Hydrogen Connection Guidelines - Thermo Scientific TSQ 9610 Hardware Manual

Hydrogen Connection Guidelines

Thermo Scientific
Before powering on the TSQ 9610 system, ensure that:
• All the covers and panels of the TSQ 9610 system are firmly attached.
• The vent valve is tightly closed if you vented the system.
• All fittings, ferrules, and o-rings are sealed.
Use the following guidelines to safely connect hydrogen to your system:
• Piping—Hydrogen must be delivered to equipment using appropriate piping and be
done in such a way as to pose essentially no hazard to end-users. Piping systems for the
delivery of hydrogen should be designed and installed by a person qualified by specific
training and experience with hydrogen piping systems.
Stainless steel is usually recommended because it is a safe, cost-effective material. Piping
of black iron or copper must not be used, as the pipe can become brittle with age.
Elastomeric/plastic tubing of various plastics and polymers should not be used, unless the
tubing is approved for use with hydrogen. If elastomeric/plastic tubing is used for
hydrogen gas delivery, the tubing should be tested for hydrogen permeability to minimize
leakage.
The hydrogen piping system must be flexible enough to endure routine thermal
expansion and contraction. The system should also include considerations for the most
severe condition of temperature and pressure expected during service. Piping and
supports must be able to withstand static loading introduced by such things as ice and
snow; and dynamic loading from high wind and earthquake.
Caution should be used if burying hydrogen piping. Proper controls should be used to
protect against damage and corrosion, and also to prevent Hydrogen from entering a
building if there is any leakage.
• Fittings—All fittings must be of the proper type approved or designed for use with
hydrogen gas. Use as few fittings as possible to minimize the potential for leaks. After
installation, ensure that leak testing is carried out prior to system use, and on a regular
basis.
There must be no PTFE tape or other things like plumber's putty used to enhance a seal, as
this actually is a detriment to a good seal. Ideally the best installation would use stainless
steel tubing with appropriate gas-tight fittings.
Welding is usually preferred for joints in hydrogen piping systems since welding provides
a better connection and reduces the potential for leaks compared to mechanical fittings.
Soft solder joints are not permitted for hydrogen systems (due to the low melting point of
soft solder and its potential for brittle failure at cryogenic temperatures). Brazed joints are
permitted, but such joints should be protected against the possibility of external fire.
Preface
Hydrogen Safety Precautions
TSQ 9610 Hardware Manual xxiii