The Closed Drying System

by | Apr 19, 2022 | Juvenaire News, Water Damage, Restoration

A closed drying system is achieved by creating a drying chamber which is not open to the outside environment, this can be achieved by simply closing the window and entry door to the room if it is a small event or by closing all windows and external doors if the event is large. Large open areas that are only partially affected can have containment put in place to target only the affected area that requires to be dried.

Air Movers

Air movers as the name implies create air flow which in turn increases the rate of evaporation (turning liquid water into a vapour). Air movers should be placed at a 45 degree angle to the wall and in the same direction to create a circular rotation of the air mass in the area. Please ensure that you check that no loose items can be dislodged and become stuck on the inlet grills of the air movers and as such restrict the air flow into the air mover. Some items that could cause this condition are loose paper, curtains etc. Remember to tape down power cords where a trip hazard may occur (use painters tape on timber floors)


As stated air movers create air flow which increases the rate of evaporation, however if we do not remove this water vapour from the air mass then very quickly the air mass will become saturated (100% RH). Water vapour in the air mass can begin to condense into liquid on surfaces once dew point is reached inside the drying chamber creating the potential for secondary damage to occur.

This is why we use dehumidifiers to remove the water vapour in the air mass that the air movers have evaporated from the affected surfaces inside the drying chamber.

Dehumidifiers remove the water vapour from the air mass by reducing the temperature of the air mass passing through the evaporator coils in the dehumidifier to dew point.

At dew point the water vapour condenses into a liquid, is collected and pumped out through a hose to the nearest sink, toilet or drain. After the air exits the evaporator it then passes through the condenser in the dehumidifier where it absorbs heats, this added energy allows two processes to occur. Firstly warm dry air can absorb much more moisture than cold dry air, in other words it increase its thirst for moisture.

Secondly, heat in the air allows surrounding materials to absorb this heat energy from the air which increases the temperature of the medium being dried, this in turn means that more heat energy is available to allow the liquid water on or in that medium to be evaporated( go from a liquid to a vapour).

The dehumidifier should be placed in the middle of the area if possible with the outlet air travelling in the same direction as the air movers, be careful not to allow the air flow coming out of the dehumidifier to impact directly onto doors as it could cause them to buckle. Try the keep the room temperature in the 26 to 32 degree range, this will allow the dehumidifiers to work at their peak efficiency. Again tape down power cords and drain hoses where a trip hazard may occur (use painters tape on timber floors)

Balanced Drying System

A balanced drying system is when you have sufficient dehumidification in place to remove the moisture (vapour) from the air that the air movers are evaporating. In other words a whole house event with 12 air movers and 1 dehumidifier is not a balanced drying system.

If you are in the situation that you have limited power available I would prefer that you reduce the number of air movers instead of dehumidifiers (1 air mover in a room instead of two for example)

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