dryer vent

[mtCDCcb]

I live in a 3 unit stacked condo complex. We recently found out that our dryers were venting directly into our crawlspace. Needless to say this was causing a moisture problem. We had it vented to the outside but I noticed that the contractor didn't use solid piping for the work. Is piping required by the IBC? If so can you provide a reference? Thanks.
Seems to me this could be a fire hazard as built.

[Jerry Peck - Codeman]

[mtCDCcb]

They are all vented in one duct. It used to exhaust into the crawlspace but we routed out of the crawlspace to the exterior of the building. The part added to exhaust it out of the crawlspace was semi rigid clothes dryer transition ducting. Is there a code reference in the 2006 I-codes that I can reference to the contractor? Thanks.

[Jerry Peck - Codeman]

[mtCDCcb]

The code reference for the requirement for the ducting material.

THe contractor is not who originally vented the dryers. We noticed that they vented into the crawlspance and had for 20+years and that this wasn't good and hired someone to vent them to the outside. Upon review we thought the material used was a fire hazard and wanted to double check the requirement for the ducting material. I do know that the governing codes in our community is the 2006 icodes. Thank you.

[Jerry Peck - Codeman]