Appendix B: Procedure - Anhydrous Ammonia Tank Car Emission Standard

B1. Instrument for Emission Measurement

B1.1 The emissions from the protective housing of a tank car containing anhydrous ammonia may be measured with colorimetric indicator tubes, or by any other method which provides a degree of accuracy equivalent to the indicator tubes. The measurement system must be used in accordance with the instructions and recommendations provided by the supplier of the system, including: 

  1. if specified, by using a proprietary sampling pump;
  2. taking the specified precautions in the handling and storing of the tubes, as applicable;
  3. not using a tube or any other sensor that has exceeded its maximum shelf life;
  4. adhering to the recommended maintenance and calibration practices for the system; and
  5. following the recommendations relative to the selection of the sensor and measurement methods applicable to ammonia in the concentration range of interest.

B2. Measurements and Acceptance Criteria

B2.1 The ammonia concentration must be measured, the results evaluated, and the corrective actions taken as necessary in accordance with the following requirements:

B2.1.1 Measurements — The gas samples must be taken within the protective housing of the anhydrous ammonia tank car. The protective housing cover, portholes, and flaps must have been closed for a minimum of 10 min before taking the sample. The sampling must be done from a downwind porthole. The sampling and measurement methods must be in accordance with the instructions and recommendations of the supplier of the instrument.

B2.1.2 Definition of Leaking — The anhydrous ammonia tank car is leaking if: 

  1. emission originating from the reclosing pressure-relief device or the joint between the manway cover and the manway nozzle can be detected; or 
  2. the measurement performed in accordance with the requirements set out in clause B2.1.1 gives a result of 100 ppm or more.

B2.1.3 Corrective Action — If the anhydrous ammonia tank car is leaking, the source of the emissions must be investigated and corrective action must be taken to stop or reduce the leaking.

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