||Fired heaters are used for heating hydrocarbons fluids in the refineries and petrochemical plants. They are used for high temperature heat transfer. In most fired heaters, we are burning fuel gas as source of heat . Heaters that are processing hydrocarbons services are prone to coking and cracking depending upon the nature of the hydrocarbons being processed. Typically heaters may run length of anywhere from 3 months for coking service to 6 years for different services. Heater designers and operators are always faced with the challenge of providing uniform heat transfer to all the tubes. Engineers use equations that assume uniform heat transfer to heater tubes when designing fired heaters. However, in reality, most fired heaters do not experience uniform heat transfer, and as a result, hot spots develop on the tubes. These hot spots cause coking inside the tubes which requires the heater be shutdown periodically to remove the coke and clean the tubes. Any shutdown to clean the tubes in a fired heater causes a substantial production loss. Furnace Improvements has developed a new patented firing technology that provides uniform heat transfer to heater tubes. This technology can be applied to most fired heaters. Our patented technology reorients the burners at a slight angle away from the tubes. We are able to direct the hottest part of the flames and flue gases away from the tubes without affecting the heat transfer in any way. FIS has installed this in 6 heaters ranging from 14 MMBtu/hr. to 280 MMBtu/hr. The clients are experiencing significant reduction in tube metal temperatures. This is translating into lower coking rates and higher tube life. We have been able to increase the capacity of the heaters in most of the cases. In this paper, we will present two case studies utilizing new firing patterns. in the first, the Inclined Firing System was installed in a very large vertical cylindrical crude heater. The client experienced 250 F to 350F lower tube metal temperatures after the heater was fitted with inclined firing system. In the second study, IFS was incorporated in a small vertical cylindrical heater Diesel Hydrotreater heater. In this case, the heater duty was increased from 14 MMBtu/hr. to 21 MMBtu/hr.