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Chlorine Dioxide Unit Rental and Flexible Agreements for Effective Water Treatment

Here at Dantek, we manage a collection of Chlorine Dioxide Rental units, which include both Tristel TTec2000 and Grundfos Oxiperm Pro Units. These units are adaptable, with the option for wall or floor mounting, and they can be customized to either dose directly into flowing pipework (whether mains or other) or into a water storage vessel. Additionally, these units possess the capability to dose proportionally based on a pulse-sending water meter or under the control of a Chlorine Dioxide measuring cell.

The limitation of Chlorine Dioxide dosing shares a similarity with temperature in that it relies on water turnover for effectiveness—it can only eliminate the contaminants it meets. Consequently, a Chlorine Dioxide unit cannot directly replace flushing in unoccupied or partially occupied buildings. However, Chlorine Dioxide proves to be a more potent control method compared to temperature alone, especially in addressing biofilm and tackling fouled systems.

Opting for a Chlorine Dioxide unit rental is not cost-effective when the need extends beyond a year; in such cases, purchasing a unit is a more economical choice. The installation costs for rented units can vary and, in certain situations, match those of a permanent installation. This is due to potential expenses related to pipework modifications, the installation of water meters, and the provision of electrical supplies.

Our rental agreements are adaptable in terms of both duration and coverage. Typically, the minimum hire period is one month. We provide a comprehensive service that encompasses installation, commissioning, supply of chemicals, continuous maintenance, de-commissioning, and removal. On the flip side, we also offer ‘dry hire’ options for proficient operators of water treatment equipment.

Our rental units have demonstrated success in various scenarios, including:

  • Before occupation in new buildings, especially in partially occupied ones.
  • Prior to demolition or extensive remodeling in older properties.
  • As a temporary control measure while awaiting other works, such as the installation of new calorifiers or boilers.
  • In situations where speed is crucial, and/or the delivery times for purchased units are extended.
  • As a proof of concept before committing to capital expenditures.

 

Contact us now to discuss your requirements and receive a personalised quote. Call us at 01454 417 920 or drop us an email at sales@dantek.co.uk

Simplifying Water Hygiene Monitoring for Retail Facilities Managers: Dantek’s Tailored Solutions

As a facilities manager in the retail industry, overseeing multiple sites comes with its fair share of challenges. Ensuring health and safety compliance, particularly in water hygiene, is paramount. This is where we step in, offering water hygiene monitoring contracts designed to cater to the unique needs of retail facilities managers. With a focus on convenience, compliance, and effectiveness, Our solutions have proven themselves time and again in national retail contracts.

One of our standout features is our commitment to crafting water hygiene monitoring contracts based on each individual site’s specific needs. This means that whether you’re dealing with a low-risk site needing minimal monitoring or bustling flagship headquarters requiring frequent checks, we have you covered. Our individual personalised site approach ensures that you’re not overextending your resources on sites that don’t require excessive attention, while still maintaining strict adherence to health and safety standards.

Efficiency through the Patch System

Managing a nationwide network of retail sites demands a well-structured approach. Our patch system has proven to be a game-changer in this regard. Once armed with a property list, our team will categorize your retail units into manageable geographical patches. This segmentation facilitates the creation of a comprehensive schedule of works and visiting plan, all subject to your approval. The result? A streamlined and efficient system that ensures timely monitoring and maintenance without the usual logistical headaches.

Log Book: A Cloud-Based Convenience

We don’t only monitor and maintain your retail sites but also offer a seamless complimentary electronic log book service. All outlet documentation and recorded readings are stored electronically in our cloud-based log book. This convenient tool grants you instant access to the information you need, eliminating the hassle of physical record keeping. With the log book’s user-friendly interface, you can easily review and manage data at your convenience, ensuring transparency and accountability in water hygiene management.

COMING SOON: Discover more about Dantek’s cloud-based electronic log book and how it enhances water hygiene management efficiency later in our blog post.

Proven Success in National Retail Contracts

Our success in national retail contracts is a testament to the effectiveness of our water hygiene monitoring solutions. Whether you require minimal checks or a comprehensive program, Our flexibility, expertise, and commitment to excellence set us apart as an industry leader.

Contact Us for Tailored Water Hygiene Solutions

At Dantek, we’re dedicated to simplifying water hygiene management for retail facilities managers across the nation. If you’re interested in exploring our water hygiene monitoring contracts and benefiting from our streamlined approach, don’t hesitate to get in touch with us.

Email: sales@dantek.co.uk

Phone: 01454 417920

Our team of experts is ready to address your queries, provide more information, and work with you to design a customized solution that fits your specific needs. Whether you’re overseeing low-risk sites or bustling headquarters, we have the experience and tools to ensure your water hygiene compliance is seamless and hassle-free.

Legionella control FAQs

Legionella control FAQs

What is Legionnaires’ Disease?

Legionella control FAQs – Legionnaires’ disease is a potentially fatal pneumonia caused by bacteria called Legionella pneumophila. Exposure to the Legionella bacterium can happen when you inhale contaminated mist or breathe in droplets of water contaminated by the bacteria.

There are many ways to prevent legionnaires’ disease, including routine inspection, temperature monitoring, and maintenance of cooling towers, water tanks, and plumbing systems.

Legionella control FAQs

Who can catch Legionnaires’ disease?

