Safe Handling of Anhydrous Ammonia

Agricultural Tailgate Safety Training for Operators and Supervisors
AEX-591.4.9
Agriculture and Natural Resources
Date: 
08/29/2019
Agricultural Safety and Health Program

Objective: To incorporate adequate safety precautions when working with or transporting anhydrous ammonia (NH3). 

Trainer’s Note

Present a dry run safety demonstration on how to work with NH3 correctly and demonstrate the proper use of personal protective equipment (PPE). After reviewing the checklist below, encourage discussion about NH3 incidents with participants. Involve employees and a NH3 sales representative in the demonstration, if possible. Remember, reacting quickly to an NH3 incident is critical. This module is intended as a refresher for employees who work with NH3 and is not intended as a sole source of information on the safe use of this product. Contact your dealer for more information on in-depth training for your employees. Review the true or false quiz.

Background

Personal protection is the responsibility of both the employer and the employee. Anhydrous ammonia is a strong alkali that can cause death or severe injury to body tissue due to its caustic, corrosive, freezing, and dehydrating action. An almost instant freeze-drying process occurs when the liquid NH3 comes in contact with body tissue, which can blind and disfigure an individual.    

Review the fact sheet “Towing Anhydrous Ammonia Tanks” included with this series.

Ample Water Supply for Flushing Eyes/Skin

  • Five gallons of water must be carried in each vehicle used to tow NH3.
  • Each employee should carry 6 to 8 ounces of water in their pocket for rapid emergency access.
  • Each vehicle must carry a 5-gallon water container of clean water.

PPE Necessary For Working With NH3

  • Goggles/face shield
  • Approved respirator
  • Rubber gloves
  • Long-sleeved and loose fitting shirts

Basic First Aid for NH3 Exposure

  • Washing with water is the emergency measure to use when skin or eyes are exposed to anhydrous ammonia. Time is important! Get water onto the exposed area of the skin or eyes immediately and flush for at least 15 minutes.
  • Contaminated clothing should be removed quickly but carefully. Thaw clothing frozen to the skin with water before attempting removal. Wash the affected skin area with abundant amounts of water and do not apply anything except water for the first 24 hours. Stay warm and get to a physician immediately.

Care and Maintenance of NH3 Tank

To handle NH3 safely, it is imperative that all equipment is properly maintained and checked daily. A regular, scheduled maintenance program will ensure that all the valves and the tank are safe for handling the high pressure liquid and its vapor form. Perform a daily visual inspection to locate any defects in the tank or hoses.

Important Valves And Components List

Checklist for Safety

  • Do not fill the NH3 tank more than 85 percent full.
  • Do not use a faulty hitch pin or a wagon with a weak tongue.
  • Check the condition of the tires and frame of the tank.
  • Always disconnect the fill hose before moving the tank.
  • Replace deteriorated or out-of-date hoses and faulty valves. Hoses must be replaced within five years of the date stamped on the hose.
  • Always wear the proper protective equipment (as noted above).
  • Bleed pressurized NH3 from the hose before connecting or disconnecting.
  • Tank valves, includes liquid withdrawal valve, liquid fill valve, and vapor return valve—Be sure valves are functional and will shut off. Any leak detected in the valve is cause for immediate repair or replacement. Each valve should be removed every five years and inspected for internal corrosion and thread deterioration.
  • Excess flow valve—Check the valve for movement of the valve plunger, corrosion of springs, valve seat and guide, and out of round disk. This valve should be replaced every five years.
  • Pressure gauge—Check the consistency with other tanks of similar volume. Make sure the lens is clean and the dial face is clearly readable.
  • Fixed liquid level gauge—Clean, repair, or replace as needed.
  • Liquid level float gauge—Check against the 85 percent level gauge for accuracy. An inaccurate reading, leaking at the seal, or unreadable lens should be repaired or the defective item replaced.
  • Safety relief (SR) valve—Stand to one side and use a mirror for viewing. The SR valve should be free of dirt and rust. Replace the rain cap if it is damaged or missing. Leakage or discharge below 250 psi is cause for replacement. The SR valve should be replaced every five years.
  • Hydrostatic relief (HR) valve—Inspect the valve for leakage, corrosion, or damage. The HR valve should be replaced every five years.
  • Transfer hose—Examine the hose closely for cuts, abrasions, soft spots, bulges, kinking, or flattening and similar defects. Check for slippage of the hose at coupling. The hose must be replaced five years from the date of manufacture (stamped on hose).
  • Tank condition—Prevent corrosion and excessive pressure buildup from direct sunlight by keeping the tank painted with a reflective paint. Dented or damaged tanks should be taken out of service until checked by an authorized inspector and repaired as necessary. All welding on the tank must be done by a certified welder. Be careful in repairing or replacing these parts to prevent incidental exposure to NH3. Most retailers will assist you in repairing your nurse tank or applicator.illustration of valve and gauge types to recognize.

Review The Following Points

  • Have an ample water supply.
  • Wear personal protective equipment.
  • Never fill a tank over 85 percent of the tank’s capacity.
  • Inspect and replace hoses and valves as needed.
  • Bleed off pressure in the hose before disconnecting.
  • Stay clear of hose and valve openings.
  • Follow step-by-step procedure when using the equipment.

About These Modules

The Ag Tailgate Training Series was developed by members of the Agricultural Safety and Health Program in the Department of Food, Agricultural and Biological Engineering. Revised by Dee Jepsen, State Agricultural Safety Leader, with editing assistance by Lisa Pfeifer and Cody McClain.

True or False Answer Key

  1. F
  2. F
  3. T
  4. T
  5. F
 

Quiz: Safe Handling of Anhydrous Ammonia

 

Name____________________________________     

True or False?    

1. There is no benefit to protecting the face and eyes is when using NH3. T F
2. Leaving the fill hose connected while moving the tank is a safe practice. T F
3. An ample water supply must be available while working with NH3. T F
4. Anhydrous ammonia is a colorless gas. T F
5. Overfilling the tank with anhydrous is harmless. T F