b. Output Verification: Independent certified testing shall indicate that when Emitter first installed total output per one inch arc length shall not be less than 9 W/cm2, at one meter, in a 500 fpm airstream of 50 F, and at end of manufactures tube warrantee period, or 9000 hours, which ever is longer, shall have output per one inch arc length not be less than 4 W/cm2 at one meter, in a 500 fpm airstream of 50 F.