There is no legal requirement for the installation of an LPG detector. This is not mentioned in the license conditions or THE GAS CYLINDERS RULES 2004.
In February 2016, the Controller of Explosives in Hyderabad conducted a meeting with all companies in Hyderabad. During the discussion with the authorities, they mentioned that there are no such requirements.
However, the concerned authority has the right to insist that we install a gas detector for safety concerns.