Everyone is potentially susceptible to infection, but some people are at a higher risk e.g. those over 45 years of age, smokers and heavy drinkers, those suffering from chronic respiratory or kidney disease, and people whose immune system is impaired. Symptoms of Legionnaires’ disease may include fever, chills, headache, muscle aches, and tiredness.

Where is legionella found?

Legionella bacteria (legionella pneumophila) are common in natural water courses such as rivers and ponds.  Since legionella is widespread in the environment, they may contaminate and grow in man-made water systems such as cooling towers and hot and cold-water services.  Spa baths, Jacuzzi’s and hot tubs also provide a potential breeding ground for legionella bacteria as they provide optimum conditions for the bacteria to grow and multiply to sufficient numbers for a system to be colonised.

The bacteria thrives at temperatures between 20 and 45 degrees, particularly if there is a supply of nutrients such as rust, sludge, scale, algae, and other bacteria.

The risk of legionnaires’ disease is increased if water droplets are produced and dispersed in aerosol form for example, in a shower or spa bath.

It is possible to reduce the risk by removing exposure to water droplets and aerosol and by removing the nutrients on which the legionella bacteria feed.  This can be done by keeping water systems clean by cleaning and disinfecting cold water storage tanks and showerheads.

How do I the with latest HSE guidance?

The current HSE guidance documents for the legionella control are the L8 Approved Code of Practice and the HSG274 Legionella technical guidance.

The first thing to do is a Legionella Risk Assessment, to consider the risks from legionella that may affect your staff or members of the public, and then take suitable precautions to control and prevent the risk.

Is it a legal requirement to have a legionella risk assessment?

There is a legal duty for employers and landlords to consider the risk legionella bacteria in buildings under your control or management. You must identify and assess the source of risk i.e carry out a legionella risk assessment. Manage the risk. Put in place measures to control or prevent any risks.  Keep good records to prove you are taking the appropriate action and to show to external agencies you are following the HSE guidance for legionella control.

What can be used to control legionella bacteria?

Temperature is usually used in hot and cold-water systems, by keeping hot water at above 60 degrees and ensuring it is above 50 degrees at the outlets. Cold water should be kept below 20°c.

There are other methods that can be used if the temperature is not an option, such as copper/silver ionisation and chlorine dioxide.  Cooling towers/systems are often treated with biocides.  There are other treatment strategies available such as ultraviolet (UV) irradiation.

Do I need to take Legionella samples?

This depends on the risk assessment and control methods being used.  In some circumstances it will be required, however, it needs to be done at a UKAS accredited laboratory and will require specialist help.  Dantek can provide advice on sample frequency and locations, and what to do if Legionella is detected.

Routine Legionella testing however is not a requirement in domestic hot and cold-water systems.  It would only be recommended in hot and cold-water systems due to exceptional circumstances where typical control measures are not working.  A full legionella risk assessment would identify the best course of action to reduce the risk.

What will a legionella risk assessment cost?

The cost will depend on what assets are on your site and how many buildings.  For large sites or multi-site portfolios a site visit by one of our team is the best way to establish exactly how much a risk assessment will cost. However, we are often able to provide a guide price if you know roughly the size and type of building.  For example, how many floors, what it is used for, whether there are any cold-water storage tanks, number of calorifiers and if there are any cooling towers. An asset register of plant and equipment can be very helpful in determining how long the on-site assessment will take and therefore the cost.

One of our team would be happy to talk through on the phone any requirements and enquiries.

What do Landlords need to do about Legionella control?

The law clearly states if you are a Landlord and rent out your property then you have a duty under Health and Safety Law to consider the risk posed by Legionella bacteria. The ACoP L8 (3rd edition) also states Landlords must assess the risk from exposure to legionella to their tenants.

In most cases the risk assessment is simple and straight forward, however for more complex systems or if the Landlord is not able / competent to carry out the assessment they can use a specialist Water Treatment Company like Dantek, to carry out the legionella risk assessments and advise on any actions required.

A simple risk assessment will identify if a system is considered a low legionella risk and no further actions are required other than to review the assessment regularly in case anything changes which may affect the risk for example the water system in the building changes.

Examples of low risk systems include;

  • A small building occupied by people not considered at risk from legionella bacteria.
  • Where there is enough usage of water per day to ensure the entire system is changed at least once.
  • Mains fed cold water supplies the entire system, so there are no cold-water storage tanks.
  • Hot water is fed from combi boilers/ instantaneous heaters or low volume water heater where the hot water is supplied at no less than 50°c
  • The only outlets at the property are toilets and wash hand basins with no showers present on site.

http://www.hse.gov.uk/legionnaires/legionella-landlords-responsibilities.htm

What is meant by the term water system?

A water system includes all plant and equipment for example all the pipework, pumps, cold water storage tanks, valves, showers, water softeners, chillers, heat exchangers, cooling towers, calorifiers, little used outlets and dead legs, humidifiers, air washes, car washes, indoor fountains and water features.

How do I choose a water hygiene company? Legionella Control Association logo

Choosing a water hygiene company with the knowledge and skills to manage and control the risk of legionnaires’ disease at your site is made easier with the help of the Legionella Control Association.  The LCA hold a register of members who have met their requirements on an annual basis and have passed their annual audit of systems.

