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 How to Read a Steam Table Contents: Just as a map (or GPS navigation system) is necessary when driving in a new area or a flight timetable is indispensable when taking the plane, steam tables are essential to steam users in industry. This article will introduce steam tables, pointing out the different types and offering an overview of the different elements found within them. Saturated Steam Tables A saturated steam table is an indispensable tool for any engineer working with steam. It's typically used to determine saturated steam temperature from steam pressure, or the opposite: pressure from saturated steam temperature. In addition to pressure and temperature, these tables usually include other related values such as specific enthalpy (h) and specific volume (v). The data found in a saturated steam table always refers to steam at a particular saturation point, also known as the boiling point. This is the point where water (liquid) and steam (gas) can coexist at the same temperature and pressure. Because H2O can be either liquid or gas at its saturation point, two sets of data are required: data for saturated water (liquid), which is typically marked with an "f" in subscript, and data for saturated steam (gas), which is typically marked using a "g" in subscript. Example of Saturated Steam Table Legend: P = Pressure of the steam/water T = Saturation point of steam/water (boiling point) vf = Specific volume of saturated water (liquid). vg = Specific volume of saturated steam (gas). hf = Specific enthalpy of saturated water (energy required to heat water from 0°C (32°F) to the boiling point) hfg = Latent heat of evaporation (energy required to transform saturated water into dry saturated steam) hg = Specific enthalpy of saturated steam (total energy required to generate steam from water at 0°C (32°F)). * Source: 1999 JSME Steam Tables Heating processes using steam generally use the latent heat of evaporation (Hfg) to heat the product. As seen in the table, this latent heat of evaporation is greatest at lower pressures. As saturated steam pressure rises, the latent heat of evaporation gradually decreases until it reaches 0 at supercritical pressure, i.e. 22.06 MPa (3200 psi). Tip Looking for TLV's online steam tables?Access them here: Saturated Steam Table by Pressure Saturated Steam Table by Temperature Superheated Steam Table Two Formats: Pressure Based and Temperature Based Since saturated steam pressure and saturated steam temperature are directly related to one another, saturated steam tables are generally available in two different formats: based on pressure and based on temperature. Both types contain the same data that is simply sorted differently. Pressure Based Saturated Steam Table Press.(Gauge) Temp. Specific Volume Specific Enthalpy kPaG °C m3/kg kJ/kg P T Vf Vg Hf Hfg Hg 0 99.97 0.0010434 1.673 419.0 2257 2676 20 105.10 0.0010475 1.414 440.6 2243 2684 50 111.61 0.0010529 1.150 468.2 2225 2694 100 120.42 0.0010607 0.8803 505.6 2201 2707 Temperature Based Saturated Steam Table Temp. Press.(Gauge) Specific Volume Specific Enthalpy °C kPaG m3/kg kJ/kg T P Vf Vg Hf Hfg Hg 100 0.093 0.0010435 1.672 419.1 2256 2676 110 42.051 0.0010516 1.209 461.4 2230 2691 120 97.340 0.0010603 0.8913 503.8 2202 2706 130 168.93 0.0010697 0.6681 546.4 2174 2720 140 260.18 0.0010798 0.5085 589.2 2144 2733 150 374.78 0.0010905 0.39250 632.3 2114 2746 Different Units: Gauge Pressure and Absolute Pressure Saturated steam tables can also use two different types of pressure: absolute pressure and gauge pressure. Absolute pressure is zero-referenced against a perfect vacuum. Gauge pressure is zero-referenced against atmospheric pressure (101.3 kPa, or 14.7 psi). Saturated Steam Table using Absolute Pressure Press(Abs.) Temp. Specific Volume Specific Enthalpy kPa °C m3/kg kJ/kg P T Vf Vg Hf Hfg Hg 0 -- -- -- -- -- -- 20 60.06 0.0010103 7.648 251.4 2358 2609 50 81.32 0.0010299 3.240 340.5 2305 2645 100 99.61 0.0010432 1.694 417.4 2258 2675 Saturated Steam Table using Gauge Pressure Press.(Gauge) Temp. Specific Volume Specific Enthalpy kPaG °C m3/kg kJ/kg P T Vf Vg Hf Hfg Hg 0 99.97 0.0010434 1.673 419.0 2257 2676 20 105.10 0.0010475 1.414 440.6 2243 2684 50 111.61 0.0010529 1.150 468.2 2225 2694 100 120.42 0.0010607 0.8803 505.6 2201 2707 Gauge pressure was created because it is often easier to reference measured pressure against the pressure we normally experience. Steam tables based on gauge pressure indicate atmospheric pressure as 0, while steam tables based on absolute pressure indicate it as 101.3 kPa (14.7 psi). Also, to distinguish gauge pressure from absolute pressure, a "g" is typically added to the end of the pressure unit, for example kPaG or psig. Converting Gauge Units to Absolute Units For SI Units Steam Pressure [kPa abs] = Steam Pressure [kPaG] + 101.3 kPa For Imperial Units Steam Pressure [psi abs] = Steam Pressure [psiG] + 14.7 psi Important note: Problems can easily occur when absolute pressure is mistaken for gauge pressure (or vice versa), so it is always extremely important to pay close attention to the pressure units used in the table. Summary Table Gauge pressure: Zero-referenced against Atmospheric Pressure* Zero pressure = Atmospheric Pressure Absolute pressure: Zero-referenced against Absolute Pressure Zero pressure = Perfect Vacuum *Atmospheric pressure is 101.3 kPa (14.7 psi) Superheated Steam Tables Values related to superheated steam cannot be obtained through a regular saturated steam table, but rather require the use of a Superheated Steam Table. This is because the temperature of superheated steam, unlike saturated steam, can vary considerably for a same pressure. In fact, the number of possible temperature-pressure combinations is so great that it would be virtually impossible to gather them all in a single table. As a result, a large number of superheated steam tables use representative pressure-temperature values to form a summary table. Example of Superheated Steam Table The above superheated steam table contains data about Specific Volume (Vg), Specific Enthalpy (Hg) and Specific Heat (Sg) at typical values of pressure and temperature. Flash Steam Heating with Steam Also on TLV.com Saturated Steam Table by Pressure Saturated Steam Table by Temperature Wet Steam vs. Dry Steam: The Importance of the Steam Dryness Fraction Steam Bulletin: Archive - Email Magazine