A method for reducing pressure in an enclosed volume of a ground-based pressure chamber that simulates cabin or cargo pressurization/depressurization cycles during operation conditions, the method comprising: inserting a first quantity of steam into a condensation chamber ; condensing substantially the first quantity of steam in the condensation chamber ; extracting a first quantity of air from an enclosed volume into the condensation chamber ; closing a first valve to block a first steam flow of the first quantity of steam into the condensation chamber ; and opening a second valve to allow an airflow of the first quantity of air from the enclosed volume into the condensation chamber ; characterized in that the method further comprises: closing the second valve to block the airflow from the enclosed volume into the condensation chamber ; opening the first valve to allow a second steam flow of a second quantity of steam into the condensation chamber ; expelling substantially the first quantity of air from the condensation chamber during the second steam flow; inserting at least one additional quantity of steam into at least one additional condensation chamber ; condensing substantially the at least one additional quantity of steam in the at least one additional condensation chamber ; and extracting at least one additional quantity of air from the enclosed volume into the at least one additional condensation chamber . inserting a first quantity of steam into a condensation chamber ; condensing substantially the first quantity of steam in the condensation chamber ; extracting a first quantity of air from an enclosed volume into the condensation chamber ; closing a first valve to block a first steam flow of the first quantity of steam into the condensation chamber ; and opening a second valve to allow an airflow of the first quantity of air from the enclosed volume into the condensation chamber ; characterized in that the method further comprises: closing the second valve to block the airflow from the enclosed volume into the condensation chamber ; opening the first valve to allow a second steam flow of a second quantity of steam into the condensation chamber ; expelling substantially the first quantity of air from the condensation chamber during the second steam flow; inserting at least one additional quantity of steam into at least one additional condensation chamber ; condensing substantially the at least one additional quantity of steam in the at least one additional condensation chamber ; and extracting at least one additional quantity of air from the enclosed volume into the at least one additional condensation chamber . closing the second valve to block the airflow from the enclosed volume into the condensation chamber ; opening the first valve to allow a second steam flow of a second quantity of steam into the condensation chamber ; expelling substantially the first quantity of air from the condensation chamber during the second steam flow; inserting at least one additional quantity of steam into at least one additional condensation chamber ; condensing substantially the at least one additional quantity of steam in the at least one additional condensation chamber ; and extracting at least one additional quantity of air from the enclosed volume into the at least one additional condensation chamber . <EOS>