A Tootsie Roll of APCP is HAZMAT, But a Pack of APCP Life Savers Is Not. Why?

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GlueckAuf

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As I was assembling a few RMS Plus motors this evening, as I looked at how the propellant grains were packaged in their shipping tubes it puzzled me why the multiple grains in, for example, the non-HAZMAT Aerotech H268R-14A, all stacked together in the liner as shipped (think, like a package of Life Savers), were any less inherently hazardous than they would be as a single grain of the same overall length (think, Tootsie Roll).

Aerotech's non-HAZMAT, high-power motor packaging of old used to physically separate the grains, placing just one in the liner and the other(s) in a separate plastic sheath. But now they all seem to ship with NO physical separation of the grains.

How does cutting up the propellant grains into many smaller, lighter grains then stacking them all back together inside the liner in any way constitute a less hazardous product than if they remained as one solid grain shipped in that same liner?
 

Antares JS

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How does cutting up the propellant grains into many smaller, lighter grains then stacking them all back together inside the liner in any way constitute a less hazardous product than if they remained as one solid grain shipped in that same liner?
First, in general, the reason propellant grains are cut up is to give the ends the ability to burn so you get a more neutral burn, not for Hazmat shipping purposes. The surface area of the grain ends decreases at the same time the core area increases during the burn. This is called a BATES grain.

There are some motors, such as the H130W and lots of 38mm Loki motors, that are cut into smaller pieces for the specific purpose of being able to ship without Hazmat, but this is the exception rather than the rule.

Second, Hazmat requirements for the USPS are just one of those dumb laws thought up by some politician who had no idea what he was doing and we just have to live with it to keep rocketry legal. As long as each separable piece is less than a certain weight, it can be shipped without Hazmat no matter how it is packaged.
 

UhClem

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They are all HAZMAT but some (1.4s) qualify for the USPS exemption. See Pub52 for the details.

How Aerotech drives their product through that classification (from the DOT) is another story. But Aerotech seems to have torn down their web site with that information since all I get now is a redirect to a web store.

I remember reading a document once long ago which described the limits on propellant mass in "inner packagings". Perhaps those requirements changed.
 

TigerHawk

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the reason propellant grains are cut up is to give the ends the ability to burn so you get a more neutral burn, not for Hazmat shipping purposes. The surface area of the grain ends decreases at the same time the core area increases during the burn. This is called a BATES grain.
BATES is an acronym for BAllistic Test and Evaluation System
 

rharshberger

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They are all HAZMAT but some (1.4s) qualify for the USPS exemption. See Pub52 for the details.

How Aerotech drives their product through that classification (from the DOT) is another story. But Aerotech seems to have torn down their web site with that information since all I get now is a redirect to a web store.

I remember reading a document once long ago which described the limits on propellant mass in "inner packagings". Perhaps those requirements changed.
Aerotech has been experiencing issue with their website for a couple of weeks now, looking like they might be rebuilding the entire website based on posts by the current AT representative posting to the AeroTech Open Thread.
 

jsdemar

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For small BP motors and very small APCP motors: DOT 1.4S is an exemption for model rocket motors with less than 30 grams of propellant. They can be shipping ground only as DOT 1.4s/4.1 through the USPS if packaged and labelled correctly AND you request an authorization letter from USPS HQ. This also applies to individuals.

For small APCP motors: more than 30 grams, and less than or equal to 62.5 grams, the manufacturers have a DOT exemption to ship motors as flammable solids 4.1 instead of explosive class 1.4C. Authorized shippers can use this exemption, but not individuals.

For larger APCP motors: with more than 62.5 grams, they are DOT class 1.3 explosive. These require hazmat shipping by an authorized shipper.

Here's the "tootsie roll, life saver" loop hole. For reloadable motor kits, if the propellant is packaged in quantities of no more than 62.5 grams, the DOT 4.1 class exemption is used. You'll see some of the propellant in the liner (no more than 62.5g total) and each additional grain in a plastic baggie (each no more than 62.5g). This is done to fulfill the requirement of "no more than 62.5g in each internal package", as if the releoad kit were a bunch of G motors.

