Professional pet groomers share a common goal -- drying pets faster while maintaining a healthy grooming environment. As it turns out, groomers can gain valuable insights from unrelated industries that study and apply the science of drying.
For example, drying is taken to its highest levels in wood processing, the manufacture of ceramics, food and grain processing, and home/carpet restoration. What can we learn from these industries? And how can we apply that information to the drying of pets in the grooming salon?
First, we must understand the drying process. Drying occurs through the mechanical removal of water and evaporation., Mechanical methods include absorption by toweling or air pressure removal with a high-velocity dryer. Evaporation is the process by which water molecules develop enough kinetic energy to move from a liquid state attached to a surface to vapor in the air. In order for this to happen, the surface tension of water -- what causes water to cling to itself and adhere to surfaces -- must be reduced.
Three interrelated components determine how fast something dries, according to Darren Hudema, a drying educator for Dri-Eaz Products Inc. (Burlington, Wash.): relative humidity, temperature, and air movement.
RELATIVE HUMIDITY
The air in any given space has a certain capacity to hold moisture. Relative humidity (Rh) is the amount of water vapor in the air expressed as a percentage of the air's holding capacity. The smaller the drying space, the more quickly the humidity will rise. At 100 percent Rh, the air is considered saturated at a given temperature, and condensation begins to occur. That is, the water vapor in the air condenses as a liquid on surfaces. This not only can cause windows to fog up, but it also can lead to mold and rust problems.
Here's a key concept: evaporation slows down as humidity rises. Hence, the more saturated the air, the slower the drying. At higher humidity, vapor starts returning to water, and when the air is totally saturated, drying stops.
According to experts in the restoration industry, drying is significantly impeded when the humidity exceeds 60 percent saturation. The Society of Cleaning and Restoration Technicians (Franklin, Tenn.) recommends that dehumidifiers be used if the relative humidity in a space is above 60 Rh.
Using high-velocity dryers to force water off the animal speeds up drying, but can quickly add considerable moisture to the air in a grooming room.
Hudema of Dri-Eaz maintains that high relative humidity in the grooming environment is the biggest challenge facing today's professional groomers. "Many groomers fail to appreciate that the capacity of the air in a given space to absorb water is finite. Unless saturated air is treated to remove the excess humidity or replaced with less humid air, the drying rate will become sluggish regardless of the dryers used," he said.
While air conditioning units can act as dehumidifiers to a certain degree, Hudema explained, they turn on and off intermittently as the air in the vicinity of the thermostat requires cooling. This may not be sufficient to counteract the accumulation of moisture in the bathing/drying area, thus air conditioning is not a reliable tool for humidity control. The most important thing a pet groomer can do to improve the rate of drying in the salon is to install a dehumidifier, he said.
TEMPERATURE
Raising the temperature of drying air decreases the relative humidity and increases the moisture capacity of the air. From a technical report about grain drying, we learn that, "As a general rule of thumb, increasing the air temperature by 20 degrees F doubles the moisture-holding capacity of air and cuts the relative humidity by half."
Drying in a cold space is going to be slower than in a warmer room. Warmer air provides more kinetic energy to change the water into vapor. Cooler temperatures, such as those in the winter season or in basement grooming rooms, will require lower relative humidity and warming for efficient drying to occur. Also, allowing the grooming space to become cold overnight can drastically affect drying efficiency in the morning.
It also reduces the potential of the room air to dry out overnight. Because the moisture capacity of a space decreases as the temperature decreases, the relative humidity in a damp grooming room with lowered temperature could rise overnight. (This could also create the conditions for mold and microbial issues.) Thus, groomers who are attempting to save on utility costs by lowering the thermostat of the grooming room overnight may have their savings offset by increased drying times during the day.
The ideal drying environment would have a temperature of 70 degrees F to 80 degrees F and a relative humidity of less than 45 Rh.
Most hardware stores and home improvement stores offer inexpensive devices to measure indoor temperature and relative humidity. This is an easy way to monitor the saturation level of the air in a drying area. By recording beginning, middle and end-of-day temperature and humidity readings over a week, you can obtain a good profile of the drying efficiency in your grooming area.
AIR MOVEMENT
The relationship between air flow and evaporation is both simple and complex. On a simple level, we can appreciate that clothes on a line dry faster if there is a breeze. Movement of air over a wet surface acts almost as an "air towel, " according to Hudema, "wiping" moisture off the surface and absorbing it. More complicated is the concept of "boundary layer effect," which means that without movement, the air immediately surrounding a drying object will become saturated and drying will be reduced.
So, not only does there need to be air movement around the animal being dried, there also needs to be air movement within the immediate space, such as the bathing room or the mobile van. The saturated air surrounding the drying area needs to be replaced with drier air from other parts of the room (or outside).
This information would suggest that the ideal grooming space would include an air exhaust fan over the tub so that the most saturated air in the space can be removed and less saturated air drawn to the area.
Andy Kalmanash, a groomer and professional handler at Ruff-Wave Kennels (Stamford, Conn.), has such a setup. "When I use a high-velocity dryer on a dog, I can see the spray of water literally sucked up by the exhaust so it isn't falling back onto the work," he said.
It also makes sense to consider air circulation and air exchange throughout the facility. When the air is confined to a small space, it will become saturated more quickly. If the air is circulated throughout a larger space, the air in the grooming area will have a greater capacity for drying. Likewise, in dry climates, a source of fresh air, such as a fan in an open window, can help achieve a much greater drying capacity in the bathing room.