A key factor should be the training of site staff to carry out water hygiene work competently.  A provider will be able to demonstrate how their employees are trained and audited to ensure continual compliance with current standards.

The LCA code of conduct sets out the standard of service a client should expect from a water hygiene provider.  The code requires a Service Provider to set up an appropriate management system for the control of legionella complying with the latest HSE guidance for the control of legionella bacteria.

How many cases of Legionnaires Disease were there last year?

The figures from 2021 – 2022 are not available yet however between 1st January – 31st October 2020 according to a report by Public Health England, there were 254 cases of Legionellosis cases reported in England and Wales.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/948028/Legionella_Mthly_Rprt-Aggregate_rprt_Jan-Oct20.pdf

If you have any questions in regards to Legionella control FAQs or any other questions, please do not hesitate to call us on 01454 417 920

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How much should my Legionella risk assessment cost?

Legionella risk assessments: We are all faced with the current climbing inflation across products and services that we require. Compliance can be a huge concern, and we all want the best value without compromising the quality and level of service we receive from our suppliers.

This blog will hopefully shed some light on how to get a fair price for your legionella risk assessment and how you can compare your quotes against each other, allowing you to decide what you are confident with.

As a starting point, visit the legionella control association website, https://www.legionellacontrol.org.uk.  All approved LCA Members must provide a range of products and services for the control of legionella bacteria in water systems. They would have also demonstrated that they have complied with the LCA Code of Conduct and LCA Service Standards and are committed to helping their customers prevent legionellosis and keep their water systems safe. The website allows you to search a directory of approved contractors within your area. Legionella Control Association logo

How much will a Legionella risk assessment cost?

A Legionella risk assessment is a consultancy service that will require a physical visit to your site, and follow-on report writing time to produce your document. For your chosen contractor, to provide an accurate quotation for your site, they will first need to establish how long the report will take to complete. Once this is figured out, multiply the time by a day rate, and bingo! A price.

Estimating how long a survey will take is a fine art, but there are some variables

Ask what the standard day rate is for a surveyor, but be careful, some include administration time some don’t. Ask the question.

Geography?

Where is the site? Or where are the sites? Travel time is working time, and you pay for it. Ideally, you’ll use someone local if you have a big single site or cluster of buildings, but sometimes this isn’t practical. If you have multiple sites, you can get some great reductions from contractors out of your area allowing you to compare multiple quotes. Also, these are fun for the surveyors. Here at Dantek, we assess nationwide contracts including retail, care homes, and even memorial parks. The attending assessors have a great time traveling across the country.

Once you understand the logistics of getting the surveyor to and from the site, how long will they be there? The two big factors in this debate are what water services do you have? And how hard will they look?

Water Assets and system complexity?

I have seen many different approaches to convey what is on-site, varying from line-item asset registers, and copies of the previous risk assessments to lists of the gross internal areas of properties. The surveyor’s point of view generally stems from, how difficult is this system going to be for me to understand and how many assets will I have to survey. For example, a large modern office block could seem like a big beast but may only have a plant room in the basement, a single wet riser by the lift shaft, toilets and kitchenettes on each floor plus a couple of cleaners cupboards, simple. In contrast, a stately home converted to halls of residence can contain multiple systems and a dog’s breakfast of assets and pipework that would reduce the finest to tears.

Legionella risk assessment – Top tip: Give what information you have, including building use, number of storeys, and location

The industry refers to all hot and cold-water systems for toilets, sinks, showers etc. as domestic systems. These are almost universally included in risk assessments, but what about cooling towers, industrial uses of water, humidifiers, water features, and medical equipment? The survey should cover all water assets in one way or another.

In the industry, we benefit from huge amounts of experience so in talking about your buildings we build a picture of what we are dealing with, by being as honest and open as you can get the most realistic estimate possible.

Begin with the end in mind

The Legionella risk assessment certainly ticks a box for compliance but if done well is a tremendous source of information regarding your water assets. Think about practical outputs, for example, how do you expect to see non-compliances reported? Do you want them separated in a way you could pass to a mechanical contractor or your onsite plumbing team?

Talking to your suppliers about Legionella control in a wider context beyond the risk assessment can pay dividends in understanding how the document could support your efforts to implement a successful control regime later on. You’ll be amazed at what you can get for free during the risk assessment process just by asking, consider;

  • Do you want accurate schematics drawn in AutoCAD?
  • Would it be handy if the pipe runs are overlaid on your existing building schematics?
  • Would you like an electronic copy of the asset register in excel?
  • Do you want the assets in an electronic logbook?

At the end of the day

All Legionella risk assessment quotes have at their core have an estimation of how long the survey is going to take and the report to produce, as a buyer you should understand and be comfortable that your supplier will do a job that is acceptable to you in the time they have quoted. Industry rates vary from £350.00 to £600.00 per day for a qualified Legionella risk assessor as a guideline.

There are many decent companies out there, and all of them should welcome sensible discussions on the big question – how long is it going to take?

Dantek is a specialist provider of Legionella control services including Legionella risk assessments.

If you have any further questions or would like to speak to one of our sales team, please call us on 01454 417920 or e-mail sales@dantek.co.uk

Keep up to date with our news on Linked in.

https://www.linkedin.com/company/dantek-environmental-services-uk-ltd

 

Join us for a responsible person training course at our head office in Thornbury

Due to recent customer feedback, we have decided to host the responsible person training course at our head office in Thornbury on Wednesday 18th January 2023.

