Procedures for creating a green-zone room using UV-C after discharge of patientwith COVID-19 from hospital within 72 hours
OKEN Co., Ltd：Naofumi Kagimoto, Nobuyuki Hode, Masaaki Yamaguchi【Summary】
Once the patient with COVID-19 gets discharged, the red-zone room needs to return
to a normal hospital room (green-zone room) within 72 hours. In order to create a greenzone room, we used the UV-C ultraviolet irradiation machine and TPP-DIN. Also, we used
an EPA registered chemical to disinfect and perform cleaning tasks. The organizeddisinfection and cleaning tasks are as follows.
Under the supervision of the leader in control, once all the patient left from the hospitalward specially designated for COVID-19, we disinfected and cleaned the common use
space (bathroom, toilet, hallway, etc.) within 72 hours in order to create a safe hospitalenvironment. All common use space such as the patient’s room, hallways, toilet, shower
room, and other common spaces were disinfected by the UV-C. The whole area wasirradiated from 2.5m distance for 3 minutes as a baseline. The single patient room withthe toilet was irradiated one extra time. We usually irradiate the UV-C at the end, however
in order to lessen the psychological burden of the workers, we irradiated the UV-C first,
since the SARS-CoV-2 was an unknown virus. Once the area was irradiated, theprofessional trained worker used TPP-DIN and EPA registered chemical to clean thehospital rooms. The tasks are as follows; remove curtain in the room, and clean frequently
touched surface, such as the light switch, bed, floor, bed cabinet, nurse call button, sink,windows, common use shower room and toilet.

【Introduction】
Our company, OKEN Co., Ltd, is an integrated building maintenance company inHiroshima, Japan, a place where our headquarter is located. We have been specializing
in improving the environment for medical facilities. In 2003, we created “I-CoSS®”:
Infection Control Support System, which is our company’s one-of-a-kind hospital-acquired
infection controlled system registered as a trademark. In 2012, we started up seminars “ICoss-jyuku” to develop human resources of understanding the standard precaution androute transmission based precaution. We have been upgrading our cleaning techniques
according to the accomplishments of fast-evolving medical studies. In 2015, once theantimicrobial resistance (AMR)’s sense of threat was announced by WHO, global action
1plans were adopted. In recent years, we are facing the issue of how to prevent nosocomial
infections caused by AMR, such as MRSA and MDRP that are commonly found in thehealth-care facilities. In order to deal with the AMR’s threat, UV-C ’s effectiveness has
been proved through many research results.1) Our company has been using it in public
hospitals since we purchased the UV-C UV irradiator in 2014.
On December of 2019, the new coronavirus (SARS-CoV-2) has created a causeof a newly emerging infectious disease (COVID-19). It has been confirmed in Japan inearly 2020, and we were forced to deal with an unknown virus. On March 6th, 2020, thefirst infected individual was confirmed in Hiroshima City and that individual has beentreated at the health-care facility specially designated for COVID-19. From that day
onward, we have been working to create ongoing performances to maintain safe hospitalenvironment.
As of End of June
2021 2)
World

Confirmed Individuals
with COVID-19
182,153,508

Total Deaths
3,946,015

Japan

799,550

14,784Hiroshima Pref.

11,494175

Since the first confirmation of the COVID-19, many medical research results havebeen accumulated. Especially in Hiroshima Pref., there have been studies on thepossibilities of environmental contamination at long stay medical accommodations for
mildly symptomatic and asymptomatic individuals. There were studies that showed theeffectiveness of using the UV-C to be effective when used in the health-care environment.3）
However, there were little to none researches that reported on how to disinfect and clean
the place where the COVID-19 patients get medical attention. In other words, researches
on sterilization and cleaning procedures performed after the discharge of patients with
COVID-19 were not reported clearly.
There were many unknown things regarding the COVID-19 at that time when
SARS-CoV-2 was found. Droplet transmission and contact transmission of COVID-19
were identified. However, the amount of viruses and duration of viruses in the health-care
environment were unknown. On the other hand, we wanted to accommodate a requestfrom health-care facilities in creating a safe environment at the same time as a mission asa cleaning company. In order to create a feeling of being safe in such an environment
especially for those in the health-care facilities, creating the procedure of cleaning was anurgent matter.
2

