Frequently Asked Questions

Find answers to commonly asked questions about Flood Rentals Hawaii, the science of restorative drying and water damage drying equipment

Equipment Questions

What's an LGR dehumidifier and why do I need one?
LGR stands for Low Grain Refrigerant. An LGR dehumidifier is designed to work in conditions with a low specific humidity/humidity ratio.

For instance, when the relative humidity drops below 40% or 35 GPP, an LGR dehumidifier will continue to remove water from the air and surrounding materials. You can start and finish a job with LGR dehumidifiers instead of changing out equipment to get the lower specific humidity that you need for complete drying. Both the DrizAir 2400
 and LGR 2000 are equipped with low grain refrigerant technology. 

What's the difference between desiccant and refrigerant dehumidifiers?
Desiccant and refrigerant dehumidifiers both remove moisture from the air, but they use different technology to do so.

A desiccant dehumidifier uses a silica gel rotor to remove moisture from the air. As wet air passes through the rotor, the silica gel adsorbs moisture. A desiccant returns dry air to the affected area and exhausts wet air to the outside of the structure. Since a desiccant does not depend on air temperature to dehumidify, it's an excellent choice for difficult drying situations.

A refrigerant dehumidifier uses the process of condensation to remove moisture from the air. First, wet air passes over a cold evaporator coil. The evaporator coil cools the air below its dewpoint temperature. Moisture condenses on the cold coils, runs down into the drain pan and gets pumped out. Now that the air is dry it passes over the warm condenser coils. The condenser coils heat the air back up before returning it to the affected area. Refrigerant dehumidifiers operate very well in closed drying systems near room temperature. They can remove a higher volume of water per day than a desiccant.

What are the differences between Dri-Eaz airmovers?
Dri-Eaz airmovers differ by both feature and function. Santana and Sahara TurboDryers
 are designed to create laminar airflow and increase evaporation for water damage restoration. The Vortex Axial Fan is a high-velocity ventilator. It provides enough static pressure to operate with 125 feet of 12" ducting. The AirWolf balances high volume and high static pressure for specialty applications like drying hardwood floors.

Every Dri-Eaz airmover features a rugged, high-density polyethylene housing for incredible durability, a UL Listing for safety and a 7-year limited warranty.

What is psychrometry?
Psychrometry is the science and practice associated with atmospheric air mixtures, their evaluation, control and effect on material and comfort. In other words, psychrometry is the study of how water vapor (among other gases) affects materials and how it can be controlled.

What is vapor pressure?
Vapor pressure is the force exerted by water vapor on the surrounding environment. In simple terms, this means that water vapor has weight. The more water vapor is in the air (called specific humidity), the greater its weight. The more it weighs, the more pressure it exerts on surrounding materials. This pressure drives water molecules through walls and structural materials as it tries to find equilibrium with its environment.

What's GPP?
GPP stands for Grains Per Pound. In simple terms, a grain is unit of measurement for weight. It is used to determine the specific amount of water present in a pound of air. On average, one pound of air has a volume of 14 cubic feet and a weight of 7000 grains. This means that one grain equals 1/7000th of a pound. GPP shows the actual weight of water vapor in the air. It is often referred to as specific humidity or humidity ratio.

What is dewpoint?
Dewpoint is the temperature at which air holds all the water vapor it can possibly contain. If the temperature drops below dewpoint the air must "give up" water vapor in the form of condensation.

Refrigerant dehumidifiers operate on the principle of dewpoint. Moisture-laden air passes over cold evaporator coils. The cold coils lower the temperature of the air below its dewpoint. Moisture condenses on the coils and drains into the pan to be pumped out.

How do I know when the structure is dry?
You can only be certain of a dry structure by taking thorough measurements with 
moisture detection instruments.  All affected materials should be returned to pre-loss condition within 4 percent (or points) of dry standard for your area.

Where should I use moisture meters?
Dri-Eaz offers several moisture detection instruments: the
HydroSensor, the GE Protimeter Aquant, the GE Protimeter Surveymaster and the GE Protimeter HygroHawk. Each instrument is designed for a specific application.

Hydrosensors determine where moisture has migrated to in carpet in pad. They detect moisture content as low as 17 percent. Use Hydrosensors to map out affected areas.

An Aquant reads moisture content in materials without penetrating the surface. It has three settings for use with a variety of structural materials. Use it on vinyl flooring, furniture, drywall or any other surface that should not be penetrated. The Aquant reads to a depth of 1".

