General Equipment Rules of Thumb Thermal Imaging Ready.
Amount of equipment is determined by the class of water loss and drying method used. Type of equipment is based on material types and existing indoor and outdoor humidity and temperatures. Equipment placement is based upon the drying method used.
- Class 1 – Ensure air movement across all wet surfaces (as little as one per 300 sq. ft. to one per 150 sq. ft.)
- Class 2 – One air mover per 50-60 sq. ft.
- Class 3 – One air mover per 50-60 sq. ft.
Regardless of class, ensure air movement across all wet surfaces.
Air Mover Installation:
- Clockwise rotation at 45 angle touching wall.
- Inlet towards wall.
- Turbulence air flow.
- One for every 10-14 linear feet of wall space (more applicable for in place drying)
- Determine cubic feet first (cubic feet = length x width x height) When determining amount of dehumidification necessary, you must first consider cubic feet in the affected area.
- Types of dehumidifiers
- Refrigerant and standard refrigerant (Works to 35 degrees, 35-40% relative humidity out)
- Low Grain Refrigerants (Works to 28-33 degrees, 20% relative humidity out)
- Desiccant Dehumidifiers (Works to below freezing, 0% relative humidity out)
- Determine type of water loss
- Class 1 – no carpet and pad
- Class 2 – carpet and pad
- Class 3 – Carpet and pad with water from above or water more than 24“ up walls
- Class 4 – Specialty focus on bound water
- Refrigerants: Cubic feet/Flow chart = AHAM pints necessary
- Desiccants: AEH x Cubic feet/60 = CFM of process air necessary
- General rule: Large room-One refrigerant dehumidifier per 4 air movers. Multiple Small Rooms-one refrigerant dehumidifier per 2 air movers.
- Pint Removal: CFM x Grain Depression 71 = pints
Things to Watch For:
Length of time equipment is in the home
- There should be enough equipment in the home to insure that it is dry in approximately three days.
- Class 3 and 4 water losses can frequently take four to five days to dry out.
- Class 4 water losses are the only water losses that should go beyond the four to five day point.
- You have 72 hours to mitigate, if you are not half way done drying by day two you need to reevaluate your drying process.
- No marked signes of improvement by day two means you either need more equipment or more demolition.
Types of equipment in the home
- Extra large or desiccant dehumidifiers
- Used typically for class 3 and 4 water losses only.
- In a class 4 water loss, conventional dehumidifiers don't do anything past day one.
- Air Scrubbers
- For water mitigation purposes air scrubbers are generally reserved for category 3 water losses only.
- This may change when the IICRC releases a revised edition of the S500.
- If any vendor cannot explain and prove through documentation why any piece of equipment was needed they should not be compensated