I hate to admit it, but it’s true.  The From the Porch Swing column isn’t always written from my porch swing.  I moved a couple of years ago, and the swing that was happily under a covered and screened porch is now mostly out in the elements and the bugs, subject to leaves and rain and mosquitos and wasps and wind.  So sometimes, heck, often, this column is written from an airplane seat.

Not just any airplane seat, but the one, best, golden seat on Southwest Airlines.  Well, at least the one, best, golden seat if you want to work while you are flying.  The rows on most airplanes are too close together for a man 188 centimeters tall (6’2”) with proportionate arm length to type into a laptop.  When the lid is open far enough for me to look down onto the screen, the keyboard is too close to my belly (like jammed into it) for me to type upon it.  And conversely, when the keyboard is at typing distance, the lid with the screen on it is up against the back of the seat in front of me and won’t open enough for me to see it.  And, no, i can’t afford first class airfare, even if Southwest did offer it.  But, but, but, and again but (Ian Fleming’s Chitty Chitty Bang Bang), in just one exit row, on just one side of all of Southwest’s planes, there are only two seats instead of three.  The window seat next to the emergency exit is missing, but there is still a tray table behind the seat in front of that space.  So, so, so, and again so (I made that one up), if i sit in what is normally the middle seat in that row, i can use the missing seat’s tray table by pivoting about 45 degrees.  At that diagonal angle (not Diagon Alley), i can both type and see my laptop screen at the same time!  Woo-hoo!

This makes my spot in the boarding line crucial.  Southwest doesn’t assign seats, they’re ‘first come, first served’ upon entering the airplane.  But they do assign spots in the queue (that’s “line” to you Americans reading this) for boarding.  I can tell U that i have watched the person directly in front of me in line (“queue” for you Europeans reading this) take my one, best, golden seat.  Being in the right order in the boarding line/queue can make my day (Clint Eastwood as Dirty Harry), while being in the wrong order can break it.  Sequence is thus very important to me.

Sequence in DG can be important, too.  And U are probably thinking (if, that is, i haven’t put U to sleep yet) that shipping documents are the best example of that.  And U’d be right.  But documentation isn’t the only area in which sequence can be important to a Dangerous Goods (DG) professional.  Just look at the layout of the DG regulations.  Except for 49CFR, they put classification & identification before packaging, marking & labeling before documentation, and shipper functions before carrier functions.  This makes great sense because this is normally the way the real world works.  Yay, regulators!  Thank you.

But before we get too effusive in congratulating those that create DG regulations, we have a few situations where sequence considerations have gone out the window.  In my courses, I usually call these ‘Packaging Dependent Classifications’.  Let’s discuss a few of these non-sequential, but not non-consequential situations.

Explosives  —  A bottle, jar, can, or block of pure explosive chemical gets a different classification than when put into a firework, weapon, or safety device.  Yes, we can recognize the explosive hazard, but we cannot assign a class, division, nor Proper Shipping Name (PSN) without knowing how the explosive material is contained.

Chemical and First Aid Kits  —  The ‘other stuff’ we put into a package with the DG can change the classification.

Articles in general  —  From batteries to fuel cells to lamps and switches to vehicles to capacitors to safety devices to machinery and more, the classification of articles differs greatly from the classification of the enclosed DG when packaged without the article.  (BTW, is a lead-acid battery in a vehicle actually a DG within an article within another article?)

Combustible liquids  —  In smaller packagings these can be non-dangerous, but in larger packagings HazMat.  And don’t think this is just a USA issue, because it definitely has an impact on a large number of international shipments.         

Gases (gasses)  —  Today’s first intentionally trick question is “what is the PSN of pure 1,1,1,2-Tetrafluoroethane?”.  Sure, I dare you, look it up in your DG List (it’s there), and answer me with “1,1,1,2-Tetrafluoroethane”.  If we’ve packaged that gas into an aerosol container, such as those used to blow crumbs off your keyboard or as Poop Freeze (Google it), the PSN will be different, and will begin with “Aerosols, …”.  Yes, a cylinder of the pure stuff has a different PSN than an aerosol container of the pure stuff.  (Get with the program, PHMSA, and either harmonize your aerosol definition, or stop prohibiting us from using the global definition).

And there I was, thinking that packaging was a function that followed sequentially after classification/identification.  What am i supposed to do?  Pick a packaging, complete the classification, and then use the usual process of looking up the PI to verify the compliance of my packaging choice?  What if it isn’t in full compliance, do i go back to packing or back to classification/identification or both, and if both, in which order?  Sigh…

So, while sequence is usually important in DG, sometimes we seem to violate our own general rules about the process of achieving compliance.  And unless you are trying to fill out Section 14 of an SDS, it probably isn’t a big deal.  After all, don’t all DG professionals know that for every general rule there is/are an exception or twelve?  And don’t get me started on exceptions to the exceptions.  Again, sigh…

And oh, by the way, I don’t actually smoke a pipe, either.