UK Barrels
A UK barrel is 36 imperial gallons (not to be confused with American gallons), about 163.659 liters or 0.163659 cubic meters. It is based on the traditional wine barrel used in the United Kingdom.
Teaspoon
There is more than one type of teaspoon:
A US teaspoon is 4.93ml: US teaspoon
A UK teaspoon is 5ml: UK teaspoon