Thermal insulation (network insulation)

Pipe insulation involves thermally insulating hot and cold networks and equipment (heating/DHW pipes, cooling loops, tanks, heat exchangers, rooftop networks) to reduce heat loss, prevent condensation, ensure stable temperatures, and protect people. When properly designed, it reduces energy consumption (kWh), stabilizes temperature differences (ΔT) at emitters, improves generator efficiency, and extends the lifespan of installations.

Thermal insulation: operational definition

In practice, a continuous insulating layer is placed around the sections to be treated, taking care with the joints and critical points (elbows, tees, valves, supports). Common materials:

- Elastomer (flexible foam) : good vapor sealing for cold/cold DHW, quick installation.

- Mineral wool (rolls/shells) : high temperature resistance for heating/low vapor, good acoustics, requires vapor barrier in cold conditions.

- Polyurethane (PUR/PIR) or phenolic: very low λ → high performance at low thickness, beware of fire reaction depending on range.

For the finishes: aluminum/stainless steel cladding, rigid covers and shells, PVC skins in technical rooms, and metal skins on the exterior. The thickness is sized to maintain a target surface heat flux (W/m²), avoid falling below the dew point in cooling applications, and respect safety temperatures in heating applications. Valves and flanges are treated with removable insulating covers to allow for maintenance. The supports are fitted with insulating collars/brackets to minimize thermal bridging.

Advantages, limitations and points to consider regarding thermal insulation

Interests

• Energy: linear losses ↓, generation/production efficiency ↑, ΔT respected up to the terminals.
• Comfort & safety: stable temperatures, anti-scalding when hot, anti-condensation when cold.
• Durability: less corrosion under thermal insulation if sealed details and vents are provided.
• Operation: traceability (color/flow labeling), removable coats for rapid interventions.

Boundaries

• Additional initial cost (materials + labor), quick return but needs to be demonstrated.
• Sensitivity to water (rain, washing, leaks): risk of CUI if finishing and drainage are neglected.
• Poorly handled singular points = hidden losses despite "nice straight lines".

Points to consider

• Continuity: treat elbows, valves, flanges, supports (insulating jackets, thermal inserts).
• Vapor & cold: continuous vapor barrier and taped joints to prevent dew; choose high μ elastomer.
• Exterior: waterproof cladding + neat joints, slope/drainage to evacuate water.
• Fire & classification: select products suitable for the premises and heights (reaction to fire).
• Maintenance: provide removable hatches and covers on operating mechanisms and instruments.
• Identification: colour codes/direction arrows and fluid marking for quick reading in operation.
• Installation quality: closed beads, limited breaks, clean cut; control of thermal bridges at the supports.

Anecdote — “The pipes that stopped sweating in Rennes”

In Rennes, a chilled water loop in the basement dripped in during the summer, spreading dampness throughout the building. The existing insulation was inadequate: open joints, exposed valves, and bare metal supports created thermal bridges. The team overhauled the system: high-μ elastomer with a continuous vapor barrier, removable jackets on the valves/flanges, insulating inserts at the clamps, and a sealed aluminum skin over the entire system. The result: condensation eliminated, corrosion stopped, and the temperature difference (ΔT) met at the fan coil units. The technical manager summarized: "We stopped cooling the corridor... and finally cooled the rooms."