3.1.13

1. 3.1.13 Identifying Procedures for Converting ASME Tanks in Ammonia Service to Propane Service Storage, cargo, and nurse tanks used in anhydrous ammonia service must not be used to store or transport propane until they have been properly converted to propane service. Ammonia contamination is a serious hazard to employees and customers. • In this training module you will identify: • Physical properties, hazards and characteristics of ammonia • Procedures for converting anhydrous nurse tanks to propane service

2. Physical Properties, Hazards & Characteristics of Anhydrous Ammonia • Anhydrous ammonia (NH3)is a hazardous material with the following physical properties: • At room temperature and atmospheric pressure, anhydrous ammonia is a pungent, colorless gas, approximately 40% lighter than air. • Compressed and cooled, it is a colorless liquid about 68% as heavy as water. • Its boiling point at atmospheric pressure is -28°F.

3. Physical Properties, Hazards & Characteristics of Anhydrous Ammonia • Anhydrous ammonia (NH3)is a hazardous material with the following physical properties: • Anhydrous ammonia in closed, pressurized containers behaves similarly to propane. • Anhydrous ammonia is an inhalation hazard; at a concentration of more than 5000 parts per million, it will disable a person and suffocation results. Exposure to body tissue is harmful, resulting in caustic burns. Exposure to liquid ammonia results in frostbite. Eye exposure in concentration causes blindness.

4. Physical Properties, Hazards & Characteristics of Anhydrous Ammonia Figure 1. Pressure Gauge and Valve on Anhydrous Ammonia Nurse Tank

5. Physical Properties, Hazards & Characteristics of Anhydrous Ammonia • Anhydrous ammonia (NH3)is a hazardous material with the following physical properties: • Anhydrous ammonia is corrosive, especially to brass valves and fittings, and other metals that contain alloys of copper and zinc. • Under certain conditions it may be flammable. • It is highly chemically reactive, and in the presence of other materials may be highly explosive. • Anhydrous ammonia in the presence of water will burn body tissue.

6. Physical Properties, Hazards & Characteristics of Anhydrous Ammonia Warning: Exposure to anhydrous ammonia is dangerous and can result in injury or death. Always use proper personal protective equipment (PPE) and handling procedures when working around it. Be sure you read a current material safety data sheet (MSDS) provided by the chemical’s supplier & understand the information it contains. Know how to react in the event of a chemical release or exposure.

7. Converting ASME Tanks in Anhydrous Ammonia Service to Propane Service Note: One of the steps in these procedures requires the replacement of the NH3 tank steel valves with valves used in propane service. In propane service, many of the valves, fittings, and distribution lines are made with copper or a metal alloy containing copper (i.e., brass, etc.). Because of the chemical nature of NH3, any mixture of NH3 and water can easily destroy the copper or brass equipment. For this reason, follow special procedures to ensure that all traces of ammonia are removed from the tank before placing it into propane service.

8. Converting ASME Tanks in Anhydrous Ammonia Service to Propane Service

9. Converting ASME Tanks in Anhydrous Ammonia Service to Propane Service NOTE: Although NH3 gauges operate in the same manner as propane gauges, the maximum permitted filling level of NH3 is not the same as propane. As a result, the markings on the gauge faces, as well as the length of the dip tube for a fixed maximum liquid level gauge, are not designed for propane service. If a standard NH3 gauge is used for filling with propane, the container can be overfilled!

10. Converting ASME Tanks in Anhydrous Ammonia Service to Propane Service

11. Time to See If You Got the Key Points of This Module… • Complete the Review on page 7. • See if you are ready for the Certification Exam by checking off the performance criteria on page 8.