Key Performance Indicators of NBR Rubber Foam Insulation

NBR (Nitrile Butadiene rubber) rubber foam insulation is a widely used closed-cell insulation material for HVAC, refrigeration, marine, and industrial applications. To ensure safety, durability, and long-term energy efficiency, it is essential to evaluate NBR insulation based on verified technical indicators rather than appearance or price alone.

This article explains the core performance indicators of NBR rubber foam insulation, with reference to the performance levels commonly achieved by high-quality products manufactured under strict quality control standards.

1. Oxygen Index (OI ≥ 32): Fire Safety Performance

The Oxygen Index (OI) represents the minimum oxygen concentration required for a material to sustain combustion. Since normal air contains approximately 21% oxygen, a higher oxygen index indicates better flame resistance.

High-quality NBR rubber foam insulation typically achieves an oxygen index of 32 or higher, which means:

• The material is self-extinguishing under normal atmospheric conditions
• Fire spread is effectively limited
• Overall system fire risk is significantly reduced

An oxygen index ≥ 32 reflects optimized rubber formulation and controlled production processes, making the material suitable for projects with enhanced fire safety requirements.

2. Thermal Conductivity (K / λ ≤ 0.032–0.034 W/m·K)

Thermal conductivity, commonly expressed as K value or λ value, determines how efficiently heat is transferred through the insulation material. Lower values indicate better insulation performance.

Premium NBR rubber foam insulation typically maintains:

• K / λ value ≤ 0.032–0.034 W/(m·K)
• Stable thermal performance over long-term service life

Long-term stability is critical in HVAC and refrigeration systems, where temperature fluctuations are frequent. High-quality NBR rubber foam retains its thermal insulation properties over time, helping reduce energy loss and operating costs.

3. Water Vapor Resistance (μ 4,500–8,000): Anti-Condensation Capability

The water vapor resistance factor (μ value) measures a material’s ability to resist water vapor diffusion. This is a key indicator for preventing condensation on cold pipelines and equipment.

High-performance NBR rubber foam insulation generally provides:

• μ value ranging from 4,500 to 8,000
• Excellent moisture resistance in humid environments
• Reduced risk of condensation and corrosion under insulation (CUI)

Due to its closed-cell structure, NBR rubber foam functions as both thermal insulation and an effective vapor barrier, often eliminating the need for additional vapor control layers.

4. Environmental & Health Performance: Formaldehyde-Free and Dust-Free

Environmental and health considerations are increasingly important in modern construction and industrial projects. High-quality NBR rubber foam insulation is formulated to meet stricter material safety expectations.

• No formaldehyde, supporting better indoor air quality
• No dust or fiber release during cutting or installation
• Safer handling for installers and maintenance personnel

These characteristics make NBR rubber foam insulation suitable for commercial buildings, public facilities, ships, and enclosed technical spaces.

Conclusion: Choosing Reliable NBR Rubber Foam Insulation

When selecting NBR rubber foam insulation, verified technical indicators provide a reliable basis for decision-making. Key factors such as oxygen index, thermal conductivity, water vapor resistance, and environmental safety directly affect performance and service life.

High-quality NBR rubber foam insulation manufactured under controlled processes can deliver enhanced fire resistance, long-term thermal efficiency, effective anti-condensation protection, and clean, environmentally responsible material performance—meeting the demands of modern insulation applications.