Drop headers

Tinman

I've been playing around with drawing some different, steam near boiler piping schematics. Putting pencil to paper is a good learning tool for me. I've yet to draw one with a drop header. It's seems to be the preferred method here? What are the reasons for that?

ChrisJ

Easy of installation, you have more swivel points which makes it a lot easier to line things up.


Risers feeding into top of header in theory works better for drying steam than feeding into the side.

It looks cool.

Tinman

Is it common to pre-pipe the drop header before you even get to the job? I'm thinking it would be a big time saver?

Tinman

It looks cool?

SWEI

It gives you a way to create sufficient "A" dimension in limited overhead space, and (on counterflow systems especially) when the system piping comes in below the top of a new boiler.

EzzyT

If I have the time to prepipe the header at the shop then I will. Usaully im piping the header on the vise while my apprentice is tearing down the old boiler and by the time the old boiler is torn down and moved out of the way I have the header all ready for the new boiler.

Sailah

Man I need to come hold a pipe wrench for some of you guys one day. Seeing all these great piping jobs on the board recently makes me appreciate all the time and foresight it takes to do a job well.

I bring donuts and buy lunch!

Tinman

@SWEI - I suspected it had to do with limited ceiling height but wasn't sure. Thanks for clarifying.

@ChrisJ - I agree. It does look cool

ChrisJ

Stephen Minnich said:

@SWEI - I suspected it had to do with limited ceiling height but wasn't sure. Thanks for clarifying.

@ChrisJ - I agree. It does look cool

That was one I forgot about, and was one of the reasons I did it. The header can be down by the top of the boiler and your risers can still come up a good 30"+

Tinman

And so the longer the risers, the better?

EzzyT

Yes

Dave0176

Stephen Minnich said:

Is it common to pre-pipe the drop header before you even get to the job? I'm thinking it would be a big time saver?

Do it all the time

SWEI

I knew I had seen photos of a prefab drop header but I couldn't remember exactly where. Nice work!

delta T

Dry steam is happy steam!

New England SteamWorks

Stephen Minnich said:

Is it common to pre-pipe the drop header before you even get to the job? I'm thinking it would be a big time saver?

We do it in the winter to cut down on heat down-time. Hard to get anything done on day one when the disposal guys are there. Usually you get sucked into their activity. So we prefer to quietly build the header at the shop while they dispose, then bring it over when they are gone in the afternoon.

Summers, I prefer to have the disposal guys come a day early, then we go and build the header on site.

ChrisJ

Stephen Minnich said:

And so the longer the risers, the better?

To an extent.
The longer they are, the further the water has to jump out of the boiler to make it into the header, which, will then send it to the equalizer, but the less the better.

Two risers means even less water getting out, and larger risers means even less.

I don't know what the highest worth going is, but I'd say 25-30" above the top of the boiler is a nice height.

Fred

I think the less water carried by the steam into the header, the better (makes for dryer steam) Then any residual water that falls out of the steam, while in the header will flow to the equalizer.

ChrisJ

Fred said:

I think the less water carried by the steam into the header, the better (makes for dryer steam) Then any residual water that falls out of the steam, while in the header will flow to the equalizer.

True,
But do you think anyone should run risers from the basement up into the attic, and then back down into a drop header?

Trying to give the OP an idea of what to work with.

Fred

ChrisJ said:

Fred said:

I think the less water carried by the steam into the header, the better (makes for dryer steam) Then any residual water that falls out of the steam, while in the header will flow to the equalizer.

True,
But do you think anyone should run risers from the basement up into the attic, and then back down into a drop header?

Trying to give the OP an idea of what to work with.

Hummm, Something to think about. Tuesday night pondering

Tinman

I don't think the OP would ever think that.

Hap_Hazzard

ChrisJ said:

Fred said:

I think the less water carried by the steam into the header, the better (makes for dryer steam) Then any residual water that falls out of the steam, while in the header will flow to the equalizer.

True,
But do you think anyone should run risers from the basement up into the attic, and then back down into a drop header?

Trying to give the OP an idea of what to work with.

I can't remember where I heard it, but I remember someone telling me that water droplets can't go higher than 36". That's not always feasible, but I think the main idea is to make your vertical run before the header instead of after it. Consider these two options:


Header A


Header B

Aside from the equalizer, the lengths of pipe used are the same, but Header A gives you drier steam.

ChrisJ

Hap_Hazzard said:

ChrisJ said:

Fred said:

I think the less water carried by the steam into the header, the better (makes for dryer steam) Then any residual water that falls out of the steam, while in the header will flow to the equalizer.

True,
But do you think anyone should run risers from the basement up into the attic, and then back down into a drop header?

Trying to give the OP an idea of what to work with.

I can't remember where I heard it, but I remember someone telling me that water droplets can't go higher than 36". That's not always feasible, but I think the main idea is to make your vertical run before the header instead of after it. Consider these two options:


Header A


Header B

Aside from the equalizer, the lengths of pipe used are the same, but Header A gives you drier steam.

