API RP 2350 (3rd edition 2005) "Overfill Protection for Storage Tanks in Petroleum Facilities" specifies that high-high-level detector shall be independent of the automatic tank gauge system to provide greater reliability and to comply with the requirements of NFPA 30-2003, Section 4.6.1.1(2) and 4.6.1.1(3). Further there is a Note that State-of-the-art equipment with integrated (not independent) hardware can provide superior reliability for detecting high and high-high levels. NFPA 30-2003 Section 4.6.1.1(4) allows for the use of non-independent alternative systems, provided they are approved by the authority having jurisdiction.

What are the types and specifications of the '"State-of-the-art" level instruments with integrated hardware for tank gauging and overfill protection? Do radar type level instruments qualify for this? I will be thankful for clarification on these points. Thanks.