I didn't know that, there is an Expiry Date for LPG Gas Cylinders we use in our day to day life for cooking.
On one of three side stems of the cylinder, the expiry date is coded alpha numerically as follows A or B or C or D and some two digit number following this e.g. D06 or D-06
The alphabets stand for quarters -
1. A for March (First Qtr),
2. B for June (Second Qtr),
3. C for Sept (Third Qtr),
4. D for December (Fourth Qtr).
The digits stand for the year till it is valid. Hence D06 would mean December qtr of 2006.
Its Good to Return Back the Cylinder that you get with a Expiry Date, they are prone to Leak and other Hazardous accidents...