Ask X3What does 49 CFR 173.137 (Class 8—Assignment of packing group) require?
Generated guidance. Confirm the source and its applicability before you act. How we check sources.
As a motor-carrier owner, when your 49 CFR 173.137 table provides more than one packing group for a Class 8 material, you must determine the correct packing group using test data, alternative skin-corrosion testing, or specific methods for mixtures.
Here is what is required based on 49 CFR 173.137:
* Testing Methods: You must use data from tests conducted according to OECD Guidelines Test No. 435 ("In Vitro Membrane Barrier Test Method for Skin Corrosion") or Test No. 404 ("Acute Dermal Irritation/Corrosion").
* Alternative Methods: You may consider a substance or mixture *not* corrosive to human skin if tested using OECD Guidelines Test No. 430 (TER), Test No. 431 (RHE), or Test No. 439 (RHE skin irritation). However, if tests 430 or 439 show the material is corrosive, you must either assign it to Packing Group I or perform further testing using Test No. 435 or Test No. 404. If Test No. 431 indicates corrosion but cannot clearly distinguish between Packing Groups II and III, you must assign it to Packing Group II unless you perform further testing.
* Criteria for Test No. 404: Assign packing groups based on the time it takes to cause irreversible damage to intact skin tissue:
* Packing Group I: Causes irreversible damage within an observation period of up to 60 minutes, following an exposure time of 3 minutes or less.
* Packing Group II: Causes irreversible damage within an observation period of up to 14 days, following an exposure time of more than 3 minutes but not more than 60 minutes.
* Packing Group III: Causes irreversible damage within an observation period of up to 14 days following an exposure time of more than 60 minutes and up to 4 hours; *or* does not cause irreversible damage to skin, but corrodes steel or aluminum surfaces at a rate exceeding 6.25 mm (0.25 inch) per year at a test temperature of 55 °C (130 °F).
* Mixtures: If dealing with an untested mixture, you must use a tiered approach to assign a packing group:
1. Bridging Principles: If data exists on similar tested mixtures or individual ingredients, you may use specific bridging principles (dilution, batching, concentration of packing group I mixtures, interpolation within one packing group, or substantially similar mixtures) to classify the mixture.
2. Calculation Method: If no test data or sufficient information on similar mixtures is available, you must use the calculation method outlined in appendix I, factoring in all Class 8 ingredients at a concentration of 1% or greater (or under 1% if relevant), provided there are no synergistic effects that make the mixture more corrosive.