Cylinder Certification and Recertification
Cylinders are subject to recertification (also known as requalification) twelve years from their date of manufacture and every five years after that. For example, a cylinder manufactured in January of 2000 will have to be recertified in January of 2012 meaning if you take your bottle to the propane company in April of 2012 to be refilled, it will have to be requalified by authorized personnel before it can be filled. The recertification process is simple and does not take too long to complete.
The place doing the inspection should apply a dated sticker to the tank. This supersedes the stamped date so others will refill without questions.
(I’ve never had anyone refuse to fill my tank and I’m sure it is more than 12 years old.)