Steam Theory 1. Basics of Steam What is Steam? Principal Applications for Steam Types of Steam Flash Steam How to Read a Steam Table 2. Steam Heating Heating with Steam Steam Heating Mechanism Overall Heat Transfer Coefficient What is Vacuum Steam? Tracing the Causes of Heat Maintenance Issues 3. Basics of Steam Traps What is a Steam Trap? The History of Steam Traps #1 The History of Steam Traps #2 How Mechanical Traps Work: A Look at their Mechanism and Merits How Disc Traps Work: A Look at their Mechanism and Merits How Bimetal-Type Thermostatic Steam Traps Work: A Look at their Mechanisms and Merits 4. Steam Trap Selection Steam Trap Selection: How Application Affects Selection Steam Trap Selection: Understanding Specifications Steam Trap Selection: Safety Factor and Life Cycle Cost Traps and Orifices Part 1 Traps and Orifices Part 2 Casting vs. Forging Applications of Different Types of Steam Traps Don't Get Steamed : Selecting Steam Trap Design Understanding Steam Traps Compare Two Fixed Orifice Venturi Products to a Variable Orifice Free Float Steam Trap 5. Steam Trap Problems Is My Trap Leaking Live Steam? Temperature Control Trap Precautions Trap Installation Orientation Trap Back Pressure Double Trapping Group Trapping Steam Locking Air Binding My Steam Trap Is Good - Why Doesn't It Work? 6. Steam Trap Management Introduction to Steam Trap Management Steam Trap Losses - what it costs you A Guide to Steam Trap Testing Implement a Sustainable Steam Trap Management Program Impact Plant Performance by Improving the Steam System 7. Water Hammer Water Hammer: What is it? Water Hammer: The Mechanism Water Hammer: Cause and Location Water Hammer: In Steam Distribution Lines Water Hammer: In Equipment Water Hammer: In Condensate Transport Piping Identifying Water Hammer Using a Thermal Camera Mitigation of Water Hammer in Vertical Flashing Condensate Transport Piping Stop Knocking Your Condensate Return Steam Trap Management: Do Something; Anything. Please! 8. Risk Mitigation Steam System Optimization and Risk Mitigation Risk Based Methodology for Industrial Steam Systems Why Bad Things Happen to Good Steam Equipment Beware of the Dangers of Cold Traps Steam System Winterization: How to Protect Your Plant 9. Steam Quality Wet Steam vs. Dry Steam: The Importance of the Steam Dryness Fraction Separators and their Role in the Steam System Clean & Pure Steam Temperature Problems Caused by Air Removing Air from Steam Equipment Air Vents for Steam Steam Quality Considerations 10. Steam Distribution Best Practices for Condensate Removal on Steam Lines Installation Tips for Steam Traps on Steam Mains Erosion in Steam and Condensate Piping Corrosion in Steam and Condensate Piping Allocate New Plant Focus to Steam System Design—Part 1 11. Condensate Recovery Introduction to Condensate Recovery Returning Condensate and When to Use Condensate Pumps Condensate Recovery: Vented vs. Pressurized Systems Condensate Recovery Piping What is Stall? Methods of Preventing Stall Cavitation in Condensate Pumps Steam Heat Exchangers are Underworked and Over-Surfaced Allocate New Plant Focus to Steam System Design—Part 2 Optimize Reboiler Performance via Effective Condensate Drainage Vent Away Condensate Pump Frustrations in a Flash 12. Energy Efficiency Tips to improve steam plant efficiency Advice on Winter Preparation for Steam Systems Insulating Traps Steam Compressors Why Save Energy? Management Strategies for Conserving Energy Recovering Steam Clouds and Waste Heat Waste Heat Recovery Boiler Energy Saving Tips Steam Line Energy Saving Tips Steam-Using Equipment Energy Saving Tips Preventing Steam Leaks Handle Steam More Intelligently Optimize the Entire Steam System Use Available Data to Lower System Cost 13. Compressed Air / Gas Removing Condensate from Compressed Air Preventing Clogging of Air Traps Air Compressor Energy Saving Tips Improving Compressed Air Quality and Countermeasures Against Leaks 14. Other Valves Types of Manual Valves Bypass Valves Check Valve Installation and Benefits Pressure Reducing Valves for Steam Steam Trap Selection: Safety Factor and Life Cycle Cost Contents: Following the previous section regarding some physical factors that influence steam trap selection for applications, this section focuses on the trap Safety Factor and Life Cycle Cost (LCC) considerations. What is the Safety Factor? The safety factor is a coefficient used when selecting the trap’s required discharge capacity. It helps provide a buffer zone for instances when condensate volume exceeds calculated/predicted values. The estimated condensate load should always be multiplied by the recommended safety factor for trap selection. The following is a table that summarizes how trap type