Hospital Disinfection Systems

Hospitals installing or testing UV-C and Far UV-C units:

1. UV Medico reports that their UV222 Far-UVC lamp is now operational at King Hamad American Mission Hospital (opens in a new tab). The company says it provides “continuous, real-time decontamination without disrupting the essential and life-saving work performed by healthcare professionals.”
2. Duke Health hospitals (Duke University Hospital, Duke Regional Hospital, and Duke Raleigh Hospital) have implemented UVC disinfection machines as part of their infection control protocols (opens in a new tab). These are not Far UV-C; Duke uses UV-C light for “isolation discharge cleaning and as an adjunctive measure to assist with ‘deep cleans’ or workrooms, breakrooms, and common spaces.”
3. Outside hospitals, a six-month trial in 12 Danish care homes (opens in a new tab) found fewer hospital-treated infections where lamps lit common rooms; it was not randomized, and its authors call the results preliminary. A randomized trial in US care homes (opens in a new tab) is testing the same question.
4. The NHS in the UK has issued guidance on considering UVC devices for air cleaning in occupied healthcare spaces (opens in a new tab).
5. Some hospitals are testing handheld Far-UVC devices for surface disinfection (opens in a new tab), among them the Central Texas Veterans Health Care System.

Interest is growing and a few hospitals have started, but daily use of installed Far UV-C units is still emerging. Most facilities appear to be testing or considering it.

222 nm systems marketed to hospitals for disinfection:

1. R-Zero Healthcare Solutions (opens in a new tab)

• Product: UV-C Disinfection Systems
• Description: Offers a range of UV-C disinfection products intended to reduce microorganisms in hospital settings, providing continuous and mobile non-medical device surface disinfection.

2. Ushio Care222® (opens in a new tab)

• Product: Care222® Filtered Far UV-C Excimer Lamp Module
• Description: Designed for microbial reduction in occupied and unoccupied spaces, this system uses filtered 222nm Far UV-C technology to ensure safety and effectiveness.

3. UV Medico Healthcare Solutions (opens in a new tab)

• Product: UV222 Technology
• Description: Provides continuous, human-safe decontamination in hospitals, targeting pathogens like Candida auris and coronaviruses. It is designed to reduce hospital-acquired infections (HAIs) and surgical site infections (SSIs).

4. Acuity Brands HDM™ with Care222® Technology (opens in a new tab)

• Product: HDM™ with Care222® Technology
• Description: Designed to neutralize pathogens on surfaces and in the air, even with people present, using the patented Care222® filtered 222nm technology.

5. Nukit Torch Far-UVC Lights (opens in a new tab)

• Product: Nukit Torch Far-UVC Lights (set of four battery-operated lights)
• Description: Battery lamps from Nukit, the maker of the Lantern on our Far UV-C light page. A low-cost way to start testing far UV-C. Not sold to Canada.

Hypochlorous acid (opens in a new tab) (HOCl) is a weak acid that forms when chlorine dissolves in water. In water it partly splits into hypochlorite (OCl⁻), the active ingredient of bleach; the more acidic the water, the more of it stays as HOCl.

How it disinfects

HOCl is a strong oxidizer and an effective disinfectant (opens in a new tab). It kills bacteria, viruses and fungi by breaking down their proteins, cell membranes and DNA.

Where it’s used

• Disinfection: surfaces in healthcare, food handling and general cleaning.
• Skin care: commercial products use it for acne and eczema (opens in a new tab).
• Wound care: commercial solutions are used to clean wounds (opens in a new tab). In 2021 WHO declined an application from Briotech (opens in a new tab) to add HOCl to its essential medicines list for wound care, finding the clinical evidence sparse and inconclusive (opens in a new tab).

Skin and wound products are made and tested for that use. A home-made solution is not.

Brands you may know. In the FDA clearances for these wound cleansers, HOCl is listed as a preservative of the solution, and the cleared action is mechanical: irrigating and cleansing the wound.

• Vashe (Urgo Medical, formerly PuriCore): 0.033% HOCl, 330 ppm (opens in a new tab), cleared as a prescription product (opens in a new tab) for cleansing, irrigating, moistening and debriding wounds.
• Microcyn and Microdacyn (Sonoma Pharmaceuticals): the 2024 Microdacyn clearance (opens in a new tab) lists 0.003% HOCl and 0.004% sodium hypochlorite, 140 to 150 ppm available free chlorine. Its over-the-counter use is limited to the face, eyelids and eyelashes.
• Puracyn Plus (Innovacyn): cleared in 2014 (opens in a new tab) for professional and over-the-counter wound and skin cleansing.
• Briotech: an EPA-registered surface disinfectant (opens in a new tab) (AQUAVERT, 0.018% HOCl) labeled for hospital patient care areas, and a 0.014% topical skin spray. We found no FDA clearance for the spray.

Hospitals can make it on site

Hospitals can make HOCl on site by passing an electric current through salt water.

Gentler than bleach, still a disinfectant

HOCl is less irritating and less corrosive than bleach (opens in a new tab). It is still a disinfectant: never mix it with acids or ammonia, which can release toxic gas (opens in a new tab).

Sodium dichloroisocyanurate (opens in a new tab) (NaDCC), also called sodium troclosene (CAS 2893-78-9), is a white solid sold as tablets and granules. Dissolved in water, it releases HOCl and leaves cyanuric acid behind.

