[Answer] How To Disinfect Ships in Times of Corona!


As COVID19 wreaks havoc worldwide, disrupting life and trade, it has important that we take basic disinfection procedures seriously. Ships being a confined space, the spread of the disease is faster here. Keeping that in mind, ABS has formulated a thorough plan regarding ship disinfection procedure.

Here’s an excerpt from that guidance for shippers and the crew.

List of Disinfectants

But before we begin with the procedures let us first look at the types of disinfectants that best serves the purpose

Disinfectant products based on the following chemical compounds are understood to be effective against SARS-CoV-2 virus:

  1.  Bleach (sodium hypochlorite or calcium hypochlorite)
    This is a fast-acting disinfectant that does not leave a toxic residue and is unaffected by water hardness.
  2.  Alcohol Isopropyl alcohol (also known as isopropanol, 2-propanol) and ethyl alcohol (also known as ethanol or drinking alcohol) are frequently used in rubbing alcohol, hand sanitizers, and disinfection pads and wipes.
  3.  Quaternary Ammonium Compounds (QAC) – Quaternary ammonium compounds are often found in disinfectants. Their effectiveness depends on other chemical compounds in the disinfectant.
  4. Hydrogen Peroxide – Commercially available hydrogen peroxide (3% ~ 6%) is a stable and effective disinfectant when used on surfaces.

Two other disinfectants are being increasingly used to disinfect medical facilities, laboratories, schools, etc. Their performance has not been independently verified by ABS.
i) Hypochlorous Acid (electrolyzed water)
Hypochlorous acid is very effective against bacteria, fungi, and viruses. In concentrations used for disinfection, e.g. 50 ppm, it does not irritate skin and is very mild to mucous membranes. It is often used for sanitizing food and contact surfaces.
ii) Accelerated Hydrogen Peroxide® (AHP®)
AHP® contains hydrogen peroxide that has been accelerated to increase its germicidal potential.

Other chemical compounds may be considered as disinfectants if their effectiveness against the virus that causes COVID-19 has been confirmed by national or international health authorities e.g. United States Environmental Protection Agency (US EPA) [12] and European Chemicals Agency (ECHA) [13]).

When evaluating a disinfectant that is not listed above, the following characteristics may be considered:
i) Fast acting and effective against the virus that causes COVID-19
ii) Compatible with soaps, detergents, and other cleaning chemicals
iii) Nontoxic
iv) Should not corrode instruments and metallic surfaces and should not cause the deterioration of cloth, rubber, plastics, and other materials
v) Easy to use with clear instructions on the label
vi) Stable in concentrate and after being diluted
vii) Not harmful to the environment when disposed of

The list of SDS kept on board any asset for each chemical being carried should be updated if new disinfectant agents are brought on board

Disinfectant Concentration Guidance

For the disinfectant to be effective against the virus that causes COVID-19, the following concentrations of chemical compounds are recommended:

  • Diluted bleach solutions should be used with at least 1000 ppm sodium hypochlorite (e.g. five tablespoons of bleach per one gallon of water)
  • Spray-on disinfectant or sanitizers should contain a minimum of one of the following: 0.5%sodium hypochlorite, or 70% isopropyl or ethyl alcohol, or 0.5% hydrogen peroxide
  •  Hand sanitizers should contain a minimum of 70% alcohol (isopropyl or ethyl)

Preparation and Handling of Disinfectants

The typical concentration of chemicals found in commercial disinfectants can have adverse effects on human health.Bleach at the concentrations recommended for cleaning has generally a low incidence of serious toxicity according to the CDC. However, contact with the eyes can be serious even at relatively low concentration.

In high concentration (e.g. from the original container) bleach can irritate mucous membranes, the skin, and the airway, and is especially toxic if splashed into the eyes.
Isopropyl and ethyl alcohol can cause skin itching, redness, rash, drying, and cracking under repeated exposure. Skin exposure to quaternary ammonium compounds can lead to skin rashes and inhaling can irritate the lungs.

Hydrogen peroxide is mildly irritating to the skin and mucous membranes.

All of these chemicals can cause serious eye irritation and damage. Therefore, the manufacturer’s guidance for wearing personal protective equipment (PPE) while working with disinfectants should be followed. If such guidance is not available, reference should be made to Section 3/4.

