Gas transmission · High Consequence Area · 49 CFR 192.903
High Consequence Area (HCA) Determination
Screens whether a gas transmission segment is an HCA under 49 CFR 192.903 using Method (1) or Method (2), and reports the Potential Impact Radius (PIR) and Potential Impact Circle (PIC). Building counts and identified-site flags are operator field-survey inputs.
Screening only. Final HCA designation must come from the operator’s documented, continuously-updated class-location and HCA identification process per Subpart O. This tool screens a single Potential Impact Circle and does not draw the axial HCA boundary across contiguous circles.
Pipe & Pressure
in
psig
—
HCA Method & Survey
count
Engineering Basis
PIR (ft) = 0.69 · √(p · d²) = 0.69 · d · √p; p = MAOP (psig), d = OD (in). 0.69 is the natural-gas factor (49 CFR 192.903).
Method (1): Class 3 or 4 ⇒ HCA; Class 1/2 ⇒ HCA if the PIC contains an identified site, or PIR > 660 ft with ≥20 occupied buildings.
Method (2): PIC contains ≥20 occupied buildings or an identified site (class-independent).
Identified site = outside area (≥20 persons, ≥50 days/yr), building (≥20 persons, ≥5 days/wk × 10 wk), or confined/mobility-impaired facility.