Acronyms & Units
AHJ
Authority Having Jurisdiction
AHJ stands for authority having jurisdiction — the office or official whose rules, procedures, and approvals govern operations in a given area. Real fireground decisions follow the AHJ's requirements, not a training estimate.
Standards, hose coefficients, target pressures, and procedures vary by department and locale, and the AHJ is the final word on which apply. What a training tool teaches as a general principle, the AHJ may specify differently in practice.
This glossary and the rest of this training aid are simplified estimates for learning. On real operations, follow your department's SOPs and SOGs, your apparatus manuals, your instructors, and the AHJ.