Guide Contents
- 1. What is a sandwich panel and why it is the core of any cold room?
- 2. Insulation core types: PUR vs PIR vs EPS
- 3. Thickness selection table by temperature and Saudi climate
- 4. U-value and practical calculation method
- 5. External cladding options and applications
- 6. Panel joints and thermal leakage control
- 7. Floor panel special requirements and loads
- 8. Saudi and Gulf environment design considerations
- 9. Required quality standards and certificates
- 10. How to choose the right panel for your project
What is a sandwich panel and why it is the core of any cold room?
A sandwich panel is a composite building element with two metal skins and a rigid thermal insulation core in between. In refrigeration projects, this assembly forms the building envelope that controls heat gain and moisture behavior.
In Saudi summer conditions, external air temperature may approach 50 C while the room can operate at -30 C. This very high delta temperature means panel specification directly affects compressor run hours, electricity cost, and long-term system reliability.
Choosing low-grade panel systems can cause progressive efficiency loss, condensation risk, and shorter plant life. A specification-based approach is essential.
Basic engineering principle: with large temperature difference, every additional centimeter of effective insulation reduces total thermal load and operating cost over the full life cycle of the facility.
Insulation core types: PUR vs PIR vs EPS
Insulation core performance drives the panel thermal behavior. Three common options are used in the market, with distinct fire, moisture, and long-term stability characteristics.
A. PUR (Polyurethane)
Widely used with good thermal conductivity and balanced cost. Suitable for standard cooling and medium freezing in many projects.
B. PIR (Polyisocyanurate)
Improved chemistry relative to PUR, usually offering better fire behavior and thermal stability. It is commonly preferred for deep-freeze and higher compliance projects.
C. EPS (Expanded Polystyrene)
Lower-cost option with weaker thermal performance and higher moisture sensitivity over time. Usually not recommended for serious industrial freezing applications.
| Property | PUR | PIR | EPS |
|---|---|---|---|
| Thermal conductivity lambda (W/m.K) | 0.022-0.025 | 0.020-0.023 | 0.035-0.040 |
| Density (kg/m3) | 38-42 | 40-45 | 15-25 |
| Fire behavior | Medium | Better | Weak |
| Moisture absorption | Very low | Very low | Medium to high |
| Temperature range | +80 to -40 C | +120 to -50 C | +70 to -20 C |
| Relative cost | Medium | Medium to high | Low |
| Typical use | General cooling and freezing | Deep and industrial freezing | Light cooling only |
Elfarida Ice recommendation: for industrial freezer rooms, PIR in walls and ceiling with higher-density floor system provides a practical performance and durability balance.
Thickness selection table by temperature and Saudi climate
Required thickness must be selected using target room temperature, ambient conditions, and insulation thermal conductivity, not generic catalog values.
| Room Type | Temperature Range | PUR Thickness | PIR Thickness | Target U-Value |
|---|---|---|---|---|
| Fruit and vegetable cooling | +2 to +8 C | 80-100 mm | 80 mm | <= 0.28 W/m2.K |
| Meat and dairy cooling | 0 to +4 C | 100 mm | 100 mm | <= 0.25 W/m2.K |
| Pre-cooling | -2 to +2 C | 120 mm | 100 mm | <= 0.22 W/m2.K |
| Medium freezing | -18 to -20 C | 150 mm | 120 mm | <= 0.18 W/m2.K |
| Deep freeze | -25 to -30 C | 200 mm | 150-180 mm | <= 0.14 W/m2.K |
| Blast freezing | -35 to -40 C | 250 mm | 200 mm | <= 0.11 W/m2.K |
| Floor system | As per room class | +25-50 mm extra | +20-40 mm extra | Load-adjusted |
Saudi design note: very hot ambient conditions typically require thicker or better-performing panel systems than many mild-climate reference tables.
U-value and practical calculation method
U-value represents total heat transfer through one square meter per degree of temperature difference. Lower U-value means better insulation and lower energy use.
The simplified model uses serial thermal resistance terms.
R_total = R_si + R_facing1 + R_core + R_facing2 + R_se
// Core resistance:
R_core = t_insulation / lambda_insulation
In practice, better lambda and greater thickness reduce U-value and directly lower compressor load.
Daily heat loss calculation
A quick estimation can be performed using envelope area, U-value, and total temperature difference.
// Daily energy impact scales strongly with both U and DeltaT.
Meaning in operation: reduced daily thermal gain accumulates into major annual electricity savings, often exceeding initial panel upgrade cost over project lifetime.
