Why Pipe Insulation Really Matters
Chris Ridge explains why appropriate insulation of pipework can be vital to energy reduction, yet is far too often overlooked in specification – and if the findings in the industrial sector is true for domestic and commercial applications, it could be wasting the equivalent of a million households’ worth of energy.
Thermal insulation of pipework is a genuine ‘no-regrets’ option for decarbonisation in domestic, commercial and industrial applications. Yet, thermal insulation of pipework is often an afterthought and passive carbon reduction opportunities are being missed – both on newbuild projects and in retrofit applications.
As the saying goes, “What gets measured gets done.” A report by the European Industrial Insulation Foundation (EiiF) indicates that the potential energy saving from improving insulation in the UK’s industrial sector alone is 1.183 ktoe – equivalent to the annual energy consumption of 863,000 households. This clearly indicates that a huge amount of pipe insulation retrofit isn’t “getting done.”
But can the losses from inadequately insulated pipework be accurately measured in the first place? The answer is yes – but, in some cases at least, it’s complicated.
Measuring heat loss in the industrial sector
The EiiF has already conducted a huge amount of research into the potential scale of energy losses within the European industrial market. Given that many industrial facilities operate with process pipework at high temperatures – significantly higher than standard HVAC systems – and that associated heat losses on high temperature applications will be accordingly higher, the industrial market is already a step ahead in terms of recognising the issues associated with energy losses on pipework systems.
There are huge carbon and financial savings to be made by insulating both the pipework and associated components such as valves and flanges. This can be measured through tools such as the EiiF’s TIPCHECK (Technical Insulation Performance Check).
An accurate model of the energy and financial savings can be reported to the customer and TIPCHECK even aligns with the new thermal insulation energy classification system, enabling a client to specify a minimum energy classification for their facility. The subsequent report will deliver a full breakdown of the energy and financial savings that can be made by implementing a thermal insulation installation to the required energy class.
In industrial applications where the Delta T can be significant, the payback time for what are often non-invasive measures (i.e. application of valve jackets) can often be measured in weeks rather than years (see heat loss images above).
For the industrial market, the measurement tools are already in place, but what is needed is greater awareness of the issues, so that the industrial sector can recognise thermal insulation as the low hanging fruit for decarbonisation that it is.
Above: Non-UV resistant nitrile rubber installed in external locations can quickly degrade
Insulation issues in the commercial sector
Traditional water-based heating and cooling systems are designed to operate at set temperatures. Heat gains and heat losses can therefore be calculated in a straightforward manner and the return on investment can therefore be calculated (again TIPCHECK is a good tool for representing this). Commercial HVAC projects naturally will typically have a lower Delta T than industrial process applications, yet the payback period for retrofitting pipe insulation and valve jackets can still be inside two years.
However, things get a little more complicated when it comes to commercial refrigeration systems. VRF and DX systems can operate at various temperatures and understanding how poor insulation affects the system performance is not so straightforward, as refrigeration expert Lawrence Leask explains: “The complexity of a VRF systems is exacerbated by the fact that they can provide both heating and cooling at the same time, which dramatically boosts performance. Some systems will also have heat recovery and so will utilise either two or three pipes. If the external insulation is either poor or saturated, this could destroy any potential heat recovery – negating the costs of running extra pipework; additional refrigerant charge; or the cost of installing a more efficient system.”
This is no trifling concern. A significant proportion of commercial refrigeration projects utilise non-UV-resistant materials which can fail quickly in an external environment.
Lawrence has been so concerned by such widescale issues that he has been collecting examples of failed nitrile rubber insulation and conducting simple tests on them. The results showed that failed nitrile will double its weight within five minutes when in contact with water, with moisture meter levels increasing from 0% to 20%.
He has also tested several VRF systems in heating mode whilst on site and found that here the moisture levels varied from 5% to 15.5%, even though the applications were similar in age, pipe arrangement, and condition of the insulation. This is most likely because some of the systems were running whilst others were not, so the heat may be evaporating moisture out of the insulation.
“Nothing could be worse than having a cold, wet sponge in direct contact with an externally located thin-wall copper pipe trying to deliver heat into a building,” Lawrence says, “But, the big takeaway from this is that we just can’t be sure of the actual impact and further research needs to be conducted if we are to be able to measure the impact of poorly insulated refrigerant pipework,”
Again, raising awareness is key, and with the refrigeration market continuing to grow, we cannot afford to leave these questions unanswered.
For hospitals, municipal buildings, offices and other commercial and industrial facilities the plant room is often “out of sight, out of mind”, but the financial costs of not addressing poorly insulated pipework are very real.
Brittle insulation often an issue in residential applications
The first thing to note is that a huge amount of work has gone into measuring and improving thermal insulation performance on communal heating pipework for heat network projects. The new technical standards under HNTAS (Heat Network Technical Assurance Scheme) make it very clear that thermal insulation is a key consideration at the design, installation and aftercare stages of heat network installations.
However, the rise of MLCP pre-insulated pipework in multi-residential applications outside of heat network standards, shows that further improvement is necessary. A large proportion of pre-insulated MLCP pipes are marketed with insulation thicknesses that do not meet the minimum requirements of Building Regs Approved Document L and BS 5422.
We should also consider thermal insulation of heat pumps in individual domestic properties. Until the recent publication of the TICA Guidance for Domestic, Communal and Commercial Heat Pump Installations, very little guidance existed. Furthermore, the thermal insulation of heat pumps is typically carried out by the installer and very much treated as a secondary consideration. Some examples are shown below.
As a result, a large proportion of domestic heat pump projects suffer from the same insulation embrittlement and degradation issues that are seen in commercial refrigeration applications. More research is needed to ascertain the impact that poor insulation has on domestic heat pump efficiencies, but when we add this all together we believe it could be significant.
The target for annual sales of heat pumps was reduced by 25% in the recent Warm Homes Plan to 450,000 units a year by 2030. However, this still represents a huge volume and we need to get the insulation right as soon as possible, otherwise it will be a death by 450,000 cuts to our net zero aims.
