Air Admittance Valves
Q. How does the Studor Air Admittance Valve work?
A. The Studor Air Admittance Valve (AAV) is a one-way valve that
allows air to enter the plumbing drainage system when fixtures discharge.
The valve closes by gravity when discharge is completed and under
no flow conditions preventing sewer gas from escaping into the valve.
Q. Why is it important to allow air to enter the plumbing
system?
A. When fixtures discharge negative pressure develops in the
drainage system due to water flowing downstream in the pipes.
If air does not enter the system and balance the pressure
the water in the fixture trap will be siphoned allowing sewer
gas to enter the building.
Q. Are Studor AAV's suitable for all applications?
A. YES! Studor manufactures various models which fit pipe sizes
of 1 1/2", 2", 3" and 4". The valves are suitable
for single fixtures, branches and stack applications in residential
and commercial buildings.
Q. Can Studor AAV's be used in extreme temperatures?
A. All Studor AAV's are tested to temperatures of -40°
F and +150° F as required by the ASSE Performance Standards.
In addition some models are provided with insulation material
as part of the packaging which provides additional protection.
Chem-Vent FAQ
Q. What is a Chem-Vent?
A. The Chem-Vent is a specialty Air Admittance Valve (AAV)
manufactured by Studor.
Q. What is its intended purpose?
A. The Chem-Vent was purposely designed to be used in specialized
acid waste systems as a replacement of conventional vent pipes
and loop vents (very commonly used in lab style layouts).
Q. What kind of acid waste systems?
A. The kind commonly installed in schools, hospitals and labs
in general.
Q. Can the valve be used in systems handling bio-hazardous
or otherwise toxic waste?
A. The valve CANNOT be used in any
applications where the fumes contained in the waste systems
would require filtration before humans could be exposed to
them.
Q. Can any material AAV be used in acid waste systems?
A. No, technically, only the Chem-Vent since all its components
are designed to handle the corrosive and temperature environment
of an acid waste system. Standard (residential or other commercial)
AAV have neither the chemical resistance nor the temperature
range to operate in such systems.
Q. Is the use of the Chem-Vent in acid waste systems
code approved?
A. Currently the plumbing codes do not allow the use of any
AAV's in an acid waste system. This application was correctly
excluded in the codes because no manufacturer produced a suitable
product. Studor’s Chem-Vent is different and Studor is working
with the code authorities to make an exception for AAV's manufactured
from chemical- and acid-resistant material.
Q. Can the Chem-Vent be used before the code language
is changed?
A. Even before the code is changed it will be possible to
use the Chem-Vent as part of an engineered system.
Q. What makes the Chem-Vent different from all other
AAV's?
A. Its Flame Retardant Polypropylene (FR-PP) material of construction
and its chemical resistance EPDM seat.
Q. Why FR-PP?
A. For the last 20 years FR-PP has been the material of choice
in the vast majority of institutional lab installations (e.g.
schools, hospitals, etc.)
Q. Are there any other material used in acid waste
systems?
A. Yes, starting from the oldest to the newest:
• Ductile Iron (Duriron®)
• Borosilicate glass
• FR-PVDF
• CPVC
Q. When, where and why are these materials used instead
of FR-PP in Acid Waste piping systems?
A. Duriron was the very first system used in acid waste system
before better materials came along. Its chemical resistance
is very poor and so is its life expectancy. The Chem-Vent
can be comfortably specified and used on any Duriron systems.
• Glass replaced Duriron as the material of choice and is
still extensively used today in return air plenum applications
as well as with some extreme chemicals. Cost, limited jointing
styles, brittleness and difficulty of installation of glass
have allowed FR-PP to become the predominant choice. If FR-PP
is deemed resistant to the chemical waste in a glass system,
the Chem-Vent can be used on glass systems unless the system
is installed in a return air plenum.
• FR-PVDF is a relatively new material designed specifically
to replace glass in return air plenum installations. Although
comparable in material cost its versatility, light weight
and available jointing systems makes the installed cost of
FR-PVDF systems in return air plenum very competitive with
glass. If FR-PP is deemed resistant to the chemical waste
in a glass system, the Chem-Vent can be used on glass systems
unless the system is installed in a return air plenum.
• CPVC is the newest material in acid waste system. Like FR-PP
it cannot be used in return air plenum applications; additionally
it cannot be used if solvents are part of the waste flow.
Thanks to its proven solvent cement jointing system CPVC is
easy to install and does not require specialty equipment.
The Chem-Vent can be comfortably specified and used on any
CPVC systems.
Q. How does the Chem-vent connect to an FR-PP system?
A. The valve’s extended tail piece can be directly installed
on any mechanical joint or fusion sanitary Tee currently available
(regardless of the manufacturer) following the acid waste
system manufacturer jointing instructions.
Q. How can the Chem-Vent be installed on dissimilar
material systems?
A. Through adapters designed to transition from FR-PP to glass,
ductile iron or CPVC.
Q. Where can I find these adapters?
A. FR-PP to glass or ductile iron adapters are readily available
through the different FR-PP piping system manufacturers. FR-PP
to CPVC adapters are readily available through the different
CPVC piping system manufacturers.
Q. Why does the Chem-Vent have an extended tail piece
connection?
A. To make sure that the vent will always comply with the
code required minimum of 4” above the trap, no matter which
FR-PP manufacturer or system is selected.
