A single data centre fire can cost £500 million and disrupt services for millions. As the UK builds more data centres than ever, is the industry's fire safety keeping pace?. The Digital Economy's Achilles Heel The UK's data centre industry is booming — £4.6 billion in investment in 2024, with 30+ new facilities planned by 2027. These buildings house the digital infrastructure that keeps the economy running: banking, healthcare, government services, and communications. But a single fire in a major data centre can: Cost £500 million+ in direct losses and business interruption Disrupt services for millions of users Destroy irreplaceable data despite backup strategies Trigger cascading failures across interconnected systems Unique Fire Risks The Fuel Load Problem A typical Tier III data centre contains: 500+ km of cabling — much of it PVC insulated (toxic smoke, high fire load) Thousands of lithium ion batteries in UPS systems Diesel generators with 72 hour fuel supplies Plastic server housings — cumulative fire load of 800 1,200 MJ/m² HVAC systems — creating air movement that can accelerate fire spread Thermal Runaway in UPS Batteries Large scale lithium ion UPS installations present thermal runaway risks that dwarf e bike batteries. A single UPS room may contain 20,000+ cells. Cable Fire Propagation Cable fires can propagate through cable trays, risers, and containment systems across the entire facility. The 2021 OVH data centre fire in France destroyed 3.6 million websites because fire spread through cable routes. Fire Protection Strategies Detection: VESDA Is Non Negotiable Very Early Smoke Detection Apparatus (VESDA) provides air sampling detection that can identify smoke particles before visible smoke develops . Response times of 60 90 seconds vs. 3 5 minutes for conventional detection. Suppression: The Clean Agent Debate FM 200 (HFC 227ea) — effective but being phased out due to GWP Novec 1230 — zero ODP, low GWP, safe for occupied spaces Inergen — nitrogen/argon blend, unlimited supply, no environmental concerns Water mist — increasingly popular for large facilities, minimal water damage Pre action sprinklers — double interlock systems to prevent accidental discharge Compartmentation: The Critical Layer Data centres must be divided into fire compartments to prevent cascading failure. Typical requirements: 2 hour fire rated walls between server halls Fire rated cable penetrations — every cable route must be sealed Fire dampers in all HVAC routes crossing compartment boundaries Fire rated doors with access control integration Designing for Resilience Tier III vs Tier IV Fire Safety Requirement Tier III Tier IV Fire compartments Per hall Per row Detection VESDA VESDA + thermal imaging Suppression Clean agent Clean agent + pre action sprinkler UPS isolation Per room Per rack Fire resistance EI 60 EI 120 Backup detection Spot detectors Beam + aspirating The ROI of Fire Engineering A comprehensive fire engineering design for a 10 MW data centre costs approximately £250,000 — 0.3% of construction cost. The alternative: a fire that can cost 2,000x that amount. Magnus Opifex has designed fire protection for 15+ UK data centres. For specialist data centre fire engineering, contact us.