Water heaters safety - Learn the Important Details
In 1982 a hot water heater exploded at Star Elementary School in Spencer Oklahoma killing 7 and injuring many more. This is a particularly sobering example of the risks associated with water heaters but these accidents can be devastating and are quite common even today. Just this week a water heater explosion injured 9 people in Philadelphia not to mention the significant structural and financial damage also caused. The potential for injury is considerable unless precautions are observed and safety devices are introduced.
Explosions are usually the most feared risk associated with water heaters due to their ability to cause damage to human life, including fatalities as well as structural damage. The likelihood of this happening is usually associated with older boilers and homes. Most of us never bother to check our hot water boilers for leaks or defects. The main risk of explosion in water heating comes from excess heat. When water temperature gets high it can generate steam which can expand to fill a volume 1,700 times great than that if filled as water. And a defective tank can explode more easily under this intense pressure. The main warning sign for a possible imminent tank explosion is steam coming from the hot water faucet. This may indicate that the thermostat which regulates heat in the water heater is malfunctioning and needs to be replaced. For safety a temperature or pressure release valve is normally located on the water heater to dump water if temperature or pressure becomes too high inside. In houses where water heaters are part of a space heating boiler, an automatic gas shut-off system may be used to shut off gas supply and prevent further heating when water gets too hot.
Another more common if less fatal safety risk associated with water heaters is burning and scalding. Human skin can burn as quickly as 5 seconds in temperatures of 60 degrees Celsius (140 degrees Fahrenheit). A tempering valve can be used to reduce risk of burning by mixing enough cold water to the hot water to keep the outgoing water temperature at a safe level (about 50 degrees Celsius). Without this valve, the setpoint temperature of the water temperature is used to maintain outgoing water at a safe level, but then outgoing water also needs to be at a level which allows effective sanitation. In a survey of 1,000 homes in Baltimore, USA, 41 percent of homes were found to have their water heater setting unsafely high. Young children are especially at risk as their skin is thinner; the elderly are also at a higher risk because they can be less sensitive to temperature, so may be slower to react to scalding water.
As mentioned previously, a balance must be maintained in ensuring water temperature is sufficiently hot to carry out proper sanitation but not dangerously hot encouraging incidences of scalding. Water heaters play a major role in prevention of bacterial contamination and there is a risk of incubating bacterial colonies if the water is not hot enough to kill them. For control against Legionnaires disease, European guidelines state a hot water temperature of 60 degrees Celsius be maintained, and this is higher than the 55 degrees at which scalding can occur. Lowering the temperature of the water heater to 45 degrees may be enough to reduce risks of burns but may also increase the likelihood of water contamination. To resolve this, the installation of tempering valves or other devices are encouraged to ensure that while the water in pipes are maintained at a sufficiently high temperature to guard against legionella and other bacteria, the water coming from the faucet is mixed at a level which is safe for the occupant.
Water heaters are incredibly important multi-purpose devices and vital to our everyday lives. But in the interests of safety they need to be checked regularly, maintained and updated as necessary. Nowadays with technological developments the risks of accidents and injuries can be drastically reduced, keeping you and your loved ones safe.