Q. Does the Chem-Vent meet any performance standards?
A. Yes the Chem-Vent is tested to and certified to; NSF 14
Maxi-Filtra FAQ
Q. What is a Maxi-Filtra?
A. The Maxi-Filtra is a device that serves as a two way vent
that allows air to pass through a carbon filter and eliminate
sewer gas odors.
Q. Can the Maxi-Filtra be use indoors?
A. No, the Maxi-Filtra is designed for outdoor use only, particularly
for use with septic systems.
Q. Can the Maxi-Filtra be installed horizontally?
A. Yes, the Maxi-Filtra can be installed in the horizontal
or the vertical position.
Q. Can the Maxi-Filtra be installed in an existing
system?
A. Yes, the Maxi-Filtra can be retro-fitted on an existing
system.
Q. How long does the carbon filter cartridge last?
A. The cartridge can last up to 2 years.
Q. Does the Maxi-Filtra require maintenance?
A. No maintenance is required other than replacing the cartridge.
Q. Is the Maxi-Filtra protected from UV rays?
A. Yes, there is also an optional cover available for additional
protection.
Q. What size pipe does the Maxi-Filtra fit?
A. The Maxi-Filtra fits a 3" or 4" pipe.
P.A.P.A. FAQ
Q. What does P.A.P.A. stand for?
A. Positive Air Pressure Attenuator
Q. What is the P.A.P.A. used for?
A. It is used to neutralize positive air transients in the DWV system of multi-story buildings.
Q. What is a Positive Air Transient?
A. It is a low amplitude, high speed air pressure wave traveling through the system.
Q. How fast does it travel?
A. 1056 ft/sec - the speed of sound.
Q. Does it represent a large volume of air?
A. No, typically it is no more than 1/2 gallon of air. It can, however, be greater depending on conditions.
Q. Why are Positive Air Transients created into a
DWV system?
A. Fluids discharged into a DWV system, after reaching terminal velocity, begin to swirl inside the pipe, dragging air into the center of the pipe. After the pipe transitions from vertical to horizontal (bottom of the stack or change of directions) a curtain of water is formed.
The air hitting this curtain bounces off of it and travels backward through the system.
Q. Are Positive Air Transients the only potential
for positive air pressure in a DWV system?
A. No, positive pressure can also travel into a buildings DWV system from sewer (or septic tank) or be generated by a blockage(or belly in the pipe).
Q. Is the P.A.P.A. designed to neutralize all positive
air pressure conditions?
A. No, just Positive Air Transients.
Q. Why are Positive Air Transients harmful to a DWV
system?
A. They can result in the loss of water seals or, at a minimum,
contribute to the depletion of the traps. Positive air transients
ave been proven to resonate inside of conventionally designed
systems up to three days. In addition they can be the source
of bubble through; a condition that allows sewer gases as
well as pathogens to be introduced in to the living space
without loss to the trap seal.
Q. How are Positive Air Transients typically dealt
with?
A. Relief Vent
Sovent System - This system deals
indirectly with the positive air transient slowing down the
flow in the system thus preventing terminal velocity to be
reached. Special aerator and de-aerator fittings must be used
at each branch in order to prevent the formation of positive
transients.
Single Stack system - (Philadelphia
system) - The Single Stack system relies on venting through
the roof, with consequent increased roof penetrations.
Q. Is a P.A.P.A. / AAV system better than these other
systems and if yes, why?
A. Technically it is better for four reasons:
• System balancing in 0.2 seconds
• Neutralize almost 100% of the transient
• Eliminates floor and roof penetrations
• Maintains the natural flow in the system
In addition, it also represents substantial savings over the other designs.
Q. Why would most of the transient naturally flow
in into the P.A.P.A. if it is attached to a smaller branch,
much like a relief vent?
A. Because the instant a minimal portion of the transient begins to inflate the P.A.P.A. bag a differential pressure is created at the branch-off point
making the branch and the P.A.P.A. the path of least resistance for the air.
Q. What happens to the air transient once it enters
the P.A.P.A.?
A. Its velocity (1056 ft/sec) is instantly (less than 0.2 sec) cut to 40 ft/sec after which the small (and now slow) air volume is harmlessly re-introduced into the
system.
Q. What if it is determined that there is the potential
for a greater than average air volume?
A. Up to four P.A.P.A.'s can be serial mounted for up to a
total volume capacity of 4 gallons.
Q. Is the P.A.P.A. a maintenance item?
A. No, it does not require maintenance since there are no stress pieces, springs or mechanical devices that could wear or lose tension and consequently fail.
Q. What kind of warranty does it carry?
A. The P.A.P.A. has a limited lifetime warranty for replacement of defective product.
Q. Must the P.A.P.A. be installed vertically?
A. No, it can be mounted in any position and orientation (unless used with an AAV on top)
Q. Where should the P.A.P.A. be installed?
A. It should be installed at the bottom of each stack in the building below the first branch and before the sweep transitioning the pipe from vertical to
horizontal. Additional units may be required on each stack, depending on the number of branches (see our installation guide)
Q. Can the P.A.P.A. be retrofitted to an open pipe
vent system?
A. Yes
Q. Can it be engineered as an integral part of an
open pipe vent system as additional protection?
A. Yes
Q. What can the P.A.P.A. be compared to in order to
give customers a quick understanding of its function?
A. In essence, the P.A.P.A. performs a function similar to that of a water hammer arrestor, but for air.
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