What Is the Minimum Pressure for a Fire Sprinkler System in Atlanta?

If you're installing a new fire sprinkler system, it'll need to have enough pressure to be effective. But what is the minimum pressure for a fire sprinkler system? As one of the most trusted Atlanta fire sprinkler companies, Cliff's Fire Extinguisher Company can help you understand the right pressure for your fire sprinkler system and how to test it.

The Importance of Proper Water Pressure

You might think that your sprinkler system can extinguish almost any fire, provided it has enough water. However, the amount of water is only half the equation.

Your sprinklers rely on flow rate and water pressure to put out fires. Adequate water pressure ensures the water can reach the fire and penetrate the base enough to extinguish the flame at its source, preventing it from spreading.

According to Fire Fighter Nation, fire travels from areas of high pressure to areas of lower pressure. When fire sprinkler systems use high-pressure water, it helps direct the fire out of the building (a lower-pressure location) rather than spreading throughout the interior. This makes it much easier for firefighters and emergency responders to extinguish the flames.

Measuring Sprinkler Pressure

While many people use pounds-per-square-inch as the standard unit for measuring water pressure, many fire experts convert the measurement into bars for more easily readable measurements. One bar equals 14.5 psi.

To measure the amount of pressure in your sprinkler system, your technician will perform a flow test. The National Fire Protection Association mandates annual flow tests to confirm your sprinkler system can extinguish a fire. To perform the test, the technician uses the following steps:

1. Connect the fire pump to the test header using a hose stream
2. Measure the amount and rate of water flowing through the hose to determine the pressure
3. Compare the results with factory specifications and results from previous years
4. Schedule another examination or repairs if the water pressure's too low

Factors Affecting Minimum Water Pressure Requirements

For a four-bedroom house with a residential sprinkler system, you'll find a standard water pressure of around 2.5 bar at the water source. However, several factors determine the minimum required pressure for your residential sprinkler system.

Local Ordinance

What is the minimum pressure for a fire sprinkler system? The Georgia State Amendments to the International Residential Fire Code require a minimum pressure of .5 bar at each sprinkler head for one- and two-family residential buildings. This corresponds with the standards set by the NFPA. 

However, other states or municipalities may require higher minimum pressure amounts, so always check your local ordinance when establishing the absolute minimums for sprinkler system pressure.

Depending on other factors, .5 bar might not provide adequate pressure for your sprinkler system. Also remember, since this law only requires you to measure the pressure at the sprinkler head, you'll need a higher pressure where the water enters your home from the main city line, since the longer the water travels, the more pressure it loses.

Size of System

If you're attempting to determine the right pressure where your water enters your home, consider the size of your system. The more sprinkler heads you have, the more you divide your overall pressure.

For example, imagine you have five sprinkler heads in your home, each of which needs a half bar of pressure. Assuming you don't lose pressure elsewhere in the system, you'll need a total system pressure of 2.5 bar (.5 pressure at each head x 5 total heads).

Distance From Water Supply

As water travels through pipes, it rubs against it, creating friction and losing pressure. The faster the water travels, the more friction loss it experiences. This effect multiplies over a greater distance.

The further away each sprinkler head is from the water supply, the greater the minimum pressure you'll need at the source to maintain that required half bar of pressure.

Pipe Diameter and Construction

Your pipe size affects your system's friction loss. The smaller the pipe's diameter, the more friction loss per foot your water experiences. 

The material of your pipe also affects the friction loss. The rougher the material, the more friction it creates. In general, pipes also become rougher as they age.

Let Cliff's Fire Extinguisher Company Manage Your Fire Sprinkler System in Atlanta

What is the minimum pressure for a fire sprinkler system? You need at least a half bar at each sprinkler head, but much greater pressure at the beginning of your system. Cliff's Fire Extinguisher Company can help you determine the correct minimum pressure and teach you ways to prevent electrical fires.

To speak with one of their experts or book an appointment, contact them today.