Cold Store Temperature Requirements
Cold storage facilities operate across a wide temperature range, each with specific insulation requirements that are determined by the temperature differential between inside and outside:
| Storage Type | Temperature Range | Typical Products Stored |
|---|---|---|
| Deep freeze | -25°C to -18°C | Frozen food, ice cream, frozen ingredients |
| Frozen storage | -18°C to -12°C | Frozen goods, frozen ready meals |
| Chill storage | 0°C to +5°C | Fresh produce, dairy, meat, pharmaceuticals |
| Controlled atmosphere | +1°C to +4°C | Fruit, vegetables (long-term) |
| Cool room | +5°C to +12°C | Wine, chocolate, certain pharmaceuticals |
The greater the temperature differential between the cold store interior and the ambient environment, the more insulation is required and the more critical the quality of that insulation becomes. A deep freeze store at -25°C with ambient temperatures of +20°C has a temperature differential of 45°C — demanding extremely high thermal performance and absolute vapour integrity from the insulation system.
The Condensation Challenge at Dew Point Boundaries
Cold store insulation faces a unique condensation challenge that distinguishes it from every other insulation application. In conventional heated buildings, the warm side is inside and the cold side is outside — moisture drives outward. In cold stores, the warm side is OUTSIDE and the cold side is inside — moisture drives inward through the insulation toward the cold interior.
At some point within the insulation thickness, the temperature passes through the dew point of the ambient air. At this exact location, moisture that has migrated into the insulation condenses — and in a cold store operating below 0°C, it freezes. Over time, ice builds up within the insulation layer, progressively degrading its thermal performance in a vicious cycle: as the insulation degrades, the dew point boundary moves outward, causing ice to form across a larger portion of the insulation thickness.
This phenomenon — known as interstitial condensation and ice formation — is the primary cause of cold store insulation failure. It is invisible from either side of the insulation (the ice is inside the insulation layer) and can reduce thermal performance by 50% or more before it becomes apparent through increased energy consumption or temperature control problems.
Why Seamless Insulation Matters
The solution to interstitial condensation in cold stores is to prevent moisture from entering the insulation in the first place. This requires a perfect vapour barrier on the warm side (outside) of the insulation — and this is where spray foam has a decisive advantage over every other insulation system.
Closed-cell spray foam (Nexseal LE) is both the insulation and the vapour barrier. Every cell in the foam is closed and gas-filled — there are no connected pathways for moisture vapour to travel through. The foam is bonded directly to the substrate with no gaps, joints, or fixings that could provide a vapour pathway. The vapour barrier is integral and continuous.
Traditional cold store insulation — typically pre-fabricated insulated sandwich panels with PIR or EPS cores — relies on panel joints, panel-to-structure seals, and vapour barrier membranes for vapour integrity. Every joint between panels is a potential vapour pathway. Over time, sealants degrade, panels shift as the building moves, and the vapour barrier becomes compromised at joint after joint. This is why cold stores insulated with sandwich panels frequently develop ice within the panel joints within 5–10 years of construction.
Spray foam eliminates panel joints entirely. The insulation is a single, continuous, sealed layer with no joints, no sealants, and no mechanical fixings penetrating the vapour barrier. The risk of interstitial condensation is reduced to near zero.
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Spray Foam vs Insulated Panels for Cold Stores
| Property | Spray Foam (Nexseal LE) | Insulated Panels (PIR/EPS) |
|---|---|---|
| Vapour barrier integrity | Integral, seamless, permanent | Panel joints — degrades over time |
| Interstitial condensation risk | Very low (no vapour pathways) | Moderate to high (joint failures) |
| Ice formation risk | Very low | High at panel joints |
| Retrofit suitability | Excellent (any geometry) | Poor (requires flat surfaces) |
| Thermal bridging | None | At every panel joint and fixing |
| Lambda (W/mK) | 0.027 | 0.022–0.025 (PIR) / 0.035 (EPS) |
| Service life | 25+ years | 15–25 years (joint degradation) |
| Maintenance | Minimal | Regular joint inspection required |
| Hygiene | Non-absorbent surface, cleanable | Panel faces cleanable; joints trap moisture |
For new-build cold stores with simple, rectangular geometries, insulated sandwich panels remain a valid option — the panels can be installed with fresh sealants and careful joint detailing. For retrofit applications, upgrades to existing cold stores, irregular geometries, and any project where long-term vapour integrity is critical, spray foam is the superior choice.
Thickness Requirements by Temperature
The required spray foam thickness for cold stores depends on the operating temperature and the target U-value. Higher temperature differentials require thicker insulation:
| Operating Temp | Ambient Temp | Target U-value | Nexseal LE Thickness |
|---|---|---|---|
| +5°C (chill) | +20°C | 0.25 W/m²K | 105mm |
| 0°C (chill) | +20°C | 0.20 W/m²K | 130mm |
| -10°C (frozen) | +20°C | 0.18 W/m²K | 145mm |
| -18°C (frozen) | +20°C | 0.15 W/m²K | 175mm |
| -25°C (deep freeze) | +20°C | 0.12 W/m²K | 220mm |
These thicknesses use Nexseal LE's declared thermal conductivity (I.S. EN 14315-1) of 0.027 W/mK. The actual specification for your cold store will be calculated by Duratite's technical team based on the specific operating temperature, ambient conditions, building construction, and energy efficiency targets.
Food Safety and Hygiene Compliance
Cold stores used for food storage and processing must comply with food safety legislation including EC Regulation 852/2004 on the hygiene of foodstuffs, and are subject to inspection by Environmental Health Officers and food safety auditors (BRCGS, SQF).
Key requirements relevant to insulation:
Surfaces must be smooth, impervious, and cleanable. Closed-cell spray foam has a non-absorbent surface that can be cleaned and sanitised. Where a smoother surface is required, the foam can be coated with a food-safe paint or covered with a hygienic wall cladding panel.
No harbourage for pests or bacteria. Spray foam is bonded directly to the substrate with no voids, cavities, or joints where pests can harbour. Traditional insulated panel systems create joints and cavities that are known harbourage points for insects and rodents — a frequent finding in food safety audits.
No moisture accumulation. Closed-cell foam does not absorb water and prevents condensation at the insulation-substrate interface. This eliminates the moisture that bacterial and fungal growth requires.
Temperature stability. The seamless insulation layer maintains stable temperatures without the thermal bridges at panel joints that can create localised warm spots where product temperature rises above safe limits.
Energy Savings: The Numbers
Refrigeration is one of the largest energy costs in the food supply chain, and it runs around the clock. Insulation upgrades directly reduce this cost by reducing the heat gain that the refrigeration system must remove.
Typical energy savings from spray foam insulation upgrades to existing cold stores:
| Starting Condition | After Spray Foam | Energy Saving |
|---|---|---|
| Uninsulated walls/ceiling | Nexseal LE 105–175mm | 40–55% |
| Degraded panel insulation (ice damage) | Spray foam overlay 40–60mm | 25–40% |
| Adequate panels with failed joints | Spray foam joint sealing | 10–20% |
For a 1,000m² cold store operating at -18°C, a 35% reduction in refrigeration energy is a substantial annual saving. On typical upgrade projects, the payback period is 3–5 years, depending on your electricity tariff and operating hours.
Beyond energy savings, spray foam extends compressor life (less running time), reduces defrost cycles (less ice on evaporator coils due to reduced moisture ingress), and improves temperature stability — all of which reduce maintenance costs and improve product quality.
Contact Duratite on info@duratite.ie for a free cold store insulation survey.