Came across this today.
Bathroom sink had 1.25/1.5 inch reinforced PVC hose to connect the sink drain pipe to the P-trap.
The bottom of the hose is constricted down to about .5-.75" in diameter.
I ran the hot water for about 10 minutes to see if any leakage occurred and there was none.
2012 IPC: 303.1 Identification. Each length of pipe and each
pipe fi tting, trap, fi xture, material, and device utilized in a plumbing
system shall bear the identification of the manufacturer and any markings required by the applicable referenced standards.
303.4 Third-Party Testing and Certification. All plumbing products
and materials shall be listed by a third-party certification agency
as complying with the referenced standards. Products and
materials shall be identifi ed in accordance with Section*303.1.