[AIVC, Air infiltration and ventilation glossary, 1992]:the uncontrolled inward leakage of outdoor air through cracks, interstices, and other unintentional openings of a building, caused by the pressure effects of the wind and/or the stack effect.[ASHRAE Standard 62.1]:uncontrolled inward air leakage to conditioned spaces through unintentional openings in ceilings, floors, and walls from unconditioned spaces or the outdoors caused by the same pressure differences that induce exfiltration.[ASHRAE Standard 62.2]:uncontrolled inward leakage of air through cracks and interstices in any building element and around windows and doors of a building.[EN 16798-3:2017, 10]:Leakage of air into building through leakage paths in elements of structure, unintended air from outdoor. (INF; colour Green)[EN 12792:2003, 224]:uncontrolled passage of air into a space through leakage paths in the shell of that space. (coded green)[ISO 16814:2008, 3.20]:uncontrolled passage of air into a space through leakage paths in the building envelope.