Completed the ADR course last week and a question on transporting SADT substances within class 5.2 organic peroxides cropped up… … …
Scenario
Transporting a SADT substance within the following temperature range … … .
Control Temp = -15 deg
Emergency Action Temp = 0 deg
SADT Temp = 15 deg
Question
At what temperature does decomposition start and a reaction (explosion or fire) become inevitable/irreversible?
I ask because I did not expect the answer I got from the instructor.
MickyB666:
Completed the ADR course last week and a question on transporting SADT substances within class 5.2 organic peroxides cropped up… … …Scenario
Transporting a SADT substance within the following temperature range … … .Control Temp = -15 deg
Emergency Action Temp = 0 deg
SADT Temp = 15 degQuestion
At what temperature does decomposition start and a reaction (explosion or fire) become inevitable/irreversible?I ask because I did not expect the answer I got from the instructor.
Hi MickyB666,
The answer to your question lies in knowing what the initials “SADT” stand for.
Self
Accelerating
Decomposition
Temperature
The SADT for a substance in Class 5.2 is the temperature at which the self accelerating decomposition occurs for that particular substance. The SADT for the substances in Class 5.2 varies from substance to substance.
As a (very) rough rule of thumb, once the SADT of a substance is known, the consignor will give the emergency temperature which is usually 10deg C cooler, and the control temperature is another 5deg C less again.
The control temperature is the temperature at which the 'fridge should be set.
The emergency temperature is the temperature, which if reached, the driver stops and alerts the emergency services.
The SADT is the temperature at which the whole lot goes up in a puff of smoke, or on a bad day, an explosion.
Some substances in Class 4.1 have an SADT, and follow the same pattern as above.
dieseldave:
…
The answer to your question lies in knowing what the initials “SADT” stand for.Self
Accelerating
Decomposition
Temperature
Yes SADT was explained to us prior to this question arising, which is why I was surprised by the instructors answer, so could you clarify using my example of Control Temp = -15 deg, Emergency Action Temp = 0 deg, SADT Temp = 15 deg at which temperature the decomposition starts and a reaction (explosion or fire) becomes inevitable/irreversible?
DD has answered your question?
Control temp -15deg - ie temp that the substance should be kept/ transported at.
0 deg - if this temp reached then stop and alert emergency services
15deg - If it rises to this temp then the reaction starts and b comes irreversible.
Don’t have ADR but from DD explanation that’s my understanding using your temp figs.
What did your instructor say then ?
The instructor said that if the temperature reached the Emergency Action Temp (0 deg in the example) then an explosion/fire was inevitable and nothing could be done from that point to reverse it and basically it was just a matter of time before it went boom.
It did not make sense to me as I thought the clue must be in the name (self accelerating decomposition temperature) and I asked him on two separate occasions to clarify that the information he was giving us was correct and on both occasions he was (very) adamant that what he was saying was correct.
MickyB666:
The instructor said that if the temperature reached the Emergency Action Temp (0 deg in the example) then an explosion/fire was inevitable and nothing could be done from that point to reverse it and basically it was just a matter of time before it went boom.It did not make sense to me as I thought the clue must be in the name (self accelerating decomposition temperature) and I asked him on two separate occasions to clarify that the information he was giving us was correct and on both occasions he was (very) adamant that what he was saying was correct.
Hi MickyB666,
Your thought on this is spot-on and dcgpx has this exactly correct too. 
To put this very clearly…
What you say the instructor said for emergency temperature is actually correct if he’d said … this happens once the SADT is reached.
The idea of a driver alerting the emergency services once the emergency temperature is reached is so that the fire brigade can arrive, assess and decide what they’re going to do about it, whilst they have the time it takes the temperature of the inside of the 'fridge to rise by (usually) 10deg C.
Due to the thermal efficiency of the 'fridge, they have the option to call a fridge repair engineer, or to put some kind of coolant into the 'fridge such as dry ice or CO2. They’ll possibly also consult a qualified industrial chemist to gain the full info relevant to the substance in question.
ADR says that substances in Class 5.2 (and some substances in Class 4.1) have many other requirements that must be met in order for carriage to be safe and legal.
