Thread: Are mechanical vents allowed on island kitchen sink vents in Florida

I'm installing a kitchen sink in an island and want to use a air admittance valve so I don't have a vent stack in the middle of the room. Is this allowed in Florida? I find the building code doesn't do a very good job of describing whether or not it is and what the rules are.

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"Are mechanical vents allowed"

Originally Posted by kelly logan

I'm installing a kitchen sink in an island and want to use a air admittance valve

You asked two entirely different questions between the title and the post:
- 1) No, mechanical vents are not allowed ... basically not allowed anywhere in the US, and definitely not in Florida.
- 2) Yes, air admittance valves are allowed in most places, including Florida, but ... air admittance valves must be installed properly and in accordance with the manufacturer's installation instructions and the code, the Florida Building Code - Residential states:
- SECTION P3114
- - AIR ADMITTANCE VALVES
- - - P3114.1 General. Vent systems using air admittance valves shall comply with this section. Individual and branch-type air admittance valves shall conform to ASSE 1051. Stack-type air admittance valves shall conform to ASSE 1050.
- -- P3114.2 Installation. The valves shall be installed in accordance with the requirements of this section and the manufacturer's installation instructions. Air admittance valves shall be installed after the DWV testing required by Section P2503.5.1 or P2503.5.2 has been performed.
- - - P3114.3 Where permitted. Individual vents, branch vents, circuit vents and stack vents shall be permitted to terminate with a connection to an air admittance valve.
- - - P3114.4 Location. Individual and branch air admittance valves shall be located a minimum of 4 inches (102 mm) above the horizontal branch drain or fixture drain being vented. Stack-type air admittance valves shall be located a minimum of 6 inches (152 mm) above the flood level rim of the highest fixture being vented. The air admittance valve shall be located within the maximum developed length permitted for the vent. The air admittance valve shall be installed a minimum of 6 inches (152 mm) above insulation materials where installed in attics.
- - - P3114.5 Access and ventilation. Access shall be provided to all air admittance valves. The valve shall be located within a ventilated space that allows air to enter the valve.
- - - P3114.6 Size. The air admittance valve shall be rated for the size of the vent to which the valve is connected.
- - - P3114.7 Vent required. Within each plumbing system, a minimum of one stack vent or a vent stack shall extend outdoors to the open air.

Air admittance valves are not mechanical vents. Mechanical vents are allowed in mobile homes, not site built homes.

Here is a handy link to show which states approved AAV and which do not approve them and which states have limited approvals. http://www.ipscorp.com/studor/reference/approvals

I do not know how an AAV like a Studor vent is not considered mechanical, it still has a moving part, and it still fails. Also they do not allow for positive pressure in the drainage system.

Thank you Jerry and Ron for both of your replies to my question. I was confused at first and thought a mechanical vent and air admittance valve were the same thing. I realized shortly after my original posting they are not. I appreciate all your help!

Kelly