Whats the legal alcohol limit?

Lorax

Like if there's 2.3 units of alcohol in a pint of miller. And someone drinks 2 pints of miller that's 4.6 units. But then your liver processes roughly 1 unit of alcohol an hour. Now the limit is 80mg alcohol/100ml blood. Now 1 unit of alcohol = 10ml alcohol = 8g of alcohol. So what I'm asking is could the average person have 9 units of alcohol (9 x 8g = 72mg/100ml blood = under legal limit) and still be under the limit - because that seems like an awful lot?

Please don't lock this I'm not discussing doing anything illegal nor am I advocating drink driving. I'm just curious because the way I interpret the law at the moment is someone can lash back 3 pints of miller in a short space of time and still be under the legal drink driving limit. Correct me if I'm wrong - thanks.

dr.bollocko

There is no good rule of thumb to be sure how much alcohol you can drink before you are over the limit.

Bradidup

Extracts from the new rules of the road.

It is a criminal offence to drive, attempt to drive or be in charge of a motor
vehicle if you have more than:
80 milligrammes of alcohol per 100 millilitres of blood,
107 milligrammes of alcohol per 100 millilitres of urine, or
35 microgrammes of alcohol per 100 millilitres of breath.

There is no reliable way to tell how much you can drink before you exceed the
legal limit.

Mitch Connor

Lorax wrote:

Like if there's 2.3 units of alcohol in a pint of miller. And someone drinks 2 pints of miller that's 4.6 units. But then your liver processes roughly 1 unit of alcohol an hour. Now the limit is 80mg alcohol/100ml blood. Now 1 unit of alcohol = 10ml alcohol = 8g of alcohol. So what I'm asking is could the average person have 9 units of alcohol (9 x 8g = 72mg/100ml blood = under legal limit) and still be under the limit - because that seems like an awful lot?

Please don't lock this I'm not discussing doing anything illegal nor am I advocating drink driving. I'm just curious because the way I interpret the law at the moment is someone can lash back 3 pints of miller in a short space of time and still be under the legal drink driving limit. Correct me if I'm wrong - thanks.

purely going off what you have written, the calculations are incorrect.

if 1 unit of alcolhol equals 8g, then that is the 80mg limit.

Lorax

Im not thinking of doing it nor am I advocating drink driving (as I said).
Im just curious. The way I see it - its no different than people discussing speeding (which is also illegal). That website is mostly legal info - I'm more interested in the technical side of things but what I gather from it -

81 mg - 100 mg 3 months 6 months

If you dont consume 81mg of alcohol - how can there be 81mg-100mg of alcohol in your blood? The urine concentration is

107 - 135 mg

again, do the maths - if I don't consume 107mg of alcohol, how can that amount be present in my urine?

Stephen

I seriously doubt it.

Also, 9x8g = 72 grams! i.e. 7200mg. I dunno what 1 unit equates to in milligrams, just using your figures. I just don't drive after drinking any alcohol at all.

I think that 8g figure refers to pure ethanol also.

Edit: according to this site: http://www.cleavebooks.co.uk/dictunit/notes6.htm - 1 unit is different in each country. They say that it is 10g or 12.7ml in Ireland.

Lorax

Tauren wrote:

purely going off what you have written, the calculations are incorrect.

if 1 unit of alcolhol equals 8g, then that is the 80mg limit.

Oh yeah - my mistake

What is a unit of alcohol?

One unit of alcohol is 10 ml (1 cl) by volume, or 8 g by weight, of pure alcohol. For example:

Esel

How many millilitres of blood does the average person have? A figure I heard years ago was 8 pints, so 4540ml? (give or take). What figure did you use in your calculations?

Our man in Havana

The amount of blood in a person depends of loads of factors, weight and height etc. Avg is 8 to 10 pints.

overdriver

I would say if you HAVE to have a drink - which I don't beleieve for a minute - leave it at the one. Then make sure at least an hour has passed before you drive and you'll be safe enough.

smcelhinney

overdriver wrote:

I would say if you HAVE to have a drink - which I don't beleieve for a minute - leave it at the one. Then make sure at least an hour has passed before you drive and you'll be safe enough.

Eh... no....

There should be NO circumstance where you HAVE to drink and drive, your post is essentially advocating drink-driving.

Try telling that to the countless families in Ireland who have lost relatives and friends, simply because someone decided to have "1 beer on the way home"..

I think there should be zero tolerance to this. I do believe that there is no definitive way of ensuring that blood-alcohol is 0, in that, you never know fully what it is your eating/drinking, and to a certain extent common sense should prevail, but there should be some way of distinguishing imbibement of alcoholic beverages vs other means, and zero tolerance policy applies there.

Hotblack Desiato

This zero tolerance talk is just idiotic. It's not the guys having one pint on the way home, or with a nice Sunday lunch out, etc. who are causing all the accidents. The habitual drink-drivers will have several pints and be 2 or 3 times over the existing limit, and in many areas they know they can still keep getting away with it as they have done for years. They won't give a damn if the limit goes down to 50 or 20mg as they're breaking it anyway.