Manufacturer’s instructions for preparation of any disinfectant should be followed, especially the recommended concentration levels. These levels should not be exceeded, as adverse effects on human health, surfaces (corrosion, bleaching, hardening, swelling, etc.) and the environment may occur. The manufacturer’s recommended concentration levels should also satisfy the recommendations from 3/3.2,otherwise,a different disinfectant should be used.

Disinfectants should be used within their shelf lives for maximum effectiveness against the virus that causes COVID-19. Different disinfectant products should never be mixed as this can produce hazardous vapors and oxidizing reactions (i.e., bleach and ammonia). Also, disinfectants should never be mixed with other cleaning agents.

The preparation of disinfectant solutions should be conducted in well-ventilated areas. Additional ventilation may be needed to reduce the concentration of hazardous vapors. Precautions should be taken to avoid splashing, especially to the eyes; eye goggles should be worn when appropriate. Eyewash stations should be provided in the areas where disinfectants are being prepared.

Portable handheld eyewash stations may also be used.

Bleach should be diluted with cold water as hot water reduces its effectiveness. Once diluted, bleach solutions should be stored in closed containers, and used within 24 hours.

Alcohol wipes should be transported within a container with a closed lid to prevent evaporation and combustion

Precautions for Applying Disinfectants

Disinfectant chemicals can have adverse effects when they come in contact with various types of surfaces and materials. For example, they can cause fabrics to lose color; plastics to harden, crack and discolor; and the surfaces of metal objects to oxidize.

It is important to follow the manufacturer’s recommendations for use on each specific surface or material. The disinfectant first should be tested on a small part of the
surface to see if there are any immediate adverse reactions between the disinfectant and the surface material.

The long-term effects of daily usage of disinfectants on various substrates remain largely unknown and constant monitoring of surface degradation is recommended. Appendix 2, Tables 1 and 2 contain the degradation risk of various metallic and non-metallic substrates on marine and offshore assets when in contact with common disinfectant chemicals.

The subsection below contains general precautionary measures that should be employed when applying disinfectants to various surfaces.