Where it’s used

• Drinking water (opens in a new tab): small tablets treat household water.
• Surface disinfection (opens in a new tab): hard surfaces in hospitals, factories and elsewhere.
• Pools, farms and industry: pool water, livestock and fish farming equipment, textile bleaching.

Why hospitals prefer it to bleach

• Dry tablets keep for years and are easy to dose; bleach loses strength in the bottle.
• Its solutions are mildly acidic, so more of their chlorine is HOCl, and the TURI fact sheet (opens in a new tab) suggests less chlorine gas in the air than with bleach.
• Once dissolved, a solution loses strength within days, faster when warm: in one study a 0.05% solution kept 94% of its chlorine after 5 days at 25 °C but 75% at 35 °C (Iqbal 2016 (opens in a new tab)).

Handle it with care

• Breathing it: rats that breathed NaDCC mist had irritated, damaged airways at the higher doses, easing after exposure stopped (Seo 2021 (opens in a new tab)). Do not breathe the tablet dust.
• Mixing: never mix with acids or ammonia.
• Environment: the tablets are harmful to aquatic life; keep them out of drains in concentrated form.

Studies of HOCl and NaDCC sprays and fogging for hospital disinfection, by topic:

1. HOCl fogging for surface disinfection

Study: Efficacy of hypochlorous acid (HOCl) fog in sanitizing surfaces against Enterococcus faecalis (opens in a new tab)

Journal: American Journal of Infection Control

Year: 2022

Findings: Continuous ultrasonic fogging of a commercial HOCl solution (about 550 ppm) gave a 6.59 log reduction of Enterococcus faecalis on lab surfaces. Home-made solutions did much worse.

2. Whole-room HOCl atomizing in the ICU

Study: Impact of a Whole-Room Atomizing Disinfection System on Healthcare Surface Contamination, Pathogen Transfer, and Labor Efficiency (opens in a new tab)

Journal: Critical Care Explorations

Year: 2021

Findings: A whole-room HOCl atomizing system, used alongside manual cleaning, reduced bacterial contamination on hospital surfaces, by up to 6 log10 for seeded bacteria.

3. Review of chlorine-based surface disinfection

Study: A systematic review of chlorine-based surface disinfection efficacy to inform recommendations for low-resource outbreak settings (opens in a new tab)

Journal: American Journal of Infection Control

Year: 2021

Findings: Across 89 laboratory studies, chlorine-based disinfectants were the most tested, but results depended heavily on each study’s conditions (application method, soil load, surface type), with no consistent effect of concentration or contact time. The authors recommend field testing to confirm disinfection works in practice.

4. HOCl fogging against viruses on surfaces

Study: Evaluation of Liquid- and Fog-Based Application of Sterilox Hypochlorous Acid Solution for Surface Inactivation of Human Norovirus (opens in a new tab)

Journal: Applied and Environmental Microbiology

Year: 2007

Findings: HOCl fogging reduced human norovirus on surfaces by 3 to 5 log10.

Commercial HOCl fogging systems for hospitals and emergency rooms:

1. Nevoa Nimbus (opens in a new tab): automatic whole-room fogging, which its maker says is approved for fogging an EPA-registered HOCl in hospitals.
2. Nevoa Stratus (opens in a new tab): a light handheld fogger that its maker says disinfects between cases in two minutes, for emergency rooms and other medical settings.
3. Genesis Fogger (opens in a new tab): made for use with HOCl and marketed to healthcare facilities, though not to hospitals by name.
4. Ecolox Tech Commercial HOCL Systems (opens in a new tab): disinfection systems for businesses and institutions, healthcare facilities among them.
5. Pure&Clean HOCl Systems (opens in a new tab): HOCl solutions, not a fogger, that might be used with fogging machines in medical settings.

A fogger and its solution must be made for each other, and staff need training and safety rules.

1. NHS hospitals widely use NaDCC tablets for surface disinfection and cleaning. Dissolved in water, they produce HOCl, the active disinfecting agent.
2. Common brands in the NHS include ProSan (opens in a new tab), Chlor-Clean (opens in a new tab), Actichlor Plus (opens in a new tab), and ChloroSan (opens in a new tab). These are effervescent tablets with NaDCC as the active ingredient.
3. They are often preferred to liquid bleach because they are more stable, easier to store and transport, and easier to dose accurately.
4. WHO guidance (opens in a new tab) uses chlorine at 0.1% (1,000 ppm) for general surfaces in healthcare and 0.5% (5,000 ppm) for spills of blood or body fluids over about 10 ml, made fresh each day.
5. Hospitals and other healthcare facilities can order them through the NHS Supply Chain.
6. Chlor-Clean’s maker reports (opens in a new tab) that its tablets work against bacteria, viruses, fungi and spores, tested to EN13727, EN13697, EN14476 and EN17126.
7. A tablet maker associates their use in UK hospitals (opens in a new tab) with lower Clostridium difficile infection rates, and reports that by 2010 all UK and Irish hospitals had switched to NaDCC.
8. They have some advantages over bleach solutions (opens in a new tab): a more stable source of HOCl, a longer shelf life and possibly less exposure to chlorine gas.