Now I’m wondering about your recollection of what the instructor said about the emergency temperature 
Did your course handbook say anything on the subject of SADT etc in the class specific info for Classes 4.1 and 5.2
The instructors information/material doesn’t always seem to be correct though. As there was a minor error on a slide during my ADR training.
We were shown a slide about “Flash Points” and what constitutes a flammable liquids. And on that slide, it said that any liquid that has a flash point below 60 degree’s was classified as a flammable liquid, and Diesel was included even thought the flash point of Diesel was 56. Now that didn’t make sense to me, as 56 is within the limit, and would be included by default without need for mention. So I queried that with the instructor, and after looking at the slide for a second he agreed with me! Saying that it was an error and the flash point of Diesel was 65 degees, so outside of the range, but had special inclusion as so much of it is being moved around. During the break he obviously double checked this and looked at the (normally hidden) slide notes, which confirmed that the main slide had mixed the 5 & the 6 up, and the flash point of diesel is indeed 65, and therefore normally outside the classification limit.
Then he admitted that he’d been using that slide for 4 years, and no one had ever picked up on that error! 
Evil8Beezle:
The instructors information/material doesn’t always seem to be correct though. As there was a minor error on a slide during my ADR training.
Hi Evil8Beezle,
Your observation is spot-on mate, I know that slideshow 
… I spotted the error and corrected it when I received it as an update, so I didn’t run the risk of it being spotted.
Evil8Beezle:
We were shown a slide about “Flash Points” and what constitutes a flammable liquids. And on that slide, it said that any liquid that has a flash point below 60 degree’s was classified as a flammable liquid, and Diesel was included even thought the flash point of Diesel was 56. Now that didn’t make sense to me, as 56 is within the limit, and would be included by default without need for mention. So I queried that with the instructor, and after looking at the slide for a second he agreed with me!Then he admitted that he’d been using that slide for 4 years, and no one had ever picked up on that error!
Your instructor has it correct…
ADR deals with it like this:
… diesel fuel, gasoil, heating oil (light) including synthetically manufactured products having a flash-point above 60 °C and not more than 100 °C shall be deemed substances of Class 3, UN No. 1202. [my edit: and are therefore substances regulated by ADR as “dangerous goods.”]
dieseldave:
ADR deals with it like this:… diesel fuel, gasoil, heating oil (light) including synthetically manufactured products having a flash-point above 60 °C and not more than 100 °C shall be deemed substances of Class 3, UN No. 1202. [my edit: and are therefore substances regulated by ADR as “dangerous goods.”]
It’s a large scope of inclusion for Diesel, Heating oil etc… But I guess as these products can have a wide range of flash points under their named designations, It’s better to be safe than sorry!
dieseldave:
I remember very clearly as I asked him twice, once at the end of day two and again at the start of day three after I had spent the night pondering it and still coming to the conclusion that what he was saying didn’t make any sense.
He said that once the ‘Emergency Action Temperature’ had been reached the reaction leading to an explosion or fire had already started and that it was inevitable that it was going to go ‘bang’ or burst into flames, the only thing that could be done from that point was to slow down the reaction and extended the period of time that it took for it to go bang or burst into flames.
MickyB666:
dieseldave:
I remember very clearly as I asked him twice, once at the end of day two and again at the start of day three after I had spent the night pondering it and still coming to the conclusion that what he was saying didn’t make any sense.
He said that once the ‘Emergency Action Temperature’ had been reached the reaction leading to an explosion or fire had already started and that it was inevitable that it was going to go ‘bang’ or burst into flames, the only thing that could be done from that point was to slow down the reaction and extended the period of time that it took for it to go bang or burst into flames.
Thanks for that Micky, that’s cleared that up.
If your recollection of what was said is true (I’ve no reason to doubt it,) then the most I can say is that it could have been explained in a different way.
I hope I’ve tidied it up for you though.
Evil8Beezle:
dieseldave:
ADR deals with it like this:… diesel fuel, gasoil, heating oil (light) including synthetically manufactured products having a flash-point above 60 °C and not more than 100 °C shall be deemed substances of Class 3, UN No. 1202. [my edit: and are therefore substances regulated by ADR as “dangerous goods.”]
