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ASTM C553
Standard Specification for Mineral Fiber Blanket Thermal Insulation for Commercial and Industrial Applications
Overview
ASTM C553 covers blanket-form insulation made from rock, slag, or glass fibers. This insulation, with fibers oriented primarily parallel to the face, is intended for thermal control on surfaces in commercial and industrial buildings. Service temperature range typically spans 0°F (-18°C) to 1200°F (649°C). The standard classifies insulation into seven types based on performance characteristics.
Seven Type Classifications
- Type selection based on maximum use temperature requirements
- Apparent thermal conductivity values at various mean temperatures
- Surface burning characteristics per ASTM E84 for code compliance
- Water vapor sorption limits for humidity resistance
- Corrosiveness testing to protect steel components
- Odor emission requirements for occupant comfort
Critical Vapor Retarder Requirements
For below-ambient applications like chilled water or refrigeration lines, a continuous, properly sealed vapor retarder system is essential. Without it, water vapor migrates through insulation to cold pipe surfaces where it condenses. This trapped moisture drastically reduces thermal effectiveness, promotes corrosion, and can lead to mold growth. The vapor retarder is just as important as the insulation itself for low-temperature applications.
Type Selection Strategy
Instead of generic "mineral wool blanket" callouts, specify the exact Type (I-VII) that aligns with system operating temperature and performance needs. High-temperature steam pipes require types with high maximum use temperatures (e.g., Type VII at 1200°F), while chilled water pipes prioritize low water vapor sorption. Using specific Type designations ensures the supplied product has the correct performance profile.