Thermal shock commonly results from industrial accidents. It happens when cold water is introduced to a hot boiler that is running near full power. The cold and hot water can have a serious reaction in the boiler where parts in the boiler expand or contract rapidly. This can cause damage to the boiler and injury to workers who are near the boiler. There are methods that can be used to prevent thermal shock in boilers.
What is Thermal Shock and Why Is It Dangerous?
Thermal shock can be described as a serious reaction happening in an industrial boiler when cold water is introduced to boiling water in the boiler or its tubes causing rapid expansion or contraction and serious damage. Materials in the boiler, such as glass, rocks, and ceramics, will heat up and cool unevenly because they are poor conductors of heat. These materials can crack or break.
This is dangerous because the sudden rise or drop in temperature caused by thermal shock can cause either hyperthermia or hypothermia to people near the boiler, and this can kill. The temperature near the damaged boiler can change rapidly with heat being suddenly absorbed by the bodies of those nearby. This sudden temperature change can cause people’s organs to fail and cause death.
It is Possible To Prevent Thermal Shock in Boilers?
Taking action for preventing thermal shock is vitally important for any industrial setting that includes one or more boilers since thermal shock occurrences are far too common in industrial settings. Too often, boilers are operated outside of the manufacturers’ specifications causing a dangerous situation. Then, when an accident happens and the boiler is damaged, it can take as long as four weeks to repair the boiler. This does not take into account the worker injuries that might have accompanied the incident.
There are several precautions that will help prevent steam boiler thermal shock.
- Reducing the number of boiler operating cycles limits the times it must heat water. Boilers should not be fired up more than four to six times each hour.
- The temperature of the return water should be kept to a minimum of 140 degrees Fahrenheit. When the temperature of boiler water and return water are close to the temperature, the risk of thermal shock is reduced. This temperature difference should be less than 40 degrees Fahrenheit.
- Make sure the boiler system has monitoring equipment in good operating condition. Check this data regularly to catch any system malfunctions. Make sure the boiler system is serviced regularly to the manufacturers’ specifications. Make sure the equipment has the proper settings for operating temperatures.
- Have correct strategies in place for when the pump needs cycling to prevent water of different temperatures from being sent to the boiler. Start the boiler system slowly with its smaller pumps then ramp it up gradually. The pump should always be running before the boiler is started. Make sure there is flow whenever the system is running.
When thermal shock occurs, it might be caused by manufacturing flaws and deficiencies in the design of the boiler. Incorrect sizing or tuning, poor maintenance or operating practices, or a need to replace an older boiler system all lead to an increased chance of issues developing.
Thermal Shock and the Human Body
Thermal shock can affect different parts of the human body in different ways. Thermal shock is a form of hemolysis that can occur in human red blood cells and other body parts when they are exposed to more than a critical level of osmotic stress. The higher the concentration and the higher the cooling rates, the higher the amount of hemolysis. The amount of thermal shock depends on the temperatures and time of exposure.
Controlled thermal shock is now being used in antiaging technology in the form of contrast therapy where both cold and heat are used to break down fat cells and eliminate them from the body. This is accomplished using alternating cycles of hot and cold to kill fat cells, increase blood flow and circulation, and improve skin elasticity. This form of thermal shock does not involve industrial boilers. Extreme caution and regulation is important to avoid any injury to the patient.