FAQ | Pipe Insulation Questions Answered

Product & Specification

What insulation thickness do I need?

Thickness depends on pipe size, fluid temperature, ambient conditions, and the applicable standard. For heating and chilled water systems in the UK, BS 5422 is the primary reference. Our BS 5422 Resource Centre includes thickness tables and a plain-English guide to help you specify correctly.

What's the difference between closed-cell and open-cell pipe insulation?

Closed-cell insulation (such as Armaflex and K-Flex) has a sealed cell structure that resists moisture vapour — essential for cold pipes, refrigeration, and chilled water. Open-cell foam absorbs moisture and is not suitable for below-ambient applications. See our Closed-Cell vs Open-Cell guide for a full comparison.

Do I need a vapour barrier?

For cold pipes (chilled water, refrigeration, heat pump pipework), a continuous vapour barrier is critical to prevent condensation forming inside the insulation. Armaflex and K-Flex self-seal products provide an integral vapour barrier when correctly installed. Visit our Condensation & Vapour Barrier Resource Centre for full guidance.

Which insulation is suitable for outdoor use?

For external applications, you need UV-resistant insulation. Armaflex Tuffcoat and K-Flex ST Clad are specifically designed for outdoor exposure. Browse our Outdoor Pipe Insulation collection.

What pipe OD should I use when selecting insulation?

Always select insulation based on the outside diameter (OD) of the pipe, not the nominal bore. Our product pages list compatible pipe ODs for each size. If you're unsure, our Knowledge Hub guides on pipe sizing can help.

Ordering & Delivery

Do you offer free shipping?

Yes — free UK shipping on orders over £100. Orders below £100 are subject to a standard delivery charge calculated at checkout.

How quickly will my order arrive?

Most orders are dispatched same or next working day. Delivery times vary by carrier and location but are typically 1–3 working days within Great Britain.

Can I return a product if it's not suitable?

Yes. If a product is unused and in its original packaging, you can return it within 30 days. Please contact us before returning to arrange the process.