Steam system inspection tips?

[DouginMB]

Next week i am going to a military base to perform field work for a renovation. The building is served by a campus steam system. The base engineer has asked me to inspect the condition of the existing steam and condensate branch pipes to the building and determine their condition. While i have experience with steam systems, I live in a sub-tropical climate region where steam systems are rare (mostly industrial and hospitals), so i have very limited experience with existing steam systems. Does anyone have any guidance as to what I should look for that will tell me if pipe, valves, and fittings should be replaced. I don't have any test equipment that can tell me the condition of the pipe wall, so i imagine I'll be relying on pure observation. Any advice would be appreciated.

 

[Grizzly68]

Doug,
I'd suggest visual inspection and identify missing/torn/damaged insulation, leaking steam, etc. They should have a good feel for how much condensate they're losing through leaks by looking at their makeup water volumes (unless they're using it as once through steam in some cases). I would also actuate the manual gate valves by turning them just enough to feel the gate move and then returning them to original position.
Grizzly

 

[Accystan]

DouginMB:

I don't think there's a way to easily check internal pipe corrosion but I'd note/check the following. The list is not comprehensive but it’s a start.

Find out the age of the system.

If you can, open up a few steam traps and see if the moving parts move; are they clean inside; is the seat/valve worn or wire drawn. Once again if the system is 15 years old I’d recommend that the guts of the traps, possibly even the whole trap, be replaced.

Check any strainers for dirt; properly designed trap-sets should have one.

Open up a dirt leg if there is one; that’ll give you an idea of what’s been scaling off the inside of the pipes.

Repeating what Grizzly68 said, look carefully for signs of drips/leaks at valves, trap-sets etc. Open and close (or close and open) as many valves as you can; do they all turn easily. Are the packings on the valves dried out? It might not be possible for you to do but opening up a valve or two and checking the seating (in a globe) or the gate will indicate serviceability, wear and/or problems.

A bit off the subject but be aware of asbestos. In older systems you’ll find it on the boilers heat-exchangers and on the insulated bends in the boiler room (the straight lengths of pipe are likely mineral fibre). Somebody needs to take a sample and get it checked by a lab. There’s a liability issue and you don’t want to be the professional who checked the system and forgot to mention it.

Sorry, but I’ve probably gone beyond what you asked for but there you go – grist to the mill. Good luck.

 

[KenRad]

I would look especially hard at condensate piping on atmospheric condensate receivers, both on the gravity drain side (between steam traps and the inlet to receiver) and the pumped discharge side. In my experience, this tends to be where you see the most severe corrosion, due to the constant presence of hot condensate and air. Drips at fittings can indicate that piping failure is imminent; threads are usually where you see it first.

Another potential problem area is anywhere where condensate is lifted by trap d/p instead of a continuously sloping gravity drain. These areas trap water, and can result in accelerated corrosion.

I would find some unions, and break apart the piping in several areas to determine what your're dealing with.

---KenRad