Ask X3What does 49 CFR 173.127 (Class 5, Division 5.1—Definition and assignment of packing groups) require?
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According to 49 CFR 173.127, an oxidizer (Division 5.1) is defined as a material that may, generally by yielding oxygen, cause or enhance the combustion of other materials.
To determine if a material falls under this classification and what packing group it should be assigned, it must be tested in accordance with the UN Manual of Tests and Criteria:
1. Solid Materials (except solid ammonium nitrate-based fertilizers):
* Division 5.1 Classification: A solid is classed as a Division 5.1 material if:
* Using Test O.1, the mean burning time is less than or equal to the burning time of a 3:7 potassium bromate/cellulose mixture; or
* Using Test O.3, the mean burning rate is greater than or equal to the burning rate of a 1:2 calcium peroxide/cellulose mixture.
* Packing Group Assignment:
* Packing Group I: Assigned if test O.1 shows a mean burning time less than a 3:2 potassium bromate/cellulose mixture, or if test O.3 shows a mean burning rate greater than a 3:1 calcium peroxide/cellulose mixture.
* Packing Group II: Assigned if the criteria for Packing Group I are not met and test O.1 shows a mean burning time less than a 2:3 potassium bromate/cellulose mixture, or test O.3 shows a mean burning rate greater than a 1:1 calcium peroxide/cellulose mixture.
* Packing Group III: Assigned if the criteria for Packing Groups I and II are not met and test O.1 shows a mean burning time less than a 3:7 potassium bromate/cellulose mixture, or test O.3 shows a mean burning rate greater than a 1:2 calcium peroxide/cellulose mixture.
* *Note:* If the sample does not ignite and burn, or if it exceeds the burning time/rate thresholds of the lowest mixture, it is not classified as a Division 5.1 material.
2. Solid Ammonium Nitrate-Based Fertilizers:
* These must be classified following the procedures set out in the UN Manual of Tests and Criteria, Part III, Section 39 (49 CFR 173.127).
3. Liquid Materials:
* Division 5.1 Classification: A liquid is classed as a Division 5.1 material if it spontaneously ignites when tested, or if its mean time for a pressure rise from 690 kPa to 2070 kPa gauge is less than the time of a 1:1 nitric acid (65 percent)/cellulose mixture.
* Packing Group Assignment:
* Packing Group I: Assigned to any material that spontaneously ignites when mixed with cellulose in a 1:1 ratio, or exhibits a mean pressure rise time less than the pressure rise time of a 1:1 perchloric acid (50 percent)/cellulose mixture.
* Packing Group II: Assigned to any material (that does not meet Packing Group I criteria) which exhibits a mean pressure rise time less than or equal to the pressure rise time of a 1:1 aqueous sodium chlorate solution (40 percent)/cellulose mixture.
* Packing Group III: Assigned to any material (that does not meet Packing Group I or II criteria) which exhibits a mean pressure rise time less than or equal to the pressure rise time of a 1:1 nitric acid (65 percent)/cellulose mixture.