Sounding out the benefits

Ed Peltor of Rockwool UK says that considerations of the benefits of insulation go well beyond thermal performance to acoustics and fire, when looking the whole building envelope

It’s time to look for more from insulation than just thermal performance. Acoustics and, of course, fire safety, or, more accurately, a product’s Reaction to Fire rating, are factors that have to be taken into consideration. Noise disturbance is fast becoming a major issue in today’s increasingly congested urban environments. Road, rail and air traffic, public works and associated street noise are all contributing to the heightened intrusion of external sound into working, hospitality, public and residential properties. Sound insulation is important in reducing this impact. In our own report, ‘Good Growth, Quiet Buildings’, we highlighted why noise mitigation should be incorporated into the design process of any development to support good health and well-being. Factoring in noise from the outset of a project can be the most cost-effective route to ensuring a high standard of acoustic performance and can be as simple as selecting an insulation material that delivers on both thermal needs and sounds absorption. A recent new-build project for the Crowne Plaza and Holiday Inn Express at London Heathrow Terminal 4 is a useful example. Connected via a convenient air bridge to Terminal 4, this project comprises a combined total of 750 rooms. Minimising external noise from the UK’s busiest airport, where the average number of air transport movements reached a noisy 1,295 per day in 2017, was a major consideration. By utilising insulation with strong acoustic properties and a complementary facade system on the development, the hotel was able to meet its target of a significant Rw 58dB sound reduction. External ambient noise can also be a major headache for schools, causing distraction, disruption and, at worse, impacting negatively on the academic performance of students. Stone wool insulation has helped the National Autistic Society Anderson School and Enterprise Campus, a new-build, autism-specific facility in Chigwell, Essex, address this priority issue to create a calm, productive and quiet learning environment for all students. At the outset, project designers and specifiers, RMA Architects, recognised the role that effective sound insulation could play in helping to meet this objective for the school. The school’s contemporary, low level design features extensive areas of flat roofing which could prove susceptible to noise ingress from heavy rainfall. At the same time, they required an efficient thermal solution that would meet the project’s low energy credentials and a robust durable waterproofing system, that would safeguard the building from defect for many years to come.

Fire safety

Beyond sound, fire safety is an especially important issue and is in focus more than ever before. In terms of specifying an insulation material, it is key to understand what is combustible and what is non-combustible. Firstly, considering reaction to fire, there is the distinction between what is combustible, non-combustible and of limited combustibility. Here, we should recognise the classifications given within the Euroclass system applicable under CE Marking rules. To be classified to the Euroclass system, products must undergo testing for a range of factors including: ignitability, flame spread, heat release, smoke production and propensity for producing flaming droplets/particles. The Euroclass system is accepted by all European Union States (and is mandatory where there is a Harmonised Product Standard). It includes seven classification levels, from A1 to F, plus one rating (NPD), that sits alongside but outside these ratings. UK Building Regulations (England & Wales) define classifications, under the Euroclass system, as A1 non-combustible and A2 Limited Combustibility, offering “no significant contribution to fire growth”. Products achieving a rating of B-F are deemed to be combustible. Other terms typically used by the industry to describe product performance, such as, fire safe, fire proof, fire retardant or flame proof do not necessarily define that the product is non-combustible. Manufacturers of CE-marked construction products in the UK are legally obligated to declare an RtF rating, so HVAC consultants and contractors can find out the combustibility rating of their chosen HVAC insulation in the product’s Declaration of Performance (DoP) certificate. The RtF rating is not to be confused with Class 0, a product performance classification which simply measures flame spread. Class 0 is not a measure of a product’s combustibility. In fact, many insulation products will be able to achieve Class 0 but have an RtF of C, or worse. Much has been written about the use of various types of insulation on the building envelope, particularly the facade, but the specification and use of materials in other areas is also under the spotlight. We believe that the best way to ensure public safety is to require that only non-combustible insulation be used throughout the building envelope. Why would any specifier take the risk of adding combustible materials to a building? It simply doesn’t make sense. A clear example of the need to consider the whole building envelope is the recent roof fire at the flagship Primark store in Belfast. The fire is reported to have taken three days to fully put out, and resulted in one of Belfast’s Iconic buildings being destroyed, but the effects have the fire have been felt on a much wider scale. Reports indicate that footfall was reduced by some 49 per cent into the Castle Court shopping area where the store was located, 14 local businesses have closed since the fire, and Belfast city centre is reported to be losing revenue in the region of £3m per month. We are an industry going through unprecedented change from top to bottom – the insurance industry, clients and architects, many of whom are identified and highlighted in the Hackitt Review as having key roles going forward, are focused on risk – risk to lives and, indeed, livelihoods. In short, the conversation is changing. Insurers, property owners, businesses large and small as well as specifiers are re-assessing the risk presented by fire at all levels and choosing the ‘lower risk’ approach of specifying non-combustible solutions around the building envelope and on the building services within.

Ed Peltor is commercial director at Rockwool UK