Recently, the details of SARS-CoV-2 have been understood through many study
results. The existence of the SARS-CoV-2 became identified on the high frequency
contact surfaces. Infectiousness continued for 120 hours on plastic and glasses, and 72
hours on stainless surfaces. Also, the UV-C’s effectiveness has been evident in theresearch.4）On the top of this, the amount of RNA in the SARS-CoV-2 virus was highly
detected in the feces.5 ） This shows the importance of maintaining a safe toilet
environment.6）
We have considered, “Safe” and “secure” as the highest priority for working
individuals. Since 2003, our company has given health-care professionals’ workshops on“standard precaution,” “route transmission-based precautions,” “the use of gown
techniques,” and additional job training.7）Also, we established the new use of UV-C tocreate a non-touching environment through work procedures.
As the present of July 2021, the fourth declaration of state of emergency wasannounced, the fifth wave of infection is easily imaginable. The COVID-19 has been anoverriding priority. Also, not only the antimicrobial resistance (AMR) is a problem, but
handling the new infectious disease pandemic has been issues that need to be dealt with
as well.
We as OKEN would like to release “The procedures for creating a green-zone
room using UV-C after discharge of patient with COVID-19 from hospital within 72 hours”8）

on our website to fight against the unseen enemy as our base belief.

【Overview】
Cleaning Area:
Hospital rooms for patients with COVID-19, hallway, toilet in 1 location,
waste disposal room, pantry, treatment room, rest room, laundry room, showerroom, meet-up space, nursing room, etc.
Number of Workers:
Day 1: 3 workers for 2 hours, day 2: 4 workers for 3 hours
Equipment in Use:
2 UV-C ultraviolet irradiation machines (manufactured by Ultra Violet Devices,Inc. UVDI-360®) (Fig. 1)

3

Chemicals in Use:
VIROX Technologies Inc.’s Accele diluting 17-fold, Accele Prevention
Wipes®
〈〈DIN (Canada’s drug identification number) registered product Acceleratedhydrogen peroxide 〉〉9)
Sealed Air Corporation’s Bath Mate® Cleaner diluting 13-fold.
〈〈EPA (U.S. Environmental Protection Agency) registered product）〉10) (Fig.2)
PPE (Personal Protective Equipment)11) in Use:
Protective garments®, disposable shoe cover12), face shield mask, anddisposable gloves (Fig. 3)
Materials in Use:
1 janitorial cleaning cart, 2 mop handles, 20 microfiber flat mop, 1 janitorial
sanitary ware cart (Fig.4), and 1 stepladder.

Day 1
Hospital Rooms
Room shared by
2 patients…1 room

Day 2
Hospital Rooms
Private Hospital Room (with a privatetoilet)…14 rooms

Room shared by

Room shared by 2 patients… 1 room

5 patients…2 rooms

Room shared by 3 patients … 1 room
Shared space

Shared space

Hallways, toilet ...1 location, waste disposal

Hallwaysroom, pantry, treatment room, rest room,

Toilet …1 location

laundry room, shower room, nursery room,
Fig.1

meet-up space, etc.

2UVDI

manufactured by UVDI
Device’s UVDI-360

Table 1: Range of working area4

Accele prevention wipes and bath mateFig.2 Chemicals in use

Fig. 3 PPE in use

Fig.4

Janitorial

sanitary ware cart

【Work Preparations】･Workers thoroughly wash their fingers and wrists with a medicated detergent containing
bactericidal ingredients.
･Workers wear face shield masks, protective garments, disposable shoe covers, anddisposable gloves (doubled).
《Precautions》
・To secure the workers’ “safety,” protective garments are worn, but the use of isolation
gowns is usable as well.
・It is said that infection does not come from the floor, but disposable shoe covers will
be used if there is a request from the health-care facility.
・Disposable gloves is used as double, one to prevent the intrusion of dust and water,
and the other disposable gloves to be taped on both wrists.

・Equipment is used in the dedicated red-zone area.
【Work Procedures】
1) Put the UVDI-360 and necessary equipment in the red-zone area.
2) Irradiate the curtains in the patient’s room once for 3 minutes.13）(Fig. 5)

5

〈〈Precautions〉〉
・The whole room is irradiated with the UV-C from 2.5m distance for 3
minutes as a baseline.
・The UV-C is harmful to human skin and eyes, so it is important to evacuate fromthe irradiating room.
・Since the UV-C does not go through the curtains, irradiating both sides of thecurtain is necessary.
・Since the safety is the utmost priority in working in the hospital wards for COVID19, the Accele prevention wipes with cleansing and disinfection effects were used
after irradiating with the UV-C. However, usually in the hospital wards for
infectious disease excluding the COVID-19, the UV-C irradiation operation is used
as a complementary cleaning right after wiping the area to eliminate the organic
substances and to disinfect.

