steam heat

GARY HAAR

A major boil manufacturer tells me and my customer that 30 ft per second is ok coming out off a boiler your book says that it should be 15 ft per second.

Bob W._3

I recall Dan's The Lost Art of Steam Heating stating that modern boilers are closer to that 30fps figure, which is why the near boiler piping is so critical, as it must slow the steam down to allow the water to drop out.

don_52

Correct, yet missing one...


important little thing, piping, while true that small
boilers ( mostly ) will do that, it is ( or has become )
practice to go up a pipe size ( or two ).

Looking at quite a few steam installations on this site,
it is ( or becomes ) necessary to, say step up from a
2" to 2.5" or 3" header just to "make up" to one or more
"big ole mains"

Just doing that alone cuts down the velocity. ( alot! )

Using the "pressure ratios" is one way to figure it,
"equal area method"is another.

Using either method on my system here I get between 12.99
and 13.33fps respectivly.

Regards, db

don_52

Yes indeed...

Gents,

This is one reason for increasing the pipe size, say from
a 2' riser to a 3" header, this simple formula says it all.