Best practices in decontamination and sterilization of public spaces

This document outlines the best practices for decontamination and sanitization of public places.

For city / street disinfection

Borrow from agricultural sector and spray disinfectant on streets if possible (see Delhi example)

  • Ensure you identify and track areas to disinfect periodically

  • Work on short / medium term solution and borrow equipment from Agricultural supply if possible for disinfectant spray

  • TODO: Get Delhi Government SOP for disinfectant.

Overall guidance - please localize for available resources

I. Items to Prepare for Cleaning of Premises

Prepare these items before you start to clean the premises:

1. Personal protective equipment (PPE) (where applicable)

Areas where confirmed cases have stayed*

Areas exposed to confirmed cases



N95 mask and eye goggles/face shield

Surgical mask

Disposable gowns

Change of clothes

*If the confirmed case has stayed or has been present for a long period of time at certain areas of the premises, or cleaning activities may generate aerosols, wear an N95 mask in place of a surgical mask, eye goggles, or face shields and disposable long sleeved gown. 2. An appropriate disinfectant with indication of effectiveness against coronaviruses, or bleach solution. Disinfectants should be prepared and applied in accordance with the manufacturer's recommendation. Note that different active ingredients require different periods of contact time between the disinfectant and the surfaces to be effective.

3. Plastic/Trash bags

4. Water

5. Disposable cloths or rags

6. Pail

7. Mop

Decontamination Procedure

Once you have the supplies, here are the key steps to decontaminate

  1. Seal of previously contaminated areas : Where possible, seal off areas where the confirmed case has visited, before carrying out cleaning and disinfection of the contaminated environmental surfaces. This is to prevent unsuspecting persons from being exposed to those surfaces. For enclosed spaces, leave the room undisturbed for at least 3 hours after the confirmed case has left the area so as to allow the aerosols to settle. If there is a need to enter the room before it is cleaned or disinfected, put on appropriate PPE (Section B.I.1) before entering.

  2. Ensure use of PPE's : Before you start cleaning, put on a pair of gloves, N95 mask, eye goggles and a disposable gown. If the confirmed case(s) has been present at the premises only for a short period of time (e.g. if the confirmed case passed by an area in his/her office (not the work desk), or ate at a canteen, etc), please refer to para 2 for a stepped-down PPE protocol.

  3. Prepare disinfectant : Avoid touching your face, mouth, nose and eyes during clean-up. Gloves should be removed and discarded if they become soiled or damaged, and a new pair worn. Prepare the disinfectant according to manufacturer’s recommendations or bleach solution (For bleach, dilute 1000ppm or 0.1% sodium hypochlorite; bleach solutions with 5.25-6.00% sodium hypochlorite can be diluted with 1 part bleach in 49 parts water). Alcohol can be used for surfaces where the use of bleach is not suitable.

  4. Ensure Ventilation : Keep windows open for ventilation.

  5. Keep cleaning equipment to a minimum.

  6. Mop floor with prepared disinfectant or bleach solution, starting from one end of the premises to another.

  7. Soak cloths with prepared disinfectant or bleach solution and use them to wipe all frequently touched areas (e.g. lift buttons, hand rails, doorknobs, arm rests, seat backs, tables, air/ light controls, keyboards, switches, etc.) and allow to air dry. A steady wiping motion should be used when cleaning either floors or horizontal surfaces, to prevent the creation of aerosols or splashing. Identify frequently touched areas based premises types and likelihood of use and risk of contamination.

  8. Avoid use of spray pack to apply disinfectant on potentially highly contaminated areas (such as toilet bowl or surrounding surfaces) as it may create splashes which can further spread the virus. Also, alcohol-based disinfectant is flammable, do not spray it into the air.

  9. Clean toilets with a separate set of equipment (disposable cleaning cloths, mops, etc) using disinfectant or bleach solution. Use an appropriate disinfectant and note that different active ingredients require different periods of contact time to be effective.

    a. Clean all accessible surfaces (sinks, taps, soap dispensers, toilet roll dispensers, walls, cubicle doors, cubicle locks, handles, flush buttons, etc).

    b. Urinals and toilet bowls can be disinfected by pouring disinfectant into the urinal/toilet bowl. Allow for an appropriate contact time. Clean urinals and toilets bowls with a brush and use a separate cloth for seat covers. Brush and cloths used for these should not be used for other surfaces.

    c. After disinfection, clean the floor with disinfectant from the exit inwards.

  10. Laundry Procedure : Remove curtains/ fabrics/ quilts for washing, preferably using the hot water cycle. Avoid tossing and throwing the laundry. For hot-water laundry cycles, wash with detergent or disinfectant in water at 70ºC for at least 25 minutes. If low-temperature (i.e. less than 70ºC) laundry cycles are used, choose a chemical that is suitable for low-temperature washing when used at the proper concentration. Arrange for a cleaning contractor to properly disinfect the mattresses, pillows, cushions or carpets that have been used by the person who has been confirmed to have the COVID-19.

  11. Repeat cleaning the floor with the prepared disinfectant or bleach solution starting from one end of the premises to another. Avoid going from an area that has not been cleaned to an area that has been cleaned, to avoid dirtying the cleaned area.

  12. Bio medical waste management : Throw away disposable cleaning equipment made of cloths/ absorbent materials (e.g. mop head and wiping cloths) after cleaning each area, to prevent cross contamination. Discard cleaning equipment into doubled-lined biohazard waste bags arrange for proper disposal of this waste as biohazardous waste.

  13. Disinfect non-porous cleaning equipment used in one room, before using for other rooms. If possible, keep the disinfecting equipment separated from other routine equipment.

  14. Disinfect buckets by soaking in disinfectant or bleach solution.

  15. Removal of PPE : After cleaning and disinfection is completed, remove disposable gown (if worn) and gloves, wash your hands with soap and water.

  16. All other disposable PPE such as N95 masks and eye goggles, should be removed and discarded after cleaning activities are completed. Hands should be washed with soap and water immediately after each piece of PPE is removed, following completion of cleaning. Eye goggles, if used, should be disinfected after each use, according to the manufacturer's instructions.

  17. Throw PPE into doubled-lined biohazard waste bags.

  18. All waste generated from the clean-up (disposable cloths, used PPE etc, in paras 13 and 18) should e segregated from other waste (e.g.. food waste), and disposed of as biohazardous waste as soon as possible.

  19. Air and ventilate the premises. Where possible, avoid using the area the next day.

  20. If the confirmed case(s) has been present at the premises only for a short period of time (e.g. if the confirmed case passed by an area in his/her office (not the work desk), or ate at a canteen, etc), please refer to para 2 for a stepped-down PPE protocol.

  21. The protocol can be stepped-down as follows:

    a. Prepare a change of clothes instead of a disposable gown.

    b. Waste generated from the clean-up in paras 13, 18 and 19 can be disposed of as regular waste.

    c. Instead of wearing a disposable gown, shower or wash up and change clothes immediately after the clean-up.

(Thanks to Singaporean Guidelines which we borrowed from for India)