3) Remove the curtains, put them in the AQUAFILM (water soluble laundry bag made by
MORAINE CORP.) and close it. Then, put the laundry bag in the doubled plastic bags andclose it. Afterwards, remove the laundry bag outside the red-zone area. (Fig.6)

Fig. 6 Removal of curtains

Fig. 5 Irradiation of curtains using the UV-C64) Irradiate the UV-C to the furniture, fixtures, equipment in the room, and the individualtoilet. (Fig.7)

Fig. 7 Irradiating the furniture, fixtures, equipment, and toilet in the room using the UV-C.

5) Irradiate the UV-C at the hallways, shared toilet, and shower room for 3 minutes.
(Fig.8,9)

Fig. 8 Irradiation of hallways with the UV-C

Fig. 9 Irradiation of shared toilet, shower room, laundry room and other places were irradiated withthe UV-C76) Once the irradiation of the UV-C is completed, furniture, fixtures, medical equipment,
and other equipment are wiped with the Accele prevention wipes. (Fig.10)〈〈Precautions〉〉
・Accele prevention wipes with cleansing and disinfection effects are used.
Wipes used from cleanliness to uncleanliness places and from top tobottom locations.
・Use large-sized Accele prevention wipes folding in 4, changing its’ sides
every time wiping in the same one direction.

Fig. 10 Cleaning tasks done in the room7) Use the Accele prevention wipes to wipe the high frequency contact surface at hallways
and commonly used spaces once after the place is irradiated with the UV-C. (Fig.11)

Fig. 11 Wiping hallways and the other shared spaces

88) Spray the area with bath mate of 13 -fold after the area is irradiated by the UV-C. First,
wipe the high frequency contact surface. Second, use toilet bowl brush to clean thesanitary ware. Third, wipe the area with Accele prevention wipes. (Fig.12)《Precautions》
・Spray the bath mate of 13-fold before cleaning the sanitary wares.
・Wipe the sanitary wares in order from low degree of infection to highly infected area.
・Use large-sized Accele prevention wipes folding in 4, changing its’ sides every time wiping inthe same one direction.
・Used toilet bowl brush and sponges in the red-zone area should be discarded as infectious
wastes.

Fig. 12 Cleaning the patient’s toilet9) Wipe the floor surface in the order from patient’s room, hallway, patient’s toilet with theflat mop immersed with Accele of 17-fold in advance. (Fig.13)《Precautions》
・Microfiber flat mop should be immersed with Accele of 17-fold in advance. Then, wipe thefloor surface by making turns in a shape of a “S” and move from only one direction.
・Store old microfiber mops used at the normal cleaning area and use them in the red-zone
area. Then, discard the used microfiber mops as infectious wastes.
・Use 1 mop in individual patient’s room. The mop used in the hallways and other places should
be changed once it covers the same size of the private room.

9Fig. 13 Cleaning floor surfaces of the patient’s room, hallway, and patient’s toilet, etc.

10) Discard the already used Accele prevention wipes, mop, toilet bowl brush andsponges to the infectious waste substance box.
11) Workers disinfect the doubled outer disposal gloves and take off the gloves by turningthem inside out. In the same way, disposable shoe covers and protective garments
should be turned inside out and discard them into the infectious waste substance box.
Then, take off the singled inner disposable gloves inside out into the infectious waste
substance box. Finally, sanitize hands with alcohol, take off the face shield mask, anddiscard them into the infectious waste substance box. (Fig.14)

Fig. 14 Removing the PPE12) Put on new disposable gloves and use Accele prevention wipes to wipe up the mophandle. (Fig.15)
13) The whole surface of the carried-in materials and equipment should be irradiated by
the UV-C. Then, wipe them with Accele prevention wipes to disinfect. Take out theequipment outside the red-zone area. (Fig.16)
10

Fig. 15 Wiping the mop handle

Fig. 16 The whole surfaces of the carried-in
equipment are irradiated by the UV-C

14) Workers thoroughly wash their fingers and wrists with a medicated detergent
containing bactericidal ingredients.
【Acknowledgments】
We are deeply grateful to health-care facilities from various quarters in helping
us to create this document, “Procedures for creating a green-zone room using UV-C
after discharge of patient with COVID-19 from hospital within 72 hours.” Also wewould like to appreciate the stakeholders who gave us support.
In order to create this document, many specialists gave us guidance andsupport to prepare these working procedures. In the early days of March 2020,
SARS-COV-2 was an unknown virus. We received many advises related to theSARS-COV-2. For this reason, there are no infected individuals infected in ourcompany up until now. We hope that we can provide some help to COVID-19
related facilities.
We would like to thank our colleague Kei Yamashita for English language
editing.

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