Expiry of gas cylinders

Hello ladies!
I want to share this important information that I got from a friend of mine.
On one of the side stems of the gas cylinder, the expiry date is coded alphanumerically as follows - A,B,C or D along with a 2 digit number.
A is for March, i.e the 1st quarter
B is for July, the 2nd quarter
C is for September, the 3rd quarter and
D is for December, the 4th quarter
The 2 digit number stands for the year of expiry.
Eg: C07 means the physical life of the cylinder expires in September 2007.
Please check this when your gas delivery man brings you the cylinder. And, refuse to receive it if the date has expired. It will save you a lot of problems.
Please pass on this message to all your acquaintences.
Regards,
SubhaD