PRODUCTS' EFFECTS ON DRYING
Since drying occurs more rapidly on smooth, hard surfaces and more slowly on coarse or porous surfaces, products that create a smoother surface of the hair cuticle will facilitate drying. Light conditioners and finishing sprays create this effect by filling in the cracks and crevices on the surface of the hair. Some silicone ingredients that are used in conditioning products are particularly effective at creating a quicker-drying surface of the hair shaft, say manufacturers.
On the other side of the spectrum are thick "remoisturizing" products. Because these products are formulated to hold moisture to the skin and hair, they are actually trapping water and holding it. This can result in a noticeable increase in drying time. But there are times when the benefit to the hair is worth little more drying time.
Quick-dry products formulated for use after the bath, such as Quick-Dry from Davis Manufacturing & Packaging Inc. (Scottdale, Ga.) an E-Z Groom Ultra Fast Blow Dry Conditioner from E-Z Groom (Oak Park, Mich.), utilize surfactants that reduce the surface tension of water without leaving a residue. Reducing the surface tension of water forms thinner layers or sheets, or smaller water beads, which allows for easier water removal.
Other products are designed as a one-step alternative to after-bath products. For example, Speed Dry shampoo from ShowSeason Animal Products (Tucker, Ga.) is intended to be used with forced-air drying on thick coats, said president Sandy Giorgyi. "Our proprietary formula facilitates water movement through the coat so it may be brought to the surface for drying," she explained.
Speed Dry also can be used as an additive with other shampoos for faster drying, but is not intended for use with conditioners. "Conditioners would most likely negate the effect," said Giorgyi.
A reminder: If the air in the grooming area is not dry enough to easily absorb more moisture, quick-drying products will be less helpful.
THE IMPORTANCE OF TOWELING
In the water damage restoration industry, technicians find it essential to remove as much surface water as possible before evaporative drying begins. So it is in the grooming industry. While carpet restoration professionals use powerful extracting machines that remove excess water, groomers have towels.
"Physical extraction is two thousand times more efficient than evaporation," said Hudema. "The more water you can remove by physical extraction, the quicker the coat will dry."
Toweling has one distinct advantage: It does not add to the relative humidity. There is a tendency for bathing personnel to prefer blasting excess water off animals with the high-velocity dryer as an alternative to toweling. However, as noted previously, this method can quickly lead to air saturation and a loss of drying efficiency.
To solve this problem, Pam Julian, owner of Bubblemobile, a mobile grooming service, shares a neat trick: Combine the use of a high-velocity dryer with towels. Hold a towel over or behind the dog, and place the dryer wand under the towel. As you move the dryer wand, it blows water off into the towel. This not only speeds up the drying process, it also reduces the amount of moisture going into the air as you work.
Julian also advocates wrapping small dogs and cats in towels and allowing them to sit in a kennel for 15 to 20 minutes before fluff finishing. This towel wrapping, also called "sacking," greatly reduces the time under the air dryer.
By applying an understanding of the science of drying -- as well as choosing products carefully and using towels creatively -- you can maximize the drying efficiency of your grooming operation. And that translates into a healthier environment for you and the pets in your care.
SIDE BAR ONE: THE HAZARDS OF HEAT
We have all heard tragic stories about dogs that overheated and died in grooming salons. It can happen. How can our understanding of the science of drying help us prevent this kind of tragedy?
The canine body is designed to cool through respiration and evaporation of exhaled air over the tongue and air passageways. Evaporation is the cooling mechanism. The dogs (or cats) are exhaling air that is 102 degrees F and 100 percent humidity.
The same factors of high relative humidity, small drying area and lack of air movement that negatively influence drying by reducing evaporation also can impede the cooling mechanism for dogs and cats in the groomer's care. When there is excessive humidity in the air surrounding the animal, evaporation is impeded and the animal cannot cool sufficiently.
Under conditions of high humidity and lack of air movement, it does not require very much external heat from a dryer to create a situation that can lead to heat stroke. In a small, poorly ventilated drying crate, the air surrounding a drying animal can quickly become sufficiently saturated to impede drying and the animal's cooling mechanism. Adding fans to move the air in drying cages can reduce the risk of overheating. Conversely, covering crates or muzzling noisy dogs can increase the hazard, even without extra warm air for drying.
It is also important to recognize that some animals have very poor cooling ability, especially very young, elderly, short-muzzled (brachycephalic) breeds, or animals with respiratory ailments or poor temperature regulation, such as dogs with hypothyroidism.
While heat stroke accidents in grooming salons can be related to the use of hot air dryers or unsupervised staff, it is not the dryers themselves that are to blame, but a poor understanding of how all the factors in the grooming environment interact to create hazardous conditions.
For a related GroomBlog article on Heat and Stress in the grooming salon, click HERE.
SIDE BAR TWO: TIPS FOR FASTER DRYING
- Invest in a dehumidifier. Saturated air is the biggest detriment to faster drying. Dry air allows the fastest drying as well as the healthiest conditions for groomers and animals.
- Move air through the salon. Fans on the floor at both ends of an area will promote better circulation. Circulation moves drier air to the grooming space and also dries the air as it moves.
- Install an exhaust fan in the drying area, especially above the tub or drying table.
- Use fans for cage drying and/or provide ventilation and air exchange in drying cages.
- In cold, damp conditions, leave some heat on overnight to dry the air in the grooming room. The slightly higher utility cost may translate into more efficient drying conditions during the day.
- Remove as much water as possible from the animal with toweling.
- Use towels over, under and behind the animal as you dry with a high-velocity dryer.
- Choose mildly acidic conditioners with silicone ingredients that tightly shut the hair cuticle and form a smooth surface from which water moves quickly. ShowSeason Results Rinse and Chrome Coat both will facilitate drying as well as protect the hair.