Over the years there have been many iterations and editions of the Standard as the document has evolved along with society's expectations, technical improvements and new technologies.
According to Standards Australia;
Australian Standards® are living documents that reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be issued.
The latest edition of AS1851 was published in 2012 and has been subsequently amended (Amendment 1).
The objective of Australian Standard AS1851:2012 is to maintain the reliability of fire protection systems and equipment such that they continue to meet the requirements of the approved design and are likely to do so until the next scheduled activity.
One of the core principles of the Standard is that it has been written such that it can be universally applied to fire protection systems and equipment irrespective of when it was manufactured or installed.
In practical terms this means that the Standard should be able to be applied to a fire hydrant system from the turn of last century or to one that was installed today.
The key phrase that helps make this possible within the Standard is the term approved design. The definition of this term is;
1.5.2 Approved design
The design of fire protection systems and equipment approved by the authority having jurisdiction at the time of installation or subsequent modification.
By applying this definition we can assure ourselves that the system or equipment is inspected, tested and maintained in accordance with its original design criteria.