advantages of systems steam/hot water

My experience with older commercial buildings is that there is much to gain from simply maintaining or even fully restoring the steam heat system. When thinking of conversions to hot water it should be clear that what is meant is abandoning everything steam and rebuilding a wholly new water system with new boiler, new pipes, and new radiators/convectors, all done at once. The slightly remote savings that may be envisioned through steam parts reuse are not worth the catastrophic trade off in performance you'll get from a hot water system that was not designed optimally to begin with.

Looking at a building that needs all new heat, new hot water is perfectly fine, and I would not short change myself of the low temperature radiant and condensing boilers and accompanying system design. Many who own old and drafty buildings also try forced air systems, but this in not a good choice here because of the air leaks. This also introduces small burners everywhere which are a pain to look after and where expensive gas failures go unnoticed for months. These are the same issues you get with radiant gas fired units, on top of the fire hazard. Going all natural gas, you also loose fuel flexibility opportunities.

What about steam? A decently operating set up runs with the same system wide efficiencies as low condensing temperature water does. If you have small (or large) district system with a whole boiler house set up operating at 100+ PSI, your whole system efficiency is even further increased.

What's the problem with steam? Piping layout, sizing and design do not forgive mistakes. Details can bite. On the other hand, pumped forced water allows for careless pipe flow during installation. What's even better, forced air allows the installer to be totally lax about even the sizing issues. This is not to say that good workmanship shouldn't be sought but that you can get by with total junk, which with steam, you can't.

Incidentally, this is yet another reason why steam systems are top performing. They are (or were in another age), by default, designed and built with much more care for optimum operation. If you already (or still) have it, you're in luck.

The seventies and the space age saw us abandoning many old time proven skills in exchange for short term promises. We probably believed that wearing silver colored suits with the pants tucked in the boots -like the astronauts did in TV sitcoms- would be enough to keep us warm. Well, now we know better and thanks to this HeatingHelp, steam is being rediscovered. The missing accessory to the synthetic fiber silver jump suit: the tin foil hat.

Some more about steam

Leaky pipes are very easily fixed (in the field, with clamps or repair welds). The zero pressure makes it worry free. Once old pipes are filled with water, they can't easily be fixed under pressure, they can't be opened up anywhere and certainly can't be welded anymore. Repairs prolong system life indefinitely. Steam mains are always very clean and sound, horizontal returns are the weak point (stainless makes for nice applications here).

Steam control is very intuitive. Steam comes with its own brain, it will find the coldest place to condense in a properly air evacuated system. Add non electric thermostatic valves, or orifice plates, or working manual valves and you are well on your way to a system where the individual users make the final heat decisions. Run the boiler on outdoor temperatures and only during business hours or mostly the mornings for great cost savings.

Steam pipes (properly pitched) empty themselves of all water and thus stand proud in the face of the coldest winter wind. This is a big problem in buildings with remote parts that can certainly freeze. Think of the piping along an outside wall or under a window left open for the weekend. The same old pipes filled with water is a recipe for disaster. Even if you fill them with antifreeze, if you don't monitor your fill valve you might easily dilute your glycol with a small leaks.

In a factory environment, pipes often get in the way. Steam pipes always being empty are easily taken apart and moved. Pipes with pressurized water in them are another story altogether. Pipes with water in them that are driven into with a forklift are a big splash and provide more fun than the simple broken open steam pipes. :)

For fun with steam, look for horizontal steam coils or fin tubes of which the trap is plugged or has been replaced with a cap. The tube fills with condensate, of course, which then freezes itself open into a mud spill. Worse, with an appropriately collapsing steam bubble, you get some mad ramming action that blows away a fitting. This is the most horrible bust you can get but it is very easily preventable. Tourists take just as many pictures of Old Faithful than of the Niagara Falls.

Trap maintenance is very important and very easy. With a little planning, there is no pain to it at all. The boiler requires some attention, but any appliance that guzzles thousands of dollars should never be left unsupervised. Watching it like a hawk and monitoring any problem is a must (steam or water) and is easy and pleasant to do from within one single central boiler room. One fire also gives you easy burner efficiency tuning and upgrades and fuel flexibility.

Proper maintenance comes free.

With zero maintenance, the only trouble you get yourself into with steam is steadily decreasing efficiency. But you still get heat. Which is fantastic when you think about it, and it is also the downfall of steam systems. The negligent owner does not think there is anything wrong with the zero-no maintenance plan because heat is still coming out the pipes, then, with this assumed blamelessness, all the finger point towards the poor steam boiler which is working as hard as it can (and at great cost) to heat the building. The good never get all the recognition they deserve.

Come, those of you reading who have a boiler, run downstairs, give it a big pat on the back and kiss it's forehead. That machine feeds on expensive energy and worrying about its diet is just as worthwhile as anything else: you're paying this guest's food charge, make it a good friend.

Note that water systems are by no means maintenance proof. Quite the opposite. Zone valves alone are a mess; multi-way mixing valves are a great danger to efficiency all on their own. Frozen pumps at the beginning of every heating season are good reasons for no heat calls. But, to the credit of hot water systems, whenever they suffer a problem, the need to call for help is obvious to the owner and the return of heat is the reward for proper maintenance. It's not like that with steam where an owner can savagely brutalize the central heating system for a long time before it gives up. Valved and pumped hot water and forced air systems conk out much faster from neglect.

All this considered, for your explosion proof paint factory, I would embark on a steam system restoration. After a new boiler (which seems due no matter what) and all new traps, you'll be done with major costs. Condensate returns often become functional again once a leaking trap is replaced. Then, the piping repairs and the penthouse redo can all be tackled in small manageable chunks as you go forward. If the de-aerator is beyond talk, then at least a steam heated feed water tank and water treatment should be considered.

To steal your line, peace and good luck. I hope your owners will be interested in reading all of this as I am sure you will. This sort of in-the-field trip beats any touristy destination.