Flexible pipe for kitchen exhaust fan

Who told you that? Ask THEM why. With the exception of being fire-proof and flexible pipe slows down air movement, it's up to the applicator to be sure it works as expected. ON a long run? Wouldn't be recommended. On a normal run up & thru the wall? No problem as a rule.

You gave no information to go on. That's like asking why I can't drive my Buick with a Chevy radio installed in it? I heard more than once not to do that. Why is that?

HTH,

Twayne

Sam Takoy wrote the following:

Maybe they meant flexible plastic duct pipe? Metallic flex pipe would be OK.

If fireproof I see nothing wrong with that. But, metal with a smooth interior is the preferred.

My guess - it's a grease trap. I sure wouldn't use it.

Typical cheap clothes dryer platic pipe with a wire for support is no good. Dangerous buildup of grease and you have a disaster waiting to happen. Flexible aluminun pipe is reasonable, but every bend slows down the air and provides a point for grease to accumulate.

The inside of the pipe will be corrugated, not smooth. Over time it will collect grease and dirt far faster than a smooth pipe and will potentially either start on fire or feed a fire already going. It does not happen often in the home, but a lot of restaurant fire happen in the ventilation system.

Take the time to do the job right.

No, it wouldn't. Grease collector

Not just preferred, but - required- by many building codes. Check with your local building official.

-snip-

Ask "them" that say you can't use it. I *wouldn't* use it because it is a grease trap, impossible to clean, much more resistant to airflow and much lighter gauge than rigid.

Jim

Thanks for the responses.

The reason I am looking at flexible duct work is I'm trying to build a contraption that slides sideways over the stove. The only place to build the exhaust was to the side of the stove. So in needs to be flexible enough to go from this | | | |

to this

\ \ \ \

It needs to slide by 12" over the length of 42".

Any suggested solutions would be most welcome.

Ed Pawlowski wrote the following:

So is the solid tubing. The difference is that the flex tubing will collect more grease before leaking it back onto the range.

They make elbows that can be adjusted to any angle.

Sam Takoy wrote: Thanks for the responses.

How about a smaller pipe fitting into a larger one? Make a flange to compensate for the different diameters. You can get quite a bit of movement if the pipes don't overlap too much. That might work if you don't plan to take the assembly apart too often. There are couplings made for water piping but they are probably spendy.

Sheet metal pipe is available from 3 to 10 inches diameter in one inch increments in 5' lenghts. Elbows are also available for each size that will adjust from straight to 90 degrees. They are not terribly expensive. HD/Lowes should have it. They also have the rectangular duct that is made to fit inside a wall if that will work better for you. The elbows for that are only avilable in 45 and 90 degree AFAIK. They also have adapters to go from round to the rectangular. Again, not expensive and avail at the box stores. Larry

In addition to lowes and HD, any Mom and Pop sheet metal place can fabricate anything for you, and they could make it in one piece.