WATER DAMAGE AND DRYING

Presented by

Greg Boling, CR, WLS, CMR

Water exists in 3 forms:

• Gas (water vapor)

• Solid (ice)

• Liquid

Sources of WaterLiquid & Vapor

• Exterior

Roof leaks Flooding (@ surface) Ground water

(subsurface) Pressurization Diffusion of vapor Infiltration of vapor

• Interior

Plumbing systems Washing Cooking Respiration Plants Disasters

Liquid Water as a Damage

• Can cause damage instantaneously

• Damage increases as time elapses

• As time elapses, water changes categories

Categories of Water Damage

• Category 1: Clean Water• Category 2: Gray Water (rain, clean water

in dirty carpets, laundry water, water migrating through building envelope)

• Category 3: Black Water (flooding from street or river, sewage [bacterial]

Water damage in a structure exists in 3 forms:

• 1. Free Water

• 2. Absorbed Water

• 3. Adsorbed Water

Free Water

• Refers to standing water

• Easiest to remove

Absorbed Water

• Refers to water that has become part of the structure due to capillary action

• Requires a building to need supplemental drying

• Can only be removed by (1)demolition of saturated materials (2)converting the liquid into a vapor

Adsorbed Water

• Refers to the chemically bonded water found naturally in materials

• Removal of adsorbed water damages the material.

Drying

• Drying is a science, based on established laws of thermodynamics and laws of gases

• Basically, all states of water seek equilibrium

• More to less

• High to Low

Releasing Water from the Structure

• 1. Provide an condition in which water wants to migrate from one area (where you want to get rid of it) to an area where it causes no harm

• 2. Provide tools to change the condition

• 3. Fully comprehend the area of water damage

Providing the condition

• Liquid water will flow, seeking its own level (more to less)

• Water vapor will move, from higher pressure to lower pressure

• If water can not flow out of building (drained), then it has to be converted to a vapor (evaporation)

Psychrometric Chart

Comprehending the Structure

• At the surface of the material, Water Activity occurs (conversion of liquid to vapor-evaporation)

• The further that a liquid has to migrate to the surface, the longer it takes to dry

• The permeability of a material dictates the speed of migration

• Water can travel through a material as vapor

Water Activity

Water Activity (aw) = Equilibrium relative humidity of the substrate divided by 100

• All building materials have different rates in which water vapor moves within them

•Water Activity at the surface determines the evaporation rate.

IMPORTANT POINT

“The structure of a building must be investigated, not assumed”.

Releasing Water From Saturated Elements

1. Fully assess and comprehend the area of water damage

2. Create a condition in which water wants to migrate from one area (i.e. where you want to get rid of it) to an area where it causes no harm

3. Provide tools to change the condition

Drying Tools

• Dehumidifiers- manipulating the specific humidity to allow the air to accept additional moisture in the form of vapor

• Fans- prevent “layering” of water vapor due to weight; and they transport vapor away from the surface to increase conversion rates.

Types of Dehumidifiers

• Refrigerant

• Desiccant

Refrigerant Dehumidifier

• Most efficient at optimum temperature

• Ineffective at low temperatures

• Power requirements can become prohibitive

• Require more monitoring (labor hours)

Desiccant Dehumidifier

• Least efficient• Not limited by ambient temperature• Processed air is 20+ degrees hotter than the

ambient air• Purges moisture from the building under positive

pressure- can potentially distribute contaminates

Accelerated Drying Programs

• Usually associated with schools:– Dry-Eze, Vortech, Water Out, etc

• Require specific uses of equipment or purchase of equipment

• Accelerated drying almost always results in the removal of adsorbed water, due to different materials present, thus damage almost always occurs

The Injectidry System

Injectidrying

• Forces dry air into interstitial wall & ceiling cavities and displaces the moisture by purging

• Excellent for wallpapered walls because it dries from the outside in

• Really isn’t needed in most applications

Documentation• Establish “benchmark”• Daily monitoring is required recording both

relative humidity (RH), ambient temperature and saturation of materials to determine if building is drying

• As with all removal processes (mold remediation, asbestos abatement) clearance documentation needs to be provided.

Basic Guidelines

1. Amount of drying equipment used is based on the volume of air and air exchanges

2. Materials must be made as permeable as possible

3. Drying conclusion must be documented by testing

The “air exchange” rule

• Dehumidification processes the air• When all of the air in a building or room

has been processed by the dehumidifier, then all the air has been exchanged one time through the machine.

• Dehumidifiers are rated on how much air they process per minute (cfm)

Determining the Amount of Equipment Required

• The amount of water in a structure determines the amount of drying equipment needed to process the air

• Therefore, if the cubic foot volume of the air in a building is determined, then this amount can be divided by the number of cfm that the dehumidifier can process.

• If that sum is divided by 60, then the air exchanges per hour can be determined.

Example:

• Total length X width X height = 20,000 c/f.• Divided by a 200 cfm Dh. = 100 minutes to

complete an air exchange• Divided by 60 minutes = 1.67 air exchanges

per hour• 1.67 X 2 =3.34- or 2 exchanges would

require 2-200 cfm dehumidifiers.

How many air exchanges?

• Typical standard floor saturation requires one air exchange per hour

• Lower walls wet from wicking and bases of personal property wet requires two air exchanges per hour

• Walls & ceilings wet -requires three air exchanges per hour

• Air exchanges establish optimum conditions for drying

• Once optimum conditions are met, then additional air exchanges accomplish nothing

• Because of the physical limitations of water activity & evaporation, three air exchanges are the maximum

• Therefore, adding more dehumidifiers can not lower the Rh beyond what is possible

Cost of equipment

• The daily rate for equipment use (fans and dehumidifiers) should not exceed 5% of the equipment cost per day.

• Equipment should never be charged for a period exceeding 15 days.

• 15 days X 5% = 75% of the cost of the equipment

• This applies to all servicing equipment

How many fans?

• Fans speed up the drying process nominally• Air movement increases the amount of water

activity that can occur• Helps distribute processed air throughout the

structure• Most in our industry agree that three fans per

dehumidifier are sufficient• Fans can be used to dry “from the wall/ceiling

cavities” out

Add-ons for fans

When fans should not be used

• When air movement could create bioaerosols

• Sewage- transporting pathogens into the air stream

• Mold- contaminating the indoor air quality

A word about Mold

IICRC S500

• “Standard and Reference Guide for Professional Water Damage Restoration”

• Institute of Inspection,Cleaning and Restoration Certification

• www.iicrc.org

References

• Water Loss Institute- www.ascr.org

• Priority One Mitigation- www.p1m.com

INSTAR Services Group

www.instarservices.com800.446.1620