Who is the responsible person for legionella?

The responsible person for the control of legionella bacteria is a competent individual that is appointed by the duty holder to take day-to-day responsibility for their organisation’s building.

The course is designed to give site staff a practical understanding of legionnaires’ disease and provide delegates with the confidence, understanding, and knowledge to manage their sites effectively regarding legionella control.

Topics:

  • Introduction
  • Background to the disease
  • Legislation – Health and Safety Law
  • Identification and risk assessment
  • Legionella outbreak analysis
  • Prevention and control
  • Record keeping / logbook
  • Who is responsible?
  • Risk systems
  • Overview of approved methods of control
  • The role of the responsible person
  • Q&A
  • Test

Each delegate will also receive a certificate for completing the training and course notes to take away with them.

If you would like to join us or have any questions, then please do not hesitate to get in touch.

Call 01454 417 920 Email sales@dantek.co.uk

Coronavirus And Legionella Control Testing

Advice for Legionella control during COVID-19 lockdown

The coronavirus is placing new challenges on our duty of care to minimise the risks from Legionella in our water systems on-site. Further restrictions on movement of people made last night will lead to further reductions in building occupancy increasing the risk of colonisation by Legionella.

We have been advised by the LCA (Legionella control association) & the HSE that all employers still have a duty of care to manage the risks from Legionella. The LCA website states:

 “While controls in place may need to be adapted to changing circumstances, duty holders must still be able to demonstrate control of risk to a reasonably practicable level.”

Loss of manpower due to social-distancing and self-isolation of staff could make this difficult. Our objective should be to deploy the resources we have in the best way to achieve the greatest reductions in the overall risk of Legionella becoming established in a building.

Below is a list of actions to be taken which will have the biggest impact in reducing risk in both hot & cold domestic systems and open evaporative cooling tower systems.

2. Domestic Hot & cold water systems

Buildings have already seen a significant decline in building occupancy and this is only likely to become worse. Water systems with dramatically reduced usage can quickly become hazardous if steps are not taken to mitigate this.

It is imperative that:

  • Flushing regimes are implemented whilst still in even partial operation to keep them from stagnating.
  • Where a flushing regime cannot be maintained, systems should be formally decommissioned and will need to be recommissioned before being brought back into use.

Actions required to keep domestic water systems safe

  1. Increased flushing regime & monitoring of turnover of water – Carry out building wide flushing of all domestic outlets on a weekly basis as a minimum. (2 minutes of flushing at each outlet on both hot & cold outlets)
  2. Take steps to measure water turnover within the building’s water systems. Estimated water usage can be obtained by taking water meter readings or performing drop testing of tanks.
  3. The above usage information should be used to establish the suitability of the current flushing regime.
  4. Reduce volumes of stored water where possible or as indicated by point 2 above. i.e. Where there are tanks/calorifiers balanced together consider taking some offline. 
  5. Increased Legionella sampling – Legionella sampling should be considered to check the effectiveness of the above controls. Contact Dantek for further advice.
  6. Where water is known to be stagnating consider leaving water systems charged with a Hydrogen peroxide and silver biocide (Such as Sanosil) to inhibit microbial growth.
  7. Systems that have been left without sufficient controls will need to be re-commissioned before being brought back into public use. Further guidance regarding re-commissioning is below.

3. Re-commissioning of domestic systems

Short Term – less than 4 weeks

Buildings left unoccupied for less than 4 weeks without the above controls in place.

  1. ℃.
  2. ℃ & 50℃ respectively.

Long Term – More than 4 weeks

Buildings left unoccupied for over 4 weeks without the above controls in place.

  1. Inspect cold water storage tanks for internal condition and clean if necessary
  2. Flush inlet pipework to cold water storage tanks and check for operation of all float valves.
  3. Open isolation valves on hot water calorifiers.
  4. Reinstate and check operation of secondary HWS circulation pumps.
  5. Open isolation valves on cold water storage tanks and any others which have been isolated as part of the shutdown.
  6. Bring booster sets back online and check they are primed.
  7. Carry out a chemical disinfection of the incoming mains, cold water storage tanks, calorifiers and all associated distribution pipework to all outlets. Dantek Disinfection procedures should be followed.
  8. Switch over any duty/standby pumps on the HWS secondary system.
  9. 3 days after the disinfection has been completed, take a representative number of samples and analyse for TVCC and Legionella.

 

4. Actions to reduce the risks – Open Evaporative Cooling systems

Maintain daily and weekly checks. 

  • Maintain the daily and weekly checks as an absolute minimum to ensure the tower is operating safely. This includes checking the following:
    • Dosage and control equipment is on and functioning correctly.
    • Adequate chemical stocks are in place
    • Control of primary Conductivity is satisfactory
    • Control of primary pH is satisfactory
    • Dipslide results remain satisfactory
    • Visual condition of the towers remains satisfactory.
  • Dantek will support where possible the maintenance of weekly cooling tower testing. The cooling tower should be shut down if weekly testing can no longer be completed for any reason or if there is a problem that can’t be solved immediately by the weekly testing.  
  • Consider increasing site stock of chemical to mitigate any future delivery issues.
  • If plant is controlled automatically and there is a risk of reduced demand steps to maintain circulation at all time should be taken.

