Written By: Steven Johnson, Project Engineer, Horizon Engineering Associates, LLP
When performing a steam trap survey on your building’s systems, owners/operators receive a comprehensive map of how efficiently their current steam systems are operating. A well-executed steam trap survey will also include a plan for increasing the system's efficiency by detailing which steam traps have failed or are not functioning within their peak operating parameters. Another benefit of a properly conducted steam trap survey is that, once completed, a database will be in place to monitor the lifespan of the plant’s steam traps and provide insight as to when each steam trap should be replaced. Once the failed steam traps have been replaced, significant savings, in not only energy costs but also makeup water usage, will be realized.
Other major benefits of maintaining a properly functioning steam plant originates in the mechanical room itself. Steam traps that have failed to open or are leaking will allow steam to travel through the condensate piping, resulting in high temperature condensate, or steam, reaching the condensate pump impeller. If either of these fluids reach the impeller, the fluid will flash upon an increase in pressure and cause cavitation. Cavitation is devastating to pump performance and will often require a major pump overhaul. Failed steam traps will also increase the air temperature of the mechanical room. In most cases, mechanical equipment will function optimally at lower air temperatures. The lower temperature environment that a fully functional steam plant creates indirectly increases system performance, thereby decreasing operating costs.
Steam Trap Testing 101
Building operators have been conducting steam trap surveys since the turn of the century so, as can be expected, the methods that our forefathers used have since become obsolete. Originally, the main technique used to determine the functionality of an installed steam trap relied upon the temperature differential between the inlet and outlet sides of a steam trap. While this technique can still be used today, more effective methods have been developed and are continually evolving. These improved methods involve ultrasound and infrared technologies. In utilizing ultrasound technology, a technician will use either headphones or a speaker in conjunction with an ultrasound meter and probe to listen to the sounds created inside of the trap. Steam traps produce different sounds during normal operation versus a failure condition. For example, a properly functioning float & thermostatic steam trap will produce a clicking sound each time the float lifts off of the condensate discharge port. This same type of steam trap will produce a rushing sound if it has failed in an open position or no sound at all if it has failed to close. A final indication that a steam trap has failed is a substantial temperature differential (if the trap has failed to close) or an extremely minimal temperature differential (if it has failed to open). Temperature differentials across steam traps are most effectively measured through the use of an infrared camera. Infrared cameras create a heat map of each trap which can then be quickly analyzed to pin point failed steam traps.
When Should Steam Trap Surveys Be Performed?
With the heating season just around the corner, now is the time to have a steam trap survey performed on your facility. Identifying failed steam traps and replacing them will result in a more efficient, properly functioning system that will increase occupant comfort and decrease energy costs. Steam trap surveys are relatively inexpensive to perform and generate substantial overall savings, making this process a no-brainer.