• Familiarization with key terms associated with anhydrous ammonia and hydrogen can help employers and employees avoid associated hazards.

It is important to recognize and be familiar with key terms and definitions related to anhydrous ammonia and hydrogen so that potential hazards are understandable and clear.

Anhydrous Ammonia

• Appurtenances: All devices such as pumps, compressors, safety relief devices, liquid-level gaging devices, valves, and pressure gages.
• Cylinder: A container of 1,000 pounds of water capacity or less constructed in accordance with Department of Transportation (DOT) specifications.
• Code: The Boiler and Pressure Vessel Code, Section VIII, Unfired Pressure Vessels of the American Society of Mechanical Engineers (ASME) - 1968.
• Container: Includes all vessels, tanks, cylinders, or spheres used for transportation, storage, or application of anhydrous ammonia.
• DOT: U.S. Department of Transportation. 1910.111(a)(2)(vi).
• Design pressure: Identical to the term “Maximum Allowable Working Pressure” used in the Code.
• Farm vehicle (implement of husbandry): A vehicle for use on a farm that has a mounted container of not over 1,200 gallons water capacity.
• Filling density: The percent ratio of the weight of the gas in a container to the weight of water at 60 °F that the container will hold.
• Gas: Anhydrous ammonia in either the gaseous or liquefied state.
• Gas masks: Gas masks must be approved by the National Institute for Occupational Safety and Health (NIOSH) under 42 CFR part 84 for use with anhydrous ammonia.
• Capacity: Total volume of the container in standard U.S. gallons.
• DOT specifications: Regulations of the Department of Transportation published in 49 CFR Chapter I.
• Threshold quantity for Process Safety Management: 10,000 pounds in a process, as listed in 1910.119 Appendix A.

Hydrogen

• Gaseous hydrogen system: A system in which the hydrogen is delivered, stored, and discharged in the gaseous form to consumer’s piping. The system includes stationary or movable containers, pressure regulators, safety relief devices, manifolds, interconnecting piping, and controls. The system terminates at the point where hydrogen at service pressure first enters the consumer’s distribution piping
• Approved: Unless otherwise indicated, listed or approved by a nationally recognized testing laboratory. Refer to 1910.7 for definition of nationally recognized testing laboratory. ·
• Listed: See “approved”.
• ASME: American Society of Mechanical Engineers.
• DOT Specifications: Regulations of the Department of Transportation (DOT) published in 49 CFR Chapter I.