Engineering Effective Anhydrous Ammonia Transport

By OPW | Dec 14, 2020

The designers of industrial product-handling systems, whether they be for liquid or gas, can typically take one of two approaches, with one being to engineer the application to fit the needs of the equipment. For instance, a chosen pump may have a recommended maximum flow rate of 100 gallons per minute (gpm), so the designer will engineer the system so that the maximum flow rate will never be exceeded, regardless of the fact that a 200-gpm flow rate may be more beneficial for the operator.

Conversely, Midland Manufacturing, Inc., takes the opposite approach regarding system design and identifies the outer limits of the operational parameters of the application, then engineers equipment and systems to deliver performance that can reliably meet those parameters. A recent example is the Anhydrous Ammonia Fittings Package. Anhydrous ammonia, or NH3, is one of the most commonly used compressed liquefied gases in industrial manufacturing. It is also classified as a Toxic Inhalation Hazard (TIH)/Poison Inhalation Hazard (PIH), which can be highly dangerous if mishandled.

With that in mind, the components in Midland’s Anhydrous Ammonia Fittings Package aim to deliver the following advantages for NH3 transport via pressurized railcars, all of which are designed to help prevent unnecessary exposure to the hazardous chemical:

  • Availability in a wide array of materials of construction to meet unique application needs
  • Adherence to new Next Generation Rail Tank Car (NGRTC) regulations regarding the transport of TIH/PIH commodities, such as NH3
  • Soft-seated seals offer more consistent sealing capabilities
  • All primary seals are below the railcar’s pressure plate, which helps prevent a release during a rollover incident
  • The incorporation of a rupture disc reduces risk of exposure of critical components to the commodity
  • All parts can be capped with the Midland Emergency Response Kit

Specifically, Midland’s Anhydrous Ammonia Fittings Package consists of the following pieces of equipment, all of which have been engineered to support safety and reliability in the transport of NH3:

  • A-14378-ML Pressure Relief Valve (PRV): Ensure a positive and consistent seal, while the rupture disc and PRV are independently mounted, allowing the PRV to be removed for service without releasing the commodity into the atmosphere.
  • A-180 Check Valve: The guided-seat design puts constant force on the plug to create a positive seal. All components can be removed through the top of the pressure plate, reducing time needed for valve maintenance.
  • A-713 1” Angle Valve: Corrosion-resistant construction provides increased protection, while triple seals help to reduce the number of potential leak paths.
  • Needle Valves: Allow product sampling without opening a larger transfer valve. Must be installed with a check valve to help prevent product loss if sample-valve nipple is sheared off.
  • B-612 Magnetic Gauging Devices: Provides accurate liquid-level monitoring for complete loading of railcars with reduced fill time. Small mounting flange makes it easier to position other equipment on the manway plate.
  • Thermowells: Flanged or threaded thermowells provide safe, no-contact access to the product for temperature measurement with a thermometer or thermocouple probe.

For more information on Midland Manufacturing, Inc., and its complete portfolio of tank railcar products, please visit