---
title: Is Corzan CPVC Approved for Use in Plenums?
description: Model codes restrict the surface burning characteristics of the materials that can be installed in air plenums. Is Corzan CPVC tested and approved?
---

[Corzan® CPVC Blog ](https://www.corzan.com/en-us/blog)

# [Is Corzan CPVC Approved for Use in Plenums?](https://www.corzan.com/en-us/blog/corzan-cpvc-approved-use-plenums)

 Written by [Rob Janowiak](https://www.corzan.com/en-us/blog/author/rob-janowiak) | May 28, 2018 4:00:00 AM

In most commercial buildings, the areas above the suspended ceiling used for air circulation are identified as air plenums. These cavities are particularly challenging during a fire, [explains Sewell Direct](https://sewelldirect.com/learning-center/plenum-space): They contain a lot of fresh oxygen that can make a fire grow quickly and because the air is forced, smoke and fumes can spread throughout the building.

As a result, model codes restrict the surface burning characteristics of the materials that can be installed in air plenums.

Various tests are used to evaluate the surface-burning characteristics of constructions materials. The most common requirement is to restrict materials permitted within plenums to those meeting a 25/50 fl­ame spread/smoke developed when tested in accordance with ASTM E84. As a reference, asbestos cement has a 0/0 fl­ame spread/smoke developed rating and red oak has a 100/100 ­flame spread/smoke developed rating.

Corzan® and FlowGuard Gold® pipe and fittings have been listed by ICC-ES under PMG 1264. The following models have been tested water filled or dry in general accordance with UL 723/ASTM E84 test methods for surface burning characteristics and have been found to meet the 25/50 ­flame spread/smoke developed requirements of the International Mechanical Code® (IMC) and the Uniform Mechanical Code® (UMC) for installation in ducts and plenums:

- 1/2" – 6” water filled Corzan CPVC pipe and fittings have a ­flame spread index of 0 and a smoke developed index of no more than 20.
- 1/2″ – 2” dry Corzan pipe and fittings for condensate lines have a flame spread index of no more than 0 and a smoke developed index of no more than 20.
- 1/2" – 2” water filled FlowGuard Gold CPVC pipe and fittings have a ­flame spread index of no more than 5 and a smoke developed index of no more than 35.
- 1/2" – 2” dry FlowGuard Gold CPVC pipe and fittings for condensate lines have a ­flame spread index of no more than 5 and a smoke developed index of no more than 25.

For more information, [visit our plenum rating page](https://www.corzan.com/en-us/specification/plenum-ratings) or [download the full ICC-ES report](http://www.icc-es-pmg.org/Listing_Directory/pdf/PMG-1264.pdf).

[View full post](https://www.corzan.com/en-us/blog/corzan-cpvc-approved-use-plenums)

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