Your best source for complete information on the NFPA 70E Standard is via the actual standard, available for purchase at www.nfpa.org. In 2000, the NFPA 70E Standard first addressed electric arc flash hazard and required flame resistant arc flash clothing to protect workers. The current edition of the NFPA 70E standard was released in 2012, and further details personal protective equipment.
Fluoride ions exist predominantly as hydrofluoric acid in acidic environments with a pH below 5.2. Fluoride ions corrode the glass. Therefore, the pH measurement with the glass electrode for a solution which includes fluoride ions is basically impossible. Although the useful life of the electrode may be shortened, however, the measurement with immersing the electrode in the sample for a given short time is possible.
PH is the abbreviation for potential hydrogen. The pH of any solution is the measure of its hydrogen-ion concentration. The higher the concentration (pH reading), the more alkaline and oxygen rich the fluid is. The lower the concentration of hydrogen ions, the more acidic and oxygen deprived the fluid is. Complete healing of chronic illness can only take place when tissue is restored to a slightly alkaline pH. Tissue pH is reflected externally through urine and saliva. The pH range is from 0 to 14, with 7.0 being neutral.