A FLT CREW DECLARES A LOW FUEL EMER AND DIVERTS.

Narrative

FLT PLAN TIME ESTIMATE 2 HRS 38 MINS. FUEL AT DEP 19100 LBS. FLEW FLT PLAN ALT AND MACH WITH NO DELAYS AT INTERMEDIATE ALTS. NOTICED LOW FUEL DURING DSCNT (30 MINS PRIOR TO LNDG) AND CALCULATED APPROX ARR FUEL AT 2000 LBS TOTAL (1000 LBS PER SIDE); SO OPTED TO DECLARE AN EMER AND LANDED AT CRP. UPON ARR FLT TIME WAS ABOUT 3 HRS 5 MINS AND FUEL BURNED WAS 16100 LBS. FOB AT LNDG WAS 3000 LBS TOTAL. TFC VECTORING INTO IAH DUE TO SATURATION. THE RECENT EMPHASIS ON FUEL SAVINGS HAD ME THINKING OUTSIDE MY USUAL '6000 LBS PER HR' RULE OF THUMB BURN RATE. AT FL370 I THOUGHT THAT MAYBE THE FUEL FLOW WAS SIGNIFICANTLY LOWER THAN I ANTICIPATED AND THEREFORE I ACCEPTED MY DISPATCH FUEL LOAD/FLT PLAN. REVIEWING WX; THE FLT PLAN WOULD HAVE PUT US ON THE GND IN IAH AT 5000 LBS TOTAL. THIS IS MINIMUM FUEL FOR ANY PLT. AT 2500 LBS PER SIDE EVEN A GAR BECOMES AN EYE OPENING EVENT. ANY ALT CHANGES ENRTE DUE TO TURB OR TFC SATURATION/RWY CLOSURE ETC; PUTS US ALL AT RISK. I COULD USE SOME EASY-TO-ACCESS FUEL BURN CHARTS (LBS/HR/ALT) IN OPS/WX ROOMS TO ASSIST MY PLANNING. BY THE WAY; ATC DID A WONDERFUL JOB THE ENTIRE WAY. SUPPLEMENTAL INFO FROM ACN 610173: RAN QRH CHKLIST; CONSULTED OPS MANUAL AND DISPATCH. SUSPECT FLT PLAN ERROR OR POSSIBLE FUEL SYS MALFUNCTION.