5. Recommissioning of open evaporative cooling towers shut down:  

Cooling towers shut down for less than 1 week

  1. Visually inspect tower sumps, packing and drift and clean if required.
  2. Reinstate dosage and control equipment and check operation of chemical dosage pumps.
  3. Open any isolation valves and bring circulation pumps back online
  4. Check water quality (pH, TDS, Bromine/Chlorine levels) and adjusted so that it is within satisfactory limits.
  5. Once up and running take a dipslide and incubate.   

Cooling towers shut down for more than 1 week and less than 4 weeks

  1. The below should be carried out with w water treatment Engineer in attendance.
  2. Visually inspect tower sumps, packing and drift and clean if required.
  3. Reinstate dosage and control equipment and check operation of chemical dosage pumps.
  4. Check controller settings ad operation.
  5. Open any isolation valves and bring circulation pumps back online
  6. Check water quality (pH, TDS, Bromine/Chlorine levels) and adjusted so that it is within satisfactory limits.
  7. Once up and running take a dipslide and Legionella sample.  

Cooling towers shut down for more than 4 weeks

  1. Carry out full cleaning and disinfection of cooling towers systems as per Dantek Method statement
  2. Reinstate dosage and control equipment and check operation of chemical dosage pumps.
  3. Open any isolation valves and bring circulation pumps back online
  4. Check water quality (pH, TDS, Bromine/Chlorine levels) and adjusted so that it is within satisfactory limits.
  5. Once up and running take a dipslide and incubate.  
Children Washing Hands At School

Legionella control case study at a large boarding school

Dantek have provided legionella control services to Marlborough College for a number of years, below is a case study about how we work together to ensure ACoP L8 compliance and the safety of the students and staff.

Since its establishment in 1843 by a group of Church of England clergymen at the Castle Inn at Marlborough, Marlborough College has never been frightened of change. 

In its recent history, numerous academic initiatives have been fostered at the College including, Business Studies, SMP Maths, Combined Science, Pre-U examination syllabuses and the teaching of Arabic and Chinese. In 1968 Marlborough was one of the first of the traditional boys’ boarding schools to admit girls into the Sixth Form.

In 1989, the College became fully co-educational with the admission of girls into the Lower School and with the establishment of the first of the all-girl boarding houses.

Today the College caters for 936 pupils (of which just over 40% are girls) and the great majority of whom (98%) are boarders.  The remaining four “Out-College” houses accommodate 13-16-year-old boys, plus a mixed Sixth Form of both girls and boys.

School size: 201-500 employees

Based at: Marlborough, Wiltshire

The support Dantek provides

As a school, Marlborough College provides care for a large group of students most of which board on site, this means that they must adhere to strict health and safety guidelines. One of these areas is the need to protect students and staff from potential Legionella infection. Dantek has worked with the school for many years ensuring they comply with all regulations thus providing a safe environment for their students to thrive in.

As part of their on-going activity, Dantek engineers monitor the water quality, carry out remedial work and run regular testing and Legionella risk assessments. The College compliance team benefit from using Dantek’s electronic logbook which saves time and helps them keep on top of the various requirements. Dantek has provided a long-standing service to the college and act as part of their team which supports the quality of environment and interaction required by the College.

What does the client say?

We caught up with Kelvin Neale, M&E and Energy Manager at Marlborough College to find out how he views working with Dantek;

How did you hear of Dantek?

I have worked at Marlborough College for 8 months so Dantek were already in place when I joined. However, I did work with Dantek through another employer. I can certainly say that Dantek are known for their sound reputation in the industry.

What are the most important elements you look for in a contractor?

The most important elements for me are timely communication and a conscientious, effective manner. Due to the nature of the work Dantek provide, I also look for clear paperwork and accurate paper trial. We do consider the price, but it is not the only factor. When it comes to compliance, we must make sure we are choosing the right supplier who has the knowledge and systems which we require.

What do you like about working with Dantek?

I am very happy with their work in general. Three things stand up for me in particular:

  1. All engineers are professionals and knowledgeable, DBS checked and employed directly. They will always provide a service that goes beyond their contractual requirements and nothing we ask is ever an issue.
  2. The level of knowledge and expertise the company holds is impressive, they clearly know their stuff. I am also very impressed with the fact that on the rare occasion when they come across something they don’t know; they will go away to research for the right solution. It really demonstrates how competent they are and allows me to trust their advice implicitly.
  3. The electronic logbook is helpful and saves me a lot of time. It means I always have the data I need available to me and we never miss any tests and activities we need to complete.

How do they stand out against the competition?

As mentioned before, Dantek has a strong reputation in the industry. I think the main elements that make them stand out for me are as follows:

  1. The concise and timely completion of every job
  2. The electronic logbook which allows me to stay on top of compliance requirements, documentation and paperwork
  3. The level of knowledge and expertise they demonstrate about water treatment and legionella control

 

Cleaning And Chlorination Of Cooling Tower

Cooling tower water treatment – FAQ’s

What do I need to do if I am responsible for a cooling tower?
The first step is to carry out a Legionella Risk Assessment, it will need to be conducted by a competent water treatment professional with expertise in cooling towers. The risk assessment will form the basis of control measures put in place to reduce the risk of legionnaires’ disease.

