Hot Water Temperature, Scalding, and Legionnaires' Disease
Hot water temperature and its impact on the incidence of scalding and Legionnaires’ disease is a hot topic in the industry at the moment.
The issue is being discussed at Plumbing Code hearings and not a month goes by that the subject is not mentioned in the trade magazines. We have assembled a range of information here related to the issues. We hope you find it interesting and informative.
The issue is being discussed at Plumbing Code hearings and not a month goes by that the subject is not mentioned in the trade magazines. We have assembled a range of information here related to the issues. We hope you find it interesting and informative.
- An estimated 8,000 to 18,000 people get Legionnaires' disease in the United States each year.
- Destroying the bacteria that causes Legionnaires' disease requires raising the temperature of water to at least 140F.
- In a recent test, 24% of a 21-family test group was found to have Legionella bacteria in their home water.
Scalding Facts:
Destroying the bacteria that causes Legionnaires’ disease requires raising the temperature of water to at least 140°F (60°C). But, at 140°F (60°C), water can cause third-degree burns in children in one second and adults in five seconds.The U.S. Consumer Product Safety Commissions states that approximately 3,800 injuries and 34 deaths are directly related to dangerously hot tap water in residences (The National Safe Kids Campaign lists the number of scalding injuries as high as 6,500).
The answer to preventing both Legionnaires’ disease and harmful water temperatures is to store the water at a high temperature and temper it with a valve to a safer temperature before distribution to the fixture.
Using Solar Thermal:
The benefits of solar thermal water heating is that it can achieve very high temperatures destroying bacteria in the storage tanks. We set our temperatures to reach 185°F (85°C) at the bottom of the tanks to eliminate any possible growth in the water tank temperature stratification from the top. This means that reaching temperatures in excess of 200°F (93°C) at the top of the tanks is very common in our systems. Using fossil fuel energy to reach these temperatures just to kill bacteria then lowering it to safe temperatures is not very cost effective and only contributes to more global warming.
Legionella Facts:
Legionnaires' disease acquired its name in 1976 when an outbreak of pneumonia occurred among persons attending a convention of the American Legion in Philadelphia.
The bacterium is spread through inhalation, which can occur while showering, washing or drinking the water.
An estimated 8,000 to 18,000 people get Legionnaires' disease in the United States each year (5% - 30% of the cases are fatal).
Legionnaires' disease can cause fever, chills, and a cough, which can be dry or may produce sputum. Some patients also have muscle aches, headaches, tiredness, loss of appetite, and, occasionally, diarrhea. Legionella may also cause cases of pneumonia that may be difficult to diagnose.
Improved design and maintenance of cooling towers and plumbing systems to limit the growth and spread of Legionella organisms are the foundations of preventing the disease.
Benefits of Copper and why we do not use stainless or pex tubing in any installation.
Microbiologist describes copper's antibacterial properties as 'remarkable' Copper is recommended to combat Legionella in hot water system. Copper will also eradicate MRSA, E-coli and Avian Bird Flu in less than 5 Hours. In tests it took 34 days for E-coli 0157 to die on Stainless Steel, 4 days on brass and just 4 hours on copper. 99% of the bacterial population introduced into a copper plumbing system, will disappear in under five hours. It is thought that the metal 'suffocates' germs, stops them from feeding and destroys their DNA.
Hospitals have recently started replacing all of their commonly touched fixings with copper versions due to the metal's anti-bacterial properties. In a trial at Selly Oak hospital, in Birmingham, copper taps, light switches, toilet seats and door handles, all but eliminated common bugs.
Researcher Professor Peter Lambert, of Aston University, Birmingham, said:
"The numbers of bacteria decreased always on copper but not on the steel surfaces."
Professor Tom Elliott, the lead researcher and a consultant microbiologist at the hospital, added:
"The findings of 90 to 95 per cent killing of those organisms, even after a busy day on a medical ward with items being touched by numerous people, is remarkable. I have been a consultant microbiologist for several decades and this is the first time I have seen anything like copper in terms of the effect it will have in the environment."
The healing power of copper has been recognized for thousands of years. More than 4,000 years ago, the Egyptians used it to sterilize wounds and drinking water and the Aztecs treated skin conditions with the metal.
Read more about the use of copper in hospitals
Watch a video about the hospital's copper trial
Limitations of the Water Heater:
The thermostat of a water heater is a static control device intended only to allow the heater to perform its intended function as a hot water generator and storage device.
The thermostat can be “set” with an accuracy of ±5°F (±3°C) at best.
The difference between the “off” and “on” points of the water heater can be as much as 15°F (9°C), resulting in decreased efficiency.
Ideal Conditions for Legionnaires' Disease:
Legionella Pneumophilia, the bacteria that causes Legionnaires’ disease, thrives in warm, stagnant water.
