform load ≥ 12.5 kN/m² and reduce pedestal spacing to 400×400 mm.