You will also need to register the Cooling Tower with your local authority.

(The Notification of Cooling Towers and Evaporative Condensers Regulations 1992). These Regulations require employers to inform their local authority, in writing, if they operate a cooling tower or evaporative condenser and include the location of the tower to be used in case of an outbreak of Legionnaires’ disease. It is also a requirement for employers to notify when cooling towers are no longer in use. Notification forms are available from your local environmental health department.

https://www.gov.uk/cooling-tower-notification

What are cooling towers used for?
Cooling towers provide cooling for a wide range of industrial processes and air conditioning.

Cooling tower means a device whose main purpose is to cool water by direct contact between the water it holds and a stream of air.

Evaporative condenser means a device whose main purpose is to cool a fluid by passing the fluid through a heat exchanger which is itself cooled by contact with water passing through a stream of air.

Essentially, they are both arranged so that the air moves against the direction of the water.

The process of using evaporative cooling of water is widely used to deplete heat from air conditioning, refrigeration and industrial process systems. There are a range of evaporative cooling systems that use the evaporation of water to achieve this cooling effect and these include cooling towers and evaporative condensers. Open-circuit cooling towers are the most common and range in size from small packaged towers used in air conditioning and light industrial sites, up to large towers, including hyperbolic towers for heavy industrial uses.

Water boils at 100℃ and freezes at 0℃ and these changes of state from liquid to steam require an additional input of energy known as the latent heat of vaporisation.

The energy required to change 1 gram of water into steam is the highest of any known liquid which makes it particularly good as a cooling medium. As the water evaporates it takes a large amount of energy with it which cools the remaining liquid considerably.

Why cooling tower water treatment is needed?
The water used in cooling towers needs to be treated because impurities in the water cause the following problems all of which require actions for the system to run efficiently:

  • Scale
  • Corrosion
  • Suspended solids
  • Microbiological growth

It is important to have in place an effective water treatment programme to prevent the growth of legionella in the cooling water. A cooling tower water treatment programme should be capable of controlling not only legionella and other microbial activity but also corrosion, scale formation and fouling to maintain the system’s cleanliness. Appropriate water treatment may involve a range of chemical and physical techniques to control corrosion, scaling and fouling potential of the cooling water and to control microbial growth. Any water treatment regime must be monitored regularly to ensure they remain effective. The exact techniques that are required may vary significantly with different water supplies, the design of the cooling system and local operating conditions so it is important to engage a water treatment consultant to ensure the correct selection of control measures for your site.

How do you prevent legionnaires disease in cooling towers?
The first action is to identify and assess the sources of risk and appoint an individual who is managerially responsible for the system. This person must be trained and competent and must also have the authority and budget to act when necessary. The next step is to prepare a written scheme to include temperature monitoring, chemical treatment and any remedial works required to ensure compliance with current guidance. Once a scheme has been prepared it needs to be implemented, managed and monitored. Information must be held in a logbook so records are accessible and can be used to check the scheme remains effective. The records must be regularly reviewed, and any changes made to ensure effectiveness. Records must be kept for 5 years.

It is a legal duty to control the risk of exposure to legionella bacteria. As legionella bacteria are more likely to grow and proliferate in a cooling system fouled with sludge, scale and other deposits, maintaining system cleanliness and the water in it is an essential part of the control regime. The cleaning and disinfection frequency must be determined by a risk assessment and this should be based on inspection and the history of the water treatment control of microbial activity, scaling tendencies and other factors that may result in fouling of the system. In relatively clean environments with effective control measures, it may be acceptable to extend the period between cleaning operations, provided you can demonstrate that system cleanliness is maintained.

Water quality monitoring
The composition of the make-up and cooling water must be routinely monitored to ensure the continued effectiveness of the treatment programme. The frequency and extent will depend on the operating characteristics of the system. There are some checks which must be carried out weekly for example TDS and pH, while others are much less frequent for example legionella testing which is typically carried out quarterly.

Routine checks on cooling towers:

There are various checks which must be performed daily; these include a visual check of the cooling tower, check on the internal condition, dosage equipment and chemical drum levels check.

Every week the oxidising biocide levels, conductivity (TDS), pH, microbiological activity, pumps and softener must be checked and records updated in the logbook.

Why is scale a problem is cooling towers?
Scale is one of the four main issues found in cooling towers below are 5 of the key implications of scale:

  • Scale reduces heat transfer
  • Scale promotes corrosion
  • Scale promotes microbial growth for example legionella bacteria
  • Scale absorbs chemical treatments
  • Scale can obstruct pipework causing inefficiency and increased energy costs

Scale is the localised build-up of normally water-soluble inorganic hardness salts. Its formation is influenced by the concentration of calcium salts, pH, surface and bulk water temperatures and the concentration of the total dissolved solids (TDS). As an evaporative cooling system operates, the concentration of these various dissolved solids increases and the pH of the water tends to rise, which results in the scaling potential of the water increasing.

Scale formation results in loss of heat transfer, reduced flow rates and loss of efficiency and contributes to deposition. Legionella can be associated with such deposits. The scale protects the bacteria and so reduces the effectiveness of any biocidal treatment.

