(CNN) -- A rigorous green certification system is recognizing
the next phase of eco design, which its founders describe as
"the world's greenest buildings." Founded by Jason F. McLennan
in 2006 through the Cascadia Green Building Council, the Living
Building Challenge (LBC) is a green ratings system for design
and construction that judges a building based on its actual
performance, not just its projected performance at the design
stage. To date, it has recognized six buildings for their green
credentials. Only three have been successful in meeting all its
stringent requirements and consequently fully certified as
"living." "These are the world's greenest buildings," says
McLennan. "It is a huge leap forward from conventional green
construction. These buildings will never get an energy or water
bill again." Projects must be in operation for a minimum of 12
months before they become eligible to participate in the
challenge and they can only achieve "living" status after
fulfilling requirements in the categories