A lightweight and portable inflatable assembly includes an inflatable structural component and a chemical reaction based inflator device. The inflatable structural component includes a flexible housing defining a cavity. The inflatable structure is uninflated in a first operational mode and filled with an inflation fluid retained for at least 4 hours in a second operational mode. At least one primary and at least one secondary charge unit are in fluid communication with the cavity. The primary charge unit includes a first gas generant material configured to generate a first predetermined volume of inflation medium for filling the cavity, while the secondary charge unit includes a second gas generant material configured to generate a second predetermined volume of inflation medium for filling the cavity in the second operational mode. The second predetermined volume is ≤about 40% by volume of the first predetermined volume.