TL;DR
K-factor is the discharge coefficient of a fire sprinkler, relating water flow to the square root of pressure in the formula Q equals K times the square root of P, so a head's flow at any pressure can be calculated directly. Standard residential and light-hazard heads run K-5.6, while storage occupancies use K-11.2 and larger to move volume at lower pressures.
What it means
K-factor is the discharge coefficient of a fire sprinkler, relating water flow to the square root of pressure in the formula Q equals K times the square root of P, so a head's flow at any pressure can be calculated directly. Standard residential and light-hazard heads run K-5.6, while storage occupancies use K-11.2 and larger to move volume at lower pressures. Designers select it during hydraulic calculations, and replacing a head with the wrong coefficient quietly unbalances the calculated protection, which is why the value is stamped on the deflector.
Where it sits in the glossary
K-factor is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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