Legal limits are either explained as a Blood Alcohol Concentration (BAC) or Breath Alcohol Concentration (BrAC) measurement.

 

BLOOD ALCOHOL CONCENTRATION (BAC)

 

The results of a breath analysis may be expressed in any of the common methods for blood alcohol concentration:

  •    mg% – milligrams of alcohol in 100 millilitres of blood
  • %BAC- grams of alcohol in 100 millilitres of blood
  • Promille – grams of alcohol in 1 litre of blood

 

The relationship between these expressions is illustrated as follows:

 

             50 mg % = 0.05 % BAC = 0.50 % Promille

 

BREATH ALCOHOL CONCENTRATION (BrAC)

 

The results of a breath analysis may also be expressed directly in terms of breath alcohol concentration:

  • mg/litre – milligrams of alcohol in 1 litre of breath
  • mg/210L – milligrams of alcohol in 210 litres of breath
  • µg/100 mL – micrograms of alcohol in 100 millilitres of breath

 

The relationship between these expressions is illustrated as follows:

 

             50 mg % = 0.24 mg/L = 50 mg/210L = 24 µg/100 mL

 

The above illustrations illustrate the legal driving limit for non-professional drivers.

 

Below is a table that gives you a wide range of BAC and BrAC measurements and comparisons.

Alcohol Legal Limits

Alcohol Legal Limits

 

WHAT DOES THIS ACTUALLY MEAN?

The rule of thumb is a maximum of one unit of alcohol per hour, which constitutes 10ml of pure alcohol, based on an adult weighing 68kg. Our bodies can process only one unit of alcohol each hour. However, it is important to be aware that if you weigh less than 68kg your body will need more time to process the same amount of alcohol.

 

WHAT DOES ONE UNIT REPRESENT IN LAYMAN’S TERMS?
  • It is equal to two thirds (225ml) of a beer or spirit cooler per hour with 5% alcohol content (a whole being 340ml).
  • For those who drink wine, 75ml of red or white wine per hour with an alcohol content of 12% to 14% is acceptable.
  • Whisky and brandy connoisseurs can drink up to one 25ml tot of alcohol per hour.

In case you are wondering if there are any quick-fix solutions, drinking coffee to get sober is a myth, as is taking a cold shower or drinking a litre of water. Once the alcohol is in your system your liver is going to need time to process it, and restricting yourself to only one unit per hour will give your body the time it needs to stay sober in the eyes of the law.

          

                                                                                                                                    – The AA

If you fail to abide by these laws this might well be your punishment (click here).