The maximum energy demand – 50-70% – in a building is for conditioning (heating or cooling) the interiors. “Building Envelope” (roof, walls & floor) contributes to 60-75% of the heat gain/loss in a building and is the major contributor to the high load on air-conditioning. Insulation of building envelope has become one of the key practices across the globe to effectively manage heat incidence in the buildings and save on the high energy cost.
LEED-India, the green rating system for buildings advocates over-deck insulation for roofs as against the conventional way of under-deck insulation. In under-deck thermal insulation, the terrace slab gets heated up by direct solar radiation and this heat passes through the under-deck insulation and increases the load on the air-conditioning system.
In over-deck insulation, a thermal insulation with waterproofing is provided over the RCC.This provides a barrier against direct solar heat on RCC roof slab preventing the slab from heating up. Over-deck insulation not only avoids thermal bridging but also increases the life span of the building due to decreased heat stresses in slab. Insulation materials like Water Resistant Expanded Polystyrene, Fire Retardant Expanded Polystyrene, Rigid Polyurethane Insulation & Extruded Polystyrene are globally the most effective and widely used building insulation materials. Materials like rockwool & glass-wool using formaldehyde as resin – are carcinogenic (may cause cancer) – and banned in Europe & the US.
BASF offers a wide range of insulation materials for over-deck suitable for different usage conditions.
- Peripor Board: The Water-resistant insulation.
Water absorption has a significant detrimental effect on thermal insulation. Peripor Board has been developed specifically for over-deck applications with extremely low water absorption.
- Elastopor Board: Thermal Insulation PUR Board.
Polyurethane Resin (PUR) based thermal insulation boards offer best in class insulation performance. Higher densities make the boards tough and can be used in trafficked system built-ups.
- Masterseal 755 SPF: Spray applied PU Foam Insulation.
This thermal insulation is spray applied at site and offers a monolithic insulation layerSpray application is especially suited for complex substrate shapes and confined spaces.
Though a major contribution to heat gain in a building is from walls, wall insulation has been neglected. Some traditional ways of providing thermal insulation to the walls have been in the form of using light coloured stone tiles on exteriors to minimize sunlight, double-wall with air cavity, cavity wall with insulation material as infill, insulating panels on interiors, etc. However, each of these methods has its own disadvantages. Apart from not offering a high thermal insulation, they have the problem of rain water seepage, water filling the cavity, poor indoor air quality and decrease of valuable internal space.
BASF offers “SENERGY External Insulation & Finishing System” (EIFS) on the walls that use Neopar – Fire Retardant Expanded Polystyrene as insulation. EIFS is done on the exterior wall on the outside face and combines the performance of insulation with aesthetics as the system offers a variety of textures and colour shades for exterior. The advantage of EIF apart from its effectiveness is that it can be applied to new & existing structures, is virtually seamless and offers design flexibility, shapes, colors and textures.
The state governments and town planners should make building envelope insulation mandatory and electricity connection and building occupancy certificate should have building insulation as a pre-requisite. Adopting Green Building practices will substantially reduce or eliminate adverse environmental impacts and improve upon existing unsustainable design, construction and operational practices.Himanshu Agrawal Senior Manager – Sustainable Building Solutions BASF India Limited Construction Chemicals Division