One more DOT threshold is for preloaded motors (or very large grains) with more than a certain threshold of propellant. This kicks the DOT class up to higher explosive, some of which cannot be shipped by common carrier (Fedex & UPS). They have to be shipped by individual truck by a certified driver.
 

UhClem

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Here's the "tootsie roll, life saver" loop hole.
UN 4.1 is still hazardous and USPS cares nothing about that DOT special permit. (It appears that only ORM-D items are acceptable 4.1 materials for the USPS.) The exemption is good for only two specific UN 1.4s classifications. (UN0454 or NA0323)

Even SP7887 (1.4C and 1.4S shipped as 4.1) has a limit of 62.5 grams propellent in each inner packaging.

I don't see how the current packaging of the H268R (for example) meets the USPS packaging requirements. Even the old practice of putting grains in sealed thin plastic bags seems a bit iffy.
 

jsdemar

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UN 4.1 is still hazardous and USPS cares nothing about that DOT special permit. (It appears that only ORM-D items are acceptable 4.1 materials for the USPS.) The exemption is good for only two specific UN 1.4s classifications. (UN0454 or NA0323)

Even SP7887 (1.4C and 1.4S shipped as 4.1) has a limit of 62.5 grams propellent in each inner packaging.

I don't see how the current packaging of the H268R (for example) meets the USPS packaging requirements. Even the old practice of putting grains in sealed thin plastic bags seems a bit iffy.
The USPS packaging requirement is only for the 30 gram exemption. They won't accept anything within the 62.5g DOT exemption. Beyond 30g "devices", you have to ship Fedex or UPS. See: USPS regs 341.22 Mailable Explosives.

The ORM-D designation has been phased out. It's called "Limited Quantities" now. Not all DOT classes are allowed, and the max inner package and total package weight differ from class to class. It may be possible to ship 4.1 as LQ but I don't think 1.3 or 1.4 are allowed.
 

Neutron95

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Here's the "tootsie roll, life saver" loop hole. For reloadable motor kits, if the propellant is packaged in quantities of no more than 62.5 grams, the DOT 4.1 class exemption is used. You'll see some of the propellant in the liner (no more than 62.5g total) and each additional grain in a plastic baggie (each no more than 62.5g). This is done to fulfill the requirement of "no more than 62.5g in each internal package", as if the releoad kit were a bunch of G motors.
At some point the Aerotech packaging was changed. All of the 29mm HPR reloads that I've purchased have had all of the grains stored inside the liner, and they've all shipped without the hazmat fee. This included both an H268 and an I200. Any idea if Aerotech got some sort of exemption or what?
 

3stoogesrocketry

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"First, in general, the reason propellant grains are cut up is to give the ends the ability to burn so you get a more neutral burn, not for Hazmat shipping purposes. "

This is not correct . The grains are designed with a neutral-ish burn profile . Think of all the moon burning motors that require you to bond the grains back together to form one segment ( no not gluing the grains into the liner to keep them from being spit out ) . The single grain segment would need to be shipped 1.3 .


"There are some motors, such as the H130W and lots of 38mm Loki motors, that are cut into smaller pieces for the specific purpose of being able to ship without Hazmat, but this is the exception rather than the rule."

Aerotech had dozens of these motors as well....

"Second, Hazmat requirements for the USPS are just one of those dumb laws thought up by some politician who had no idea what he was doing and we just have to live with it to keep rocketry legal. As long as each separable piece is less than a certain weight, it can be shipped without Hazmat no matter how it is packaged."

This is very misleading and wrong.
 

Antares JS

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This is not correct . The grains are designed with a neutral-ish burn profile.
You might want to rethink this - you said I was not correct, then your very next sentence makes the same point I did; that it's about making the motor have a more neutral thrust curve. Moonburners are an exception and the reason I prefaced what I said with "in general."

