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Class Location & HCA Determination Calculator

PIR, Class Location, HCA/MCA per 49 CFR Part 192 / 195

Compute pipeline class location, PIR, HCA/MCA status, and IMP triggers. Implements the 49 CFR Part 192 (gas) and 195 (HVL/liquid) procedures including the 2019 Mega Rule MCA definition.

Pipeline Data

in
in
psig
mi
Sliding-mile length

Site Survey (sliding mile)

Intended for human occupancy
Class 4 trigger if prevalent
Schools, hospitals, prisons, etc.
Within 100 yards of pipeline

Liquid Pipeline (Part 195)

Used only when product is HVL or Crude.

bbl

Key Equations & Rules

Potential Impact Radius (192.903):

PIR (ft) = 0.69 · √( P · D2 )

0.69 for natural gas, 0.95 for HVL.

Class Location (192.5):

Class 1≤ 10 buildings
Class 211 – 45 buildings
Class 3≥ 46 OR ≥ 20-person assembly w/in 100 yds
Class 44+ story buildings prevalent

Design Factor F (192.111):

Class 1 = 0.72 | Class 2 = 0.60 | Class 3 = 0.50 | Class 4 = 0.40

MAOP (Barlow):

MAOP = 2 · SMYS · t · F · E · T / D

E=1.0 seamless/ERW post-1970; T=1.0 ≤ 250°F.

Frequently Asked Questions

How is pipeline class location determined?

Per 49 CFR 192.5: count buildings within ¼ mile of either side of a continuous 1-mile pipeline section (sliding mile). Class 1: ≤ 10; Class 2: 11–45; Class 3: ≥ 46 or 20-person assembly within 100 yards; Class 4: 4+ story buildings prevalent.

What is the PIR?

Potential Impact Radius (49 CFR 192.903): the distance from a rupture where 99% mortality probability would result. PIR = 0.69·√(P·D²) for methane; 0.95 for HVL. P in psig, D in inches; PIR in feet.

Does a class location change require action?

Yes — 49 CFR 192.611 requires the operator to confirm or reduce MAOP within 24 months when growth shifts the segment to a higher class.