Sprinkler K-Factors

Sprinkler k-factors are a measure that determines the water distribution performance of a sprinkler system. The k-factor indicates how much water a sprinkler head can discharge at a given water pressure. Below is a list of commonly used sprinkler k-factor values and an explanation of what they signify:

Common Sprinkler K-Factor Values:

1. K2.8 (40):

• Suitable for small areas and low hazard classifications.

• Provides small volume water distribution.

• Usage: Residential buildings, offices, small commercial areas.

1. K4.2 (60):

• Suitable for low to moderate hazard classifications.

• Provides medium volume water distribution.

• Usage: Offices, schools, small warehouses.

1. K5.6 (80):

• The most commonly used k-factor value.

• Suitable for ordinary hazard classifications.

• Preferred for general-purpose use.

• Usage: Offices, commercial buildings, warehouses.

1. K8.0 (115):

• Suitable for moderate to high hazard classifications.

• Provides larger volume water distribution.

• Usage: Industrial facilities, large warehouses, shopping centers.

1. K11.2 (160):

• Suitable for high hazard classifications.

• Provides very large volume water distribution.

• Usage: Warehouses, high hazard industrial facilities.

1. K14.0 (200) and Above:

• Suitable for very high hazard classifications.

• Offers maximum water distribution capacity.

• Usage: Very high hazard industrial facilities, large warehouses, rack storage systems.

K-Factor Calculation:

The k-factor is used to calculate the flow rate and pressure of the sprinkler head. The formula is as follows:

• Q: Flow rate (GPM or L/min)

• K: K-factor

• P: Pressure (psi or bar)

This formula determines how much water will be discharged from the sprinkler head at a given pressure. Selecting the correct k-factor in sprinkler system design is critical for optimizing fire safety performance.

Application Notes:

• The k-factor value should be selected based on the design criteria of the system, the hazard classification of the area to be protected, and the capacity of the water supply.

• Any sprinkler system design should comply with local fire safety standards (e.g., NFPA 13) and regulations.

Careful consideration should be given when selecting the k-factor, and assistance from a fire safety engineer or expert should be sought if necessary.

Below is a selection table for appropriate sprinkler k-factors based on hazard classification and ceiling height according to the NFPA 13 standard. This table shows the recommended k-factors for different hazard classifications and ceiling heights:

Sprinkler K-Factor Selection Table According to NFPA 13

Hazard Classification	Ceiling Height	K-Factor
Low Hazard	0 - 9.1 m (0 - 30 ft)	K5.6 (80)
	9.1 - 12.2 m (30 - 40 ft)	K8.0 (115)
	12.2 m (40 ft) and above	K11.2 (160)
Ordinary Hazard 1	0 - 9.1 m (0 - 30 ft)	K5.6 (80)
	9.1 - 12.2 m (30 - 40 ft)	K8.0 (115)
	12.2 m (40 ft) and above	K11.2 (160)
Ordinary Hazard 2	0 - 9.1 m (0 - 30 ft)	K5.6 (80)
	9.1 - 12.2 m (30 - 40 ft)	K8.0 (115)
	12.2 m (40 ft) and above	K11.2 (160)
Extra Hazard 1	0 - 9.1 m (0 - 30 ft)	K8.0 (115)
	9.1 - 12.2 m (30 - 40 ft)	K11.2 (160)
	12.2 m (40 ft) and above	K14.0 (200)
Extra Hazard 2	0 - 9.1 m (0 - 30 ft)	K11.2 (160)
	9.1 - 12.2 m (30 - 40 ft)	K14.0 (200)
	12.2 m (40 ft) and above	K16.8 (240)

Explanations:

1. Low Hazard:

• Areas with low fire risk, such as offices, schools, and residences.

• Small volume water flow is sufficient.

1. Ordinary Hazard 1 and 2:

• Areas with moderate fire risk, such as stores, restaurants, and hotels.

• Requires medium volume water flow.

1. Extra Hazard 1 and 2:

• Areas with high fire risk, such as industrial facilities, warehouses, and chemical plants.

• Requires high volume water flow.

1. Ceiling Height:

• As the ceiling height increases, sprinkler heads with higher k-factors should be selected. This ensures that the water reaches the fire area effectively.

1. NFPA 13 Standard:

• This table is based on the general guidelines of the NFPA 13 standard. For specific applications, local fire safety regulations and standards should be consulted.

By using this table, you can select the appropriate k-factor sprinkler heads according to the hazard classification and ceiling height. It is always recommended to consult an expert in fire safety design and comply with local regulations.