A Multi-Objective Fire Safety and Sustainability Screening Tool for Specifying Insulation Materials

Fire safety and sustainability goals in building design are frequently interdependent. Design elements chosen for their fire safety can have energy efficiency implications and vice versa. Furthermore, the environmental damage and carbon emissions from a single fire event can negate the utility of green features invested in the building. Therefore, while not obvious, fire safety and its impact on sustainability are inextricably linked. One of the decisions related to both sustainability and fire safety is the selection of thermal insulation materials. Insulating materials have always been an integral part of building design, serving as a key component in thermally controlling indoor environments. Modern designs and construction techniques often incorporate sustainability goals by seeking to minimize life cycle energy consumption and environmental impact. A well-insulated building reduces thermal load on the HVAC system, thus reducing energy consumption of the building. Therefore, a sustainably designed building is typically a heavily insulated building. In addition to thermal resistance characteristics, the choice of insulating material is often based on acoustic damping and cost. However, fire safety is generally overlooked as a factor for insulation material selection. Few treatments have considered how the competing objectives for sustainability and fire safety should be assessed when choosing insulation. This paper discusses a methodology for balancing these requirements by evaluating the aforementioned attributes of various insulating materials through implementation of a weighted mean. Each variable is normalized and then weighted according to the emphasis placed on each attribute, using experimental data for the relevant material property. Four weighting scenarios are presented, each emphasizing a different area of consideration: installed cost, fire safety, life-cycle assessment, and thermal. Materials considered are cellulose (newspaper), denim (cotton), fiberglass, stone wool, polyurethane, and polystyrene. Results of this analysis rank the materials in order of desirability and provide a method to reorder this ranking based on the priority assigned to each attribute. For the weighting scenarios presented herein, stone wool was consistently ranked as the best performer, while extruded polystyrene was typically the weakest. The intent is that this methodology would be informative for designers selecting materials and for planners contemplating revised building codes.