Engineering guides

Causes, Risk Points and Engineering Countermeasures Water hammer in steam and condensate systems is one of the most severe operating phenomena that can occur in industrial steam installations. It is not simply pipe noise. It is a mechanical impact load that can stress valves, flanges, steam traps, heat exchangers, supports, pipework and control instruments. In practice, most water hammer incidents in steam systems are related to condensate being present where controlled steam flow is...

Wet Steam, Enthalpy and Steam Separation Steam dryness fraction is used to describe the amount of dry saturated steam contained in a steam-water mixture. In real steam systems, water droplets may be present due to boiler carryover, heat losses in pipework, poor drainage or incorrect pipe sizing. For engineering purposes, steam dryness is not a theoretical parameter. It directly affects available thermal energy, heat transfer, steam trap operation, valve wear and the risk of water hammer.

Flash steam is generated when hot condensate at a higher pressure is released to a lower pressure. This typically occurs downstream of steam traps, pressure reduction points, condensate headers or return systems operating at a lower pressure than the steam-consuming equipment. In terms of thermodynamic properties, flash steam is not different from saturated steam. The term describes the way it is generated: it is not produced in the boiler, but results from pressure reduction of hot...

Valve material selection should not be based only on nominal pressure or valve size. Operating pressure, temperature, fluid compatibility, corrosion risk, mechanical loads, connection type, design standards and installation requirements must be evaluated together. The following tables provide indicative material equivalents according to EN, DIN, WNr and ASTM designations, together with typical temperature limits. These limits do not replace pressure-temperature ratings from applicable...

In steam and hot fluid systems, pipe length increases as temperature rises. Thermal expansion must be considered during system design in order to avoid high mechanical stresses, excessive loads on fixed points, pipe deformation and forces transmitted to valves, flanges, steam traps, heat exchangers and other equipment. Proper arrangement of pipe guides, supports, fixed points and expansion joints allows the pipework to move in a controlled manner and absorb the change in length caused by...

Flash steam is generated when hot condensate at a higher pressure is released to a lower pressure. The pressure reduction lowers the saturation temperature, and part of the heat contained in the condensate is converted into steam. This phenomenon commonly occurs downstream of steam traps, pressure reducing points, condensate return lines and flash vessels. Correct estimation of flash steam quantity is important for sizing condensate lines, flash vessels, vents and energy recovery systems.

The presence of air and other non-condensable gases in a steam system affects saturation temperature, heat transfer and equipment operation. Even a small percentage of air can cause a significant reduction in the actual steam temperature at the point of use. Correct air venting, removal of non-condensable gases and proper selection of steam traps and air vents are therefore important factors in the operation of industrial steam systems.

Pressure drop in a steam distribution network directly affects the available pressure at the point of use, as well as the operation of control valves, pressure reducing valves, steam traps and heat exchangers. For preliminary technical checks, pressure drop may be estimated using the steam density, flow velocity and the total resistance coefficient of the pipework and installed components.

The following values may be used as an indicative guide for preliminary checks of flow velocities in industrial steam, condensate, feedwater, cooling water and compressed air piping systems. Proper flow velocity selection affects pressure drop, noise, erosion, water hammer risk, condensate transport and the operation of valves, steam traps, pressure reducing valves and control equipment.

The following table presents basic thermodynamic properties of saturated steam as a function of absolute pressure. The data may be used as a technical reference for preliminary calculations and equipment selection in steam systems, including steam traps, control valves, pressure reducing valves, safety valves, condensate lines and heat exchange applications.