The hatch of the International Space Station (ISS) has been designed based on the “NASA STANDARD”. This hatch has been designed for the transportation of equipment, and wasn't for the use of man. In case of using of civilian who aren't trained, the hatch of the ISS isn't secure enough to ensure their safety. We observed the emergency evacuation behavior of crowds flocking to the hatch, under microgravity conditions. This underwater experiment simulates microgravity conditions. This study also verified the validity of the appropriate positions of handrails used to evacuate. The underwater experiments where the 3 handrails were positioned in the direction of the exit, allowed for the shortest evacuation times. It was proven that the specific alignment of the handrails decreased the speed of the crowd, which allowed for all participants to exit in an orderly manner. We can conclude that an efficient and controlled evacuation of a crowd is a result of the handrails and their strategic positioning.
