High Temperature, or Both. The test uses a cylindrical tensile specimen tested into an enclosure pressurized with hydrogen or helium. ASTM F1624 is the Standard Test Method for Measurement of Hydrogen Embrittlement Threshold in Steel by the Incremental Step Loading Technique. The test uses the incremental step loading (ISL) or Rising step load testing (RSL) method for quantitatively testing for the Hydrogen Embrittlement threshold stress for the onset of Hydrogen-Induced Cracking due to platings and coatings from Internal Hydrogen Embrittlement (IHE) and Environmental Hydrogen Embrittlement (EHE). F1624 provides a rapid, quantitative measure of the effects of hydrogen both from internal sources and external sources (which is accomplished by applying a selected voltage in an electrochemical cell). The F1624 test is performed by comparing a standard fast-fracture tensile strength to the fracture strength from a Rising step load testing practice where the load is held for hour(s) at each step. In many cases it can be performed in 30 hours or less. ASTM F1940 is the Standard Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners. While the title now explicitly includes the word fasteners, F1940 was not originally intended for these purposes. F1940 is based on the F1624 method and is similar to F519 but with different root radius and stress concentration factors. When specimens exhibit a threshold cracking of 75% of the net fracture strength, the plating bath is considered to be 'non-embrittling'. There are many other related standards for hydrogen embrittlement: NACE TM0284-2003 (NACE International) Resistance to Hydrogen-Induced Cracking ISO 11114-4:2005 (ISO)Test methods for selecting metallic materials resistant to hydrogen embrittlement. Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments Notable failures from hydrogen embrittlement In 2013, six months prior to opening, the East Span of the Oakland Bay Bridge failed during testing. Catastrophic failures occurred in shear bolts in the span, after only two weeks of service, with the failure attributed to embrittlement (see details above). In the City of London, 122 Leadenhall Street, generally known as 'the Cheesegrater', suffered from hydrogen embrittlement in steel bolts, with three bolts failing in 2014 and 2015. Most of the 3,000 bolts were replaced at a cost of £6m. See also Hydrogen analyzer Hydrogen damage Hydrogen piping Hydrogen safety Low hydrogen annealing Nascent hydrogen Oxygen-free copper Stress corrosion cracking References External links Resources on hydrogen embrittlement, Cambridge University Hydrogen