Perspectivas de integración de la Región del Alto Segre

The three aerated and strengthened soap samples were compared with the petroleum counterparts, polystyrene and polyisocyanurate. This was in order to justify or discount if soap based insulation could be shown to be an effective alternative to those petroleum counterparts. The criteria identified included financial cost, environmental manufacturing cost, thermal resistance, weight, working performance (durability) and end of life disposal. These subjects were utilised for this comparison. Because soap based insulation is a rigid board type, only insulations of petroleum based rigid board types were compared. This meant that both fibreglass and multifoil insulations were omitted from this comparison study. Because of the multitude of performance variant types on sale within the UK, the lowest performing petroleum based insulation, expanded polystyrene was used a comparable, alongside the best performing petroleum based – foil faced polyisocyanurate. This eliminated the need to compare mid-performing thermal insulations such as extruded polythene (XPE). Both expanded polystyrene and polyisocyanurate insulations give a benchmark to aspire to within the same insulation type category, whilst allowing for a

scale to be established to show where soap insulation is, compared to these two. The laboratory results revealed that none of the three soap samples gave particularly good thermal resistance results. In comparison with the petroleum based counterparts, plastic covered soap insulation fared better for its end of life disposal and environmental / financial costs. However, petroleum based insulation has a better size to weight ratio, durability and more importantly, it gives better thermal performance. The results are shown in Table eleven below.

Criteria Sample 1 Sample 2 Sample 3 Expanded

polystyrene Polyisocyanurate (Foil Faced)

Financial Cost o o o o o Environmental Manufacturing Cost o o o o o Thermal Resistance 0.684(m 2_{K)/W 0.642(m}2_{K)/W 0.516(m}2_{K)/W 1.25m}2_{K/W 2.0m}2_K/W Thermal Conductivity 0.0746W/mK 0.0799W/mK 0.0989W/mK 0.04W/mK 0.025W/mK Weight 1,084g 1,843g 4,650g 67g 135g Thickness 51.1mm 51.3mm 51.1mm 50mm 50mm Working Performance (Durability) o o o o o End of Life Disposal o o o o o

Table 11 Soap Comparison Table

Key:

Good Moderate Poor

Small aerated soap samples have been exposed to six months of cavity wall and freezer placement (Section 4.3.1) and have performed without any adverse effects to the either their external or internal composition make-up. However, slabs of soap insulation utilising straw as a component part were too heavy to be stacked upon each other, as would be required in the wall of a building. At a height of 3.3m, the compressive force of 51.150kg acting upon the bottom insulation sample, created a small yet significant split in the plastic casing. This could create a path for possible

moisture ingress and as such, the failure of this heavy insulation meant that research into the soap/straw combination was discontinued.

Working on the result that plastic cased insulation could fail with a 51.150kg load applied, it was calculated that at a height of 8.3m, an equal weight of 51.150kg would be produced using Expancel soap with a plastic casing, if the insulation was stacked directly on top of each other. This height is possibly within the realms of a three storey building. This meant that plastic surrounded soap insulation with added Expancel as the bottom supporting slab, could also fail and so this insulation type was also discontinued. Calculations revealed that the lighter plastic surrounded soap insulation aerated via the vacuum method, would be adequate to use in a three storey property but could fail in higher rise buildings if the insulation is stacked as opposed to mechanically supported. The results of the first tests also reveal that 100mm thick aerated soap surrounded with a plastic casing performs to an equivalent level of 50mm expanded polystyrene and 25mm polyisocyanurate generally.

4.7.1 Condensation Risks and Breathability

The plastic casing surrounding the soap could also create problems because of its smooth face. In a capillary active solid brick or stone constructed wall, moisture could condense on the plastic surface and if there is a lack of means for the moisture to be dealt with, problems to the structure can occur. If these walls are insulated internally, heat flow to the external (outside) face can be reduced. This impedes the ability of the brick/stone wall to properly dry out after a wetting from rain and in turn this higher water content increases the thermal conductivity of the masonry (Burberry, 2014) The vapour resistance of the plastic casing can also reduce the moisture movement and therefore drying potential to the insideof the wall. As the wall establishes its new higher equilibrium moisture content, there is a risk of decay to any organic materials (joist ends or battens) that are in contact with it (Browne, 2012). It is possible that moisture levels in this environment could exceed mould growth and decay conditions, creating an environment that could be detrimental to human health and accelerating degradation to the insulation. After all, “Insulation should offer a reasonable service life” (Aegerter et al, 2011), and be robust enough for the efficient management operation of thermal resistance applications (Turner & Doty, 2007). Because of the

potential problems associated with the soap insulation’s plastic casing, it was decided to stop research into plastic coated thermal insulation. However, the answer to these problems could be as simple as an air “barrier” to wick away any moisture before it can do any damage, or to use a breathable thermal insulation. Breathable insulation frustrates the dew point from occurring on or within the insulation and thus stops it becoming wet (Allen & Thallon, 2011). This breathability is recognised by built environment professionals as being a useful function for maintaining a durable and healthy building.