The Panel recommends performing a pressure test at 110% of design pressure. This requirement should be applied to all systems regardless of construction type since the intent is to ensure pressure integrity and proper installation. All fitting types have modes of failure during installation. For example, there are numerous examples where compression fittings have had ferrules installed incorrectly, tubing improperly inserted, and have been inadequately tightened. In addition, leak checking and pressure testing should always be done in accordance with the locally adopted piping code.  Examples include ASME B31.3 and the Pressure Equipment Directive. 

 
System pressure relief devices will usually need to be removed for the test and temporarily replaced with higher setpoint devices to protect the system during the pressure test. Also, consider a proportional acting relief device.  Piping systems do not require a pop-acting ASME relief valve that are used for pressure vessels since piping system relief devices are more likely to chatter. Chatter can lead to lower than intended flow rate and damage or failure of the valve to operate correctly.   
For high-pressure systems, pneumatic testing is almost exclusively done given the challenge of removing water from a hydro test from the system after the test. Although one might question the wisdom of pneumatically testing at such high pressures, precautions can be taken to ensure a safe test, such as requiring an exclusion zone during the testing.   
 

It varies slightly due to different density of LH2 at different temperatures, but a gallon of LH2 at atmospheric pressure (0 psig) is ~113 SCF of H2. The expansion ratio is about 840:1. In metric units, a liter of LH2 at atmospheric pressure (0 MPa) would expand to about 840 liters of STP of gaseous pressure.

This can be a complex problem and response to insulation failure should be considered in the emergency response guidelines and procedures. 
First, a tank with an insulation failure may boil off at an elevated rate which applicable codes build into the relief device and vent system design.
Second, ice and oxygen enriched liquefied air can form where inadequately insulated surfaces are exposed to air. Ice is the most likely symptom of insulation failure, and this can lead to various issues such as higher probability of seal leaks, additional weight loads on piping, and frost heaving of the foundation. Loss of vacuum insulation rarely leads to creation of liquified air, but as a precaution, any material that could be exposed to liquid air must be compatible for both oxygen and cryogenic hazards. For example, flammable materials such as asphalt are not permitted below LH2 systems.