Are your farmer customers giving anhydrous ammonia the respect it deserves when working with it? Are they using properly maintained equipment with parts replacement done according to a schedule for NH3 equipment? Are they modifying equipment such as applicators up to standards of the American National Standards Institute, as required of NH3 dealers?

It doesn't seem logical to leave farmers that purchase their own NH3 storage tanks and nurse tanks unregulated or regulated at a much lesser degree than NH3 dealer storage tanks, plumbing, piping and nurse tanks. NH3 anywhere is a hazardous material and dangerous to be working around.

In my opinion, it's illogical thinking when state legislators roadblock on-farm regulations related to such dangerous materials. Farmers don't want intrusion into their business, but when they are buying their own NH3 facilities and building their own NH3 equipment, they then become a danger to the environment, the public, employees and themselves if not properly regulated.

The number of farmers who have purchased NH3 storage and/or nurse tanks is quite low, but it is something that has been on the increase. What is more prevalent is farmers owning their applicator/tool bar, but the innovative ones doing their own modifications.

Potential farmer lapses in thought or possible low recognition of the danger associated in working with NH3 caused an Iowa State University biosystems engineer to issue a safety warning earlier this spring. Mark Hanna, ISU Department of Agricultural and Biosystems Engineering, noted that the increase in ideas for precision agricultural operations might have some farmers improperly modifying NH3 equipment.

"On the farm regulations for ammonia equipment are nearly non-existent at the state level in many states," Hanna said. Besides modifying NH3 applicators without requirements for passing an inspection, more farmers are buying their own toolbar applicators and thus are responsible for maintenance.

"Any operators who may have purchased their own nurse tanks need to be aware that those nurse tanks are not going to last forever. They need to be aware of the tanks' age and its condition," he noted. He also explained that hoses need inspected often and replaced on a periodic basis. Additionally, quick release valves and some shut-off valves are dated by manufacturers and should be considered for replacement after a few years of service.

Row by Row NH3 Shut Off
"With the price of fertilizer, there has been a fair amount of interest in row-to-row shutoff with liquid fertilizer applicators, and also with anhydrous ammonia applicators," said Hanna. "It is a great idea, but it also is one of those technical innovations that carries some safety implications. If people aren't thinking, they can get themselves into hot water."

One example he noted is the use of a NH3 hose line that isn't reinforced for the pressures that might flow from the NH3 nurse tank and the proper valves and connections to handle ammonia and withstand extended pressure.

"We have to remind everyone that once they get out of that tractor seat, everything has to be properly bled out before working around the equipment. And if they are plumbing their own equipment for row-to-row shutoff, they must realize the use of reinforced hose in some of those areas is necessary because lines can be subject to tank pressure (100 to 130 psi) if all valves at the injectors are closed before main flow is stopped," Hanna said.

"Often from the distribution manifold or flow divider, we use low pressure type hose. Those lines aren't typically subject to high pressure. But if you have some shut-off valves down by the knives or upstream from the knives and you shut most or all of them off before you shut off the main valve, you have the same pressure in those lines as you do from the tank to the applicator itself."

Bleeding Valves Important
As Hanna explained in his safety warning, "installing a small bleeder valve upstream of any section or knife shut-off valve allows an operator to bleed off trapped, pressurized ammonia before working on those sections or lines. Because these systems are relatively new, and bleeder valves may not be present, it is important to empty all lines before working around the equipment.

To bleed pressure from the applicator, operators should:

  • Shut off ammonia flow first at the supply field nurse tank.

  • Then open individual knife or section valves farthest downstream in the plumbing system.

  • Follow this by opening any upstream section-control valves.

  • Finally, open the main flow valve.

"This procedure opens valves successively upstream in the plumbing system allowing system pressure to be released."