NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

October 1, 1998

Breakaway Valves on Anhydrous Ammonia Tanks Can Prevent Deadly Releases

An uncontrolled release of anhydrous ammonia can be deadly even when it happens in the middle of a farm field. The emergency breakaway valve between field applicators and nurse tanks is specifically designed to prevent such a dangerous incident, says a North Dakota State University safety specialist.

"Hitch pin can be a weak link between towed implements," notes George Maher of NDSU's Extension Service. "And if the hitch pin between the anhydrous ammonia applicator and the nurse tank should fail, the breakaway valve will allow the hose to separate safely from the applicator and stop the flow of ammonia from the nurse tank."

However, the breakaway valve won't be of much use if it doesn't work properly, Maher notes. The valve has a limited lifespan. Rubber and metal parts can degrade with exposure to ammonia and additives. One popular manufacturer recommends replacing breakaway valves every three years.

The breakaway valve is a part of the field applicator. If the breakaway valve should pull apart and automatically stop the flow of anhydrous ammonia from the nurse tank hose, here's what should be done to get ammonia flowing to the applicator again:

1. Put on the protective gloves and goggles and have emergency water directly available.
2. Be sure anhydrous ammonia is not escaping from the hose end. Always approach the hose end from up-wind or side-windnever down-wind.
3. Close the nurse tank valve and then the nurse tank hose valve.
4. Open the bleeder valves on the nurse tank hose and on the distributor assembly/breakaway valve assembly to bleed off any trapped ammonia. Leaving ammonia under pressure in these locations can make re-attaching dangerous and very difficult.
5. Inspect the nurse tank hose and distributor assembly for damage. Replace or repair as necessary.
6. Use a safety clip on the hitch pin when re-attaching the nurse tank to the applicator.
7. Close all bleeder valves after they have released all trapped ammonia.
8. Connect the nurse tank hose to the distributor assembly and open the nurse tank hose valve then the nurse tank valve to re-pressurize the system.

"Without a breakaway valve, anhydrous ammonia will gush from the broken end of the nurse tank hose," Maher says. "This is a situation that is too dangerous for you to handle by yourself. If you're in an unpopulated area, move upwind and let the ammonia flow from the nurse tank until the tank is empty. It may be expensive, but it's a safe way to handle the situation."

Unless you are wearing the required personal protective equipment, (a self-contained breathing apparatus and fully protective rubber suit), never wrestle with the nurse tank hose in an attempt to gain control. "Attempting to do so can cost you your life," Maher says.

In a populated area, call the fire department to control the situation, he advises. Alert everyone in the vicinity to the ammonia hazard and urge them to evacuate the area. It is too dangerous to attempt work at the scene of an uncontrolled release without the proper safety equipment.

For more information on safety issues relating to anhydrous ammonia applications, refer to "Anhydrous Ammonia: Managing the Risks" (AE-1149), a new publication from the NDSU Extension Service available through your county office. Or contact Maher at (701) 231-8288.

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Source: George Maher (701) 231-8288

Editor: Tom Jirik (701) 231-9629