Heat production from gas fuels such as propane or natural gas depends on the amount of gas burned measured in cubic feet per hour. The Btu produced by the burning of the gas specifies how much heat is available for heating.
1 Symptoms of a kidney stone include flank pain (the pain can be quite severe) and blood in the urine (hematuria). 2  People with certain medical conditions, such as gout, and those who take certain medications or supplements are at risk for kidney stones.
Problems that may occur with kidney stones include: 1  An increased risk of urinary tract infection, or making an existing urinary tract infection worse. 2  Kidney damage, if stones block the flow of urine out of both kidneys (or out of one kidney, for people who have a single kidney).