As we work to create a safe environment in public spaces, using a dedicated airless disinfectant sprayer is the fastest way to provide complete coverage of disinfectant materials on surfaces to meet chemical dwell time requirements.
Airless spray atomizes, or breaks up, liquid disinfectant materials into small droplets without the use of compressed air. In an airless system, with a fluid path that has been properly designed and built with materials compatible for use with chemicals found in most disinfectant materials, the liquid disinfectant is pumped under high pressure through a spray tip. The tip size and pressure are what determines the material flow rate. The tip also creates the fan pattern.
In airless spray, the fast-moving high-pressure liquid stream provides the energy necessary to overcome the fluid’s viscosity (resistance to flow) and surface tension (a force that bonds the surface of a liquid together) to form a fine spray.
In the depiction of spray from a gun, high pressure forces fluid through a small nozzle (spray tip). The fluid emerges as a solid stream (sheet) at high speed. When the solid stream hits the air, it becomes disrupted. This disruption initially breaks the fluid into fragments, then ultimately very small droplets that form the spray pattern.
KEY COMPONENTS OF AN AIRLESS SPRAYER
A) SPRAY TIP
- Controls the amount of fluid sprayed by using different orifice sizes
- Orifice shape determines the spray pattern
- Graco LP spray tips are recommended for disinfecting applications to provide better control and the ability to quickly blow out clogs by reversing the position of the tip
B) MOTOR & DRIVE SYSTEM
- A heavy-duty system that drives the pump
C) PRESSURE CONTROL
- Used to regulate the fluid pressure delivered from the pump
- Delivers a steady stream of high-pressure fluid through the hose to the spray gun
- Acts as the on/off valve for the material
THE BASICS OF AIRLESS SPRAYING OF DISINFECTANTS
Dedicated airless disinfectant sprayers provide an easy and economical way to properly apply disinfectants and effectively disinfect, sanitize, and deodorize surfaces. Professional contractors prefer to use airless sprayers to disinfect spaces for several reasons, the most popular being:
- Speed: Airless spraying of disinfectant materials is faster than spray bottles, pump sprayers, and electrostatic sprayers, so more jobs are completed in less time.
- Coverage: Airless sprayers produce an even coat of disinfectant while providing the most consistent coverage on all types of surfaces.
- Versatility: Airless sprayers can be used for a wide variety of disinfecting, sanitizing, and deodorizing jobs, including interior and exterior jobs, and can easily be transported from jobsite to jobsite.
Watch Graco's Disinfectant Airless Sprayer Video:
AIRLESS SPRAYING TECHNIQUES
The information provided below is meant to be general application guidelines. Before spraying disinfectant materials, it is critical to always refer to the chemical manufacturer’s application recommendations according to the EPA approved label.
A good spray pattern indicates that the disinfectant material is completely atomized and distributed evenly on the surface. Once selecting a dedicated airless disinfectant sprayer, several techniques can help maximize the quality of the spray pattern and the uniformity of the coverage when disinfecting surfaces:
- Adjusting the Pressure
- Tip Size
- Aiming of the Spray Pattern
- Triggering Technique
- Movement of the Spray Gun
Adjusting the Pressure
To achieve the best spray pattern, always start at the lowest pressure and slowly increase the pressure until you achieve the desired results. A good spray pattern will always have even, soft edges. If you have visible lines or “tails” at the top and bottom of each pattern, try increasing the pressure in small increments until the edges of the pattern soften.
Selecting the right spray tip will help determine the amount of disinfectant fluid sprayed and the spray pattern of the materials. Low Pressure (LP) tips are recommended when spraying disinfectants using a dedicated airless disinfectant sprayer to better control the spray and also provide the ability to reverse the tip to quickly clear out any potential clogs that may impact the spray pattern. Using the LP tip also reduces chemical exposure for the operator.
Aiming of the Spray Pattern
Start each pass by holding the spray tip between 12-24 inches from the surface. Aim at the middle of each previous pass so you’ll overlap it by 50%. If you’re working with a sprayer that uses a separate hose and spray gun, hold the hose with your other hand to keep it out of the way.
The spray gun should be triggered after beginning the stroke (also called the lead stroke) and released before ending the stroke (also called the lag stroke). Start and stop the gun after each pass. The gun should move during both the trigger squeeze and trigger release. This technique prevents blotches of disinfectant materials at the beginning and end of each stroke.
Movement of the Spray Gun
To help blend each spray pass and create a fuzzy edge around the entire spray pattern, flex your wrist so the gun stays perpendicular to the surface. Fanning the gun one-way or the other will result in uneven spray patterns and possible uneven distribution of disinfectant materials on the surface. Make sure not to overreach – reach as far as is comfortable.
In order to effectively kill pathogens that cause the transmission of infectious diseases, always make sure to completely wet the surface and ensure it remains wet to meet chemical dwell time requirements as specified by the chemical manufacturer. As mentioned earlier, always follow the chemical manufacturer’s application recommendations.
Practice Spraying First
In order to refine spraying techniques when using a dedicated airless disinfectant sprayer, it’s best to do some practice on a piece of cardboard. This will provide the opportunity to fine-tune your technique and while learning how to adjust the sprayer pressure for the best spray pattern and proper atomization of disinfectant materials.
Before you begin spraying, be sure you’ve read all safety and operational instructions that came with your airless disinfectant sprayer and have proper personal safety gear, such as eye protection and a respirator. Always be aware that airless sprayers can put out a lot of pressure – often enough to pierce skin. So, never point the gun at yourself or anyone else. It’s also important to make sure to adequately ventilate your work area before spraying.