m.a.n rules:
m.a.n rules:
when i was on the petrol we called it vapour recovery or is this totally different?
hi dd is there a difference ?
Hi m.a.n rules,
I’m thinking there’s a question of terminology here.
On an ADR course, you’ll probably have heard of “vapour recovery” to be the system that I described for the gas in the OP.
I chose to use the term ‘vapour pressure balance.’
I think the difference is that somebody might be confusing the ‘open’ system with the ‘closed’ system.
The ‘open’ system is when the manlids of two atmospheric tanks are opened so that the pressures in both tanks are equal.
The advantage of this is that only one hose is needed for delivery.
The disadvantage is that an amount of unpressurised vapour equal to the transferred load is ejected to atmosphere from the receiving tank. Not a good idea in the handling of chemicals! 
The ‘closed’ system is the one that I described in my post answering the OP.
The ‘closed’ system needs a way of preventing implosion to the emptying tank and explosion of the receiving tank, so this is achieved by “recovering” the vapour that needs to be ejected from the receiving tank and putting it back into the emptying tank, thereby saving implosion/explosion and safeguarding the environment as well.
dieseldave:
Franglais:
dieseldave:
UKtramp:
I wouldn’t fancy driving the stuff around, I don’t mind transferring gases and liquids but can imagine a bit hair raising to drive. I would be worried of the slightest of leaks or accidents. Hats off to tanker drivers.
It’s not as bad as you might think UKT, and htat’s due to the safety systems.
As a general rule, an ADR liquid tanker usually has to have three independent means of closing each opening that is below the level of the liquid.
1.) Internal valve (aka ‘footvalve.’)
2.) External valve
3.) Blanking cap
Add to that an ADR requirement for baffles (aka ‘surge plates’) which break up longitudinal surge to obey the rule in ADR that you’re not allowed to drive around with your own personal tsunami in the back, and you’ll see that they’ve got the safety features pretty well specified.
As already discussed, there’ll be plenty of on-the-job training when the OP gets properly to work.
Is the ADR requirement for baffles a newer one Dave? Ive memories of 33 Inflammable Liquids in ISO tanks with no baffles. At least I think theyre true, not false, memories! Im thinking of the mid to late 90s. Could be confusion on my part as we did both Haz and non-Haz tanks. The baffles were good to stop surging, but a pig to clean when reloading with a different product.
Hi Franglais,
There was a bit of an earthquake that went through the UK road tanker game that came about in as from 10th May 2004.
From then, all new tank vehicles (tankers) had to have baffles, except in some circumstances.
There was also a rule that I call the 80/20 rule to do with the % fill that an unbaffled ‘old’ tank could carry.
ISO tanks have different rules, primarily for the difficulty in cleaning that you mentioned.
Thanks for the reply.
Several years since I did that work. If I remember it was Kemmler 336 or 33 depending on who was doing the export docs. UN 1170. 90% plus pure.
Doing only food tanks we had to get them really clean, and the odd tanks and road barrels (non haz) we had with baffles were a pain to clean. The ISO tanks were used between different EU countries, not for outside the EU. They rode fine with just a little ullage in, but some of the reloads were very dense, and not very viscous, so 16,000 litre of liquid at 24tons in a 26,000 tank slops like a ****! They were non haz reloads, BTW. The step frame skellys we were running take a lot of damage because of this. Truck transmissions, sliding fifth wheels etc didnt have an easy ride at all either.
thanks for the reply dave. as you know with petrol this is a continual cycle with the loading/unloading procedure.
Franglais:
Several years since I did that work. If I remember it was Kemmler 336 or 33 depending on who was doing the export docs. UN 1170. 90% plus pure.
Hi Franglais,
I’m thinking there’s a mis-memory at work due to the passage of time. (It happens to me too!!)
UN 1170 ETHANOL (ETHYL ALCOHOL), 3, PG II (OR PG III) shouldn’t have a ‘6’ in the HIN, because a ‘6’ indicates toxicity.
The PGII version should have a HIN of 33, whilst the PGIII version has a HIN of 30.
At a guess, the HIN of 336 would be correct for UN 1230 METHANOL, 3 (6.1) PG II, did you also carry methanol?
m.a.n rules:
thanks for the reply dave. as you know with petrol this is a continual cycle with the loading/unloading procedure.
Yes indeed mate, in this case… ‘vapour pressure balance’ has exactly the same meaning as ‘vapour recovery,’ because you certainly wouldn’t want to vent the vapour with all the risks involved. 
dieseldave:
Franglais:
Several years since I did that work. If I remember it was Kemmler 336 or 33 depending on who was doing the export docs. UN 1170. 90% plus pure.
Hi Franglais,
I’m thinking there’s a mis-memory at work due to the passage of time. (It happens to me too!!)
UN 1170 ETHANOL (ETHYL ALCOHOL), 3, PG II (OR PG III) shouldn’t have a ‘6’ in the HIN, because a ‘6’ indicates toxicity.
The PGII version should have a HIN of 33, whilst the PGIII version has a HIN of 30.
At a guess, the HIN of 336 would be correct for UN 1230 METHANOL, 3 (6.1) PG II, did you also carry methanol?
One of the suppliers, a French one, insisted on 336. The Trem card had a warning about “vapours causing mental confusion” or some such! Our other suppliers of the stuff didn`t use the 6. All of it was food grade ethanol.
