Those responsible for public buildings and other spaces need to know how to disinfect areas which may have been used by people carrying the coronavirus responsible for the current Covid-19 pandemic.

  • Subject: Disinfecting coronavirus
  • Date: May 2020

This technical note draws on information from a number of sources, to give clear guidelines for disinfection methodology, in the context of an understanding of this novel virus.

How does Covid-19 spread?

Covid-19 is the illness caused by the novel virus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2).

Coronaviruses are a group of viruses that include those that have caused SARS and MERS, as well as common colds. Because the COVID-19 virus is new, its behaviour is not completely understood.

But based on what is known so far, and our experience with other, similar coronaviruses, it seems that person-to-person transmission happens most frequently among close contacts (within about two metres). This transmission seems to be chiefly via respiratory droplets, though infectious aerosols may also be involved.

So close contact in the form of a hug, handshake, or being in a busy public space allows infected individuals to easily spread their respiratory droplets, which are typically sneezed or coughed and may travel several metres.

But because the larger respiratory droplets are heavy, they typically fall towards the ground. Depending on where they land, they could persist on a surface before being touched by a hand that carries the virus to a nose or mouth, leading to infection.

Current evidence suggests that the Covid-19 virus can remain viable for hours on soft, porous surfaces like paper and cardboard, and up to days on steel and hard plastics. Cleaning of all surfaces followed by disinfection is best practice for preventing the spread of Covid-19 and other viral respiratory illnesses in community settings.

The guidance from Public Health England (PHE) on cleaning and disinfection where Covid-19 contamination is indicated is quite clear. The general guidance comes next here; its application to swimming pool premises follows.

PHE guidance on cleaning and disinfection

Public areas where a symptomatic individual has passed through and spent minimal time, such as corridors, but which are not visibly contaminated with body fluids can be cleaned thoroughly as normal.

All surfaces that the symptomatic person has come into contact with must be cleaned and disinfected, including:

  • objects which are visibly contaminated with body fluids
  • all potentially contaminated high-contact areas such as bathrooms, door handles,
    telephones, grab-rails in corridors and stairwells

Use disposable cloths or paper roll and disposable mop heads, to clean all hard surfaces, floors, chairs, door handles and sanitary fittings, following one of the options below:

  • use either a combined detergent disinfectant solution at a dilution of 1,000 parts per million available chlorine


  • a household detergent followed by disinfection (1000 ppm Follow manufacturer’s instructions for dilution, application and contact times for all detergents and disinfectants


  •  if an alternative disinfectant is used within the organisation, this should be checked and ensure that it is effective against enveloped viruses

Avoid creating splashes and spray when cleaning.

Any cloths and mop heads used must be disposed of and should be put into waste bags as outlined below.

When items cannot be cleaned using detergents or laundered, for example, upholstered furniture and mattresses, steam cleaning should be used.

Any items that are heavily contaminated with body fluids and cannot be cleaned by washing should be disposed of.

Swimming pool environment

If bleach is applied to a surface with a lot of dirt, the dirt will use up some of the available chlorine as it is oxidised, so the amount available to kill virus is reduced.

At the same time, irritant by-products are released. So, as the PHE guidance above makes clear, surfaces should be cleaned before disinfectant is used. Wash surfaces with hot soapy water (detergent) to clean. Thoroughly rinse off the detergent and allow to air dry.

Disinfect by applying a solution of chlorine bleach as detailed in the table below. To deal with coronavirus, a stronger than usual solution is recommended (right-hand column in the table).

Chlorine-based disinfectants are very effective against a wide range of viruses and bacteria, both in the pool and elsewhere in the pool building. They work with bacteria cells by collapsing proteins, causing the bacteria to die. Chlorine is also able to kill viruses, though how is less well understood.

Preparing disinfectants solutions

Use appropriate personal protective equipment (PPE) throughout preparing and application.

Why use detergent as well as chlorine against Covid-19?

For nearly 5,000 years, humans have concocted cleaning products, yet the simple combination of soap and water remains one of the strongest weapons against infectious diseases, including Covid-19. Yet the recent emergency has seen people rush to buy all sorts of chemical cleaners, many of which are unnecessary or ineffective against viruses.

