What captures the imagination of an engineer more than the elegant lumbering of a steam locomotive? The “stoker” shoveling coal into a firebox while the engineer sounds the train whistle to alert passersby. On one vacation when I was young, I remember my parents taking me on a train ride in the redwood forests of Northern California. Many areas of the country still have steam locomotive rides you can take. It’s fascinating to study the engineering of what makes a machine like a steam locomotive work. When it comes to utilizing steam for building systems, it can be daunting for plumbing engineers mainly because it’s just not as common as it used to be.
I had a design issue come up recently where I had to calculate the amount of treated water being fed to a clean steam generator. The purpose of the clean steam generator was to, quite simply, generate steam. The steam would be injected into an airstream in order to meet the minimum requirements for humidification, which my colleague explained, is prescribed in ASHRAE Standard 170 for health care facilities. The HVAC engineer shared the cut sheet for the steam generator with me and it was designed to use 2,000 pounds per hour of steam. I took a deep breath and prepared myself to brush away the cobwebs from my brain and do some serious calculations. How much treated water would I need to feed to this generator? The water required was being produced by a reverse osmosis system, so the quantity was important to get right.