3.7.4

1. 3.7.4 Identifying Testing Procedures for Anhydrous Ammonia (NH3) Contamination Because many propane marketers sell both propane and anhydrous ammonia, it is important the ammonia not contaminate the propane vapor. For safety purposes, it is important to understand the testing procedures for anhydrous ammonia contamination. • In this module you will identify: • Physical properties, hazards & characteristics of anhydrous ammonia • Procedures for testing for anhydrous ammonia contamination

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. Procedures For Testing Propane For Anhydrous Ammonia Contamination When it is known or suspected that a container may have been used in anhydrous ammonia service, a test should be done to assure that all residue is gone. Even though the container may have been thoroughly purged with water, some NH3 vapor may still be mixed with propane vapor. If this is allowed to remain in the container, it can easily damage or destroy any copper or brass equipment in the propane system

8. Procedures For Testing Propane For Anhydrous Ammonia Contamination Caution! Do not allow the litmus paper to touch any part of the hand or any portion of the tank or tank valves. This can easily cause the paper to accidentally turn blue.

9. Procedures For Testing Propane For Anhydrous Ammonia Contamination

10. Procedures For Testing Propane For Anhydrous Ammonia Contamination

11. Procedures For Testing Propane For Anhydrous Ammonia Contamination Note: If contamination is found, the container must be evacuated, cleaned and purged following the instructions in module 3.1.13, “Converting ASME Tanks in Ammonia Service to Propane Service.”(All brass cylinder valves & fittings must be replaced after the cylinder is cleaned & purged.)

12. Time to See If You Got the Key Points of This Module… • Complete the Review on page 4. • See if you are ready for the Certification Exam by checking off the performance criteria on page 5.