Foam hand cleansers are disappearing from store shelves, even though many lack the necessary amount of alcohol – at least 60% by volume – to kill viruses. Chlorine-based disinfectants (bleach) will kill viruses, but only if used properly.

Chlorine for cleaning

When chlorine is added to water, a chemical reaction produces a weak acid called hypochlorous acid. This is able to penetrate microorganisms like bacteria and viruses and kill them.

All viruses are bits of genetic code bundled inside a collection of lipids and proteins, which can include a fat-based casing known as a viral envelope.

Destroying an enveloped virus takes less effort than their non-enveloped compatriots, such as a norovirus, which can last for a month on surfaces.

Enveloped viruses typically survive outside of a body for only a matter of days and are considered among the easiest to kill, because once their fragile exterior is broken down, they begin to degrade.

As long as disinfectant persists at an appropriate concentration, it will continue to kill microorganisms in the water. Chlorine works well for systems like swimming pools and water tanks, which allow chlorine to sit in water over time.

E coli, a common bacterium spread through faeces, dies in less than a minute when exposed to the chlorine concentrations used in a pool. Chlorine takes much longer to kill gastrointestinal parasites like Cryptosporidium and Giardia, which are a threat in swimming pools.

This is why such tactics as filtration, superchlorination and secondary disinfection are used.

Swimming pool disinfectants

In a pool setting, chlorine comes in four forms:

  1. Sodium hypochlorite is a chemical compound with the formulae NaOCl or NaClO. It may also be viewed as the sodium salt of hydrochloric acid. Sodium hypochlorite solutions are clear, greenish to yellow liquids with an odour of chlorine. Swimming pool grade sodium hypochlorite solution has a chlorine concentration of between 10 and 14% weight for weight.
  2. Calcium hypochlorite is an inorganic compound with the formulae Ca(Cl 0)2. It is a relatively stable, usually white solid. It smells strongly of chlorine, owing to its slow decomposition in moist air. There are various compositions, each with different concentration of calcium hypochlorite, but up to 78% available chlorine.
  3. Household bleach is a water solution of sodium hypochlorite. Common household laundry bleach (unthickened), used to whiten and disinfect laundry, is typically 5% chlorine. As a surface disinfectant, chlorine bleach is approved for use in safe food production. It is also used to help prevent the spread of infections in homes, hospitals, nursing homes, schools and day care facilities.
  4. Sodium dichloroisocyanurate (dichlor) is the sodium salt of a chlorinated hydroxytriazine and in its diydrate form is used as a source of free available chlorine (as hypochlorous acid) for the disinfection of water. It is widely used as a stable source of chlorine for the disinfection of swimming pools and in the food industry. It is a colourless, water-soluble solid.

JAK Christmas & New Year 

All at JAK would like to thank you for your custom over 2019 and look forward to the opportunity of working with you again next year.

Please note that our offices will be closed from Friday 20th December 2019 and reopen on Thursday 2nd January 2020.

Please note that between these times you can still contact our engineers by calling our office on 01789 333313, and your call will be diverted to our engineer, for all technical enquiries and call outs.

To ensure pre-Christmas delivery, chemical orders must be placed by Monday 9th December. For all other orders the deadline is the 16th December (subject to availability)

If you have any queries, please do not hesitate to contact our offices.

From everyone at JAK, we would like to wish you a very Merry Christmas and Happy New Year.

Kind Regards

JAK Water Systems Ltd

BPR application date for Calcium Hypochlorite

The BPR replaces all existing national legislation governing the registration and/or authorisation of biocides in the EU plus Switzerland, Norway, Iceland, Serbia and Liechtenstein.

Calcium Hypochlorite has been approved for product types (PT) 2, 3, 4 and 5 and the approval date is 1st January 2019. That means relevant companies should submit product authorisation application before the end of this year.

Melspring is preparing EU authorisation dossiers for all Melclorite products, containing Calhypo produced by Nippon Soda Co., Ltd. for PT 2 and PT 5 applications. For our distribution partners that prefer to continue offering Calhypo under their own private label, we can offer the possibility for On-boarding with Melspring and Same Biocidal Product registration.

Please contact your JAK for more detailed information. We would be pleased to help you with your individual registration process or BPR issues.