affects the safety factor: TLV Trap Type Minimum Recommended Safety Factor Float 1.5 Bucket 2 Disc 2 Thermostatic (X-element) 2 Bimetal 3 to 5 The safety factor is influenced by at least two elements: peak condensate load and the trap type relative to response time. Peak Condensate Load The peak (or maximum) condensate load on equipment may be higher than the average load for several reasons. Cold equipment at start-up, for example, typically causes much greater condensate loads than during regular operation. The condensate load can also severely increase during the period when the product is the coldest in batch processes. For steam traps on steam distribution mains, whenever a single trap blocks, the next trap in line may be required to drain condensate for two condensate drainage locations (CDL). The Safety Factor Numerical Value Manufacturer safety factor recommendations can vary between 1.5 to 5.0, or more. These depend on factors such as trap design, conservative capacity rating, orifice wear characteristics, how critical an application is, etc. Since condensate discharge capacity on specification sheets is calculated assuming continuous discharge, some steam trap types that operate intermittently (on/off), such as disc and bucket type traps, may require the use of a larger safety factor to minimize back-up issues in between cycles. Moreover, some manufacturers’ traps have higher safety factor recommendations simply to provide larger orifice sizes to lessen blockage. In comparison, traps that discharge condensate continuously, such as conservatively rated float type traps, typically only require a safety factor of 1.5. The safety factor may also help compensate for when an insufficient pressure differential across the trap impedes condensate discharge, such as when backpressure increases. During steam trap selection, it is therefore extremely important to apply the trap manufacturer’s recommended safety factor after calculating the application load, making sure that the trap size also offers a sufficient capacity for the application. Trap Life Cycle Cost (LCC) Steam traps are an essential and permanent part of steam systems, and should be selected according to their Life Cycle Cost (LCC) to offer the lowest system cost over the long-term. This means that initial purchasing cost should only be one of the decision factors when selecting a trap. Other costs related to maintenance, installation, replacement, as well as operational monetary losses from functional and failure steam leakage, etc. should also be taken into account. Rapid wear of internal components such as the valve seat causes steam leakage to increase over time, eventually leading to premature steam trap replacement. The timing for replacement is usually determined by evaluating replacement costs and comparing these to increased losses from steam leakage and other losses such as those caused by trap failure. Alternatively, some trap designs leak more steam than others even while in perfect accordance with the design specifications. These traps can be eliminated in the design phase. The following is an example of the influence of Life Cycle Cost (LCC) on steam trap selection. Model A and model B are two different types of traps. Model A has a higher initial purchasing cost, but a longer service life than model B. Item Model A Model B Purchasing Cost $300 $100 Replacement Costs* $80 $80 Initial Functional Steam Loss 0.05 kg/h 1.0 kg/h Yearly Increase in Steam Loss from Wear 0.06 kg/h (per year) 0.4 kg/h (per year) Typical Service Life 8 years 3 years * Costs related to man-hours and replacement of parts such as gaskets, etc. The Life Cycle Cost of both these traps over a 9-year span can be calculated. Assuming both traps are operated 24 hours a day, 365 days a year at an average steam cost of $20 per ton, the estimated cost of model A is $1180, including purchasing and replacement costs in year 9. The estimated cost of model B, on the other hand, is $3060 including purchasing and replacement costs in year 4 and 7. Despite it's lower initial cost, model B is therefore 2.4 times more expensive than model A when Life Cycle Cost is taken into account, showing the importance of calculating long-term costs when selecting a trap. Life Cycle Cost of Model A vs. Model B Trap reliability / service life, maintenance costs, and functional / failure steam losses are all important economic factors when determining the best model for steam trap selection. Steam Trap Selection: Understanding Specifications Traps and Orifices Part 1 Also on TLV.com Understanding Steam Traps Free Float® Steam Traps for Process Use Free Float® Steam Traps for Steam Mains and Tracer Lines Steam and Condensate Training Seminars