[AIVC, Air infiltration and ventilation glossary, 1992]:the leakage of air in or out of a building or space usually driven by artificially induced pressures.(see pressurization test)[EN 16798-3:2017, 9]:unintended airflow through leakage paths in the system. (LEA; colour Grey)[EN 12792:2003, 25]:unwanted air flow paths in the installation (coded grey)