Transcript Investigation - IDS Emergency Management

WATER DAMAGE AND
DRYING
Presented by
Greg Boling, CR, WLS, CMR
Water exists in 3 forms:
• Gas (water vapor)
• Solid (ice)
• Liquid
Sources of Water
Liquid & 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.com
800.446.1620