A Test Chamber for Experimental Hydrogen Fluoride Exposure in Humans

• Published in: American Industrial Hygiene Association journal 1997-07, Vol.58 (7), p.521-525
• Main Authors: S⊘strand, Per, Kongerud, Johny, Eduard, Wijnand, Nilsen, Terje, Skogland, Margareth, Boe, Jacob
• Format: Article
• Language: English
• Subjects: Air Pollutants; Air pollution; Aluminum; Aluminum industry; Applied sciences; Asthma; Atmosphere Exposure Chambers; Atmospheric pollution; Environmental Exposure; Equipment Design; Exact sciences and technology; Fluorides; Gas flow; Gases; homogeneity; Humans; Hydrofluoric Acid; Hydrogen; hydrogen fluoride; Indoor pollution and occupational exposure; Industrial gases; inhalation chamber; Materials Testing; Occupational safety; Pollutants; Pollution; Sensors; stability; Studies
• ISSN: 0002-8894; 2163-369X
• DOI: 10.1080/00028894.1997.10399308

An inhalation chamber was built to perform experimental studies with hydrogen fluoride (HF), other gases, and particulate matter. The present study sought to describe a new gas delivery system and the distribution and concentration of HF gas in the chamber. The aluminum chamber has a volume of 19.2 m 3 and a variable ventilation rate of about 1 to 10 air changes per hour. The negative pressure difference between the chamber and outside air can be regulated from 0 to 300 Pa. HF was fed at concentrations of up to 4000 mg/m 3 directly into the ventilation duct feeding the chamber through openings with diameters as small as 50 μm, oriented opposite to the airflow. Gas flow was varied from about 0.1 dm 3 /min at a pressure of 4 atm. The dilution factor of HF concentration from cylinder to chamber was on the order of 10 3 to 10 4 . The standard deviation (SD) of the HF concentrations at a fixed measurement point during a 1-hour test was typically 0.05 mg/m 3 at a time-weighted average (TWA) concentration of 2.66 mg/m 3 . The SD of the TWA HF concentrations at six locations in the chamber was typically 0.05 mg/m 3 and 0.29 mg/m 3 at 0.61 and 3.46 mg/m 3 , respectively. Human exposure could be predicted from calculations based on ventilation data, gas flow, and observed ratio between calculated and measured concentrations. When the target exposure concentration was 1.5 mg/m 3 , the measured mean exposure concentration was typically 1.54 mg/m 3 (range: 1.4-1.7 mg/m 3 , SD 0.09 mg/m 3 , n=8). The chamber is well-suited for inhalation studies in humans. Chamber atmosphere was controlled and has proved to be stable and homogeneous, even in tests with HF, a highly reactive gas in the class of superacids.