This standard BS 2G 115:1956 Specification for sensitive altimeters for aircraft is classified in these ICS categories:
49.090 On-board equipment and instruments
This British Standard specifies the design and performance requirements for sensitive altimeters for aircraft. It is applicable to mechanical instruments operated directly by an aneroid barometer movement.
The performance requirements are based on two ranges — 1 000 to 35 000 ft and — 1 000 to 50 000 ft respectively.