Without using ventilation system in windless environment, the oxygen concentration of the inside goes down and soon becomes below 18%, which is regarded the minimum safety level.Generally speaking, oxygen concentration of 10% or less makes a human-being paralyzed, and of below 6%, faint.Our experimentation shows that the oxygen concentration goes down steadily almost indifferent to the sizes of ventilation hole.It is necessary to have a ventilation system in the shelter which does not have enough air circulation.Thus, we have introduced mechanical ventilating fan to intake atmosphere to keep oxygen concentration.The ventilating fan, once started, immediately brought back the oxygen more than the safety level.A large-capacity battery is equipped to run the ventilating fan for maximum 3 days.
The ventilating fan is fixable to the ventilation hole and run by the mobile battery provide as accessory.The fan intakes atmosphere from outside to circulate internal air to avoid an oxygen shortage.The fan can be easily replaced with the water prevention-cap to avoid water invasion.
The mobile battery supplies power to ventilating fan, LED lamp, cell phone and so on, that makes it possible to wait for rescue operation for a longer time.
The battery box provided as accessory can supply power in the same manner from your dry cells even after the mobile battery is over.
The mobile battery and battery box are stored in the dedicated bag, which can be fixable to the hatch to save precious space.