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PWTAG Annual Conference – 4th December 2018

Book Tickets Here ->

A day of invaluable information AND the launch of PWTAG’s new spa book.

Water treatment optimization for keeping your pool infection free
Impact of swimming and spa pool problems on the travel industry
Hot tubs for Business – Publication Launch – free copy for every delegate!


9:00 Registration with Tea and Coffee

9:30 Welcome & introduction

Janice Calvert – Chair PWTAG

Janice Calvert – PWTAG Chair will welcome delegates to the PWTAG annual conference and will provide an update upon PWTAG activities during 2018

9:50 Background numbers of Cryptosporidium in Pools, advice to the Operator.

Rachel Chalmers – Consultant Clinical Scientist/Honorary Professor, Public Health Wales

Professor Chalmers will provide delegates with an insight into the findings of our UK study of the background numbers of cryptosporidium in pool water and its implications for the operator.

10:20 Understanding and optimization of filtration systems in commercial swimming pools using particle counting
Dr Martin Wood – Pool Sentry Ltd
Results from a range of examples of sand filters in action in commercial pools will be discussed, highlighting the wide range of filter performance. The talk will introduce ideas on how information on circulation and filtration can be combined to provide valuable performance indicators that have, up until now, been just theoretical rather than practical tools.

10:50 Tea and Coffee break

11:20 Filtration – a glimpse into the future
Speaker TBA
This paper considers filtration from past to present and the advances now being made with new techniques, which could revolutionise the way we think about filtration systems in the UK.

11:50 Problems associated with Pools and Hot Tubs in the holiday industry
Angie Hill, Senior Destinations Manager, Health, Safety, Crisis & Operations, ABTA
From drownings to diarrhoea, and Legionnaires’ disease, Angie will provide us with an overview of the impact on consumers and the travel industry of not designing, operating and managing pools properly and the measures needed to prevent them? With examples from her vast experience of dealing with problems in the travel industry, this will make an excellent paper.

12:15 Morning Question and Answer Session

12:45 Lunch

13:45 Hot tubs in Business – why you need the PWTAG publication
Janice Calvert – Chair PWTAG
Domestic-style hot tubs – perhaps badly chosen or installed, poorly maintained or wrongly used – can be lethal when they’re used for business purposes. There have been a number of outbreaks, including fatalities, linked to hot tubs in holiday park rental units, hotel bedrooms, holiday lets, on hire and even on display.
The hot tub market has grown exponentially in recent years. No holiday destination or hotel is today complete without one. Purpose built or off the supermarket shelf getting the basics right is fundamental to their success. Janice will lead you through the whys and wherefores in the business of hot tubs and explain the training requirements.

Two of the lead authors of both the PWTAG publication and the HSE publication HSG282 will give their insight into the risks and pleasures, highs and lows of the business of hot tubs:

14:10 Hot tubs, their planning, design and installation – getting it right
Dr John Lee, Public Health Microbiology Consultant, Leegionella Ltd
The new book draws on the guidance in HSG282 but supplemented by the expertise represented on PWTAG – and presented in the clear and definitive fashion that the many thousands of readers of PWTAG’s Swimming Pool Water have appreciated over the years. Anyone operating, or contemplating installing, hot tubs as part of a business activity will need to hear this paper in conjunction with reading the book if they want to be both safe and up to date with the latest guidance.

14:35 Operation of Hot Tubs in Business
Howard Gosling, Pool and Spa Advice
Getting it right and avoiding infectious outbreaks is a must for the hot tub business operator. The session will guide you through the operational essentials to minimize the risk of infections and the threat of prosecution.

15:00 Hot tubs from the business perspective
Ruth Hollins, Head of Health and Safety, Center Parcs
Center Parcs operates and maintains significant numbers of hot tubs within their parks. In their business there is no room for mistakes or coming second best. Ruth Hollins the Health and Safety Manager for Center Parcs will describe how they have structured this growth area of their operation and how they manage hot tub health and safety for success and guest satisfaction.

15:30 Questions and answers

16.00 Close – Tea and Coffee

Drayton Manor Hotel
Drayton Manor Drive
B78 3SA
United Kingdom

Room: Park View Suite