Before You Treat Your HVAC, Read the Label
Air handling is the part of the grow most sanitation programs skip. Here’s what to check before you add it to yours.
Walk through a well-run cultivation facility and sanitation discipline is everywhere. Benches get wiped down between runs, trays go through a wash station and reservoirs get drained and scrubbed.
Then look up.
The air handlers, intake vents and ductwork serving a grow room run around the clock, pulling warm, humid air across coils, through ducts and back into the room. Moisture and organic dust collect in the cracks and crevices of that system, exactly where mold fungus and odor-causing bacteria settle in. Yet HVAC upkeep often belongs to a mechanical contractor, on a different calendar with different products, if it’s on a calendar at all.
Ductwork is not a bench, though, and a product that works on one isn’t automatically allowed in the other. For a registered antimicrobial product, the label is the legal instruction manual, and it says so: it is a violation of federal law to use the product in a manner inconsistent with its labeling. Here are five things to check before anything goes into your system.
1. Is HVAC actually a listed use site?
Most surface disinfectants are labeled for hard, non-porous surfaces like benches, floors and tools. Air handling systems are a separate use site. If they aren’t named on the label, using the product there is off-label, no matter how well it performs on your benches.
Look for HVAC systems, air ducts, or ventilation and air handling systems named specifically, with a dedicated set of directions to match.
2. What does the HVAC claim actually cover?
Hard-surface disinfection claims don’t automatically carry over to the ductwork. HVAC directions are often narrower: they may cover control of odor-causing bacteria and mold fungus inside the system rather than disinfection of the system.
That isn’t a weakness; it’s a different job. Read the heading of the HVAC section and the organisms it names, and build your SOP around those words.
3. How is it applied, and with the system on or off?
Application methods vary: spraying into intake vents, treating coils directly, fogging. Some directions call for the fan to be running so the air stream carries the product through; others don’t. The method determines who does the work and whether your mechanical contractor gets involved.
Check the time requirement, too. Surface disinfection uses a contact time, measured by how long the surface stays visibly wet. HVAC directions may specify a penetration time instead. Follow whichever the label gives for that site.
4. Will it be compatible with your components?
An air handling system mixes metal coils and fins, drain pans, fan assemblies and duct linings. Some of those, like fibrous duct liners, are porous, and porous materials usually fall outside hard-surface claims.
Check how the label describes the product’s effect on materials, and follow any direction to test compatibility first. It’s a five-minute step that belongs in the SOP.
5. How often, and what does it cost you in downtime?
Frequency is a label question, not a guess. Some HVAC directions give a fixed interval; others say to repeat as necessary, which puts the schedule in your sanitation log.
Then read the directions the way your crew will. What PPE is required? Is rinsing or wiping required afterward? Does the room have to be cleared, or a waiting period observed? In a facility that runs 24/7, that last answer decides whether HVAC treatment actually happens on schedule.
Putting it together
Adding air handling to your sanitation program works best when it doesn’t add a new product, vendor and set of rules. John Sharp, lead propagation and lab director at Flora Farms in Missouri, put it this way:
“When you’re responsible for a facility of this size, sanitation is not something you can take lightly. You need something that fits into the operation, something your crews can easily use, and something you can feel confident putting into your sanitation program.”
John Sharp, Lead Propagation and Lab Director, Flora Farms
How CannaGuard PRO answers the five questions
CannaGuard PRO is EPA registered (EPA Reg. No. 91603-3-104256) and was built for cultivation and plant facilities.
Use site. Greenhouse ventilation and air handling systems are listed on the front panel, with a dedicated HVAC section in the directions for use.
Scope. The label covers antimicrobial control of non-pathogenic microorganisms in HVAC systems and air ducts, including odor-causing bacteria, mold fungus and odor-causing fungi. Deodorization works by oxidation, not by masking odors.
Application. Ready to use, with no mixing. Spray into the system intake vents while the fan is running, wet the surfaces with special attention to cracks and crevices, and allow 10 minutes for penetration.
Compatibility. The label lists the product as non-corrosive, non-caustic and non-reactive, and directs testing for compatibility on the surface of concern first.
Frequency and downtime. Repeat application as necessary. No rinsing or wiping is required. The personal protective equipment called for on the label is appropriate protective eyewear, and the directions do not call for clearing a room or observing a re-entry waiting period.
The rest of the facility. The same product is labeled for one-step cleaning and disinfection of hard, non-porous surfaces with a 60-second contact time, across greenhouses, indoor grow facilities, irrigation systems, water tanks, propagation trays, tools and containers. It is not for use on plants; the label directs a 1:20 dilution for any cleaning that may come into contact with plants. One product and one protocol, from propagation trays to air handlers.
Whatever product you choose, start with the label. Always read and follow label directions. To walk through the CannaGuard PRO label with our team, call 800-530-3332 or visit CannaGuard.pro.