Applications of Hypochlorous Acid

Hypochlorous acid is used for an unusually wide range of jobs because it is one chemistry that can be produced at different strengths, applied in different ways and used close to where it is made. This page organises those uses by task and by industry, with the application method and the precautions that go with each.

Two principles apply throughout. First, clean before you sanitise or disinfect: hypochlorous acid is not a detergent. Second, where a task requires an EPA-registered disinfectant with label claims, use a registered product such as HOCl-AS200 according to its label.

Applications by task

Hard surfaces

Tables, counters, stainless steel, glazed tile, sealed plastics, handles and other high-touch points. Applied by spray, wipe or mop after cleaning, with the surface kept wet for the contact time in the SOP. For disinfection with label claims on hard, non-porous surfaces, HOCl-AS200 is used per its label: pre-clean, spray from 6–8 inches, keep visibly wet for 5 minutes, air dry.

Food-contact surfaces and equipment

Cutting boards, conveyors, slicers and processing equipment after cleaning. Food-contact sanitising is regulated; the concentration, product and any rinse requirements are set by the applicable rules and your food safety plan.

Floors, walls and drains

High-volume environmental work, often at a higher set point than surface work because soil loads are heavier. Drains and floor junctions are common harbourage points and deserve mechanical cleaning as well as chemistry.

Footbaths and entry points

Used to reduce tracking between zones. Footbath solution becomes contaminated quickly and needs regular replacement and strength checks.

Water lines and wash water

Used in animal drinking-water lines, irrigation and, where permitted, process and wash water. Water treatment is regulated separately; dosing and monitoring must meet the applicable requirements.

Fogging, misting and electrostatic spraying

Solution can be applied as a fine mist or charged spray to reach complex surfaces and large areas. Equipment such as the Jet H2 electrostatic sprayer, ByoPlanet sprayers and the NebulaOne nebulizer is used for this. Follow the product label for any application method and area.

Deodorising

Oxidation of odour compounds on surfaces and in materials. The HOCl-AS200 label includes deodorisation directions: spray until thoroughly wet, let stand for 5 minutes, then wipe clean.

Cleaning

For light soils, HOCl-AS200 carries cleaning-only directions: spray the soiled area and wipe clean. Heavy soils still need a detergent.

Application methods compared

Applications by industry

Each of our fourteen industry programmes has its own applications page covering tasks, methods and SOPs in detail.

Zoning and frequency

Most facilities organise sanitation by zone, from the surfaces that touch product or people to the general environment. The zone decides the frequency, the chemistry and the verification.

Setting strength by task

With onsite generation, strength is a setting rather than a product choice. The set point for each task comes from your SOP, your food safety or infection control plan, any regulatory limit that applies, and the registered product label where one is being relied on. Heavier soil, drains and biofilm-prone areas are usually specified at higher strength than routine surface work; anything that contacts food or skin is governed by the applicable rules. Whatever the set point, verify it at the point of use, because strength drops in storage and in contact with soil.

Choosing application equipment

Building an application SOP

Every application should have a short written procedure that anyone on shift can follow. A good one answers seven questions:

1. What surface or item, in which area and zone?
2. When and how often: between uses, at changeover, end of shift, weekly?
3. Clean how? The detergent and mechanical step that comes first.
4. Which solution, at what strength? The set point, or the registered product and its label directions.
5. Applied how? Spray, wipe, mop, foam, electrostatic, fog, dose.
6. For how long? The contact time, and whether a rinse or air-dry follows.
7. Verified how? Strength check, visual check, ATP or swab frequency, and where it is recorded.

Our industry programmes include implementation and SOP pages that follow this structure for each sector.

Precautions that apply everywhere

• Clean first. Soil consumes available chlorine.
• Verify strength. Check free chlorine and pH with test strips or a photometer before use and log it.
• Respect contact time. Keep surfaces wet for the full time in your SOP or on the registered product’s label.
• Do not mix. Never combine with acids, ammonia or other chemicals.
• Mind the metals. Prolonged contact may cause pitting or discoloration; wipe or rinse where required.
• Store correctly. Closed, opaque containers, cool and out of sunlight; test stored solution.

Verifying that an application works

Every application needs a way to show that it was done correctly, and that the result is what the programme expects. Three layers of verification are common. Process checks confirm the solution was right before it was used: free available chlorine and pH measured at the point of use and logged. Visual checks confirm the surface was cleaned, fully wetted and left for the contact time. Outcome checks — ATP swabs for residual organic matter, and microbiological swabs where the programme calls for them — confirm the overall cleaning and sanitation result.

Trend the results rather than reading them one at a time. A slow rise in ATP readings in one area, or a run of low strength readings from one outlet, is an early signal to look at the cleaning step, the distribution line or the set point before it becomes a finding in an audit.

Frequently asked questions