One or more of the following techniques generally control scale formation:

  • removing the hardness from the make-up water by pre-treatment, e.g. water softening
  • adding specific scale inhibitors that extend the solubility of the hardness salts and so prevent precipitation
  • acid dosing to lower the pH and alkalinity and reduce the scaling potential
  • limiting the system concentration factor to a range within which the hardness salts can remain soluble

What is TDS in a cooling tower?
Conductivity or Total dissolved solids (TDS) the quantity of solids dissolved in the water, measured in mg/l. These solids will typically include calcium and magnesium (sodium in softened water), bicarbonate, chloride, sulphate and traces of other materials. TDS indicates general water quality.

What are dipslides used for in cooling towers?
Dipslides are used to measure the level of bacteria. They are incubated at 30°C for 48 hours and bacteria will show as red spots. A comparison chart is used to assess the level of bacteria.

For further information about water treatment service contracts for cooling towers contact us to talk through how we can help keep your cooling tower running efficiently and compliant with the latest HSE guidance for Legionella control.

HSE Logo

HSE Legionella e bulletin

The HSE published another useful round up of the latest news about Legionnaires’ disease. It includes details of the prosecution in December 2018 of Tendring District Council pleaded guilty to breaching Section 3(1) of the Health and Safety at Work Act 1974 and was fined £ 27,000  plus £ 7,500 costs, after a member of the public contracted Legionnaires’ Disease from a leisure centre hot and cold water system.

There is also a very useful link to download free factsheets about Rapid Microbiological Testing Methods produced by the WMS. Information about events coming up and the HSE Water Treatment Contractor Intervention Programme.

To read the full bulletin click: HSE Legionella Ebulletin

You can subscribe to the HSE Legionella bulletin’s and have them delivered directly into your inbox, ensuring you are kept up to date on Legionella control.

Legionella Sample Testing

Legionella testing – when do you need to take legionella samples?

Legionella sampling
UKAS accredited Legionella sampling

Do I need to take Legionella samples? 

It is a common misconception that taking Legionella samples is a requirement for Legionella control in domestic hot and cold water systems.  In fact, microbiological monitoring of domestic hot and cold water is not normally a requirement for compliance with current guidance. However, Legionella sampling would be required in high risk situations or in systems where current controls are shown to be failing. For example, if temperature control is consistently unachievable or disinfection concentrations are not satisfactory then alternative precautions should be carried out such as weekly microbiological sampling.

In high risk properties such as hospitals and health care premises, taking samples is a requirement. For specific guidance on microbiological monitoring refer to the BS 7592:2008 – Sampling for Legionella Bacteria in Water Systems – code of practice. 

It is very important to know that taking Legionella tests from domestic water systems does not achieve compliance with the HSE guidance document The Control of Legionella Bacteria in Water Systems ACoP L8.  The first step to compliance is to carry out a Legionella risk assessment and, then, to put in place a control scheme based on the findings of the risk assessment.

Whilst the ACoPL8 guidance are not law, they are enforceable under the Health and Safety at Work Act 1974 and the Control of Substances Hazardous to Health (COSHH) regulations. A Legionella risk assessment will define actions required for compliance with the guidance, and provide a schedule for any required ongoing monitoring e.g. temperature and biological monitoring if required.   

How long does it take to get a legionella sample result?

The most common question about legionella samples is how long will the results take?  Legionella tests must be analysed at an independent UKAS accredited laboratory. The incubation time for a Legionella test, using the standard culture method, is 10 days, so this is not a quick test to carry out. In the event of a Legionella positive result, the customer will be informed immediately by phone or email with advice about what to do next.

Different methods are available for Legionella testing which reduce the time to get a result from the lab. Some methods can produce a result in as little as 24hours. Please contact the Dantek office for further information if a fast turnaround is required. 

Where do samples need to be taken?

For sites where Legionella monitoring is a requirement in hot and cold water systems, sampling should be carried out in accordance with: BS 7592 Sampling for Legionella Bacteria in Water Systems. Depending on the complexity of the system, the actual number of samples will be worked out. It is important to ensure the sample is representative of the water flowing around the system and not just of the area downstream of the fitting; samples should be taken from separate hot and cold outlets rather than through mixer taps or outlets downstream of TMVs or showers. This will help to identify where any potential colonisation is and will help to inform on appropriate actions going forward.

A sampling plan should be put in place detailing the sampling locations and the type of sampling to undertaken. Whenever possible, samples should be taken from locations considered most likely to contain the highest numbers of legionellae.

Locations for Legionella samples in cold water systems

  1. From the point of entry of the mains or nearest outlet to the point of entry into the building
  2. Cold water storage tanks
  3. From nearest & furthest outlets (Sentinel points) on each branch of the system

Locations for taking Legionella samples in hot water systems

  1. From the nearest outlet to the calorifier
  2. From the base of the calorifier
  3. From the nearest & furthest outlets (sentinel points) on each branch of the system for single pipe systems
  4. From nearest & furthest outlets (sentinel points) on each loop of a circulating system

How is a legionella sample taken?

The scope and type of sampling (pre or post flush) should be set out in the sampling plan. Methods for the different types of sampling are detailed below.  If not specified pre-flush samples will be taken as standard.

A sample will be collected in a new, unused, capped, sterile litre sample bottle using aseptic techniques.  This minimises the chance of cross contamination of the sample and reduces the risk of a resample being required.  The bottles need to be labelled with the exact location where the sample was taken and the exact time and date. 