Jocksy

I use that one drink one hour rule. Or two 2 drinks 3 hours. Or some nights it would be 4 drinks 6 hours.

romperstomper

realistically speaking ZERO tolerance is ridiculous as there will be some residual alcohol in my system the next day. So I drink some wine with dinner Friday night, then next day I can't drive my car to go shopping?? On a off chance that there may be 1mg of alcohol in my blood??

try and think things through before getting on the high horse

wexford12

The only way of been sure is NOT TO DRINK AND DRIVE why would you even want to chance it.Its not worth it even as most say you will loose your licence "fcuk" the licence if you kill someone there family has to live with it for ever more.If it means you have to live with it on your mind also hard luck.One pint why would you bother having one pint go have your few pints and enjoy yourself and get a taxi home.And the excuse off no taxis is rubbish its your too mean to pay the fair.Twenty odd quid would be the most you would be charged your local cant be that far away and for 20euro is it worth killing someone or yourself.Sorry for the rant and yes i have a family member who was killed by getting into his car drunk.

unkel

Beware about any "rules". As others have said, there is no reliable way to know how much alcohol is in your blood unless you do not drink

Apart from the amount of alcohol consumed and the time it was consumed over, there are many other factors that play a role, such as sex and weight. Even then, one person metabolises alcohol much quicker than another person of the same sex and weight

Hotblack Desiato

unkel wrote:

Apart from the amount of alcohol consumed and the time it was consumed over, there are many other factors that play a role, such as sex

Interesting way of sobering up

unkel

LOL - classic "bank holiday is only hours away" humour

overdriver

smcelhinney wrote:

Eh... no....

There should be NO circumstance where you HAVE to drink and drive, your post is essentially advocating drink-driving.

Try telling that to the countless families in Ireland who have lost relatives and friends, simply because someone decided to have "1 beer on the way home"..
e.

Read it again. Did you see where I said " I don't believe this for a minute"?

Guy:Incognito

romperstomper wrote:

realistically speaking ZERO tolerance is ridiculous as there will be some residual alcohol in my system the next day. So I drink some wine with dinner Friday night, then next day I can't drive my car to go shopping??

Assuming you weigh more than 1 stone and have some serious isses going on in your body, a few glasses of wine at dinnertime (7/8/9) on a Friday night will not leave any alcohol in your system 12 -14 hours later.

Hotblack Desiato

unkel wrote:

LOL - classic "bank holiday is only hours away" humour

The ol' quote out of context never fails...

On a serious note, bank holiday weekends are dangerous times on the road and no doubt a few more lives will be needlessly lost this weekend. Be careful out there.


Disclaimer - sex is not a reliable method of reducing blood alcohol level. (Actually - more research is needed - could there be a grant in this?)

smcelhinney

overdriver wrote:

Read it again. Did you see where I said " I don't believe this for a minute"?

Then why make the point!? You pretty much just contradict yourself in that whole sentence.

overdriver

I was intercepting a reply before it happened.

royob

The "Sex and Weight affecting the amount of alcohol you consume" issue rings true with me on account of the amount of alcohol I have to drink before I even consider having sex with my fat girlfriend, God I hope she doesn't read boards.ie or sex might be off the menu altogether !

Nissan doctor

royob wrote: »

The "Sex and Weight affecting the amount of alcohol you consume" issue rings true with me on account of the amount of alcohol I have to drink before I even consider having sex with my fat girlfriend, God I hope she doesn't read boards.ie or sex might be off the menu altogether !

You dug up a 5 year old thread to say that! I'd imagine you have a few units of alcohol in you at the moment!

mathepac

The RSA are fairly consistent in their wording in their campaigns - “If you drink, don’t drive”. Let’s look at the unfortunate example of Johnny (mythical person) who falls victim to the “morning after” trap [note the irony and sarcasm].

Johnny goes to his local at 9:00pm and starts drinking. He goes home at 2:00am having consumed 10 pints, ordinary beer / Guinness, regular alcohol content. During his time in the pub Johnny’s body has had 20 units of alcohol poured into it (2 units per pint for illustrative purposes, it’s actually more than 2) and has processed and eliminated 5 units (1 unit / hour), leaving a residue of of 15 units of alcohol. Johnny goes home, has a decent night’s unconsciousness and gets up at 8:00am to go to work.

Johnny is stopped on his way to work at 9:00am and breathalysed. He fails the test as his body still has the equivalent 8 units of alcohol or 4 of last night’s pints and he is over the limit.

Why? The body’s ability to process and eliminate alcohol is fixed - there is no way to speed it up, and in fact it will slow down as more alcohol is consumed although the liver processes more efficiently while we sleep, which is why some drugs are prescribed to be taken at bed-time.

Johnny is drunk-driving as defined by the current laws and will be prosecuted. It will be in or around 5:00pm when the last of the alcohol is completely gone from Johnny’s body. This is not to say he will fail a breath-test before 5:00pm or pass one after 5:00pm - it all depends as there are no absolutes when you deal with individual human beings of different genders, weights, heights, states of health, who have recently eaten, who have different tolerance levels, etc. etc.

Alanstrainor

royob wrote: »

The "Sex and Weight affecting the amount of alcohol you consume" issue rings true with me on account of the amount of alcohol I have to drink before I even consider having sex with my fat girlfriend, God I hope she doesn't read boards.ie or sex might be off the menu altogether !

If that's all you have to say on this forum, you'd be better off not posting again.