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.