49 CFR § 173.301 & CGA TB-25 HIGH-PRESSURE TRANSPORT STANDARD

Compressed Gas Tube Trailer Spec & Cascade Manifold Manual

Operational guidelines and engineering benchmarks for seamless steel (DOT-3AA / 3AAX) and Type IV composite tube trailers transporting Hydrogen, Helium, CNG, Nitrogen, and specialty electronic gases.

01 Tube Vessel Specification & Gas Type

02 Cascade Manifold & Capacity Telemetry

Total Water Capacity
23,500 L (830 cu ft)
ASME/DOT Volume
Gas Payload (STP Volume)
145,200 SCF (3,885 Nm³)
792 lbs H₂
Max Allowable Working Pressure (MAWP)
2,400 PSIG (165.5 BAR)
Hydrostatic Re-test Pressure: 4,000 PSIG (5/3 x MAWP)
Safety Relief & Manifold Valving
Dual CG-1 Burst Disc (100% Test Pressure) w/ Fusible 212°F Backup
Air-Actuated Pneumatic Emergency Shutoff Valve (ESV) w/ Nitrogen Pilot Line
Values ground in 49 CFR § 178.37 (DOT-3AA), CGA S-1.1 PRD venting specifications, and DOT-SP Special Permits for high-pressure COPV.
01

Rear Cascade Header Architecture

Tube manifolds are segmented into High, Intermediate, and Low banks using 316 stainless steel needle valves and 10,000 PSI rated flex pigtails. Individual cylinder isolation allows selective decanting without depressurizing the entire bundle.

02

Joule-Thomson Thermal Inversion

Unlike common industrial gases that cool during expansion, Hydrogen exhibits a reverse Joule-Thomson effect above its inversion temperature (-90°F), heating during high-pressure blowdown. Manifold sensors enforce automatic flow throttling if discharge exceeds 150°F.

03

Pneumatic Fail-Safe ESV Interlock

The main discharge manifold integrates spring-return air-actuated Emergency Shutoff Valves. Emergency pull cables, melting thermal plugs (165°F), and truck brake interlocks vent the pilot air to slam the valves closed in under 500 milliseconds.

Automate High-Pressure Tube Trailer Dispatch & Hydro Tracking

Exspeedite TMS tracks individual cylinder serial numbers, 5-year acoustic emission/ultrasonic test dates, manifold valve maintenance cycles, and automated customer decant billing by SCF or kilograms.