GJB 71A-2019 in English

Standard Revision Background and Technology Evolution

GJB 71A-2019, as the third-generation version of the military liquid hydrogen standard, reflects the 34-year development of my country's aerospace propellant technology. Compared with the 1985 version, the standard name clearly defines the special scene of liquid rocket engine, the technical indicators have added helium content control (≤30×10^-6), and the detection methods have added three modern analysis technologies such as electrochemical oxygen measurement.

Comparative analysis of core indicators

Innovation in detection methods

Implementation suggestions

1. Sampling specifications: Sampling should be done at the filling and venting ports after the liquid hydrogen has stabilized for 24 hours, in compliance with the safety requirements of GB/T 3723
2. Instrument configuration: The chromatograph should be equipped with a 13X/5A molecular sieve column, and the thermal conductivity detector sensitivity should be ≤30×10^-5
3. Data rounding: According to GB/T 8170, the deviation of parallel determination should be ≤10%

Standard application scenarios

This specification is applicable to the production of hydrogen-oxygen engine fuel for new generation launch vehicles such as the Long March 5, and special provisions are made that storage and transportation must comply with the safety standards of GJB 2645 and GJB 5405.