If you pay attention to the world as you drive around you might notice that fire hydrants are not just red anymore. These days fire hydrants come in a few different colors. Now this is not a purely aesthetic thing. This color coding system provides useful information to the fire department. They are also set according to the National Fire Protection Agency guidelines.
The common fire hydrant colors and what they mean.
For the municipal fire hydrants the colors represent the flow rate of that hydrant.
- Red indicates a flow of less than 500 gallons per minute
- Orange indicates a flow of 500-999 gallons per minute.
- Green indicates a flow of 1000-1499 gallons per minute.
- Blue indicates a flow of 1500+ gallons per minute.
This is important to the firefighters because depending on how large the structure is that is on fire, indicates how much GPM (gallons per minute) they need.
A small two bedroom home with a small kitchen fire would be easily managed with a red fire hydrant (less than 500 GPM).
If you are interested in the math for that its relatively simple. To calculate fire flow you can use this formula.
Fire flow= (Length X Width)/3 = X
That would give you the needed GPM for a 100% involved building.
That means everything is on fire.
Commercial fire hydrants
Commercial fire hydrants, especially those used for big box stores suck as Lowes or Home Depot, tend to be on a private system so sometimes they are painted different colors based on local rules and fire codes. These can still be color coded to indicate the GPM but that isn’t always the case.
These hydrants are often times rated for a high GPM due to the large fire load(stuff that can catch fire) inside the structure.
Odd shaped and colorful fire hydrants.
Now not all fire hydrants are the same. Some are painted all sorts of colors and come in different shapes. Some times this is purely aesthetic for a private property that actually owns the fire hydrant a good example of this are often found in large theme parks.
Hydrants will also come in different shapes again most of the time on private properties. A lot of time this is to serve a purpose to better suit the structures and operations on that said property.
Take for example the fire hydrants at disney world in Florida. Normally fire hydrants have one valves with three ports. 1 large port and 2 smaller side ports. These hydrants are controlled by one valves so if all the caps are off then water comes out of every port.
This is not ideal so often fire fighters just use the large port. The ones at Disney World have 3 ports that all have their own individual valve.
Other fire department connections and hook ups
Outside of fire hydrants there are also several other connections fire departments use such as:
Fire Department Connection is the encompassing term for hooking into stand pipes or sprinkler systems. They both have FDCs on the outside of the building to hook the fire pump to.
Stand pipes are for mostly for multi story buildings and they will allow the fire truck to pump water to different levels of the building. Then inside crews can bring a hose to what ever level they need to and hook into the connection on that floor.
This is extremely useful for large building like hotels and apartments. otherwise crews would have to carry a lot of hose up stair wells or create an artificial standpipe by hoisting a larger hose line up the side of the building.
Sprinkler systems are mostly required these days in commercial buildings and apartments. These sprinklers are activated by a heat trigger. These are usually small frangible bulbs with a type of glycerin that expands at 155 degrees Fahrenheit.
This causes the glass plug to break and water to flow freely. On the outside of the building there can be an FDC that allows the fire truck to pump even more pressure and water to these sprinklers to aid in the extinguishment of the fire.
Fire cisterns are interesting and often in rural areas where hydrants are hard to come by. These are underground tanks of water with a large diameter pipe that comes above the ground.
The fire department can pull up to the pipe or discharge and use suction to pull water out of the underground tank and into the tank on the truck. This is called drafting in the fire service. The technique is also used with bodies of water suck as lakes ponds or even pools.
Lots of different hook ups
All in all there are several different ways for fire departments to obtain water to fight fire. Some more efficient than others for sure. Fortunately fire fighters are extremely aggressive when it comes to water supplies and will do most anything to get that water on the fire. Pros and Cons of being a Firefighter