Picking the right pipe


19 August 2021

Tom Merton, a technical specialist at Armacell, discusses how checking the fire rating of pre-insulated pipe can save you more than just money. 

The UK is preparing to host the 26th United Nations Climate Change Conference (COP26) in November to accelerate global action towards the goals of the Paris Agreement and the UN Framework Convention on Climate Change. As a result, the onus on the country to decarbonise has never been more intense.

Central to the government’s raft of strategies to achieve net zero carbon emissions by 2050 are external source heat pumps, requiring electrical energy only for power and providing an efficient means of heat generation. While the push to install 600,000 units by 2028 is spread across domestic and commercial sectors, the greatest focus is within the domestic arena.

Working patterns

Meanwhile, the last 18 months has seen a shift towards more flexible working patterns, with many people now choosing to work from home. The recent Office for National Statistics report (Business and Individual Attitudes Towards the Future of Homeworking, UK: April to May 2021) suggests that, even once the pandemic is over, hybrid working will become the norm, with up to 85 per cent of staff currently working remotely wishing to split their weeks between home and office long-term. Remote operation has been accompanied by employees adapting their homes to make them more compatible with work, and many are installing domestic air-conditioning systems.


Consumers rely on specifiers to stipulate heat pump and air conditioning systems that are as energy-efficient as possible. As a leading manufacturer of flexible equipment insulation material and engineered foams, Armacell, is encouraging them to consider the integration of pre-insulated copper pipes. The company is also urging specifiers to ensure that the products have achieved the highest possible fire rating to ensure that systems are as safe as possible.

When selecting copper piping for domestic external heat pump and air-conditioning systems, pre-insulated pipes are the best option, as they preclude the messy and time-consuming process of on-the-job insulation. Select those with a textured, adhesive finish to allow contractors to quickly and easily join and separate pipes without the application of glue.

One of the highest fire performance ratings is Euroclass BL-s1,d0. Pre-insulated pipes with this rating are guaranteed to generate no or very little smoke in the event of a fire, and no flaming particles, allowing inhabitants time to evacuate their homes safely.

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Look for products coated in a material such as polyolefin-copolymer, which makes them resistant to mechanical damage whilst also protecting against ultraviolet (UV) radiation. Those featuring insulation of closed-cell composition are also beneficial as they limit the formation of condensation, and so prevents loss of thermal efficiency over time.

Armacell’s Tubolit Split and DuoSplit pre-insulated seamless drawn copper pipes are designed for domestic and commercial use. They may be used to connect the indoor and outdoor components of split and multi-split air-conditioning systems and be suitable for external air source heat pumps. In addition, they may be used with refrigerants R410A and R407C, as well as R32 and R290 in accordance with EN 12735-1. Tubolit Split is a single pre-insulated copper pipe, while DuoSplit is a jointed pair for use when the two pipes follow the same route.

Product support

It is important to select pre-insulated copper pipes from a manufacturer that can provide contractors with technical support and application training. Not only does manufacturer training help contractors to ensure that specified products are correctly installed, but it also helps to reinforce the importance of honouring specifications, both at the stage of initial construction and repair.

According to the National Building Specification (NBS) Technology Platform, 70 per cent of respondents to a recent survey agreed that product substitution remains a real issue in the industry. There are various reasons for contractors deciding to substitute specified products, and the main one is cost.  However, in our experience, the practise can result in increased contractor costs long-term.  

In Armacell’s 55 years’ experience of supplying some of the UK’s biggest and best-known technical insulation products, we’ve seen many instances of installers substituting closed-cell insulation for open-cell versions. Unfortunately, this led to moisture intrusion and loss of thermal efficiency, and in every instance, the outcome for the contractor has been expensive remedial work.

Armacell offers one of the largest portfolios of HVAC-R and industrial insulation products, including the UK’s most popular flexible elastomeric foam (FEF), AF/ArmaFlex Class 0. An industry pioneer, the company, invented flexible foam for equipment insulation; it remains the only UK manufacturer of FEF; AF/ArmaFlex Class 0 was the first FEF to achieve British fire safety standards. It is an environmentally responsible manufacturer:  ISO 14001-certified, its manufacturing processes minimise greenhouse gas emissions and are energy-efficient.

With a UK-based dedicated customer service team, national sales representatives and a technical support and application training service, Armacell  provides an extensive range of value-added services.