One-and-a-half-way valve : A valve used in inflatable structures to regulate the pressure inside said structure. Unlike a two-way valve that readily allows a filling medium to enter and leave the object, or a one-way valve which allows the medium to enter or leave, a one-and-a-half-way valve allows (in the instance of an air inflated structure) air to enter the structure, but not leave unless the pressure inside the structure exceeds the tolerated level of the valve. This is important in situations where the structure(s) are exposed to anything that could cause the pressure already inside to increase to the point of explosion.