How to estimate EDR of planned steam pipe runs

stormbytes

In the planning stages of a soup-to-nuts replacement of a 1-pipe steam system, in a 100 year old, 2-fam in NYC. The idea was born late last winter when our Burnham IN6 started leaking steam through a rusted gash in the vessel. Have been keeping her on life support with epoxy putty and prayers, cycling through 1 psig on a vaporstat. Hoping she'll get me through the end of March.

Will be installing the new SteamMax from Burnham. I'll be replacing the 80 year old steam pipes, many of which were obvious bandaids and addons. New pipes will be routed better, but i don't have the exact lengths and fittings planned out at this point and I **NEED** to order the boiler in the next 2 weeks in order to make schedule.

My question -- likely the first of many: How to correctly estimate EDR for the intended piping runs? I have a good idea of run lengths.

The layout is fairly simple. Boiler sits in the basement at the rear of house. Primary steam trunk runs to the front of the house along the basement ceiling. Secondary steam trunk runs to the rear, through the garage (behind the house), feeding radiators in the living spaces above the garage. Single wet return carries condensate below the water line and back to the steamer.



I'm including a very rough diagram showing the layout. Thanks in advance.

PS: Understand that many would advise away from steam if replacing a whole house system. I respect your opinion but I'm set on installing steam.

Big Ed_4

The supply pipes should be insulated ....

Jamie Hall

Yes, the supply pipes should be insulated. And, if they are, there really is no need to include the EDR of the pipes in figuring the load to be powered by the boiler. Unless it's really strange, that's included in the "pickup" factor.

However.... if you are set on including it, there's no harm, and it's really really easy. Remember that EDR, while it sounds fancy, is just the equivalent square feet of radiation. So -- take the circumference of the pipe, convert to feet and multiply by the length of the pipe -- and that's all there is to it.

EBEBRATT-Ed

@stormbytes

To get the EDR you measure all your radiators Height, #of sections and number of tubes or collums.

There is some information on this site and you can go on line and find the "Burnham Heating Helper" Google it.

Piping doesn't matter yet only the radiation load needed to size the boiler

congrats on keeping steam

pecmsg

You have the time maybe get one of our experts to do a site visit just to double check. 

There’s 1 or 2 that service the city. 

stormbytes

Jamie Hall said:

Yes, the supply pipes should be insulated. And, if they are, there really is no need to include the EDR of the pipes in figuring the load to be powered by the boiler.

I completely blanked on that for some reason. Only need to factor in uninsulated pipe. Thank you for pointing that out.

JUGHNE

Could your radiators be connected for a 2 pipe system?
Are they connected across the top?

stormbytes

JUGHNE said:

Could your radiators be connected for a 2 pipe system?
Are they connected across the top?

The 1-pipe works just fine. Why would I want to add piping?

JUGHNE

You can throttle 2 pipe steam valves with the handle or orifices.
No such thing with 1 pipe....either on or off.
No air vents in the rooms, all in the basement.
Run outs to rads can be smaller.

Is it a safe assumption that each room had more than adequate heat from its radiators?

stormbytes

JUGHNE said:

You can throttle 2 pipe steam valves with the handle or orifices.
No such thing with 1 pipe....either on or off.

As I understand it, adjustable radiator vents can be used to throttle and/or balance heat distribution.

JUGHNE said:

it a safe assumption that each room had more than adequate heat from its radiators?

Mostly, yes. Will be adding/replacing some radiators in different areas to optimize heat distribution.

stormbytes

EBEBRATT-Ed said:

@stormbytes

To get the EDR you measure all your radiators Height, #of sections and number of tubes or collums.

What's the difference between EDR and Square Foot Radiation?

EBEBRATT-Ed said:

There is some information on this site and you can go on line and find the "Burnham Heating Helper" Google it.

Have it. Can't make any sense of most of it

bburd

EDR is Equivalent Direct Radiation in square feet. EDR is “square feet of radiation”.

For steam the rating is 240 BTU per square foot EDR with one psi steam in the radiator (215°F).

For hot water the rating is 150 BTU per square foot EDR with an average water temperature of 170°F. The traditional design temperature drop was 20°F, so this means 180°F supply water temperature at the boiler.

EBEBRATT-Ed

@stormbytes

EDR & square foot of radiation is the same thing.

Again, you measure up the EDR of all your rads. You need to locate them and have the EDR for all rads before making a piping layout or sizing the pipe.

You don't add anything for heating the pipes yet. You add up the square feet of steam for all rads and total that up. Lets say you have an EDR of 390.

You then pick a boiler that has a rating of 390 sq. feet or slightly more. The boiler mfg has also already added a piping and pick up factor of 1.33 to the EDR rating. You just pick a boiler with the edr rating you need and your done

JUGHNE

If you don't already have "The Lost Art of Steam Heating" by Dan Holohan, it would be well worth the money to obtain one.
Everything you had questions about is addressed in that book.
Pipe sizes, EDR, pipe fitting orientation off of the main etc.

Also the advantages of a 2 pipe system (provided your radiators would work for that).

In any case you can always come here for more questions.

Any pictures of steam piping and radiators?

stormbytes

JUGHNE said:

If you don't already have "The Lost Art of Steam Heating" by Dan Holohan, it would be well worth the money to obtain one.
Everything you had questions about is addressed in that book.

Have it right here. Been making my way through it. Many of the concepts are abstract so it will take some time to fully wrap my head round it all.