A water temperature of 120°F does not kill the bacteria; a minimum temperature of 140°F is required.
A water heater set at 120°F can contain water as low as 100°F.
To eliminate the bacteria, several steps need to be taken, including eliminating dead-legs and system flushing. But, without a storage temperature of 140°F, all other steps cannot solve the problem.
Legionnaires' Disease in Residential Environments:
In a recent test, 24% of a 21-family test group was found to have Legionella bacteria in their home water.
A combination of new and old research now suggests that the bacteria may thrive in residential hot water pipes, and the water supply used in residential homes may be directly responsible for 20% of Legionnaires cases.
Bacteria in natural water sources (not unlike those used by residential dwellings) do not undergo the processes of filtration and chemical disinfection that municipal water supplies go through. Instead, natural water sources must be treated by the private owner, a process which is often inconsistent or incomplete.
How the Issue is Being Addressed Around the World:
Several countries around the world, including many in Europe, have adopted regulations requiring water to be stored at 140°F or higher and delivered at 120°F or lower.
The aggressiveness with which countries have addressed this issue indicates the importance of water storage safety.
Product Standards:
There have been several new innovations and updates to the product standards in the water temperature control industry.
Legionella and Scalding Links & Resources:
Legionella and Scalding News Articles:
Destroying the bacteria that causes Legionnaires’ disease requires raising the temperature of water to at least 140°F (60°C). But, at 140°F (60°C), water can cause third-degree burns in children in one second and adults in five seconds.The U.S. Consumer Product Safety Commissions states that approximately 3,800 injuries and 34 deaths are directly related to dangerously hot tap water in residences (The National Safe Kids Campaign lists the number of scalding injuries as high as 6,500).
The answer to preventing both Legionnaires’ disease and harmful water temperatures is to store the water at a high temperature and temper it with a valve to a safer temperature before distribution to the fixture.
Using Solar Thermal:
The benefits of solar thermal water heating is that it can achieve very high temperatures destroying bacteria in the storage tanks. We set our temperatures to reach 185°F (85°C) at the bottom of the tanks to eliminate any possible growth in the water tank temperature stratification from the top. This means that reaching temperatures in excess of 200°F (93°C) at the top of the tanks is very common in our systems. Using fossil fuel energy to reach these temperatures just to kill bacteria then lowering it to safe temperatures is not very cost effective and only contributes to more global warming.
Legionella Facts:
Legionnaires' disease acquired its name in 1976 when an outbreak of pneumonia occurred among persons attending a convention of the American Legion in Philadelphia.
The bacterium is spread through inhalation, which can occur while showering, washing or drinking the water.
An estimated 8,000 to 18,000 people get Legionnaires' disease in the United States each year (5% - 30% of the cases are fatal).
Legionnaires' disease can cause fever, chills, and a cough, which can be dry or may produce sputum. Some patients also have muscle aches, headaches, tiredness, loss of appetite, and, occasionally, diarrhea. Legionella may also cause cases of pneumonia that may be difficult to diagnose.
Improved design and maintenance of cooling towers and plumbing systems to limit the growth and spread of Legionella organisms are the foundations of preventing the disease.
Benefits of Copper and why we do not use stainless or pex tubing in any installation.
Microbiologist describes copper's antibacterial properties as 'remarkable' Copper is recommended to combat Legionella in hot water system. Copper will also eradicate MRSA, E-coli and Avian Bird Flu in less than 5 Hours. In tests it took 34 days for E-coli 0157 to die on Stainless Steel, 4 days on brass and just 4 hours on copper. 99% of the bacterial population introduced into a copper plumbing system, will disappear in under five hours. It is thought that the metal 'suffocates' germs, stops them from feeding and destroys their DNA.
Hospitals have recently started replacing all of their commonly touched fixings with copper versions due to the metal's anti-bacterial properties. In a trial at Selly Oak hospital, in Birmingham, copper taps, light switches, toilet seats and door handles, all but eliminated common bugs.
Researcher Professor Peter Lambert, of Aston University, Birmingham, said:
"The numbers of bacteria decreased always on copper but not on the steel surfaces."
Professor Tom Elliott, the lead researcher and a consultant microbiologist at the hospital, added:
"The findings of 90 to 95 per cent killing of those organisms, even after a busy day on a medical ward with items being touched by numerous people, is remarkable. I have been a consultant microbiologist for several decades and this is the first time I have seen anything like copper in terms of the effect it will have in the environment."
The healing power of copper has been recognized for thousands of years. More than 4,000 years ago, the Egyptians used it to sterilize wounds and drinking water and the Aztecs treated skin conditions with the metal.
Read more about the use of copper in hospitals
Watch a video about the hospital's copper trial
Limitations of the Water Heater:
The thermostat of a water heater is a static control device intended only to allow the heater to perform its intended function as a hot water generator and storage device.
