Which option describes the nominal K factor for specific sprinkler types?

Which option describes the nominal K factor for specific sprinkler types?

• A. K-factor
• B. NFPA 251
• C. Nominal K-5.6
• D. Special sprinklers

Answer: (C)

The main idea here is that the nominal K factor is a standardized value used to characterize how some sprinkler types perform, making design calculations simpler. For many common sprinkler types, the published nominal value is 5.6, so we refer to the nominal K factor as K-5.6. This represents the flow-requirement relationship used in design equations (Q = K × √P) without needing the exact, variable K for every head. The other terms don’t describe this standardized rating: K-factor is the actual coefficient for a specific head, NFPA 251 is a test standard not about K factors, and “special sprinklers” is a category, not a numeric K value.

The main idea here is that the nominal K factor is a standardized value used to characterize how some sprinkler types perform, making design calculations simpler. For many common sprinkler types, the published nominal value is 5.6, so we refer to the nominal K factor as K-5.6. This represents the flow-requirement relationship used in design equations (Q = K × √P) without needing the exact, variable K for every head. The other terms don’t describe this standardized rating: K-factor is the actual coefficient for a specific head, NFPA 251 is a test standard not about K factors, and “special sprinklers” is a category, not a numeric K value.