9 months ago

Insulate Magazine Issue 12 - November 2017

The 1st Birthday issue of Insulate magazine titled "Round 12 with Recticel" features an exclusive interview with Recticel's commercial Director Kevin Bohea. If that wasn't enough we have a great exclusive inside the BBA, featuring an interview with BBA Chef Executive Richard Beale.

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The only independent insulation industry trade magazine Insulate Exclusive Part 2: When is an Insulation Manufacturer... Still not an insulation manufacturer? Last month we started looking at occasions when a manufacturer’s role risks going beyond advice on the products they make. Whether being asked to recommend defined U-value targets, or approve the installation of products, there are times when salespeople or technical help desks have to recommend seeking advice from other professionals. In part two, we look at how that applies to design advice. By Insulate Magazine. Design Professionals We all appreciate the pressures on architects and design professionals. Balancing the many and varied constraints that threaten their vision for a building, then juggling any issues that unexpectedly arise once work starts, is no easy challenge. A change in product availability here, a difference in level there, and what started life as a simple design or elegant detail quickly finds itself hammered (sometimes brutally!) into a wholly different shape. And that presents problems. After all, the position of loadbearing elements is pretty non-negotiable! The building’s footprint sets the foundation design, which dictates the line of the external wall structure and where the roof structure is supported. Floor decks and slabs, steel beams, timber components - they all have to be a minimum size and can’t be shrunk. If that sounds obvious then it is only to highlight why the insulation specification often becomes the target for potential changes or savings. Thermal performance targets set by Building Regulations result in substantial insulation layers. Everyone is as aware of insulation as they are of, say, bricks and blocks - but while materials like bricks and blocks come in standard sizes, everyone also knows there are different types of insulation, and varying thicknesses within any insulation range. Product substitution isn’t always about swapping one similar-performing product for another. Unexpected constraints that put pressure on the original design can result in a fundamental change in specification being considered, the wider implications of which need to be assessed. When questions about that sort of change come direct from the architectural practice, the key person or people who need to make that assessment are directly involved. The manufacturer can advise on best practice and help the design professional to understand how the performance characteristics of their products differ - or otherwise - compared to the material originally specified. When the questions come from clients or contractors, however, things start to get more difficult. They are less likely to understand what has driven certain detailing decisions or material specifications, and how they relate to the design philosophy of the building as a whole. Decisions about product swaps might be centred more on price or availability, putting the onus on the insulation manufacturer to make the assessment on design impact. In particular, asking an insulation manufacturer to comment on a single section or junction detail can be risky. Trying to work out why the original product was specified, or what about the site or building design requires certain product characteristics, is tricky without all of the information. And even where the information might be present, the person looking at it may not be suitably qualified to make such a judgement. Insulation manufacturers employ good technical and specification people, some of whom have architectural experience. 8 But those people cannot take on design liability, and on some projects there is a fine line between offering product advice and making design decisions. It only continues to highlight the importance of true collaboration on construction projects, ensuring the right people are involved at the right stages to aid the decision-making process. Structural Engineers examination of the times when too much is asked Does anything generate more confusion and uncertainty than structural loading and compressive strength declarations? It’s not hard to see why. The potential ramifications of using an insulation product incapable of taking the loads imposed on it would make any specifier nervous about committing to a specification they were unsure about. And from the point of view of understanding products, what is the relevance of declarations made at “10% compression”? purely on the basis of compressive strength declarations will not offer a fair comparison. There is, however, a set of technical guidelines, jointly drafted by certification bodies across Europe, that describe how insulation products for flat roofs should be evaluated. The guidelines include assessment of compressive strength and, based on testing, classification of ‘fitness for use’. It is from here that references to ‘access for maintenance’ or ‘suitable for pedestrian traffic’ can be derived. Through guidelines like these, insulation manufacturers can offer advice about their products and good practice. Asking if an insulation product is “suitable for use on a terrace”, however, is too vague. It doesn’t convey the size of the terrace, how often it might be used or, crucially, the total loads that using it could impose. When it comes to the calculation of in-service loadings, that’s where the structural engineer is needed. Some applications - like basements or floors for heavy industry - impose such substantial loads on the insulation layer that it is relatively easy to select an insulation product capable of working in those conditions. Extruded polystyrene (XPS) products, for example, can offer compressive strengths in excess of 300, 500 or even 700 kPa. At the opposite end of the scale, there are expanded polystyrene (EPS) products perfectly suitable for domestic ground floor constructions that ‘only’ offer a compressive strength of 70 kPa. Does that mean the declarations of between 120 kPa and 175 kPa offered by polyisocyanurate (PIR) and phenolic foam products for the same use are overkill? Well, no. It means that different insulation types offer a different balance of cost, thermal performance and load bearing capability - and it is up to the specifier to ensure that the one best suited to the individual project is selected. Performance declarations like compressive strength are made based on accepted test methods that form part of harmonised European standards - documents that ensure construction materials meet minimum performance levels to ensure their safety and suitability for sale. These tests examine the product in isolation to determine a particular characteristic, without accounting for how the product will be used. Flat roofs are another application where loadings are critical, and where differentiating between insulation types 9