Dantek Technicians are trained to take the sample using aseptic techniques to prevent cross-contamination.  It is important that the correct sampling technique is used to achieve the most accurate results so that correct preventative actions are completed.

What is an aseptic technique for Legionella sampling?

Aseptic sampling techniques reduce the likelihood of contamination and poor sample results.

When taking samples, the technician must observe the following best practice:

  • Never touch the neck of the bottle or the inside of the lid
  • Ensure the bottle does not come into contact anything which may introduce contamination
  • Do not rinse the bottle out prior to the sample being taken
  • Minimise the time that the bottle is open to atmosphere
  • Only use the correct sterile bottle containing sodium thiosulphate or appropriate neutraliser.
  • Wash hands when sampling
  • Use hand sanitiser when sampling
  • Samples must reach the lab within 48 hours
  • Correct transport procedures should be followed
  • Ensure an air gap is left in the sample bottle

When taking a sample from a cold-water storage tank, the samples are to be taken from the centre of the tank where possible, taking care not to collect any solids.  Move the bottle forward through the water during sampling, ensuring water is only collected from in front of the bottle.

Steps to taking a Legionella sample:

  • Legionella samples must be taken in 1 litre sterile sample bottles containing sodium thiosulphate capable of neutralising up to 5ppm of free chlorine without effecting the bacteriological population.
  • Samples bottles, which are checked to ensure they are in date.
  • Samples bottles are checked before use to ensure that the lid seal is still intact.

Prior to removing the lid, the bottle should be marked with a permanent pen detailing the following information;

  • Customer
  • Site
  • Location of sample, building name, room location, cold water storage tank, calorifier, cooling tower sump, spa pool etc.
  • System identification, mains cold water, tank feed cold, domestic hot.
  • Pre or post-flush
  • Date & time of sample
  • Temperature of the water and/or chlorine dioxide reserve

How to take a pre-flush sample?

  • Do not disinfect the tap/outlet
  • Collect the sample immediately after the tap, or fitting, is opened, ensuring that the sample consists of only the first water which leaves the outlet.
  • Continue to fill the bottle leaving a 1 cm air gap at the top of the bottle.
  • Immediately replace the cap and invert the bottle several times.
  • Place the sample in a cool box and return to the office the same day.

How to take a post-flush sample?

  • Flush approximately 1 litre of water from the outlet.
  • Remove spray any inserts and flow directors from the outlet. It may also be necessary to remove and strainers and non return valves from TMV’s, strainers and solenoid valves.
  • Whilst wearing protective googles & gloves, make up a 200ppm solution of chlorine.
  • Clean the outside of the tap using the disinfectant solution.
  • Inject disinfectant solution into the outlet until it begins to run out of the tap using a wash bottle.
  • Descale and disinfect inserts and flow directors
  • Allow a two-minute contact time for the disinfection to take place.
  • Flush the outlet for 1 minute to remove the disinfectant.
  • Fill the sample bottle without adjusting the flow of water leaving a 1 cm air gap at the top of the bottle.
  • Immediately replace the cap and invert the bottle several times.
  • Place the sample in a cool box and return to the office the same day.
  • Rinse the outlet and surrounding area to remove any remaining disinfectant.

What should I do if the legionella sample comes back positive?

Firstly, don’t panic get in touch with Dantek and we will be able to guide you through the next steps to ensure you deal with the results in the correct way and to ensure your system is back under control as quickly as possible.  What action to take depends largely on the results and if this is the first positive result for the system.

If the first positive Legionella result is less than 1000cfu/ml:

If the minority of sample results are positive but less than 1000cfu/ml then arrange for a re-sample as soon as possible and review the control measures and risk assessment.

If the majority of the samples are positive but again with less than 1000cfu/ml then there is the possibility the system could be colonised at a low level.  Immediate review of control measures and risk assessment are needed and disinfection of the system must be considered.

If the 1st positive Legionella result is greater than 1000cfu/ml take the following action:

  • Arrange for a re-sample to be taken as soon as possible
  • Shut down any processes on the system where the positive sample was taken that can generate and disseminate airborne water droplets
  • Disinfect the system
  • Keep them shut down until sampling procedures and any remedial cleaning or other work has been done
  • Retest a few days after the disinfection and at frequent intervals afterwards until a satisfactory level of control is regained.
  • Review the risk assessment and control measures.

Following positive Legionella results a review of the Legionella risk assessment, control regime and record keeping/log books should be reviewed by checking the following:

  • They are current, up to date and accurate
  • That any remedial actions/recommendations have been completed
  • That the recommended control regime is in place. Identify the failing areas if there are any.
  • That good records are being kept of the activities undertaken
  • A record of the audit including any changes is placed in the log book

The question of whether to take samples or not can seem daunting however the key point to remember is taking samples will not affect levels of contamination on its own and does not necessarily offer compliance with the ACoPL8.  Ensure you keep your legionella risk assessment and control scheme up to date and seek advice from your water hygiene contractor.  If you have any concerns about Legionella samples, do get in touch with us as we are best placed to advice you about the Legionella control on your site.

Further reading:

http://www.hse.gov.uk/pubns/priced/hsg274part2.pdf

BS 7592:2008 Sampling for Legionella bacteria in water systems – code of practice

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