Understanding Raised Access Flooring Standards
Understanding PSA MOB PF2 PS/SPU & BS EN 12825 Raised Access Flooring Standards
When choosing a raised access flooring system, one of the most important factors is ensuring the floor meets the correct performance standards. In the UK, two specifications dominate the industry: PSA MOB PF2 PS/SPU and the European standard BS EN 12825. Each system defines how raised floors are built, tested, and classified — and which environments they are suitable for.
This guide provides a clear, customer-friendly explanation of both standards, the differences between them, where each is typically used, and how to choose the correct floor grade for your project.
1. What Is PSA MOB PF2 PS/SPU?
PSA MOB PF2 PS is the long-standing UK government performance specification for raised access flooring. For over 20 years, it has been the benchmark for commercial offices, public sector buildings, computer rooms, and technical spaces. The latest version, published in 1992, is known as MOB PF2 PS/SPU, where “SPU” means Single Project Use.
Unlike a product description, PSA is a performance-based specification: every panel, pedestal, and supporting component must pass a series of controlled tests to confirm strength, durability, safety, and build quality.
PSA Covers:
- Dimensional tolerances (panel size accuracy)
- Movement under humidity and temperature changes
- Concentrated load capacity on 25mm and 300mm squares
- Uniformly distributed load (UDL)
- Fire safety and spread of flame
- Panel finishes (e.g., steel, HPL, vinyl)
- Electrical bonding & earthing continuity
These tests ensure the raised floor performs predictably under real-world conditions, particularly in office and IT environments where heavy equipment may be present.
2. PSA Load Grades Explained
PSA MOB PF2 PS/SPU defines four performance grades. Each grade reflects different load requirements and typical areas of use.
PSA Grades & Structural Performance
| Grade | Typical Use | Concentrated Load (300mm) | Concentrated Load (25mm) | UDL | Safety Factor |
|---|---|---|---|---|---|
| Light | General office environments | ≥ 2.7kN | ≥ 1.5kN | ≥ 6.7kN/m² | 3 × load for 5 minutes |
| Medium | Offices with heavier equipment, public spaces, education | ≥ 4.5kN | ≥ 3.0kN | ≥ 8.0kN/m² | 3 × load for 5 minutes |
| Heavy | Computer rooms, comms rooms, telecom spaces | N/A | ≥ 4.5kN | ≥ 12kN/m² | 3 × load for 5 minutes |
| Extra Heavy | Data centres, print rooms, heavy equipment zones | N/A | ≥ 4.5kN | ≥ 12kN/m² | 2 × load for 5 minutes Plus 11kN four-point loading test |
In simple terms: Light → Offices, Extra Heavy → Data Centres.
3. What Is BS EN 12825?
Introduced in 2001, BS EN 12825 is the European standard for raised access flooring. It is mandatory for public projects and widely used in high-spec commercial buildings and data centres.
Unlike PSA (which gives fixed grades), BS EN 12825 is based on:
- Ultimate load (the point where failure occurs)
- Working load deflection (2.5mm, 3mm, 4mm)
- Safety factor (2 or 3)
- Dimensional tolerances
This allows a project to choose an exact performance class suited to its environment.
4. BS EN 12825 Classification System
BS EN 12825 uses a four-part performance code, for example:
• 3 = Ultimate load in excess of 8kN
• A = Deflection under load less than 2.5mm
• 3 = Safety factor of 3
• 2 = Dimensional tolerance class
The system supports:
- 6 ultimate load classes (4kN → 12kN+)
- Safety factor of 2 or 3
- Deflection: 2.5mm, 3mm, or 4mm
5. PSA vs BS EN 12825: Key Differences
| PSA MOB PF2 PS/SPU | BS EN 12825 |
|---|---|
| Long-standing UK standard | Europe-wide standard (mandatory for public projects) |
| 4 fixed load grades | Custom performance classes |
| Focus on office / commercial use | Ideal for data centres, heavy loads |
| Defines both 25mm & 300mm load tests | Focuses on 25mm point load to failure |
| Commonly used in private UK projects | Required for government & EU public work |
6. Recommended Floor Classes by Environment
Below is a simplified interpretation of the BS EN 12825 classification chart to help customers select the correct floor system.
Typical Applications
| Environment | Light Use | Standard Use | Heavy Use | Typical FFH | Finishes |
|---|---|---|---|---|---|
| General Offices | 1/A/3/2 | 3/A/3/2 | 5/A/3/2 | 50–450mm | Carpet tiles |
| Computer Rooms | 1/A/3/2 | 4/A/3/2 | 6/A/3/2 | 300–600mm | Vinyl / HPL |
| Data Centres | 4/A/3/2 | 6/A/3/2 | 6/A/3/2 | 300–600mm | Vinyl / HPL |
| Call Centres | 2/A/3/2 | 3/A/3/2 | 5/A/3/2 | 150–450mm | Carpet tiles |
| Print Rooms | 4/A/3/2 | 6/A/3/2 | 6/A/3/2 | 150–450mm | Vinyl / Rubber |
7. Which Standard Should You Choose?
Choose PSA MOB PF2 PS/SPU if:
- You are fitting out a standard office or workspace
- You need predictable performance but not extreme loads
- You want a cost-effective UK-compliant solution
Choose BS EN 12825 if:
- You are building a data centre, comms room or technical space
- You require high point loads (8–12kN+)
- Your project is a public or government job
- You want precisely defined load, deflection & safety targets
8. Need Help Choosing the Correct Grade?
Access-Flooring.co.uk supplies a full range of PSA and BS EN 12825 raised access flooring systems, pedestals, airflow panels, and accessories. If you’re unsure which specification your project requires, our team can help you select the correct grade based on equipment loads, void height, foot traffic and environmental conditions.
PSA vs BS EN – Quick Comparison
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