KAIFLEX – High Performance for the Insulation in Cold Applications

KAIFLEX (Flexible elastomeric foam, FEF) is made from synthetic rubber and is particularly characterized by its closed-cell structure. This structure acts as an integrated vapor barrier, making FEF an ideal solution for cold and alternating temperature applications, as it effectively prevents the formation of condensation.

Modern rubber-based insulation materials also set benchmarks in terms of energy efficiency and fire safety.

Three Basic Principles of Effective Cold Insulation

1. Surface Preparation with an effective Corrosion Protection System

In addition to selecting the appropriate insulation material, proper preparation of the surfaces of pipes and system components is essential. This includes the application of a suitable corrosion protection system.

Whether a corrosion protection coating is mandatory or provides additional safety depends largely on the ambient conditions and medium temperatures.

·         For systems made of unalloyed or low-alloyed steel operating continuously at temperatures below -10 °C, corrosion protection is generally not strictly required but provides added security.

·         For systems operated at temperatures above -10 °C or under alternating conditions – as is the case with heat pumps – an additional corrosion protection coating is essential, as condensation can form underneath the insulation regardless of the material used.

For systems made of austenitic stainless steel or copper, the necessity of corrosion protection should always be assessed. In aggressive environments – such as swimming pools, where high humidity combines with elevated chlorine concentrations – an appropriate corrosion protection system must also be applied to stainless steel components to prevent stress corrosion cracking.

The Kaifinish corrosion protection system – consisting of Kaifinish Primer, Base, and Cover – offers an ideal solution for protecting pipes and equipment in cold applications. This single-component system is easy to apply, dries quickly, and minimizes application errors compared to conventional two-component systems.

2. Elastomeric Foams – Three different Rubber Types and their Applications

Flexible elastomeric foams are the optimal solution for condensation control due to their closed-cell structure and low water vapor permeability. High-quality FEF insulation products achieve thermal conductivity values as low as 0.033 W/m·K and water vapor diffusion resistance values of μ ≥ 10,000. This ensures high energy savings and reliable condensation protection even with minimal insulation thicknesses.

Additionally, the dark, non-reflective surface of many FEF products provides a high surface emissivity (≥ 0.9). This combination creates ideal conditions for controlling surface temperatures and preventing condensation and corrosion under insulation (CUI).

Flexible elastomeric insulation materials are primarily based on three rubber types:

·         Nitrile Butadiene Rubber (NBR)

·         Ethylene Propylene Diene Monomer (EPDM)

·         Chloroprene Rubber (CR)

NBR is the most commonly used rubber type and is often combined with polyvinyl chloride (PVC) to enhance mechanical stability and overall performance. Due to its well-balanced properties in terms of fire safety, thermal conductivity, water vapour diffusion resistance, and tactile quality, NBR-PVC blends have become the industry standard.

In addition to NBR-PVC compounds, pure NBR foams are also available. PVC, being a halogen-containing material, is undesirable in certain applications. Pure NBR insulation without PVC is therefore required to meet high-level building certifications, such as the DGNB “Platinum” standard.

EPDM stands out due to its exceptional temperature resistance from -200 °C to +150 °C and its inherent UV stability, eliminating the need for additional protection in outdoor environments. It is therefore widely used in industrial processes and solar applications for example.

CR (Chloroprene Rubber) represents a more recent development and offers excellent fire performance. It is particularly suitable for safety-sensitive environments such as public buildings. Even without additional coating, CR foams can achieve fire ratings of B_L-s1, d0, ensuring maximum personal safety.

In addition to these material-specific properties, there are several other reasons why elastomeric foams are the ideal solution for a wide range of applications.

·         They offer outstanding sound and vibration insulation, especially for pipes and ventilation ducts.

·         In hygiene-critical environments, elastomeric insulation is particularly well-suited thanks to its resistance to mold and microbes and low VOC emissions.

Thanks to their versatility and ease of installation, elastomeric foams are now widely used in all types of buildings and for applications such as:

·         Chilled water and refrigerant lines

·         HVAC systems (heating, ventilation, air conditioning)

·         Interior and exterior ductwork

·         Industrial insulation (e.g. pharmaceutical, food, and beverage industries)

·         Marine and offshore installations

·         Solar thermal systems, Heat pumps

·         Automotive applications (buses, trucks and caravans)

A perfect example of the combination of halogen-free insulation and high fire safety is the new Kaiflex HFplus s2 ALU. It contains no halogens, PVC, chlorides, or brominated flame retardants, yet still achieves a B-s2, d0 fire classification. It therefore represents the optimal solution when the high standards of personal safety must be met – especially in buildings designed in accordance with green building standards such as BREEAM, DGNB, or LEED.

3. Correct Installation of Flexible Elastomeric Foams

As with any type of insulation, selecting the right material, determining the correct insulation thickness, and ensuring professional installation are all critical factors. In cold insulation systems, even minor installation errors can lead to condensation on or beneath the insulation.

In addition to manufacturer-specific and material-specific installation guidelines, general standards must also be followed.

Cold insulation must always be installed to be vapour tight. This means all seams and joints must be fully sealed with adhesive, leaving no open areas. Furthermore, segmented sealing points must be included at defined intervals. These serve to prevent moisture from spreading throughout the entire insulation layer in the event of localized damage.

The closed-cell structure of elastomeric foam also provides a safeguard: in case of minor damage, the insulation does not become fully saturated, as each layer acts as an independent vapor barrier.

Besides maintaining the required minimum clearances between pipes and ducts and using only approved combinations of insulation materials and adhesives, many additional processing guidelines must be observed.

For example, halogen-free insulation materials require special care during installation: due to the absence of PVC – and thus the absence of mechanically stabilizing components – they must be installed without mechanical stress to avoid material fatigue or cracking.

All relevant details can be found in applicable standards, specifications, and technical guidelines.

References

https://www.kaimann.com/

https://www.isover-technical-insulation.com/