Combined Cycle Thermal Power Plant, Castejón
High-performance acoustic enclosure over HRSG boiler with full structural decoupling.
The challenge
The primary objective was to correct acoustic immission levels around the Combined Cycle Thermal Power Plant of Castejón, specifically near Group 1 and, particularly, in the Heat Recovery Steam Generator (HRSG) area, identified as one of the main sources contributing to limit exceedances at sensitive receptors in the surroundings.
Previous acoustic assessments revealed greater impact during nighttime, due to lower background noise, stricter regulatory requirements and less favourable propagation conditions. The intervention was designed to ensure compliance with Spanish Noise Law 37/2003 and the applicable regional regulations of the Foral Community of Navarra.
The solution
The adopted solution consisted of a perimeter acoustic enclosure over the boiler area, composed of high-insulation multilayer modular panels (steel sheet + interior absorbent + acoustic barrier + perforated sheet), with an estimated Rw ≥ 35–40 dB. The system incorporated interior absorbent treatment to reduce reverberation, sealed acoustic doors and specific sealing at junctions and services.
The structural decoupling design was particularly important. The enclosure was elastically anchored using anti-vibration supports and resilient layers at all contact points, preventing solid-borne noise transmission. New foundation footings were also built to support the steel structure, designed with a continuous perimeter damping system using high-durability elastomers with controlled dynamic stiffness.
The result
This system reduced structural transmission, eliminated acoustic bridges and minimised possible resonance amplifications, ensuring long-term effectiveness in a demanding outdoor industrial environment. Full compliance with both national and regional regulations was achieved, eliminating the exceedances that were especially critical during the nighttime period.
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