West Hercules is an ultra-deep-water semi-submersible drilling rig owned and operated by North Atlantic Drilling (Former SeaDrill) and is designed especially for harsh or extreme environment in the North Sea. The installation is constructed by DSME in South Korea. Hercules has been operating in the South China Sea since it was built and an AoC (Acknowledgement of compliance) were therefore never applied for. This contract was ended during spring 2012 and it was transferred to Norway for operation. To be able to operate on the Norwegian Continental Shelf, an AoC is required and HMS Design & Utvikling were therefore contracted to assist with the working environment related issues. Our scope of work for West Hercules has been to perform a complete working environment compliance inspection and HF/HMI verification of CCR/Bridge, driller’s cabin and crane cabins. These inspections were carried out during operation in the South China Sea. HMS DU has also been responsible for doing a complete mapping of illumination level all over the rig (both normal en emergency). This task was carried out during transit from Las Palmas to Norway and finalized during yard stay at Westcon in ├ślen. To summarize the working environment status for all rooms/ areas onboard, WEACs were established and filled out by HMS DU.