Volume to mass converion for HazMat

In the past, I had written about the need for the US to convert to metrics.  The fact that we are not completely on the metric system, opens up a lot of other associated difficulties with conversions and understandings of the system as a whole.

One of the things which I have encountered is the conversion of liquid volume to mass.  Now, those that know, you can't make that conversion properly without the specific gravity factor of the liquid in question.  Some liquids weigh more than others.

However, often enough, having to do those calculations is not always feasible and the SI indicates that a generic factor of 1liter can be converted to 1 kilogram based on the specific gravity of water at 40 degrees.

In aviation, the FAA has dictated that we can not load more than 25 kilograms of dangerous goods per inaccessible compartment of an aircraft (49CFR175.75).  This means that front line employees are required to determine the weight of certain commodities to establish compliance with this regulation.  The catch is that the regulators do not require shippers to provide the specific gravity of liquids being shipped.

This makes it difficult, if not impossible for front line employees to determine.  In this case, it should be allowed to use the 1 for 1 conversion factor, particularly since we are using this for quantities of 25 - 50 kilograms.

I presented a paper to the IATA DGB indicating that  this conversion factor is alluded to in a paragraph talking about chemical kits and how to convert the volume to mass for these items since they are class 9 and the weight is required rather than volume.  It allows the 1 for 1 conversion for this commodity.  However, that same conversion should be the industry standard for all applications.  Including the calculation of mass in order to determine compliance with the IATA DGR USG-13 (175.75) compliance.

The IATA DGR are not true regulations in a sense, so adding this doesnt make it a rule, but it will draw the attention of ICAO, which could make it a rule and eventually the US DOT will notice this and recognize the question and need for guidance.

So as it exists, how can I comply with the 25kg limit as placed in 175.75 if the regulator does not make the information available to the operator  which allows the operator to determine the exact calculation (Volume * Specific Gravity = Mass) .  It is in my opinion that the regulators accept the industry standard conversion factor.