K-Flex ST Self-Seal Pipe Insulation 9mm Wall

K-FLEX ST Self-Seal insulation is the fastest way to insulate AC pipework — no adhesive required on the seam, clean finish every time.

• ✔ Self-seal — no adhesive needed on straight runs
• ✔ Class O fire-rated insulation (Euroclass BL-s2, d0)
• ✔ 2m lengths — fast installation on site

Why Use Self-Seal Insulation?

Self-seal insulation reduces installation time and eliminates adhesive on straight runs. This means faster installs, less mess on site, and consistent sealing across every job — especially valuable on larger or multi-unit installations where speed and finish quality matter.

Where This Is Used

• Refrigerant pipework on split system AC installations
• Chilled water and cooling pipework
• Domestic and commercial HVAC systems
• Any application requiring fast, clean pipe insulation

Choosing the Right Size

Select pipe bore size to match your copper pipe OD, then choose wall thickness based on your application:

• 9mm — tight spaces and short pipe runs
• 13mm — standard AC installations (most common)
• 19mm — refrigeration and low temperature systems
• 25mm+ — commercial and high-specification applications

K-FLEX vs Armaflex

K-FLEX ST offers the same Class O fire-rated performance as Armaflex, with a faster self-seal installation system and excellent value for trade use — making it a popular alternative for HVAC engineers across the UK. For underground or external pipe runs where waterproof protection is required, see our Armaflex EVO Tuffcoat underground insulation.

Key Features

• Self-seal adhesive closure — fast, clean installation without separate adhesive on straight runs
• Closed-cell elastomeric foam — prevents condensation and moisture ingress
• Class O fire rating — Euroclass BL-s2, d0
• Thermal conductivity as low as 0.031 W/(m·K)
• Service temperature range: -40°C to +85°C
• Supplied in 2m lengths

Technical Specifications

Essential Accessories

• K-FLEX ST Tape — seal joints, fittings and cut ends for a complete insulation system
• K-420 Adhesive — for bends, tees and complex connections where self-seal is not sufficient

Complete Your Installation

• AC Copper Pipe — refrigerant-grade copper pipe for AC systems
• Pipe Supports & Fixings — clips and brackets for securing insulated pipework
• Trunking & Cable Management — for neat routing of pipework and cables
• Fittings & Connectors — refrigeration fittings for copper pipe

Used With

K-FLEX ST Self-Seal insulation is installed over AC copper pipe after pressure testing and before final commissioning. Seal all joints and fittings with K-FLEX ST tape or K-420 adhesive to complete the system. For underground or external runs, see Armaflex EVO Tuffcoat.

Order K-FLEX ST Self-Seal pipe insulation today — available from UK stock with fast trade delivery.