Always nervous on nights out with the stuff. Food tank with Haz plates…
dieseldave:
m.a.n rules:
thanks for the reply dave. as you know with petrol this is a continual cycle with the loading/unloading procedure.
Yes indeed mate, in this case… ‘vapour pressure balance’ has exactly the same meaning as ‘vapour recovery,’ because you certainly wouldn’t want to vent the vapour with all the risks involved.
when you mention the risks involved it reminded me of a site i use to deliver to in brum which was on the vent pipe system. the pipes come out of the ground on one side of a 3 foot wall on the other side of the wall was a snack van cooking on gas and people smoking directly under the pipes.
dieseldave:
That’s a fair comment UKT, and very understandable to me.
For my part, I know nothing about the technical side of it because I was a tanker driver, not a technician.
A tanker driver needs specific training for both the vehicle AND the product to be carried.
I was not concerned or had any understanding of what anybody did with the ‘stuff’ once I’d put it in the correct receiving tank because the bit that I do understand is that those people are far cleverer than I on their subject.
I find it interesting as we get gas delivered but I have never seen how tanker drivers load/ unload. It is every part of the supply chain that rarely people get to see. Why I thought putting my RDC ammonia charging videos would be of interest to some. Everyone does there own job and other peoples jobs sort of becomes a bit of a black magic scenario. On my videos I show the vapour recovery process as well as a leaking hose, certainly not something you see every day. I would love to see a tanker unloading gas.
m.a.n rules:
dieseldave:
m.a.n rules:
thanks for the reply dave. as you know with petrol this is a continual cycle with the loading/unloading procedure.
Yes indeed mate, in this case… ‘vapour pressure balance’ has exactly the same meaning as ‘vapour recovery,’ because you certainly wouldn’t want to vent the vapour with all the risks involved.
when you mention the risks involved it reminded me of a site i use to deliver to in brum which was on the vent pipe system. the pipes come out of the ground on one side of a 3 foot wall on the other side of the wall was a snack van cooking on gas and people smoking directly under the pipes.
Ahh yes, I remember the old type of vent system.
The theory behind it was that by the time the vapour (known to be heavier than air) had exited the usually quite high vent pipe, the vapour would be smelly, but outside of the flammable range by dilution in air.
Then (IIRC) there came a law about releasing the vapour into the atmosphere regardless of mix, so that’s when the high vent pipes started to disappear.
Franglais:
… Always nervous on nights out with the stuff. Food tank with Haz plates…
Hi Franglais,
These days, any Class 3 PG I and PGII stuff >3,000L in a tank is subject to HCDG rules, so that’s probably one of the changes since you were doing that job.
As for Haz plates on a food grade tanker, there are a couple of other substances that need this too.
UN 2790 ACETIC ACID, 8, PGII (or PGIII)
UN 1805 PHOSPHORIC ACID, 8, PGIII
The HIN for all three of those = 80
dieseldave:
Franglais:
… Always nervous on nights out with the stuff. Food tank with Haz plates…
Hi Franglais,
These days, any Class 3 PG I and PGII stuff >3,000L in a tank is subject to HCDG rules, so that’s probably one of the changes since you were doing that job.
As for Haz plates on a food grade tanker, there are a couple of other substances that need this too.
UN 2790 ACETIC ACID, 8, PGII (or PGIII)
UN 1805 PHOSPHORIC ACID, 8, PGIII
The HIN for all three of those = 80
Had a quick look up about those. Although Acetic acid is familiar, Phosphoric Acid sounds frightening doesnt it? But then combining Sodium and Chlorine doesnt sound such a clever idea either. Works well for the fried potato industry though!
Franglais:
Had a quick look up about those. Although Acetic acid is familiar, Phosphoric Acid sounds frightening doesnt it? But then combining Sodium and Chlorine doesnt sound such a clever idea either. Works well for the fried potato industry though!
You’re now way outside of my comfort zone… I’m no chemist. 
I do have a phone-a-chemist option on my phone though. 
Franglais:
Phosphoric Acid sounds frightening doesn`t it?
!
Big in the soft drink industry as an ingredient (cola) hence why Cola concentrate is transported under ADR regulation.
Some of the stuff that goes into food is proper nasty in concentrated form.
Caustic soda in chocolate, citric acid in soft drinks and sweets.
It all takes your skin off in concentrated form.
A lot of non hazardous stuff carried in Tankers can be nasty, tipping or loading wheat flour can raise the roof literally.
High pressure water, compressed air, steam, electric shock, falls from height, tank entry can cause death or injury without warning.
Wheel Nut:
A lot of non hazardous stuff carried in Tankers can be nasty, tipping or loading wheat flour can raise the roof literally.
High pressure water, compressed air, steam, electric shock, falls from height, tank entry can cause death or injury without warning.
Very true Malc.
After reading your wise words above, anybody considering climbing into a tank should have a think about what was in the tank previously.
If the vapour of that substance contains little/no oxygen ( = saturated atmosphere) then asphyxiation can be added to your list of dangers above as a very real possibility.
Asphyxiation happens very quickly and there’s not always an odour to warn of the danger!
FYI dieseldave your guess on UN 1965 was spot on. Thanks for your replies everyone.