High-Pressure & Thermal Shock Standard

Double-Pipe & Hairpin Exchangers NDT Guide

Authoritative engineering reference for concentric tube-in-tube and multi-hairpin heat exchangers. Inspect high-pressure differential U-bends, longitudinal finned inner tubes, and return bend girth welds.

Hairpin DesignASME B31.3
True Counter-Current Flow

Ideal for extreme temperature crossovers and high operating pressures where shell-and-tube thermal expansion would cause severe tubesheet stress.

Zero-Commission B2B Platform

How B2B Project Workflow Works

From initial RFP scope to direct client sign-off. NDT EXCHANGE does not charge commissions or manage project payments.

01

RFP Scope

Asset Owner Scope

Asset Owner posts turnkey B2B inspection scope with technical specifications, asset list, and required NDT methods.

02

Competitive Bids

Agency Proposals

Certified NDT agencies submit competitive proposals (Fixed-Bid / T&M) detailing technician rosters and day rates.

03

Direct Settlement / Escrow

Payment Security

Client awards bid and sets up direct milestone payment or escrow — NDT EXCHANGE never holds or manages project funds.

04

Field Execution

Testing & Calibration

Level II/III inspectors perform on-site testing (PAUT, TOFD, MFL, UT), capturing flaw data and calibration overlays.

05

Sign-Off & Payout

Audit & Settlement

Level III auditor reviews findings; upon client sign-off, funds release directly to agency with 0% platform commission.

Project Data Flow:1. RFP Scope2. Agency Bids3. Direct Settlement4. Field Execution5. Direct Sign-Off
💡 Payment Policy: NDT EXCHANGE charges 0% fees and never holds or handles project funds.