Impact of Disinfectants to Various Surfaces

  1. Structure and Bare Metal Surfaces –Chlorine causes stress corrosion cracking. The use of bleach solutions or hypochlorite wipes should be avoided on any bare metals to avoid stress corrosion cracking. Disinfectants based on QAC should not be used on copper bearing alloys (piping, components, fasteners) to avoid stress corrosion cracking.
    Hydrogen peroxide will corrode copper, zinc, and brass. lcohol-based disinfectants are recommended on bare metal surfaces. Use of flammable disinfectants should be avoided in hot-work areas.
  2. Machinery and Sensitive Equipment – Using bleach solutions or hypochlorite wipes should be avoided on sensitive machinery casings and valves. Alcohol-based disinfectants are recommended for machinery and other sensitive equipment. It is important not to oversaturate the equipment with the disinfectant and to prevent the pooling of liquids. Alcohol-based disinfectants should not be applied to machinery components that are hot to touch or energized. Alcohols may damage the shellac mountings of lensed instruments; they tend to swell and harden rubber and some plastic tubings after prolonged and repeated use. They can also bleach rubber and plastic tiles.
  3.  Coatings – In general, alcohol-base disinfectants can soften coatings. The bases for coating are variable, and there are numerous types of fillers that perform a specific function. The paint bases for accommodation and deck areas are usually:
    ● Epoxy
    ● Alkyd
    ● Acrylic
    ● Polyurethane
    To understand the influence of disinfection chemicals on a specific coating, it is necessary to know what paint systems have been applied in the areas of concern, and the paint supplier. In this regard advice from the coating manufacture is recommended.
  4.  Cables-To clean and disinfect exposed cables, use general purpose cleaning liquids and disinfecting liquids that are free of bleach, alcohol, and ammonia.
  5.  Electronics – To clean or disinfect any enclosure for electrical equipment, the equipment should first be disconnected from its electrical power sources. If this is not possible, a qualified operator or technician of the specific equipment should be present to prevent cleaning liquids from getting inside the equipment or onto sensitive electronics. Also, since alcohol-based disinfectants are flammable, the risk of combustion is greater if electronic equipment is connected or hot to touch. All electrical equipment installed on vessels should have a minimum IP (Ingress Protection) rating according to the location where the equipment is installed. See 4-8-3/Tables 1A, Table 1B, and
    Table 2 of ABS Rules for Building and Classing Marine Vessel. For example, electrical equipment installed in a dry accommodation space should, at minimum, to be rated IP 20. Electrical equipment in machinery spaces should be rated IP 22, IP 44, or IP 55. Equipment installed in exterior locations should have a minimum rating of IP 55 or IP 56. The first numeric digit in the IP rating represents the degree of protection against solid objects, such as dirt and dust. The second numeric digit in the IP rating represents the degree of protection against water. Cleaners and disinfectants may be sprayed on equipment that has an IP rating of at least IP x5. In general, cleaners and disinfectants should not be poured or sprayed directly onto any electrical equipment. It is recommended to dampen a lint free cloth with the cleaner or disinfectant, and then
    wipe the equipment with the cloth. Liquid contact with pushbutton switches should be avoided to reduce the risk of intrusion to internal electrical connections.
    It is recommended to use general purpose cleaners on electrical and electronic equipment. Bleach, ammonia, compressed air, or hydrogen peroxide should not be used. For disinfection, isopropyl alcohol-based disinfectants are recommended. Ethanol disinfectants may also be considered as effective alternatives.
    Keyboard should be unplugged before cleaning and disinfecting. Linen-free cloth dipped in isopropyl alcohol should be used. Top and sides of each key should be rubbed before proceeding to other keyboard surfaces, including its bottom. The mouse should be disinfected using a new disinfectant wipe or cloth.
    Cleaners with bleach or ammonia should not be used for coated glass or screens to avoid damage. Isopropyl or ethanol alcohol products are typically available in a range of concentrations. If no manufacturer guidance is available, alcohol-based wipes or spray containing at least 70% alcohol should be used to disinfect touch screens .
    When using alcohol-based products, one should be cognizant of the risk of combustion if the product is exposed to a spark, static electricity “shock” (especially in extremely dry
    environments), or electric current.
  6. Fabrics – Bleach should not be used on fabrics. QAC and hydrogen peroxide are recommended for disinfecting fabrics (carpets, drapes, furniture, etc.). Alcohol may also be considered

Techniques for Applying Disinfectants

The effectiveness of the disinfectant is a function of the time it remains on a surface, especially in a liquid or mist form. To a point, the longer it is on a surface, the more effective it is. It is generally agreed that disinfectants should be left on a surface for at least 10 minutes. Also, all surfaces should be free of visible dirt before applying the disinfectant.

