Experimental evaluation of the growth rate of mould on finishes for indoor housing environments: Effects of the 2002/91/EC directive

We report t he results of a study to evalu ate the growth rate of three spec ies of mould on pla sters, finish es and paints typical ly used in structu res wit h heavy weight bui lding envelopes. The aim was to determine the infl uence of the chemi cal comp osition (in terms of orga nic fraction of the ma terials) on the growth rate of mou lds. The stu dy was carrie d out in the following steps: – characterizati on of ma terials; – inoculati on of mou ld spores (3 spec ies) on 7 types of ma terial (2 plasters, 3 fini shes, 2 paints) ; – growth in a climatic cham ber (23 C an d 90% RH); – ana lysis of the mould growth rate using vari ous experim ental techniques (fluorescence mi croscopy analysi s, thermo gravimet ric ana lysis, etc.). Results show a clea r correlation between the organi c subs tances contai ned in paints, plasters and fi nishes and the growt h rate of the mo uld. This stud y is part of a more general research program wh ich addresses t he effects on indoor environment air quality based on the European directive 20 02/91/EC . This directive spec ifically indicates that energy consu mption in bui ldings should be limited and sets threshold values for the thermal resistance of t he buildi ng walls and windows. As a cons equence wi ndow manuf actu rers are improving the thermal property of wi ndows by reducing the air permeab ility, which may increase t he indoor and surface relative humidity percentage (RH%) and lead to the de velopment of mou ld in the indoor environments.