A Reserve Air Supply System (RASS) must be worn by NOAA Divers on OSHA-subject dives. In general, they are not required on dives that meet OSHA's Scientific Exemption, however, there are exceptions to this (see the "dives exempt from OSHA regulations" section below for more details). Read more about OSHA regulations on the NDP regulations page.
Dives Subject to OSHA Regulations
Divers must always have a reserve supply of air. Divers can meet this requirement by using:
For depths 0-30 feet: a spare air bottle
For depths 0-130 feet: a RASS
Dives Exempt from OSHA Regulations (Scientific Exemption)
Divers must use a reserve supply of air when diving:
Outside of no-decompression limits
In overhead environments
In low visibility where diver cannot read his/her pressure gauge
In enclosed/confined spaces
Deeper than 100 feet
Line tended solo diving
Whenever Divemaster or Lead Diver directs divers to wear one
What is an OSHA-subject Dive? What is an OSHA-exempt Dive?
Any dive that you are doing as part of your job must follow OSHA regulations. However, if the dive is conducted for the advancement of science it may fall under the Scientific Exemption. To find out if a dive qualifies for a scientific exemption, you must review the criteria set forth by OSHA and answer a set of basic questions. You can find this information and more in the Diving Program regulations page.