Steam Trap Insulation: Heat Loss & Savings
Steam traps and their strainers are small but numerous and run continuously hot; left bare they waste heat and are routinely skipped during insulation. Removable trap covers insulate them while keeping the trap testable.
Heat loss vs insulated — by surface temperature
| Surface temp | Bare loss | Insulated | Outer surface | Reduction |
|---|---|---|---|---|
| 120 °C | 1,839 W/m² | 99 W/m² | 27 °C | 94.6% |
| 150 °C | 2,564 W/m² | 138 W/m² | 29 °C | 94.6% |
| 180 °C | 3,394 W/m² | 180 W/m² | 32 °C | 94.7% |
| 200 °C | 4,012 W/m² | 210 W/m² | 34 °C | 94.8% |
Per-m² flat-surface flux, ASTM C680 / ISO 12241, 50 mm Lamella (≤220 °C) or 100 mm Wired mat (>220 °C), 20 °C ambient. Multiply by the bare area.
Worked examples (per year, 8,000 h, natural gas)
| Item | Heat saved | Energy/yr | CO₂/yr | € saved/yr |
|---|---|---|---|---|
| A steam trap station (0.18 m², 165 °C) | 0.5 kW | 5 MWh | 1.0 t | €276 |
| A strainer / y-strainer (0.16 m², 160 °C) | 0.4 kW | 4 MWh | 0.8 t | €234 |
FAQ
How much heat does a bare steam trap lose?
At 20 °C ambient (ASTM C680): a steam trap station (~0.18 m², 165 °C) loses about 0.5 kW; a strainer / Y-strainer (~0.16 m², 160 °C) about 0.4 kW. Insulating a steam trap station saves ≈5 MWh and ≈1.0 t CO₂ per year (8,000 h).
Can you insulate thermodynamic and similar?
Yes. Traps are tested and replaced regularly, so they are left bare. Removable covers come off for testing and refit in seconds. Inzonex covers thermodynamic, float, bucket and thermostatic traps plus strainers. The outer surface drops to a touch-safe ≤45 °C and the part stays serviceable.
How much does steam trap insulation save?
Each item saves 96–98% of its bare loss. A steam trap station at 165 °C saves ≈276 €/yr of energy (≈5 MWh, ≈1.0 t CO₂) at typical gas prices; payback is usually under two years.
What insulation thickness is used?
Up to 220 °C surface: 50 mm mineral-wool (Lamella); above 220 °C: 100 mm (Wired mat), because conductivity rises with temperature. Both keep the outer surface ≤45 °C.