Occupational Exposure Values - Compiled by ACGIH
(shown for reference only - verify latest values)
The chemical formula of hydrofluoric acid is HF. Its molar mass is 20.01 g/mol. Hydrogen fluoride is the gaseous form, while hydrofluoric acid is the solution of HF in water. Hydrogen fluoride is a colorless gas with a density of 1.15 g/L at room temperature, or a colorless liquid (below 20°C) with a density of 0.99 g/mL. Hydrofluoric acid (solution of HF in water), is a colorless solution. Its exact physical properties (boiling point, melting point and density) depend on the concentration of HF in the aqueous solution. Hydrofluoric acid is widely used in the preparation of many useful fluorine compounds, such as Teflon (PTFE plastic), Freon (refrigerant), fluorocarbons, and many pharmaceuticals. It is also used for many industrial purposes including Oil Refinery Alkylation processes. Since crude oil generally contains only 10 to 40 percent of hydrocarbon constituents in the gasoline range, refineries typically use a fluid catalytic cracking unit (FCCU) process to convert high molecular weight hydrocarbons into smaller and more volatile compounds, which are then converted into liquid gasoline-size hydrocarbons. Alkylation processes transform low molecular-weight alkenes and iso-paraffin molecules into larger iso-paraffins with a high octane number.
ACGIH Values - Hydrogen Fluoride | HF
Threshold limit value (TLV): 0.5 ppm, 0.41 mg/m3 TWA; 2 ppm, 1.64 mg/m3 Ceiling
OSHA PELs - Hydrogen Fluoride | HF
Permissible Exposure Limits: 3ppm TWA
NIOSH RELs - Hydrogen Fluoride | HF
Recommended Exposure Limit (REL): 3 ppm, 2.5 mg/m3 TWA; 6 ppm, 5 mg/m3 Ceiling
Hydrogen fluoride is used in the production of aluminum and chlorofluorocarbons, and in the glass etching and chemical industries.
Hydrogen fluoride serves as a catalyst in alkylation processes in oil refineries. A component of high-octane petrol (gasoline) called "alkylate" is generated in alkylation units that combine C3 and C4 olefins and iso-butane to generate petrol (gasoline).
Hydrogen fluoride is used primarily as a precursor or reactant for making other commercially important chemicals. For example, hydrogen fluoride is often used to produce aluminum. It is also used in the separation of uranium isotopes, which are radioactive versions of the uranium element. HF can be used to produce stainless steel and in the production of petroleum (oil) products. Finally, while not as common as other compounds, hydrogen fluoride may be added to water to provide fluoride ions in municipal water supplies.
Hydrogen fluoride is a highly dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture. Acute (short-term) inhalation exposure to gaseous hydrogen fluoride can cause severe respiratory damage, including severe irritation and pulmonary edema. Severe irritation and burns may occur following eye or skin exposure.
Hydrogen fluoride is highly toxic and proper safeguards, including gas monitoring, are deemed critical to industrial health and safety programs.
Oil Refining Process