Fire Sprinklers as Fire Prevention Systems
Automatic fire sprinkler system is one of the most important fire prevention tool used in commercial and residential buildings. It helps limiting the spread of fire when accidents happened and minimized the property damage. How does the automatic fire sprinkler system actually work? One of the common beliefs about fire sprinkler is that it is activated by the smoke density in the room and once triggered will activate every sprinkler in the property. These myths are simply not true.
Fire Sprinkler Operation
Automatic fire sprinkler systems are triggered by the temperature in the room. Each sprinkler is built with a temperature-sensitive element, usually, it’s a glass bulb containing glycerin-based liquid. When a blaze ignited, the temperature above the blaze rises. Once the temperature reaches a specific temperature, the liquid in the glass bulb will expands and eventually break the glass bulb, enabling the flowing of the contents in the sprinkler system to put out the fire. Bulb operating temperature is represented by its color of the liquid.
The contents in the sprinkler system can be water or pressurized gases, this is decided when designing the system for effective fire suppression predicting the potential caused of fire due to the environment and application in each location. In the event of fire, usually the sprinkler closest the fire will be activated to suppress the blaze while limiting the potential water damage. There is another type of system called, deluge system that will activate all sprinklers when heat threat is detected but it will only be installed in high hazard areas such as power plants, chemical plants or air hangars.
Wet and Dry Type Fire Sprinkler Systems
Wet pipe fire sprinkler system and dry pipe fire sprinkler system are the more commonly used system on the market today. Wet pipe is a sprinkler system connected to a piping system connected to water source. The pipe is filled with water under normal condition and it will discharge water when the temperature-sensitive glass bulb breaks. Traditionally, wet pipe sprinkler system does not apply to the areas exposed to the temperature below freezing point. NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two- Family Dwellings and Manufactured Homes, included guidelines on proper pipe insulations that allows wet pipe sprinkler system to operate in colder climates.
Conversely, dry pipe fire sprinkler system is filled with pressurized gases instead of water. During a fire event, the sprinkler will release pressurized gases when the temperature-sensitive unit breaks. After the air escapes and the pressure in the pipe dropped to a certain value, the dry pipe valve permits the water contained in a heated environment to flow into the piping system and discharge through the opened sprinkler. This sprinkler system is commonly utilized in the colder climate areas. The cost of dry pipe water sprinkler system is relatively higher comparing to wet pipe sprinkler system as it requires extra design and implementation care to prevent corrosion. In fact, corrosion is more common in dry pipe sprinkler system due to high levels of oxygen present. Besides, dry pipe sprinkler system requires extra components such as air compressor and pressure monitoring system which will increase both the cost and the challenge for maintaining the system.
Fire sprinkler systems are required to be inspected and tested regularly according to the rules and regulations stated by the authorities to ensure operation during fire emergency.