FAQs
While polypropylene vent pipe may carry a slight material premium, installers typically save up to 70% on labor because UL 1738–listed polypropylene vent systems install much faster. The overall cost of installation is often lower when using UL 1738 polypropylene vent pipe compared to alternative options.
InnoFlue® Polypropylene Special Gas Vent Systems, tested and listed to UL 1738, have been sold in the United States and Canada since 2009. In Europe, polypropylene flue gas vent pipes have been in use for over 25 years, proving themselves to be a safe, reliable, and industry-standard technology.
Yes. Centrotherm’s InnoFlue® Polypropylene Special Gas Vent Systems are fully approved by the Massachusetts Plumbing Board. This means UL 1738 vent pipe can be confidently installed in compliance with state plumbing and safety regulations.
PVC is not used in Europe as a flue gas vent material because of its lower maximum operating temperature and environmental safety concerns. Instead, Europe relies on polypropylene vent pipe, including UL 1738–listed systems, which offer higher heat resistance, improved durability, and greater safety margins for condensing appliances.
InnoFlue® UL 1738 vent pipe is available at numerous plumbing and HVAC suppliers across the United States and Canada. Installers can easily source UL 1738 polypropylene vent pipe from regional and national distributors.
InnoFlue® is approved for gas-fired Category II and IV appliances and is suitable for vertical or horizontal venting in new or retrofit installations, including chimneys, chases, and through-wall terminations. InnoFlue® Poloprophyline also meets UL-1738 code.
Connector Rimgs are required for an installation of 2″ through 5″ diameter InnoFlue® to be UL-1738 and ULC-S636 compliant. Centrotherm strongly recommends the use of Connector Rings on all installations. Diameters 6″ and larger do not require the use of Connector Rings.
InnoFlue® Polypropylene Special Gas Vent Systems can be field cut to length using a hacksaw and miter box or equivalent. InnoFlue® must be cut on the male end of the pipe, preserving the socketed (female) end. After making a cut, the end can be beveled at the contractor’s discretion. The end must be deburred using a standard deburring tool or sand paper.
Yes, the exterior of InnoFlue® can be painted. Please follow the surface preparation specified by the paint manufacturer.
Yes. For rooftop terminations, follow flashing and sealing instructions. Vertical terminations over 59” above the roof line must be supported with guy wires or braces.
Not directly. For underground applications, InnoFlue® must be installed inside a larger diameter, direct-bury-rated pipe. The vent must be pitched, supported, and allowed to expand/contract inside the sleeve.
Yes, InnoFlue® Flex can be field cut, but only in the rigid sections and when connecting to the female end of Single Wall.
When venting combustion gas, InnoFlue® Flex cannot be installed horizontally. The installation of InnoFlue® Flex in a horizontal configuration allows for the pooling of condensate. This can create sagging in the vent system leading to the creation of back pressure. Back pressure can result in a forced shut down of the heating appliance.
InnoFlue® Flex and BlitzFlex® can be installed horizontally when used as an air intake.
InnoFlue® Flex and BlitzFlex® can be installed horizontally when used as an air intake.
InnoFlue® Flex can be installed in a shared chimney, assuming the flues are separated, if the ambient air temperature does not exceed 300°F (149°C).
InnoFlue® Flex should not be installed in a sheet rock wall.
InnoFlue® Polypropylene Special Gas Vent Systems can be installed in chases with offsets that do not exceed 45°. Chases can have multiple offsets.
No, InnoFlue® Flex is UL-1738 and ULC-S636 listed exclusively for use as a combustion gas vent system inside of a chase.
The InnoFlue® Concentric vent kit must always be installed according to Centrotherm’s official installation instructions to ensure safety, compliance, and system performance.
The concentric vent system can be installed in a variety of chases, including masonry, B-vent, and sheet rock chases, offering flexibility for different construction types.
InnoFlue® Concentric vent kit combines exhaust gas venting and combustion air intake into a single concentric vent system. This design allows for a cleaner, more aesthetically pleasing installation, reduces the number of roof or wall penetrations, and helps save on labor and installation time..
A concentric vent is a type of venting system that incorporates both exhaust and intake air in one pipe-within-a-pipe design. The InnoFlue® Concentric vent kit features a durable metal outer with a polypropylene inner. Combustion gas is drawn through the space between the two pipes, while exhaust gases are safely expelled through the polypropylene inner pipe.
The InnoFlue® Concentric vent system is engineered to withstand flue gas temperatures up to 230°F (110°C).
InnoFlue® Concentric vent kits are approved for use with gas-fired Category II and Category IV appliances, making them versatile for residential and commercial applications.
InnoFlue® Lite is a lightweight, CE EN 14471-certified polypropylene venting system designed for use with Category II and IV gas-fired appliances (U.S.) and Class II C appliances (Canada). It is suitable for residential, commercial, and industrial applications with flue gas temperatures up to 230°F (110°C) and maximum pressures of 0.725 psi (5000 Pa).
Yes. Use paints approved for polypropylene, such as Rust-Oleum or Krylon. Remove ink markings with acetone, apply an appropriate adhesion promoter, and reattach the product label once dry.
Use Centrotherm-supplied support brackets when possible. Horizontal runs must be supported every 39" (1 m); vertical runs must be supported every 78" (2 m). Directional changes (elbows/tees) should be supported within 12".
Yes, InnoFlue® Lite is the perfect solution for air intake in both code and non-code markets.
Yes. All diameters of InnoFlue® Lite SW Rigid components are UV stabilized and suitable for exterior installation. Optional black components are available in 2" and 3" for aesthetic preference or enhanced performance.
Not directly. For underground applications, InnoFlue® Lite must be installed inside a larger diameter, direct-bury-rated pipe. The vent must be pitched, supported, and allowed to expand/contract inside the sleeve.
Our vision of sustainability is encapsulated in our aim to evolve into a circular brand. This means that in all aspects of our operations, we look at how we can integrate sustainability and circularity principles. It's a continuous process of analyzing, adjusting, learning, and improving, in which we strive to be transparent about what we do and what we achieve. Together with our stakeholders, we evaluate the impact our company has and identify areas for improvement.
We've deliberately chosen not to prioritize specific sustainability initiatives. Instead, we've woven sustainability throughout our entire business operations, connecting it with distinct business strategies. For example, our sustainability principles in HR are integrated into the HR strategy. And our principles in the area of safety and health are included in our group Health & Safety strategy and rolled out from there. This approach enables us to actively address multiple themes simultaneously and make continual progress. This fits into our vision: sustainability is not a standalone theme. It encompasses all our business processes and is therefore an integral theme.
This is a crucial part of our sustainability pillar 'Our Solutions'. In our product design process, it's really important to think about sustainability and circularity and make smart choices. We have a clear product design process. From the beginning, when we set the product specifications, we ask questions about sustainability and circularity. For example, can we use recycled material? Where do we get components we don't make ourselves, and do those suppliers meet our criteria? In 2024, we're also going to start using Life Cycle Assessments in our product design process. This means that in the design phase, we look at the environmental impact of our new products. If we find ways to reduce that impact, we can do it before the product is made, rather than after.
In 2023, we started with a baseline measurement, using 2022 as our reference year. Every year, we gather new data and compare it to our reference year. In the meantime, we set targets on relevant KPIs, so that we can also communicate our progress each year.