title: A test chamber for experimental hydrogen fluoride exposure in humans.
abstract: 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 m3 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/m3 directly into the ventilation duct feeding the chamber through openings with diameters as small as 50 microns, oriented opposite to the airflow. Gas flow was varied from about 0.1 dm3/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/m3 at a time-weighted average (TWA) concentration of 2.66 mg/m3. The SD of the TWA HF concentrations at six locations in the chamber was typically 0.05 mg/m3 and 0.29 mg/m3 at 0.61 and 3.46 mg/m3, 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/m3, the measured mean exposure concentration was typically 1.54 mg/m3 (range: 1.4-1.7 mg/m3, SD 0.09 mg/m3, 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.
authors.affiliation: National Institute of Occupational Health, Norway.
authors.forename: P
authors.initials: P
authors.lastname: Søstrand
authors.forename: J
authors.initials: J
authors.lastname: Kongerud
authors.forename: W
authors.initials: W
authors.lastname: Eduard
authors.forename: T
authors.initials: T
authors.lastname: Nilsen
authors.forename: M
authors.initials: M
authors.lastname: Skogland
authors.forename: J
authors.initials: J
authors.lastname: Boe
mesh_terms: D000393:Air Pollutants; D001273:Atmosphere Exposure Chambers; D004781:Environmental Exposure; D004867:Equipment Design; D006801:Humans; D006858:Hydrofluoric Acid; D008422:Materials Testing
chemical_list: D000393:Air Pollutants; D006858:Hydrofluoric Acid