A fire sprinkler system is a firefighting method, consisting of a working water supply system, providing enough pressure to a water distribution piping system that sprinklers are connected to. In the past, their use was exclusive to large factories and commercial buildings. The same cannot be said right now. Over the years, newer and affordable models of fire sprinkler systems have been invented.
These systems can be installed in small and larger buildings alike. In fact, the use of the fire sprinkler has scaled through the boundaries of developed countries and is now being used in every part of the world. Every year more than 40 million sprinkler heads are installed. The obvious reason why more and more people are turning their attention to fire sprinkler systems is that they are effective and can put out fires quickly.
In this article, we are going to be looking at the history of fire sprinklers, how they work and the various types that are available.
History of fire sprinklers
The history of fire sprinklers dates back to the 15th century. Back then, Leonardo da Vinci designed a sprinkler system that marveled many. Although it wasn’t perfect, it was effective in putting out flames.
In 1723, Ambrose Godfrey made the fire automated sprinkler system. He used special gunpowder to release a tank of fire extinguishing liquid.
The first modern sprinkler system was installed in the popular Theatre Royal in the UK in 1812 by a decorated architect, William Congreve. The system consisted of a large cylindrical reservoir that can hold 95,000 liters of water which was fed by a 250 mm water main which is branched out at every part of the theatre.
A new fire protection system (perforated pipe system) was used in many textile mills in New England from 1852 to 1885 to put out flames before they cause large-scale damage. Though the system was effective, it wasn’t automatic. This means that the system has to be manually turned off and on. Inventors took interest in developing automatic fire sprinklers in the 1860s. Their hard work and research paid off in 1872 when Philip W. Pratt of Abington discovered the first automatic sprinkler system.
Henry S. Parmalee patented the first practical automatic sprinkler head. He improved the invention of Pratt Patent and made a better sprinkler system. He installed the first fire sprinkler system into his piano factory in 1874.
In 1881, Frederick Grinnell modified the Parmalee’s sprinkler design and made an automatic sprinkler bearing his name. He dedicated his time and efforts in improving the device and in 1890, he created the glass disc sprinkler system.
In the 1940s, sprinklers were only used for the protection of large commercial buildings whose owners were the la crème of the society. As the years slowly went by, fire sprinklers became a piece of mandatory safety equipment.
Sprinklers are now installed in residential premises and schools among others. This positive change occurred because of the lobbying by the British Automatic Fire Sprinkler Association, the European Fire Sprinkler Network, and the National Fire Sprinkler Network.
Building regulations in England require that sprinkler systems be installed in certain properties to ensure the safety of its residents.
In 2011, Wales became the first country to make an installation of fire sprinklers systems in new residential structures mandatory. This law applies to newly constructed houses as well as university halls and care homes.
Usage of fire sprinklers
Sprinkler systems have been in use in the US since the late 1800s. Back then, they were only used in factories where a fire can cause large-scale damage to properties and claim lives. Today, sprinklers is now a requirement especially in buildings above 23 meters (75 feet ) or areas that are inaccessible to firefighters.
Sprinklers may be recommended by insurance companies to drastically reduce business interruption and property losses. They may also be a requirement by building code. Building codes require a working sprinkler system in an area where a lot of people assemble, such places include; dormitories, hotels, hospitals, and nursing home.
How do fire sprinklers work?
Granted, there are lots of fires fighting equipment like fire extinguishers, smoke, and heat detectors among others. But they may not be able to totally protect your building or structure from damage. A sprinkler system, on the other hand, can reduce fire damage and property loss by more than 65 percent. Unlike manual equipment like the fire extinguisher, which requires someone to operate manually, sprinklers are automatic. This means that you don’t need to turn them on in the event of a fire.
Fire sprinklers are definitely something you want in your residential or commercial facility. But how exactly do they work? Below is a brief description of the working principle of a fire sprinkler.
Many people have the false notion that fire sprinklers are triggered by smoke because they are carried upward when there is a fire. But the truth is that they are triggered by heat. If they were triggered by smoke, simply burning your toast could be enough to trigger the system to drench your home with water.
Fire sprinklers systems are effective in putting out fires and are somewhat immune to false alarms because they are only triggered when there is intense heat. When a flame ignites, the air above it heats up pretty quickly. This hot air gradually rises and spread along the top of the room or the ceiling. If the air that reaches the sprinkler head is hot enough, water will start squirting out of the head to extinguish the flame below.
Most sprinkler heads feature a special glass bulb filled with glycerine. This liquid rapidly expands when it comes in contact with airhead above 165 degrees. When the liquid expands, it shatters the glass that confines it and activates the sprinkler.
Dousing the flames
Normally, sprinkler heads are attached to a pipe that connects to a water source outside the structure. When the sprinkler head is activated by intense heat, the valves open, allowing pressurized water from the pipe to the flow out of the system.
It is critical for water in a fire sprinkler system to be pressurized. This enables the system to put out flame quickly and prevent it from re-igniting.
There is a sharp contrast between the sprinkler system in movies and the one in real life. Sprinkler systems in movies are often tied together. So, when there is a heat source, they all activate. While that may look cool and effective, it is misleading. You see, if all the sprinklers in a building are activated when there is a fire, there is likely going to be large scale water damage.
In real life, sprinkler heads function individually. At times, fires can be totally extinguished after two or three sprinklers are activated. This limits water damage to a few areas.
Since the fire sprinkler systems can put out the flame with 5 times less water than a fire hose, their quick action is going to cause less damage to your precious properties than a visit from your local fire department.
