Library / Engineering / KEVOS® original book

Process Steam by the Numbers

Steam tables, boilers, process heating, pressure reduction, pipes, traps, flash steam and condensate return, worked through one food factory

Use steam tables to size and run a plant steam system: boiler output, process steam flow, pressure reduction, pipe velocity, traps, flash steam, condensate return, cost and safety.

8 chapters · About 80 minutes · Free to read · Intermediate applied thermodynamics

Start reading
KEVOS® LibraryENGINEERINGProcess Steam bythe NumbersKEVOS® ORIGINAL BOOK8 CHAPTERS

About this book

Steam is the most common way factories move large amounts of heat. Food plants cook, sterilise and clean with it; laundries, breweries, hospitals and chemical plants depend on it. It carries a great deal of heat in a small mass, gives it up at a steady temperature, and can be piped across a site. It is also easy to waste. Steam leaks, failed traps, flash steam vented to the sky and hot condensate run to drain can cost a plant more than the process uses well, and steam plant carries risks, of burns and of stored energy, that demand respect.

This book works steam through by numbers. It starts with the steam table and what sensible and latent heat mean, then covers the boiler and the cost of a tonne of steam, the steam a process needs, pressure reduction, pipe sizing, steam traps, flash steam and condensate recovery, and finally inspection, safety and the regulations that apply. Each chapter works one question through the running case, shows a failure and how it was found, and ends with an exercise and its worked answer.

The running case

The book follows SV-8, the steam system of a fictional food factory. A gas-fired shell boiler raises up to 1,000 kg/h of saturated steam at 800 kPa absolute, about 7 bar gauge, from feedwater at 80 °C. A 60 m steam main carries it to the cooking area, where a pressure reducing station drops it to 400 kPa absolute, about 3 bar gauge, for four jacketed cooking kettles, each rated at 100 kW. Condensate from the kettles is collected and pumped back to the boiler’s feed tank; about 70% of the steam raised returns as condensate. The plant runs about 4,000 hours a year.

All quantities, prices and results are invented for teaching. This is an illustration. None of it describes a KEVOS® client, supplier or project. Heat is costed at an assumed gas price of A$22 per gigajoule and a boiler efficiency of 85%. Money is in Australian dollars, excluding GST.

How to use the book

Chapter 1 is the foundation: read it first. Chapters 2 and 3 cover making and using steam, Chapters 4 and 5 moving it, Chapters 6 and 7 getting the condensate back, and Chapter 8 keeping the plant safe and inspected. The companion book Heat Transfer by the Numbers covers insulation and heat exchangers, which steam systems use throughout.

Source limits and professional responsibility

The supplied thermodynamics notes informed the range of subjects. Steam properties are taken from a published saturated steam table and quoted as given; other values chosen for the case are labelled. Boilers and pressure equipment are regulated plant in Australia: their design, registration, operation, inspection and maintenance are governed by work health and safety law and the applicable standards, and real systems must be designed, operated and maintained by competent, appropriately qualified people. Steam and condensate cause severe burns. This book is educational and is not a design or operating manual.

Who this book is for

Plant and maintenance engineers, energy managers, boiler operators and production managers in factories that raise steam for cooking, cleaning, heating or processing.

What you will learn

  • Read a saturated steam table with absolute pressures and use sensible and latent heat correctly.
  • Calculate boiler output, fuel input and the steam a process needs, and the cost of a tonne of steam.
  • Size steam pipework by velocity and explain what pressure reduction does to steam.
  • Estimate the cost of failed traps, flash steam and lost condensate, and the value of recovering them.
  • Recognise the regulation, inspection and safety duties that come with steam plant.

