On 07/03/18 08:29, Chris Hogg wrote:
On Wed, 7 Mar 2018 07:42:23 +0000, The Natural Philosopher
wrote:
On 07/03/18 07:30, Jim K wrote:
The Natural Philosopher Wrote in message:
On 06/03/18 16:54, wrote:
We have a large open fireplace with a cast iron fire basket, but we only
burn logs so I'm considering whether to remove the basket so we can let
a layer of ash build up on the fire brick base and burn on that. Any
comments from those who burn logs in open fires?
if the flue is designed to run with a basket, ou may get smoke escaping
of you lower theh combustion area
I have seen pubs ho have done this raise the thing back with a layer of
bricks..
I suspect there were other (possibly h&s) considerations at work
there, a few inches of hearth height shouldn't have much effect
on open fire flue draw.
Its not a question of draw - its a question of aerodynamics.
I had to reserach all this totally when my builders made a cockup of
making an open fireplace.
In generat the rule of thuimb is that te aperture the place where the
air comes in ABOVE the fire - should be no larger than 3, or at worst 4
times the area of te flue at a reasonably local point.
That makes the inflow speed fast enough to pull the smoke up the chimney
not wander around the room.
I had to fit smoke hoods to achieve this
You also need a decent airflow into the room to replace that going up
the chimney. In our case we have to have the trickle vents over the
windows open and the sitting-room door open, otherwise the chimney
smokes. But it must be true to some extent for any open fi you have
to replace the air going up the chimney. Our 'fireplace' is quite
large, with the basket sitting in the recess. The aperture is 30x23
in. = 660 sq.in. and the flue itself is 12x12 in= 144 sq.in. so the
aperture area is 4.6x the flue area. That figure would be a bit less
if you take the aperture area above the fire itself. I don't think it
was 'designed'!
Well yes and no, People learned by trial and errior how to make fires
that didn't smoke.
By te late victoirian era the formula was a well known rule of thumb.
Post war, the art seems to have been lost and in any case I think that
open fires are no longer allowed to be constructed.
--
it should be clear by now to everyone that activist environmentalism
(or environmental activism) is becoming a general ideology about humans,
about their freedom, about the relationship between the individual and
the state, and about the manipulation of people under the guise of a
'noble' idea. It is not an honest pursuit of 'sustainable development,'
a matter of elementary environmental protection, or a search for
rational mechanisms designed to achieve a healthy environment. Yet
things do occur that make you shake your head and remind yourself that
you live neither in Joseph Stalins Communist era, nor in the Orwellian
utopia of 1984.
Vaclav Klaus