NFPA 326 Standard for the Safeguarding of Tanks and Containers for Entry, Cleaning, or Repair, 2005 ed. https://www.nfpa.org/assets/files/AboutTheCodes/32 6/326-F2009-ROC.pdf, (Std: Safeguarding of Tnk and Cont for Entry, Cleaning, or Repr - Amer) {298 NFC}