Inside this book

Chapters

  1. 01Reading the steam tableUnderstand saturated steam through its table: absolute pressure and boiling point, sensible and latent heat, specific volume, why steam is distributed high and used low, and wet steam.
  2. 02The boiler and the cost of steamCalculate a boiler's heat output, fuel input and efficiency from the steam table, see why feedwater temperature matters, account for blowdown and work out what a tonne of steam costs.
  3. 03Steam for a processWork out the steam a process needs: duty and steam flow, heating a batch through a jacket, how steam pressure sets heat-up time, steam per batch and its cost, and why air in a jacket slows everything.
  4. 04Pressure reduction and distributionCarry steam at high pressure and reduce it near use: what throttling does to enthalpy and dryness, the reducing station, the low-side safety valve and the cost of the main's heat loss.
  5. 05Pipes, drainage and water hammerSize steam pipes by velocity from the steam's specific volume, lay mains to fall and drain, allow for the warm-up condensate load, and prevent the water hammer that slugs of condensate cause.
  6. 06Steam trapsChoose, size and test steam traps: what each type does, sizing for start-up loads and real differential pressure, stall in controlled equipment, and the cost of traps that fail open or closed.
  7. 07Flash steam and condensate returnCalculate flash steam from hot condensate, see what venting it costs, recover it at low pressure, and value returned condensate in heat, water and treatment against what goes to drain.
  8. 08Safety, inspection and the savingsRun steam plant safely: regulated plant and registration, competent operation, low-water and safety-valve checks, isolation and burns, then add up the savings from this book's measures.

Apply This in Practice

Use these KEVOS® tools to try the method from this reading with your own numbers.

Learning pathway

Measure how wet your steam is

Learn what dryness fraction means and how a throttling calorimeter measures it, then work out the dryness from your own reading.

  1. 1 Learn

    Read Reading the steam table in Process Steam by the Numbers.

    Understand saturated steam through its table: absolute pressure and boiling point, sensible and latent heat, specific volume, why steam is distributed high and used low, and wet steam.

  2. 2 Apply

    Open Wet Steam Dryness by Throttling Calorimeter (Dryness Fraction, Calorimeter Validity) and enter your own figures.

    From a throttling calorimeter reading, what is the dryness fraction of the wet steam in the line, is the reading valid (steam superheated after throttling), and is the steam as dry as the process needs?

  3. 3 Verify

    Read the tool’s feasibility and verification checks under the result, and test your answer against its stated limitations:

    • Steam wetter than about 0.95 at moderate pressures does not superheat on throttling to atmospheric pressure, so the throttling calorimeter cannot measure it; a separating calorimeter is used ahead of it.
    • Heat lost from the sampling line and calorimeter makes steam look wetter than it is; insulate both and sample from a proper probe.
    • One sample at one moment; carryover and wetness vary with boiler load.
    • Example values are steam-table values chosen as an illustration. Replace them with your own readings and table values.

  4. 4 Improve

    Download the decision report or copy the link with your inputs to keep a record, then change one assumption at a time and compare.

    Next reading: Pressure reduction and distribution in Process Steam by the Numbers.

References and source notes

The manuscript and worked examples are original KEVOS® writing. References inform particular concepts; their authors do not endorse this book. Web references were consulted on 27 October 2026.

  • University course notes; the supplied file does not state the author. Introduction to Thermodynamics with Applications (about 2004). Supplied source, read as a subject map of energy, the first law for open systems, properties of a simple compressible substance and steady-flow devices. It is a modern copyright work; no text, figures, examples or problems are reproduced. This book's case, calculations and figures are original.
  • The Engineering ToolBox. Saturated Steam Table (current web page). Source for the saturation temperatures, specific volumes and enthalpies used at 101.3, 400 and 800 kPa absolute. Values are quoted as given there.
  • The Engineering ToolBox. Specific Heat Capacity of Water (current web page). Source for the specific heat of water, about 4.18 to 4.21 kJ/kg·K; 4.19 is used here for feedwater and condensate.
  • Safe Work Australia. Model Code of Practice: Managing the risks of plant in the workplace (current edition). Background for Chapter 8 on boilers and pressure equipment as plant. Check whether the code has legal effect in your jurisdiction.
  • Standards Australia and Standards New Zealand. AS/NZS 1200, Pressure equipment, and AS/NZS 3788, Pressure equipment: in-service inspection (current editions). Named by number and scope only, in Chapter 8. No requirements or values are quoted.

Continue exploring

← All Library books