Aerotech had dozens of these motors as well....
I am talking about motors specifically designed to be USPS-shippable. I know Aerotech has lots of 29mm reloads that are USPS-shippable, but that's because the grains happened to be small enough for the exceptions. The H130W was specifically designed to be USPS-shippable.

This is very misleading and wrong.
Given the arbitrariness of the USPS shipping rules and exceptions, what else am I supposed to think? There is no rational reason why an H130W should be USPS-shippable and its cousin, the H123W, should not be.
 

3stoogesrocketry

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You might want to rethink this - you said I was not correct, then your very next sentence makes the same point I did; that it's about making the motor have a more neutral thrust curve. Moonburners are an exception and the reason I prefaced what I said with "in general."

You Sir are 100 percent right , I miss spoke . I meant to say Bates grains.

I am talking about motors specifically designed to be USPS-shippable. I know Aerotech has lots of 29mm reloads that are USPS-shippable, but that's because the grains happened to be small enough for the exceptions. The H130W was specifically designed to be USPS-shippable.

As well as a I motor and a J motor. They use short life saver grains as you mentioned.

Given the arbitrariness of the USPS shipping rules and exceptions, what else am I supposed to think? There is no rational reason why an H130W should be USPS-shippable and its cousin, the H123W, should not be.

The H130 uses 4 short grains , the H123 uses two normal length grains . The grain weight is what makes the shorty grains shippable. I agree , it can be weird . Again I agree with you that short grains in one tube is still as dangerous as the grains in separate little plastic bags all in one big bag.
 

Reinhard

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For larger APCP motors: with more than 62.5 grams, they are DOT class 1.3 explosive. These require hazmat shipping by an authorized shipper.
Are you positive that it's 1.3 above 62.5g? It was always my understanding that it's 1.4C up to "a few kg" per grain and 1.3C above that. The latter affecting CTI Pro150 and the monolithic 98mm moonburner reloads that have now been replaced with segmented ones (e.g. N1100).

Reinhard
 

jsdemar

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Are you positive that it's 1.3 above 62.5g? It was always my understanding that it's 1.4C up to "a few kg" per grain and 1.3C above that. The latter affecting CTI Pro150 and the monolithic 98mm moonburner reloads that have now been replaced with segmented ones (e.g. N1100).
For US/DOT, everything above 62.5 grams of propellant (preloaded or per packaged grain) are 1.3 and require hazmat shipping. 1.3C classification is based on packaging and testing for a lower hazard level. 1.4C is for 30->62.5 grams (preloaded or per packaged grain), with the required packaging. Very large grains and preloaded motors are a mass explosion hazard and classified as 1.1.

All of the class groups have a limit per outer package, and per truck/vessel load.
 

jsdemar

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Regarding grain design being done for burn profile or shipping limitation, it's not a simple answer.

Aerotech and CTI motors which use a thermoplastic eroding nozzle have shorter grains to allow for more burn surface as the nozzle erodes. This helps reshape a normally regressive thrust curve.

For motors with graphite nozzles (or inserts), the grain length is chosen to give the desired thrust curve shape and to limit the mass flux on long motors.

If the manufacturer designs a unique monolithic grain (large moon or c-slot, for example) they have to decide on the shipping class needed for the end product. Cutting the grain into segments, requiring the end user to glue them face-to-face can allow the motor to be in the 62.5g and below loophole. For large specialty motors, keeping the grains below a certain threshold (1kg) allows them to avoid 1.1 classification, along with the required inner packaging per grain. Then, the end user is required to glue the grain segments together to get back to the original monolithic grain.
 

UhClem

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There is no rational reason why an H130W should be USPS-shippable and its cousin, the H123W, should not be.
It would appear that either Aerotech knows something we don't or are playing fast and loose with the rules. Perhaps DOT will notice and fine them like they did the guy for shipping "model aircraft parts".
 

