NACE Materials that are not suitable for hydrogen service

[Sullivan4874]

I'm finding conflicting information when it comes to the suitability of some NACE MR0175 materials in hydrogen service. My specific application is hydrogen blended with natural gas. Pressures range from less than 1 psi to 1500 psi. Temperatures can be from -20F to 120F. Hydrogen concentration can be from 5% to 100%. For these conditions, are there materials that meet NACE requirements but are not be suitable for hydrogen service?

Thanks!