Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
Steel-framed sports arenas, characterised by their extensive spans, high ceilings and frequent usage, require thermal insulation design that directly impacts energy consumption, occupant comfort and structural longevity. A well-considered insulation layer must integrate thermal performance, structural integrity, fire resistance, moisture control and acoustic requirements.
Fundamental Principles of Insulation Layer Design
1. External insulation takes precedence: Given the high thermal conductivity of steel structures, external insulation effectively prevents thermal bridges. Particular attention should be paid to the junctions of beams and columns, where external insulation or composite sandwich panels should be employed.
2. Determine the insulation thickness based on climate and functional requirements.
3. Anti-condensation design: A moisture barrier and a breathable waterproof layer must be incorporated within the insulation layer to prevent internal condensation that could compromise the insulation material’s effectiveness.
Selection of Insulation Materials
| Materials | Characteristics | Applicable areas |
| PU | Low thermal insulation coefficient | Complex components and joints |
| Rock wool | Excellent fire resistance and sound insulation | Wall and roof sandwich panels |
| Composite sandwich panels (metal facing + insulating core) | Structural integration, rapid construction | External wall and roof prefabricated systems |
Material selection should be based on a comprehensive assessment of thermal performance, fire resistance rating, compressive strength, ease of installation, and cost, whilst complying with local fire regulations (such as A1 fire requirements).
Thermal bridge treatment
External Structural Insulation: Install insulation layers on the exterior surfaces of steel columns and beams, with thickness determined by thermal bridge calculations. Where necessary, apply locally thickened insulation or thermal break pads at thermal bridge locations.
Double-Layer Insulation System: An outer primary insulation layer combined with an inner sandwich insulation layer forms a ‘thermal bridge barrier layer’, particularly suitable for prefabricated composite walls.
Detailed Joint Design: At beam-column junctions, support points, and wall-penetrating pipes, employ mesh fabric wrapping, staggered insulation board joints (offset ≥200 mm), and seal with moisture-proof and waterproof tape to prevent thermal bridge leakage.
Moisture-proofing, waterproofing and condensation control
Damp-proof layer: Install a damp-proof membrane or breathable waterproof layer between the insulation and the structure to prevent moisture penetration causing the insulation material to absorb water and fail.
Waterproof layer: The roof waterproofing should be positioned externally to the insulation layer or incorporate waterproofing membrane within the external insulation system, with overlaps ≥150 mm to ensure rainwater does not infiltrate the insulation layer.
Ventilated cavity: Incorporate an external ventilation cavity in external walls. Employ light-coloured finishes or reflective coatings to reduce external surface temperatures, further mitigating condensation risks.
Condensation verification: Conduct internal dew point analysis using thermal simulation software. Where necessary, incorporate a breathable layer or additional vapour barrier within the insulation layer.
