Dryer vent hoses are used to vent the exhaust from the dryer to the outside of the house. Lint can build up in the vent hose that is too long because the forced air loses speed if it travels a long distance.
There are accordion style vent hoses and the aluminium or steel pipe. The accordion style is most favoured because it is flexible, but all types of accordion vents, even the foil type has ridges inside where lint can settle and can cause a fire.
The length of any dryer vent hose or pipe should never be more than 25 feet long. If the hose or pipe must bend at a 45 degree angle, deduct 2.5 feet from 25 feet for each angle. If the hose or pipe must bend at a 90 degree angle, deduct 5 feet from the 25 feet for every bend.
Using aluminium or steel pipes with a smooth surface inside will allow the lint to flow more freely at a distance. If the distance of the vent hose must be 25 feet long, a pipe will be easier to keep clean than an accordion type hose.