Yes, and header A allows the water to go right back to the boiler without making the full trip.

ChrisJ

Hatterasguy said:

ChrisJ said:

I can't remember where I heard it, but I remember someone telling me that water droplets can't go higher than 36". That's not always feasible, but I think the main idea is to make your vertical run before the header instead of after it. .

That's correct.

When the water droplets get to 36.5" they recall the ChrisJ statement and make a U turn and head right back down the riser to the boiler. That 36" is definitely the magic number.

Hap Hazzard said that, not me.

ChrisJ realizes the height the water climbs is related to the steam velocity and likely other factors.

I believe the correct term is "Carryover".

Danny Scully

@Hatterasguy, where is your plumbing/heating contracting company located?

EzzyT

Dan he isn't in the industry he's a aeronautical engineer

Danny Scully

@EzzyT, so @Hatterasguy doesn't install/service steam and/or hot water boilers professionally? Nor does he now or at anytime manage a licensed and insured company which provides such services?

EzzyT

Correct

jonny88

I dont believe Dan Holohan ran a plumbing company either.Writes very informative books though.

Tinman

Same could be said for Siggy, I believe.

Danny Scully

Thanks for the clarification @EzzyT, and yes @jonny88, you are correct. He did, however, work as an industry rep for almost 20 years.

Jamie Hall

Interesting comment and thoughts about the maximum height of a water droplet... I doubt that one could put a single number on it! For a given vertical velocity, though, and a given initial droplet size, there will be a increase in the size of the water droplets due to collisions, and at some point they will begin to fall faster than the column of air (or steam) is moving upwards.

Consider a thunderstorm, however: the maximum height of water droplets going up is in the thousands to tens of thousands of feet!

Far more effective in ridding the steam of carryover, however, is the bends. Water droplets, being rather heavy, simply can't make the turns as fast as the steam, and will collide with each other and, perhaps more important, the pipe walls. Thus in a drop header, you have three collision points -- one of which, the last, is conveniently at a point where the water which hits the pipe wall can be swept along to the equalizer at the far end. That doesn't happen in an overhead header. I suspect that that is one of the main reasons a drop header is so effective in producing dry steam.

And a disclaimer for @Danny Scully -- I have some background in plumbing, electrical work, and HVAC, though I never had a Master's license in any of them (silly me). I am a Professional Engineer (boo) -- Civil, Agricultural, and Sanitary -- and a pilot. I give you my best thinking... for what it's worth.

jonny88

Danny I know many industry reps whats your point?

Danny Scully

I respect that resume @Jamie Hall, and my inquiry regarding @Hatterasguy was not to suggest that you need to be a professional in the plumbing/heating industry to comment.

Danny Scully

@Hatterasguy, how can you professionally install boilers when you "have the time?" Is that your primary source of income? Do you carry unemployment/disability insurance, worker's compensation, liability insurance, pay employee health insurance, employee retirement pay? And what messenger have I shot? I'm honestly just inquiring out of curiosity.

Gordy

The ad hominem is stifling.......

I find a complete deviation from what is perceived as exceptable piping practice from one steam thread to the next.

It should not matter the persons proffesional back ground when they call someone on it. So long as they are correct. Brian probably does steam velocities in his head.......

Gordy

@Jamie Hall do you still fly?

Danny Scully

@Hatterasguy, are you suggesting I have to communicate with you via PM? Because I have no interest in that. I didn't ask you to do so when you commented on my post. Or, are you suggesting that you work under the guidance of companies who incur the various costs of doing business?

Danny Scully

@Hatterasguy, I suppose it's proper forum protocols to call someone's work a "turd" and suggest they don't post anything that's not above and beyond manufacturers specifications? You don't know anything about proper. Although, you are factually correct in saying we're done.

Danny Scully

@Hatterasguy, I guess we're not done if you're commenting yet again, and breaking your own protocol. It amazes me how rude you are. If you look back at everyone of my posts (starting from my original thread), I never once insult you. In fact I do quite the opposite. And yet again you make an insulting comment that I have no understanding of steam velocity, which is factually incorrect, as you would say.

Hap_Hazzard

Guys, I didn't mean to start an argument. I didn't even think I was saying anything controversial, but since there's been some debate about it, I thought I'd go back and try to remember where I'd heard it. It turns out I was wrong about the 36" figure. The actual statement was

The higher the risers the dryer the steam. This is because water is trying to get UP the risers with the steam, but it can't rise higher than 24 inches or so. This is why piping diagrams specify a minimum riser height of 24 inches above the highest possible water level.

(The original thread is here.)
So, aside from being wrong about the distance, I took the statement out of its original context. Steamhead's comment was based on the assumption that you're dealing with the output of a given boiler and following the manufacturer's specifications for pipe diameter and number of risers, not a theoretical situation involving any arbitrary steam velocity.
I apologize for any misunderstanding I might have caused.

Danny Scully

My apologies as well @Hap_Hazzard, and @Stephen Minnich, didn't mean to stray from the original question. I hope you were able to find the answers you were looking for.