Chimney Aluminium Pipe

[namrata]

What is the need of exhaust fan backup? To provide more suction power or to serve the purpose when the chimney fails?

yes, and:

no chimney can suck all the cooking fumes, esp when indian cooking is involved. you've got an open kitchen and your chimney has <1000 m³ of suction power. i bet, the ceiling fan in the hall adjacent to your kitchen would overpower your chimney.. . you'll need exhaust fan's help here on the days of deep frying.

i've put my exhaust fan on inverter.

Don't you think it will look nicer if we just cover the exhaust fan hole and drill a 5" exhaust hole at the shortest possible length.( as you suggested)

yes, you are right but i'd suggest that you install the chimney and see how it performs with/without ceiling fans running in other rooms. if you are satisfied with it running alone then patch up that 1' hole with brick and mortar. or seal it up with cardboard and hang a picture on it, if you have to do it on your own at end of renovation.

edit: if you think you need an exhaust fan as well, get a nice, low-noise one. mine serves as a cover when not in use. your current one is exposed to outside elements. that Cata fan i posted earlier faces inwards, so all you see is the flat face and not rotating blades. get a cheaper one; Cata fans cost ridiculously high.

Can I get cowls from shops selling chimneys. What will be the cost and what are the different options. Again, your advice is required here.

yes. the one that i posted earlier costs 300~400. buy it if you want to beautify that side of the wall. mine is visible from backyard, so i used this model. several cheaper but equally functional options are also available. one is this PVC drain cover which is used by 90% of the people in india:

another option is to wrap a piece of wire mesh (mosquito screen) around the opening.

Glad that I started this thread. Architects don't really care about these fine details and I am sure I am going to have a superb installation. Thanks again for your wonderful help.

i've spent a lot of time in researching for low-maintenance options for my house. i'd be happy if my experiences could help someone!

I think hdpe (common for plastic pipes, pipe joints, fans etc) has a melting point of 120deg Celsius. So unless you put it on fire it has low chance of going up in flames.

yes, some stuff used around the house is meant to be fire/flame retardant (e.g. electric cables). but installing any such thing above the cooking area is against the construction guidelines. i tried certain stuff and though they didn't catch fire but let out a strong odor. anyways, not to pick upon you but i've noticed that people often use 100 degrees Celsius synonymous to fire. 100 deg C is the boiling point of water under ideal conditions. i think, heat directly above a gas stove can reach twice that amount.

 

[cranky]

people often use 100 degrees Celsius synonymous to fire. 100 deg C is the boiling point of water under ideal conditions. i think, heat directly above a gas stove can reach twice that amount.

From memory, the blue part of a flame from a gas stove can be as hot as 400-450 degrees C, not 200, and not only will it melt HDPE, but is also used for exactly the same purpose when plumbers do emergency repair work.

However a typical stove burner is a very small source of heat and the energy reduces rapidly as the distance increases. If there is a good thermal barrier - such as a proper utensil with at least water in it - the temperature falls off quite quickly, and thankfully so, else you wouldn't actually be able to cook at all. Human skin singes at 65 degrees, and 70 and above gives you a very painful blister. You can expect the temperature at head height to be around 50 or 55 degrees at the most, not enough to burn or boil anything at all but enough to make it hot and uncomfortable.

Unless of course, you have your head directly above the burner and nothing cooking. That will definitely result in a new hairstyle, and maybe a tattoo.

 

[laugh]

Deleted post.

 

[laugh]

yes, and:

no chimney can suck all the cooking fumes, esp when indian cooking is involved. you've got an open kitchen and your chimney has <1000 m³ of suction power. i bet, the ceiling fan in the hall adjacent to your kitchen would overpower your chimney.. . you'll need exhaust fan's help here on the days of deep frying.

i've put my exhaust fan on inverter.

Do you think a chimney of more than 1000m3 of suction will make a significant difference when compared to this?

You have your exhaust fan on inverter!

yes, you are right but i'd suggest that you install the chimney and see how it performs with/without ceiling fans running in other rooms. if you are satisfied with it running alone then patch up that 1' hole with brick and mortar. or seal it up with cardboard and hang a picture on it, if you have to do it on your own at end of renovation.

edit: if you think you need an exhaust fan as well, get a nice, low-noise one. mine serves as a cover when not in use. your current one is exposed to outside elements. that Cata fan i posted earlier faces inwards, so all you see is the flat face and not rotating blades. get a cheaper one; Cata fans cost ridiculously high.

I forgot to mention, the hall+kitchen setup is air conditioned, are there exhaust fans which will work in air conditioned rooms without leaking loads of air. Another option I see is somehow sealing the exhaust fan setup so that it's not visible and doesn't leak air and opening the seal during days of deep frying.

yes. the one that i posted earlier costs 300~400. buy it if you want to beautify that side of the wall. mine is visible from backyard, so i used this model. several cheaper but equally functional options are also available. one is this PVC drain cover which is used by 90% of the people in india:
View attachment 21063
another option is to wrap a piece of wire mesh (mosquito screen) around the opening.

Outside looks are not important here and will use the drain pipe.In our complex meshes are damaged by hyperactive pigeons.

 

[namrata]

Do you think a chimney of more than 1000m3 of suction will make a significant difference when compared to this?

no, i don't think any chimney can get rid of all the kitchen fumes and odors. i have a bigger and higher capacity one. it removes all the smoke but not the odor. i am using exhaust fan only to reduce the cooking odors. exhaust fans help recharging the air if doors/windows are closed.

You have your exhaust fan on inverter!

actually, chimney is also on inverter backup. the whole house is on inverter except for heavy kitchen appliances and ACs.

I forgot to mention, the hall+kitchen setup is air conditioned, are there exhaust fans which will work in air conditioned rooms without leaking loads of air. Another option I see is somehow sealing the exhaust fan setup so that it's not visible and doesn't leak air and opening the seal during days of deep frying.

yes, you can seal up the area around your current exhaust fan or get a smaller capacity one. if at all, your exhaust fan will impact the air conditioning in a positive way only.

usually, roof mounted exhaust fans (under false ceiling) are meant for air conditioned areas but a high wall-mounted exhaust fan will also work.
there are non-exhaust type (re-circulates air) chimneys for fully air conditioned homes but i guess they don't stand a chance against indian cooking.


BTW, you may want to have some kind of opening in the kitchen to let the fresh air in during cooking.