1.2. Anhydrous Hose

This case is derived from the NSPE Board of Ethical Review

Farmers regularly use anhydrous ammonia to fertilize their fields. The anhydrous ammonia reacts violently with water, so care must be exercised in disbursing it. Farmers’ cooperatives rent anhydrous ammonia in pressurized tanks equipped with wheels so the tanks can be pulled by tractors. The farmers also rent or purchase hoses that connect the tanks to perforated hollow blades that can be knifed through the soil to spread the ammonia. Leaks from the hose are potentially catastrophic.

The current industry standard hose is made of steel-meshed reinforced rubber, similar in construction to steel-reinforced automobile tires. Two separate trade associations have established industry-wide these standards.

Recently, a new, heavy-duty plastic became available that could replace the steel in the hoses. Your engineering team works for one company that is seeking to manufacture and market these new hoses. The plastic-reinforced hoses are less expensive, lighter, and easier to process than the steel-braided rubber. The company sees great market prospect for this new hose.

Your team is charged with ensuring the safety of the new hose. You have recently put the hoses through a variety of tests with the following results:

  • The new hose meets industry standards
  • Like the steel-mesh reinforced rubber hose, the plastic hose does not immediately react to the anhydrous ammonia
  • Unlike the steel-mesh, the plastic does degrade over the years due to the ammonia and as a result loses some of its mechanical properties.


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The Primacy of the Public by Marcus Schultz-Bergin is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.