Why Data Centre Insulation Matters
Ireland is one of Europe’s major data centre locations, and data centres are among the most energy-intensive building types in the commercial property sector. A typical data centre consumes 10–50 times more energy per square metre than a standard office building, with cooling accounting for 30–40% of total energy consumption. The building envelope — specifically its insulation and airtightness — plays a critical role in determining how much energy is required to maintain the narrow temperature band that server equipment demands.
The industry standard for data centre operating temperature is 18–27°C (per ASHRAE TC 9.9 guidelines), with recommended conditions of 18–24°C. Relative humidity should be maintained at 20–80% with a dew point range of 5.5–15°C. Any heat gain through the building envelope adds to the cooling load — and every watt of heat that the cooling system must remove costs approximately 0.3–0.5 watts of additional energy to reject (depending on the cooling system efficiency and climate).
In a 1MW data hall, even a modest 5% reduction in cooling load through improved insulation delivers a meaningful annual energy saving, and across a multi-megawatt campus the savings compound quickly — which is why envelope performance is worth specifying well beyond the regulatory minimum.
Power Usage Effectiveness and the Thermal Envelope
Power Usage Effectiveness (PUE) is the industry-standard metric for data centre energy efficiency, defined as total facility energy divided by IT equipment energy. A PUE of 1.0 would mean all energy is consumed by IT equipment; typical values range from 1.2 (highly efficient) to 2.0+ (inefficient). The cooling system is the largest contributor to PUE overhead, and the building thermal envelope directly affects the cooling load.
The thermal envelope contribution to PUE varies with climate and building construction:
- In a poorly insulated steel-clad building, solar gain through the roof and walls can add 20–30 W/m² to the cooling load on summer days — equivalent to additional server heat output of the same magnitude
- In winter, heat loss through the envelope means the cooling system must reject less heat, but the building heating system (for office areas and service zones) consumes more energy
- In Ireland’s mild, maritime climate, envelope heat gains are modest for much of the year, but a well-insulated, airtight envelope still trims peak cooling loads in warm spells and — just as importantly — keeps internal conditions stable and free of condensation
Spray foam insulation contributes to PUE reduction by minimising heat gain in summer, providing an airtight envelope that enables precise air management (eliminating uncontrolled infiltration that introduces unconditioned air), and eliminating thermal bridges that create localised hot spots and condensation risk.
Condensation Risk from Cooling Systems
Data centres face a unique condensation challenge: the combination of high-capacity cooling systems, large temperature differentials between data halls and the external environment, and precise humidity requirements creates conditions where condensation can form on building fabric elements if the insulation is inadequate.
The primary condensation risks in data centres are:
- Cold surfaces near CRAC/CRAH units — Computer Room Air Conditioning (CRAC) and Computer Room Air Handler (CRAH) units supply air at 12–18°C. Ductwork, plenums, and building surfaces adjacent to these units can reach temperatures below the dew point of the room air, causing condensation.
- Roof underside in summer — in a poorly insulated building, the underside of the roof can reach 50–60°C on summer days. When the cooling system cools the air below to 18–24°C, the massive temperature differential drives moisture towards the roof, where it condenses on any cold surface within the construction.
- Chilled water pipe penetrations — chilled water systems operating at 6–12°C create cold surfaces wherever pipes pass through walls, floors, or the roof. Without insulation and vapour sealing at every penetration, condensation forms on the cold pipe surface and drips onto equipment below.
Spray foam eliminates condensation risk by maintaining all internal surfaces above the dew point temperature, sealing every penetration and service entry point, and providing an inherent vapour barrier that prevents moisture migration through the building fabric. The ability to spray around pipes, cables, and ductwork — conforming to any geometry — makes spray foam the only insulation material that can comprehensively seal every condensation risk point in a data centre.
Airtightness for Efficiency
Modern data centres rely on controlled air management — hot aisle/cold aisle containment, blanking panels, and precision air delivery — to direct cooling air precisely where it is needed. Every uncontrolled air path (gap in the building envelope, crack in a wall, unsealed cable penetration) undermines this air management strategy by introducing unconditioned air that mixes with the carefully controlled supply air.
Spray foam is an inherent air barrier: at thicknesses above 25mm, closed-cell spray foam forms a continuous air barrier that helps a building comfortably beat the reasonable upper limit of 5 m³/(h·m²) at 50 Pa set by TGD L 2022, which is tested on completion. In data centre applications, spray foam routinely achieves airtightness values below 1.0 m³/hr/m² — the level required for high-performance commercial buildings.
This airtightness delivers two benefits for data centres:
- Reduced cooling load — every cubic metre of unconditioned air that infiltrates the data hall must be cooled and dehumidified, consuming energy. Eliminating air infiltration directly reduces the cooling load.
- Improved containment effectiveness — hot aisle/cold aisle containment systems work optimally when the building envelope does not introduce additional air paths that bypass the containment. A leaky envelope reduces containment effectiveness and forces the cooling system to work harder.
Insulation Specifications for Data Centres
Data centre insulation specifications typically go well beyond the TGD L 2022 maximum U-values because the economic case for higher performance is driven by cooling energy savings rather than just regulatory compliance:
| Element | TGD L 2022 Maximum (New) | Typical Data Centre Spec | Spray Foam Thickness |
|---|---|---|---|
| Roof | 0.20 W/m²K flat / 0.16 W/m²K pitched | 0.15 W/m²K | 170–180mm |
| Walls | 0.21 W/m²K | 0.18 W/m²K | 140–150mm |
| Floor (ground-bearing) | 0.21 W/m²K | 0.18 W/m²K | Calculated for floor size and ground |
Colocation and Edge Data Centres
Colocation facilities and edge data centres — smaller facilities located in repurposed commercial or industrial buildings — face particular insulation challenges. These buildings were not designed for data centre use and typically have poor thermal performance, significant air leakage, and condensation problems. Spray foam is the optimal insulation solution for these conversions because it can be applied to any existing structure, achieves high performance within minimal space (preserving usable floor area), and provides simultaneous insulation, air sealing, and vapour control.
For edge data centres in converted shipping containers, prefabricated units, or modular buildings, spray foam provides a rapid insulation solution that transforms a standard building enclosure into a thermally controlled environment suitable for server equipment.
Installation in Live Environments
Spray foam application in data centre environments requires careful planning:
- Phased installation — in operational data centres, spray foam is applied to individual zones while other zones remain live. Containment barriers and temporary ventilation prevent spray mist from reaching active equipment.
- Out-of-hours working — new-build data centres allow unrestricted installation. Operational facilities typically schedule spray foam application during planned maintenance windows or at night when cooling load is lowest.
- Fire protection — DC315 intumescent coating is applied over spray foam where required by the fire risk assessment. Data centres typically require Euroclass B-s1,d0 in all areas due to the high consequence of fire.
Duratite supplies Nexseal LE closed-cell spray foam (0.027 W/mK, declared to I.S. EN 14315-1) for data centre insulation applications across Ireland and Northern Ireland. Contact us on info@duratite.ie for a specification consultation.