The thermostat can be “set” with an accuracy of ±5°F (±3°C) at best.
The difference between the “off” and “on” points of the water heater can be as much as 15°F (9°C), resulting in decreased efficiency.
Ideal Conditions for Legionnaires' Disease:
Legionella Pneumophilia, the bacteria that causes Legionnaires’ disease, thrives in warm, stagnant water.
A water temperature of 120°F does not kill the bacteria; a minimum temperature of 140°F is required.
A water heater set at 120°F can contain water as low as 100°F.
To eliminate the bacteria, several steps need to be taken, including eliminating dead-legs and system flushing. But, without a storage temperature of 140°F, all other steps cannot solve the problem.
Legionnaires' Disease in Residential Environments:
In a recent test, 24% of a 21-family test group was found to have Legionella bacteria in their home water.
A combination of new and old research now suggests that the bacteria may thrive in residential hot water pipes, and the water supply used in residential homes may be directly responsible for 20% of Legionnaires cases.
Bacteria in natural water sources (not unlike those used by residential dwellings) do not undergo the processes of filtration and chemical disinfection that municipal water supplies go through. Instead, natural water sources must be treated by the private owner, a process which is often inconsistent or incomplete.
How the Issue is Being Addressed Around the World:
Several countries around the world, including many in Europe, have adopted regulations requiring water to be stored at 140°F or higher and delivered at 120°F or lower.
The aggressiveness with which countries have addressed this issue indicates the importance of water storage safety.
Product Standards:
There have been several new innovations and updates to the product standards in the water temperature control industry.
Legionella and Scalding Links & Resources:
- Information on Legionnaires’ disease
- Water heaters are not water delivery temperature control devices
- Thermostatic Reference Guide – complete technical and product data
- Europe and Australia take steps to change codes
- Recognized water temperature control devices
- AWT - Update and statement by the Association of Water Technologies
- American Society of Sanitary Engineering
- The Canadian code for water temperature has changed
- Prop 65 requirements for California
Legionella and Scalding News Articles:
- 3/19/12 - Understanding potential water heater scald hazards
- 7/15/11 - Legionnaires' outbreak reported at Las Vegas resort
- 12/14/09 - Miami Hotel Evacuated After 1 Guest Dies, 2 Sickened by Bacteria-Tainted Water
- 09/24/08 - Two die of Legionnaires' disease in NJ hospital
- 07/11/08 - One Legionella Patient Has Died; 11 Total Cases in Onondaga County
- 06/18/08 - Legionnaires' Disease in Kanawha County; 1 Dead
- 05/27/08 - Legionnaires Outbreak Linked to Car Wash
- 03/19/08 - Rochester General Lifts Water Restrictions
- 03/19/08 - Legionnaires Disease Contracted by Orlando Tourists
- 02/29/08 - Legionnaires' Confirmed at Rochester General Hospital
- 08/31/07 - Tainted Hospital water gave man fatal legionnaire's
- 08/30/07 - Bacteria found in hospital water system
- 09/19/07 - Killer Bug Probe
- 06/19/07 - Dental patients urged to watch for legionnaire's disease symptoms
- 04/18/07 - School hit with Legionella
- 03/27/07 - Legionella expert cites hospital threat
- 03/27/07 - Patient who overcame leukaemia killed by a dirty hospital shower
- 12/27/06 - Hotel re-opens after legionella
- 12/11/06 - Mine evacuated after two workers test positive for Legionnaires'
- 09/14/06 - Probe as teacher dies of Legionnaires' disease
- 01/30/06 - Scalding case judge calls for mixing valves
- 12/20/05 - Scalding death in Canada
- 06/30/05 - Case of Legionnaires' forces swimming pool to close
- 05/24/05 - Health authorities in Norway crack down on Legionnaires'
- 05/18/05 - I.M.P.W. newsletter addresses issue of Legionella
- 02/08/05 - UK Manslaughter Trial Links Deaths to Legionella Outbreak
- 01/25/05 - Three cases of Legionnaires' reported in Northern Ireland
- 10/18/04 - Scalding injuries can be deadly!
- 06/30/04 - University of Michigan launches anti-scald campaign
- 06/12/04 - Legionella confirmed at two Children’s hospitals
- 04/22/04 - Elderly Florida Man Gets $925,000 in Scald Suit
- Legionnaires’ vs. scalding issue – Demand for dhw safety now puts thermostatic valves in the right place
– The Wholesaler, 2003 - Proposed National Plumbing Code amendment will impact water heater installations in new construction
– Contracting Canada – December 2003 - Thermostatic Valves: Solution to a Double-Edged Problem – Reeves Journal
- UK manslaughter charge over Legionnaire’s Disease
- Health Minister endorses Canadian Code change
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