SCBA cylinders service life extension

I first read about this at GTA forum.

https://www.iafc.org/blogs/blog/iafc/2017/04/25/service-life-extension-of-scba-cylinders-to-pay-off-for-local-fire-departments

More details here:

https://www.phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/Special_Permit_16320.pdf