External cladding options and applications
Cladding selection controls corrosion resistance, cleanability, and long-term durability under project conditions.
| Cladding Type | Typical Thickness | Applications | Main Benefits | Limitations |
|---|---|---|---|---|
| Painted galvanized steel | 0.4-0.6 mm | General cold rooms | Competitive cost | Lower chemical resistance |
| Polyester-coated steel | 0.5 mm | Food and general cooling | Good corrosion performance | Requires careful handling |
| PVDF-coated steel | 0.5-0.6 mm | Harsh and coastal environments | High UV and salt resistance | Higher cost |
| Stainless steel | 0.4-0.5 mm | Hygienic plants and healthcare | Excellent hygiene and corrosion resistance | Highest cost |
| Aluminum | 0.4-0.5 mm | Roofs and wet environments | Lightweight and rust-free | Lower structural strength |
| FRP | 1.0-1.5 mm | Chemically aggressive plants | Strong chemical resistance | Heavier, less structural stiffness |
Coastal note: in high-salinity zones, PVDF or stainless options on exposed faces significantly improve service life.
Panel joints and thermal leakage control
Joint lines are the most sensitive points for thermal bridging and air leakage. Installation quality is as critical as panel quality.
A. Tongue and groove / cam lock systems
Proper mechanical interlock with suitable gasketing minimizes leakage and improves effective in-service U-value.
B. Expanding foam sealant strategy
Closed-cell sealants are required around joints, corners, and penetrations to avoid moisture-driven insulation degradation.
C. Corners and penetrations detailing
Pipe and cable penetrations need engineered detailing; these points are frequent sources of hidden thermal loss.
Common mistake: continuous metal fasteners bridging exterior and interior faces create direct thermal bridges and should be avoided.
Floor panel special requirements and loads
Floor systems see heavy point loads, dynamic traffic, and moisture exposure. Their design criteria differ substantially from wall and ceiling panels.
| Criterion | Cooling Floor (+2 C) | Freezing Floor (-18 C) | Deep-Freezing Floor (-30 C) |
|---|---|---|---|
| Panel thickness | 120-150 mm | 150-200 mm | 200-250 mm |
| Top face | 0.5 mm galvanized steel | 0.6 mm reinforced galvanized steel | Reinforced steel or FRP |
| Distributed load | 5 kN/m2 | 7.5 kN/m2 | 10 kN/m2 |
| Forklift wheel point load | 7 kN | 10 kN | 15 kN |
| Sub-floor requirement | Moisture control | Extra thermal layer + moisture barrier | Under-floor heating + insulation |
For deep-freeze projects, under-floor heating is often mandatory to prevent frost heave and structural damage beneath the slab.
Integrated floor solution: combine thermal insulation layer, moisture barrier, and controlled under-floor heating in deep-freeze rooms.
Saudi and Gulf environment design considerations
Regional climate introduces constraints beyond standard temperate-climate references.
A. High ambient temperature impact
Large temperature differences raise heat gain substantially, requiring stricter envelope design.
B. Coastal humidity and salt exposure
Elevated humidity with chloride exposure accelerates corrosion on insufficiently protected cladding.
C. Solar radiation on external faces
Light exterior colors and suitable coatings reduce absorbed heat under high summer sun.
D. Outdoor installation constraints
UV-resistant gaskets and exposed-joint protection are required for many freestanding outdoor rooms.
| Condition | Recommended Technical Response | Cost Impact |
|---|---|---|
| Ambient >= 45 C | Increase envelope performance relative to standard tables | Panel premium |
| Coastal environment | PVDF or aluminum on exposed outer faces | Moderate premium |
| Outdoor installation | UV-resistant gaskets and edge protection | Low to moderate premium |
| Deep freeze with high ambient | Higher-performance panel and floor heating strategy | High premium |
Required quality standards and certificates
Real panel quality must be proven by standards compliance and documented test performance, not catalog claims only.
A. European standards (EN)
- EN 14509: sandwich panel product standard and key thermal/mechanical properties.
- EN 13501-1: fire classification reference for panel systems.
- EN 10169: organic coated steel requirements.
- EN 15715: installation and field-performance related practices.
B. Additional certificates for food facilities
- HACCP compliance: cleanability and hygiene suitability.
- Food-grade declaration: where direct food-area suitability is needed.
- GCC/SASO alignment: where required by project authority or scope.
C. Field quality verification tests
Typical checks include insulation density, thermal conductivity confirmation, and bond strength validation between core and facings.
Market caution: always request third-party test evidence with shipment documentation, especially for large industrial projects.
How to choose the right panel for your project
A reliable panel decision follows engineering sequence, not purchase price alone.
- Define operating temperature class with clear room duty profile.
- Set target U-value based on thermal load and refrigeration design margin.
- Select insulation core type based on performance and safety priorities.
- Select cladding system for the specific project environment.
- Verify certificates and test reports before procurement commitment.
- Evaluate life-cycle cost using purchase plus long-term energy impact.
Elfarida Ice service: we provide engineering support for panel specification, U-value targeting, supplier offer review, and practical life-cycle optimization. Contact us for a free consultation.