  1.  Mopping
    Floors and other horizontal surfaces can be mopped using a damp cloth that has been soaked in a disinfectant and wrenched. A steady mopping motion should be used to prevent liquid splashing which may aerosolize the virus.
  2.  Wiping
    Walls, other vertical surfaces, doors, windows, furniture, armrests, tabletops, switches, electronic equipment and components, light fixtures, thermostats, lavatory surfaces, galley work area, various equipment, handrails, handles, knobs, tools and some re-usable PPE, etc. can be wiped down using a damp cloth that has been soaked in a disinfectant and wrenched, or using disinfectant wipes.
  3. Spraying
    Sprayers that offer a wide-dispersion mist can be used to dispense disinfectant on a treated surface. Delivering a stream of disinfectant should be avoided. Light mist spraying is recommended to mitigate the risk of virus re-aerosolizing from the surface.
    All types of hard non-porous and soft porous surfaces can be treated with spraying, except for the surfaces in machinery, propulsion spaces and those covering electrical equipment, components, and outlets. One coating of mist is sufficient. In general, the surfaces should not be wiped afterwards. However, if pools of disinfectant occur, the excess should be wiped off.
  4.  Other Techniques
    This subsection contains a list of other techniques for disinfection that have a limited track record for application and proven effectiveness in marine and offshore industries. Extra precautions should be exercised when using these techniques as their effects on human health and equipment have not been fully evaluated.
  5.  Fogging
    Foggers are used to uniformly dispense nonflammable and noncombustible disinfectants in the form of dry mist to all the surfaces in a room. Optimal coverage is usually achieved by setting the particulate size to 10-20 microns. Fogging is useful for disinfecting soft surfaces and hard to reach places. Considerations should be
    given to the size and type of space being fogged. All occupants should leave the room or any area being disinfected. All air ducts and gaps around room openings should be sealed off. The effect of fogging techniques on electronic equipment has yet to be sufficiently studied. Therefore, if foggers are to be used, electronic equipment should be sealed off.
    Only products approved for fogging should be used, in conjunction with the appropriate
    equipment and PPE.
  6.  Steaming
    Steam-cleaning machines may aid in the disinfection process. Handheld steam cleaners may be used for upholstered items such as chairs, couches etc. For larger areas, such as rugs and carpets, larger steamer units may be used. Because there are uncertainties related to the temperature of the steam, the relative humidity at the surface, contact time with pathogens, distance between the surface and the steam outlet, skill of the cleaning crew, etc., this processes’ ability to kill pathogens can vary significantly. Therefore, steaming on its own should not be considered as an alternative for using chemical disinfectants.
  7.  Ultraviolet Radiation
    Although not a chemical disinfectant, ultraviolet (UV) light can be effective at reducing harmful pathogens. UV radiation is a part of the light spectrum with three wavelength ranges: UVC (100 nm-280 nm), UVB (280 nm-315 nm), and UVA (315 nm-400 nm). Its maximum germicidal effect occurs between 240 and 280 nm, which is in the range of UVC light.UVC light systems are sometimes incorporated with air and water-filtration systems for sanitization purposes on marine and offshore assets. UVC lights also can be placed near the coils and drain pans of heating, ventilation and air-conditioning (HVAC) systems to keep microorganisms from increasing in these damp areas.
    UVC light products (wands, tunnels) are also available and used for sanitizing work surfaces and small devices, such as phones, small appliances, luggage and packages.
    However, there is presently insufficient information on the proper usage of UVC light and its efficacy in eliminating harmful bacteria, viruses and molds. UVC light should not be considered as an alternative to using chemical disinfectants.

Storage of Disinfectants

All disinfectant products that are brought on board an asset should be stored in accordance with manufacturer’s recommendations and the appropriate class or IMO requirements. For assets subject to the International Convention for the Safety of Life at Sea (SOLAS) or IMO Code for the Construction and Equipment of Mobile Offshore Drilling Units (MODU Code), spaces used for storing flammable disinfectants containing alcohol should be designated as high fire risk service spaces of category 9.

Reference also can be made to 4-7-2/5.1 of ABS Rules for Building and Classing Marine Vessels, which addresses paint and flammable liquid lockers.

  • Oxidizing disinfectants such as bleach (calcium hypochlorite, sodium hypochlorite) and hydrogen peroxide and flammable disinfectants containing alcohol never should be stored in the same compartment.
  • Secondary containers used to store diluted disinfectant solutions should be properly labeled with the product name, the manufacturer’s name, stock number (if applicable), date of preparation, and the nature of the hazard (e.g., flammable, corrosive, toxic, irritant, etc.).
  • When not in use, the disinfectants should be sealed to prevent the release of vapors and the evaporation of active ingredients.
  • The supply of cleaning and disinfecting products may exceed the capacity of designated lockers.
  • In that case, spaces designated as service spaces per SOLAS/IMO MODU Code, may be used to store cleaning products and disinfectants.
  • Any area that is used to store cleaning products and disinfectants should be well-ventilated, cool, and shaded.
  • Other products should not be stored in the same space.
  • Special consideration should be paid to storing alcohol, which is flammable.

Disposal of Disinfectants

Liquid disinfectants and their solutions may be disposed of by discharging them into the asset’s sanitary system. The sewage should be managed with the assumption that it contains human pathogens and treated through the asset’s sewage treatment plant, if installed, in accordance with MEPC Resolutions 159(55)[14] or 227 (64) [15] of MARPOL Annex IV, as applicable.

For assets not equipped with a sewage treatment plant (i.e. fitted with a sewage comminuting and disinfecting system or with a holding tank), discharge of sewage should meet MARPOL Annex IV provisions subject to any recommendations/instructions that might be issued by local Authorities or the WHO.

Disinfectant wipes should not be flushed down the sewage system and should be disposed of similar to other infectious waste.

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Source: ABS