{"data":{"id":"us/42-cfr-37.91","jurisdiction":"us","citation":"42 CFR 37.91","heading":"Definitions.","body":"Definitions provided in § 37.2 will have the same meaning in this subpart. Any term defined in the Federal Mine Safety and Health Act of 1977 (Pub. L. 95-164, as amended) and not defined in § 37.2 or this section will have the meaning given it in the Act. As used in this subpart:\nATS means American Thoracic Society.\nERS means European Respiratory Society.\nFET means forced expiratory time, which is the time from the beginning of a forced exhalation (the back-extrapolated “time zero”) maneuver to the end of expiration.\nFEV1 means forced expiratory volume in one second, which is the greatest volume of air that can be forcibly blown out within the first second, after full inspiration.\nFEV1/FVC means the ratio between the largest acceptable FEV1 and the largest acceptable FVC following the forced vital capacity maneuver. It is usually reported as a percentage.\nFEV6 means forced expiratory volume in six seconds, which is the greatest volume of air that can forcibly be blown out in six seconds, after full inspiration.\nFVC means forced vital capacity, which is the greatest volume of air that can forcibly be blown out after full inspiration.\nPEF means peak expiratory flow, which is the maximal airflow generated during a forced vital capacity maneuver.\nSpirometry test means a pulmonary function test that measures expiratory volume and airflow rates and may determine the presence and severity of lung function impairments, if such are present.","path":["Title 42—Public Health","CHAPTER I—PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER C—MEDICAL CARE AND EXAMINATIONS","PART 37—SPECIFICATIONS FOR MEDICAL EXAMINATIONS OF COAL MINERS","Subpart—Spirometry Testing"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-42.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:11Z","sha256":"087d22ed88a2c196ddabad396b5f1d781894b32970f8422bb81ec29a4313c541","source_id":"us-cfr","stale":true,"prev":"us/42-cfr-37.90","next":"us/42-cfr-37.92"},"notice":"GroundRules: Original legal text. Not legal advice."}