It’s a large scope of inclusion for Diesel, Heating oil etc… But I guess as these products can have a wide range of flash points under their named designations, It’s better to be safe than sorry!
That’s very true, but the normal range of flashpoints for Class 3, PGIII is restricted to…
… being within the range **>**23deg C - **<**60deg C
The piece I’ve quoted from ADR says (in connection with UN 1202) “a flash-point above 60 °C, …” so any variance is largely academic.
Anything with a flashpoint greater than 100°C is still a flammable liquid, but it’s not counted as ‘dangerous goods.’
It’s a bit like football teams… some are good enough to play in one of the leagues, but the rest are non-league, but are still football teams nevertheless.
Some dangerous goods are comparable to my football analogy, especially when in a diluted form.
dieseldave:
…I hope I’ve tidied it up for you though.
Yes, thanks for clearing that up for me, I enjoyed the course very much and the instructor was undoubtedly very knowledgeable, he obviously made a mistake but it just goes to prove that we are all human.
I like the analogy Dave, I think! - LOL
But it’s difficult to have a non technical discussion about ADR, that non ADR people can follow.
For example you mentioned PGIII, which most non ARD people wouldn’t have a scoody doo about! 
So I’ll clear that up and explain that you are referring to the Packing Groups, number 3 (low risk) to be specific.
But as they are marked as Roman Numerals, you are EXACTLY correct as always!
But I won’t go any further, as before i know it, I will be discussing Transport Categories…
Evil8Beezle:
I like the analogy Dave, I think!But it’s difficult to have a non technical discussion about ADR, that non ADR people can follow.
For example you mentioned PGIII, which most non ARD people wouldn’t have a scoody doo about!
There’s a bit of a post about ADR in the Safety and Law Forum, it’s where we generally keep all the ADR stuff in one place, but there were questions asked here, so I’ve done my best to answer them as non-technically as possible.
The post was well titled by the OP, so anybody not interested didn’t need to read it.
Evil8Beezle:
So I’ll clear that up and explain that you are referring to the Packing Groups, number 3 (low risk) to be specific.
But as they are marked as Roman Numerals, you are EXACTLY correct as always!
I’m getting the hang of it now. 
PG I = High Danger
PG II = Medium Danger
PG III = Low Danger
PGs are always written with Roman numerals to avoid the possibility of getting a PG number confused with a Class number:
UN 1202 DIESEL FUEL, 3, III
(The letters “PG” are optional on paperwork.)
Evil8Beezle:
But I won’t go any further, as before i know it, I will be discussing Transport Categories…
I’ll blow my whistle for offside if you do. 
dieseldave:
There’s a bit of a post about ADR in the Safety and Law Forum, it’s where we generally keep all the ADR stuff in one place.
Well I didn’t know that!
I’ve learnt something!
Cheers Dave, & it was clearly a goal!
I got my ADR through the post today, I think I got all the Classes but I am not totally sure as it doesn’t state any sub-divisions for class 2?
Is everyone’s card the same as mine?
The back of the card reads… …
VALID FOR CLASS(ES) OR UN Nos.:
TANKS
9.
2
3
4.1, 4.2, 4.3
5.1, 5.2
6.1, 6.2
8
9
OTHER THAN TANKS
10.
2
3
4.1, 4.2, 4.3
5.1, 5.2
6.1, 6.2
8
9
Is it because Class 2 has no packing group?
You got the lot pal!
Well, except 1 & 7 which you & I didn’t cover…
Evil8Beezle:
You got the lot pal!Well, except 1 & 7 which you & I didn’t cover…
Cheers for that
MickyB666:
I got my ADR through the post today, I think I got all the Classes but I am not totally sure as it doesn’t state any sub-divisions for class 2?Is everyone’s card the same as mine?
Hi MickeyB666,
An ADR card doesn’t state subdivisions for UN Class 2, so you’ve passed the whole lot as mentioned by Evil8Beezle above.
Congratulations!!