Fire sprinkler systems are effective in putting out flames without causing serious property damage. That said, you need to keep it in mind that all of them may not be able to protect your property. To effectively narrow down the type that will suit the needs of your structure, you have to learn a thing or two about the various types of sprinklers on the market.
Types of sprinklers
Installing a fire sprinkler system in a building is likely the best way to protect it from a fire. There are various types of fire sprinkler systems available. Below are descriptions of some of them so that you can make an informed decision and narrow down the one that will suit your structure.
Wet pipe systems
Wet pipe sprinkler systems are installed in more homes and structures than others. And this is because they are reliable and are very simple to install. Unlike other systems that are super complicated, wet pipe systems only have two components- the automatic alarm check valve and the automatic sprinklers. So if you are looking for a reliable sprinkler system that will serve you for a long time, then the wet pipe system will be perfect for you.
Wet pipe antifreeze
The difference between this system and the wet pipe system is the use of antifreeze chemical. You see, wet antifreeze systems are designed to be used in areas where pipes cannot be kept above 35 to 40 degree Fahrenheit.
Yes, wet pipe systems are effective especially in cold regions, but their use has been banned by the regulatory authority in the US. The reason why it was banned is that the system was responsible for several fires when it ran too high. In 2022, older antifreeze systems will be put to a halt in the United States. This regulatory action is definitely going to drastically reduce options for cold weather sprinklers and increase cost.
Dry pipe system
Dry pipe systems are the second most popular sprinkler system type. They are designed to be installed in areas where ambient temperature could freeze water in a wet pipe, rendering the system useless. Dry pipe systems are often used in unheated structures and buildings like parking lots, refrigerated coolers, and in regions where wet piping cannot be installed.
Water isn’t present in the piping until the system is triggered when there is a fire. When not in use, the piping is filled with air at a pressure less than the water supply pressure. To reduce the odds of the water supply pressure from forcing itself prematurely into the piping, the system is designed with a special dry pipe and valve. The valve exerts an immense force on the top of the check valve, which helps to prevent the system from malfunctioning.
When one or two automatic sprinklers are triggered, its air in the piping unit is vented from the sprinkler. Each sprinkler operates as a single unit and will only be triggered when the ambient temperature in the area where it is installed rise above its triggering threshold. As the air pressure slowly drops, the pressure across the dry pipe valve gradually changes as well. This, in turn, allows water into the piping system.
Water that flows from the sprinklers, needed to put out the fire are delayed until the air is out of the sprinkler system. In regions where the NFPA 13 regulations are in effect, the time it takes the water to reach the remote sprinkler is about 1 minute. This course of action is popularly termed the “maximum time of water delivery”. The maximum time of water delivery may be reduced, depending on the hazard classification of the area being protected.
Building owners and occupants alike may view dry pipe sprinkler systems as advantageous in protecting water sensitive areas and valuable items. This assumed benefit is due to the fear that wet systems piping are prone to slow leaks, while the dry pipe system is better and may not fail in this regard.
In this system, all sprinklers connected to the water piping system are open at all times. The system operates without a heat sensing element. They are mostly used for special hazards or in areas where fire can spread rapidly and cause large-scale damage within a short period. In an instant, the system can provide enough water to extinguish a fire in a large area.
The piping system is water free until the system is operated. The system was designed to operate this way because the piping is at atmospheric pressure and the sprinkler orifices are open. A special valve is installed to the system to prevent the water supply pressure from flooding the piping unit with water. Once triggered, the system stays open.
Since the heat sensing elements aren’t present in the sprinkler system, the deluge valve is likely going to be connected to a fire alarm system. This alarm system that will be used based on the nature of the hazard in the area (heat detectors, smoke detectors, and optical flame detectors).
The triggering device signals the fire alarm panel, which signals the deluge valve to open. The activation may be manual or automatic depending on the goal of the system. Manual activation is used through an electric pull system, which signals the fire alarm panel. This, in turn, signals the deluge valve to quickly open.
Method of operation
Activation of a fire alarm triggers the device and signals the fire alarm panel, which signals the deluge valve to open, allowing water to gush into the piping system. Water rapidly flows from all sprinklers instantaneously.
Foam water sprinkler systems
This is a special application system that is designed to discharge a mixture of low expansion foam and water, resulting in a rapid foam spray from the sprinkler head. These systems are usually used in special areas with a lot of fire hazards like airport hangers and flammable liquids warehouse. The working principle of the system as described above is dependent on the nature of the system the foam was injected into.
The working principle of the water spray is somewhat similar to that of the deluge system, but the discharge nozzle and piping are designed to protect or to address a unique hazard. The nozzles in this system are usually selected for a unique spray pattern to sync with the nature of the hazard. Common examples of hazards protected by this system are electrical transformers containing turbo-generator bearings and oil for cooling. Water spray system can also be used in areas on the surfaces of tanks containing gases and flammable liquids. Here, the water spray is intended to prevent the content of the tank from fire explosion.
Water mist systems
Water mist systems are usually used in areas where creating heat absorbent vapor is the number one objective. The system is designed to be used in areas where water supply is limited or where water damage is a serious concern. Water mist is defined as a water spray with droplets less than 1000micons at the average operating pressure of the discharge nozzle. The size of the droplet can be controlled by adjusting the discharge pressure. By creating a mist, a small volume of water will create a large surface area. The large surface area of the mist facilitates the rapid transfer of heat, allowing droplets to turn to steam quickly.
Fire sprinklers are effective fire suppression systems that can quickly put out flames before they can do serious damage. That said, before installing them, it is important that you consider the nature of the property and the likely fire hazards. Doing this will help you narrow down the right sprinkler system for your property. Let’s get into the detail of sprinkle systems, its advantages/disadvantages, false alarm, maintenance and more in this article.