Managing Fire Safety During Refurbishment, Upgrades and Retrofit Works 

Data centers are critical to the functioning of the modern world. From everyday digital services to national infrastructure, financial systems, transport and the rapid growth of artificial intelligence, uninterrupted operation is essential. As demand for capacity continues to outstrip supply, operators are under increasing pressure to maximise existing assets through refurbishment, retrofit, reinstatement and technology upgrades often in live, operational environments. 

However, periods of building disruption present a heightened and often underestimated fire risk. For mission‑critical facilities, fire safety cannot be treated as a static design exercise. It must be actively managed before, during and after change. 

Why Fire Risk Escalates During Building Disruption 

While major fire incidents in data centers are relatively rare, their consequences can be severe. A single incident can disrupt services across multiple regions, result in significant financial loss and lead to long-term reputational and legal impacts. 

During refurbishment or retrofit projects, the fire risk profile of a data center can change rapidly due to: 

• Alterations to building fabric and compartmentation 

• Temporary removal or impairment of fire protection systems 

• Construction activity within live technical spaces 

• Introduction of temporary power, cooling or containment solutions 

• Phased commissioning of new systems alongside legacy infrastructure 

• Improper integration with MEP and IT infrastructure 

These conditions create transitional risks that may not be fully addressed by the original fire strategy unless it is actively reviewed and adapted. 

 

Live Environments, Legacy Infrastructure and New Technologies 

Many data center upgrade programmes involve integrating new technologies into facilities that were designed to different standards or operational models. Common examples include: 

• UPS upgrades, increasingly involving lithium‑ion battery systems 

• AI and ML densification, with higher rack densities and increased heat loads 

• Advanced cooling strategies, including liquid or immersion cooling 

• Energy efficiency measures, such as rooftop PV installations or waste heat recovery systems 

Each of these technologies brings clear operational and sustainability benefits. However, they also introduce distinct fire safety considerations related to battery chemistries, combustibility of cooling fluids, electrical fault conditions, and interaction with existing detection and suppression systems. 

When introduced during refurbishment works, these risks are compounded by construction activities and temporary building states. 

 

Temporary Conditions 

A recurring issue during building disruption is the reliance on temporary measures that gradually become semi‑permanent. These can include: 

• Temporary cabling routes or power reconfigurations 

• Partial compartment breaches left open longer than intended 

• Construction materials temporarily stored in technical spaces 

• Detection or suppression coverage altered to accommodate works 

Over time, these conditions can significantly erode the original fire safety assumptions of the facility. 

In mission‑critical environments, even short‑term impairments can have long‑term consequences if not carefully engineered and managed. 

 

Fire Safety Must Evolve With the Project 

Effective fire safety during refurbishment or retrofit works depends on recognising that the highest fire risk often occurs during transition, not at final handover. 

Key principles include: 

• Continuous review of fire risk throughout each project phase 

• Alignment between temporary arrangements and the permanent fire strategy 

• Clear responsibility for fire safety across designers, contractors and operators 

• Early identification of cumulative risks rather than isolated hazards with risk mitigating measures in place 

• Maintaining protection during modifications between operational and construction areas 

Fire safety engineering plays a critical role in bridging the gap between operational requirements and construction realities. 

 

Managing High‑Risk Systems During Retrofit Power and UPS Systems 

Uninterruptible power supplies are essential for continuity, but modern battery UPS systems, particularly lithium‑ion, require careful consideration of: 

• Fire separation and enclosure design 

• Ventilation and thermal runaway mitigation 

• Detection, suppression, containment and emergency response integration 

• Operational redundancies 

Introducing or upgrading UPS systems during live refurbishment works demands rigorous planning and risk assessment. 

 

Cooling Systems 

High‑density environments increasingly rely on liquid cooling systems. Where hydrocarbon‑based dielectric fluids are used, combustibility becomes a key concern, particularly if these systems are retrofitted into spaces not originally designed for them. 

 

Sustainability Retrofits 

PV systems and waste heat recovery can significantly improve energy performance but may introduce new ignition sources, access constraints and interdependencies with other critical infrastructure systems. 

In each case, fire safety considerations must be embedded into the refurbishment strategy - not addressed retrospectively. 

 

The Role of Specialist Fire Safety Engineering 

Specialist fire safety engineering ensures that resilience, reliability and compliance are maintained throughout disruption. Typical services during refurbishment and retrofit projects include: 

• Live fire risk assessments and strategy reviews 

• Evaluation of temporary and phased conditions 

• Interface reviews between new and existing systems 

• Advice on international standards and best practice for emerging technologies 

• Performance-based design tailored to operations 

• Practical, buildable solutions – not just code compliance 

• Support during commissioning, handover and operational transition 

By working as part of the wider project team, fire safety engineers help ensure that operational continuity is protected while change is delivered safely. 

 

Protecting Continuity in a Capacity‑Constrained Market 

Global demand for data center capacity continues to exceed supply, driven by digitalisation and accelerated AI adoption. As a result, many operators are prioritising refurbishment, reinstatement and upgrade of existing facilities rather than waiting for new builds. 

In this environment, fire safety is not simply a regulatory requirement, it is a core component of business continuity, asset protection and stakeholder confidence. 

Building disruption is unavoidable in the lifecycle of a data center. Fire risk escalation is not. 

Whether undertaking refurbishment, reinstatement or technology upgrades, operators must ensure that fire safety strategies evolve alongside the building and its systems.  

With the right fire safety engineering input, it is possible to deliver change while maintaining resilience, protecting critical infrastructure and safeguarding uninterrupted operation. 

Get in Touch

To learn more about how Joule Group's fire safety expertise could help you better protect your project, please get in touch with us at info@joule-group.com.