A Surveymaster takes penetrating readings of moisture content. It includes a hammer probe for driving insulated pins into hardwoods, subfloors or other structural materials. This meter allows you to take exact readings at specific depths. Compare day-to-day readings from the Surveymaster to verify drying progress as moisture migrates back out of structural materials.

The HygroHawk is a digital thermo-hygrometer. It measures the temperature and relative humidity of the air. Use the readings from the HygroHawk to determine that you are controlling the humidity in the drying environment.

How do I measure relative humidity?
A hygrometer measures relative humidity by percent. Many hygrometers are sold in combination with a thermometer for measuring temperature. These hybrids are called thermo-hygrometers. Dri-Eaz offers a digital thermo-hygrometer with data logging capability called the
GE Protimeter HygroHawk.

My hardwood floor is starting to cup or crown. What can I do?
Cupping or crowning are indications of abnormal moisture content in hardwoods. It also tells you the location of the majority of the moisture. Cupping occurs when there is surplus moisture on the bottom of the wood. Crowning occurs when there is more moisture on top.

If you notice cupping or crowing, you should begin drying the floor as soon as possible. By reducing the moisture content of wood materials quickly and early you can reverse the cupping or crowning process.

How should I dry hardwood floors?
In order to dry a water-damaged hardwood floor, you will need to address the moisture content of both the floorboards and the subfloor.

To dry both sets of materials, set up the AirWolf/WolfPack Hardwood Floor Drying System. The AirWolf/Wolfpack directs high-pressure, high-velocity airflow between the floorboards and subfloor to literally drive water out of a damaged floor.

Use a dehumidifier to control the humidity level in the room and assist in the drying process. Monitor regularly with a GE Protimeter Aquant and GE Protimeter Surveymaster to prevent over-drying the wood. Remember that the floorboards and subfloor need to be returned to within 4 percent (points) of dry standard for your area.

To what moisture content should I dry a hardwood floor?
Dry a hardwood floor (and subfloor) to within 4 percent of dry standard for your region. You can determine the moisture content of hardwood materials for your area by visiting your local hardwood floor retailer.

Make certain that the final moisture content of materials is not above 16% to avoid the growth of surface fungi. You can use a GE Protimeter Aquant and GE Protimete Surveymaster to quantify your measurements.

How can I dry out a crawlspace?
Recent testing has shown that the most important factor in drying a crawlspace is to introduce properly applied heat. Raising the temperature of the affected area increases the drying power of the air. For clean, ductable heat you can use the
Dragon K-85 Portable Furnace.

In addition to heat, use negative or neutral air pressure to increase ventilation in the crawlspace. You should not place a crawlspace under positive pressure, as this could force contaminated air into living spaces. The Vortex Axial Fan is a good choice for increasing ventilation with negative/neutral pressure. Place the Vortex inside the crawlspace and duct air to the outside with Sto&Go Ducting.

How can I dry a double-drywall wall?
DriForce InterAir Drying System is your best choice for drying double drywall. The DriForce introduces dry air into the wall cavities through small injector tubes inserted no higher than the bottom plate. It dries from the inside using a combination of dry air and high pressure.

Supplement the DriForce with aggressive external airflow from TurboDryers®, low humidity from dehumidifiers and warm temperatures (75 to 80° F). Ensure that structural materials are completely dry with a GE Protimeter Surveymaster penetrating meter.

How should I dry a vinyl-surface wall?
DriForce InterAir Drying System is your best choice for drying vinyl-surface wall. A DriForce introduces dry air into the wall cavities through small injector tubes inserted no higher than the bottom plate. It dries from the inside using a combination of dry air and high pressure.

Supplement the DriForce with aggressive external airflow from
TurboDryers®, low humidity from dehumidifiers and warm temperatures (75 to 80° F). Ensure that structural materials are completely dry with a GE Protimeter Surveymaster penetrating meter.

How can I best prevent mold?
Your best defense against mold is to keep the structure clean and dry.

What's PPE?
PPE stands for Personal Protection Equipment. Depending on the type of restoration work you do, it may include safety goggles, respirator, rubber gloves, hardhat and a HAZMAT suit.

When do I need to use an air scrubber?
It is now recommended that you include an air scrubber on every remediation job AND every water damage restoration job. The restoration/remediation process sends millions of microscopic particles into the air where they may be inhaled by employees or occupants. An air scrubber filters the air to reduce the number of particles and maintain high indoor air quality. The
DefendAir HEPA 500 Air Scrubber provides up to three stages of filtration including a final-stage HEPA filter.

Do I need to contain Category 3 (sewage-related) water losses?
Yes, you must contain Category 3 losses. Containment prevents contaminants from spreading to clean areas of the structure. You should establish containment whenever contaminants are present.