Thermal Relief Designer

Thermal Pressure-Relief Design

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Designs thermal pressure-relief protection for blocked-in liquid piping at bulk terminals. Draw the tank and piping with its block points. The app finds every isolatable segment, sizes the thermal relief valves, and recommends a cascade of set pressures that relieves safely back to the tank, then writes the calculation report.

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Engineering Features

Diagram-First Design

Lay out tanks, piping runs, gate-valve block points, check valves, tees, loading arms, meters, and strainers on a live canvas — the analysis compiles directly from the drawing.

API 521 Thermal Expansion

Blocked-in liquid heat-up per API 521 §5.14.2 — solar or fire heat input drives the required relieving rate for every isolatable segment.

Cascade Set-Pressure Ladder

Auto-recommends a minimally staggered TRV set-pressure ladder that relieves safely back to the tank, with CDTP correction for conventional valves and relieving-pressure tiers per ASME Sec VIII.

Orifice Sizing & Valve Selection

API 520 Part I orifice sizing with a vendor TRV catalog (Crosby, Kunkle, Consolidated) and standard factory set-pressure checks.

Tank Types & Backpressure

Atmospheric, nitrogen-blanketed (inches WC), and pressurized tanks with dual-case analysis — static head from feet of product × specific gravity.

Piping & Flange Checks

ASME B31.3 MAWP and B16.5 flange-class limits validated for every segment; B36.10 pipe schedules with per-pipe volume and geometry.

Relief-Path Checks

Directional check-valve relief paths, reversible TRV orientation, and warnings when a relief path or valve orientation doesn't protect the segment.

Engineering Reports

A full calculation report with step-by-step equations, code references, cascade summary, and PSV data sheets — validated against independent third-party calculations.

Engineering Basis

API 521 — Pressure-Relieving and Depressuring SystemsAPI 520 Part I — Sizing and SelectionAPI 526 — Flanged Steel Pressure-Relief ValvesASME B31.3 — Process PipingASME B16.5 — Pipe FlangesASME B36.10 — Welded and Seamless PipeASME Sec VIII Div 1 UG-125

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Engineering calculations are provided for informational and planning purposes. All results should be verified by a qualified professional engineer before use in final design.