Antares JS

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It would appear that either Aerotech knows something we don't or are playing fast and loose with the rules. Perhaps DOT will notice and fine them like they did the guy for shipping "model aircraft parts".
Aerotech is not "playing fast and loose" with any rules. I have no idea where you picked up that they were. My point is that the rules themselves are stupid when you can take one motor that isn't USPS-shippable (the H123W) and make it USPS-shippable just by cutting it into smaller pieces and changing nothing else (the H130W).
 
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rcktnut

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It would appear that either Aerotech knows something we don't or are playing fast and loose with the rules. Perhaps DOT will notice and fine them like they did the guy for shipping "model aircraft parts".
No This makes it legal. (Shipping regs. still don't make any sense.) Total propellant weight of the H130 is 120g and the H123 is at 125g.
vvvvvvvvvvvvvvvvvvvvvvv
The H130 uses 4 short grains , the H123 uses two normal length grains . The grain weight is what makes the shorty grains shippable. I agree , it can be weird . Again I agree with you that short grains in one tube is still as dangerous as the grains in separate little plastic bags all in one big bag.
 
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jsdemar

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No This makes it legal. (Shipping regs. still don't make any sense.) Total propellant weight of the H130 is 120g and the H123 is at 125g.
The H123 has two 64.5 gram grains, per testing and cert docs. That makes it hazmat. Some dealers list it has 119g or 122g or 123g, but it is in the AT master list as 129 g total.

The H130 has two 60 gram grains. It falls into the exemption to ship non-hazmat ground (Fedex or UPS, but not USPS).
 

GlueckAuf

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The H130 has two 60 gram grains. It falls into the exemption to ship non-hazmat ground (Fedex or UPS, but not USPS).
Actually, J, I believe the Non-HAZMAT H130W and its big brother, the also Non-HAZMAT I180W, both get their USPS-friendly shipping clearance by virtue of their 30-gram grains (less casting tube). There are definitely 6 such grains of that weight in the I180W, and its total propellant weight (per the label) is 180 grams.

1638767574667.png


Now I don't have an example to prove it, but I'll bet the H130W contains four of those 30-gram grains to fill out its published 120-gram propellant weight (according to the AT Master Motor Matrix, extract below) and thus qualifies for the USPS HAZMAT waiver.

1638769397473.png


This is beginning to make some sense, and I appreciate all the inputs. The original puzzle remains, though. How are six, 30-gram grains that total 180 grams of propellant any less hazardous than nearly the exact same total mass of the exact same propellant, just divided into fewer, heavier grains, when both varieties' grains are ultimately stacked all together into their liner for shipping? THAT'S what defies logic. It seems to me that USPS HAZMAT waivers on any reload kits up to some total weight (where this HAZMAT waiver scheme currently ends at the J520W level for Aerotech) should be granted--unless someone in authority can reveal the hidden rationale behind the "Tootsie Roll vs Life Savers" question.

What I don't want to see, of course, is the elimination of that waiver. That would be a very bad thing for us all.
 

JoePfeiffer

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You Sir are 100 percent right , I miss spoke . I meant to say Bates grains.
As just another member of the forum, I'd request you please use the standard convention for quoting other posts. Having to distinguish your responses from the post you're responding to is unnecessarily difficult due to the way you're doing it.
 

Bat-mite

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Bottom line, for anyone who wants to skip all of the above -- in summary: Tootsie Roll is no more or less hazardous to ship than Lifesavers. Dumb law, but when you codify things, you have to draw a line somewhere.
 

Banzai88

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Bottom line, for anyone who wants to skip all of the above -- in summary: Tootsie Roll is no more or less hazardous to ship than Lifesavers. Dumb law, but when you codify things, you have to draw a line somewhere.
...and often the ones doing the codifying have no idea what they're doing.
 

rharshberger

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It's right up there with -- you can buy 25 pounds of BP, and pay one HAZMAT fee, or you can buy one J motor and pay the same HAZMAT fee.
HAZMAT charges are a paperwork fee for the carrier, they are allowed but not specified how much to charge by regulation iirc. FedEx, and UPS's fees are all about the same cost, not sure what other carriers charge.
 

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