Fire, smoke and uPVC windows.

A design team on a non-combustible building will ask whether a uPVC window is allowed. The honest answer has three parts: what the material is under the code, what testing exists, and how the approval has actually been obtained in New York City.

What the material is.

uPVC is a plastic. Under the building code it is a combustible material. "Non-combustible" is a defined term: a material earns it by passing ASTM E136, a furnace test. uPVC does not pass it, and nothing on this site will tell you it does.

A Vistaza window is a uPVC frame with steel reinforcement inside it, glazed with glass. The amount of uPVC in each unit is small and discrete. That matters in the code, as the section below shows.

The test we ran.

Vistaza had a Vi6 fixed window tested for surface burning to ASTM E84 at Intertek in 2019 (report J4854.01-121-24). The report describes the sample as "unplasticized polyvinyl chloride (uPVC) frame and connection profile, glass", in white, with the room-side face to the flame.

Measure	Result
Flame spread index	0
Smoke developed index	70
Flame front advance	0.0 feet
Dripping, or flaming on the floor	None
Sagging, delamination or shrinkage	None

For context, the interior finish table in the International Building Code treats a flame spread of 0 to 25, with smoke developed up to 450, as its best band. The test report itself assigns no class, because ASTM E84 has no classes of its own. It also cannot be used to call a material non-combustible.

The sample was a Vi6 fixed window in white. The Vi5 is extruded uPVC as well.

How a uPVC window is approved on a non-combustible building.

Type I and Type II buildings have to be built of non-combustible materials, except where the code says otherwise. Section 603.1 of the New York City Building Code is that list of exceptions. One item on it reads: "Millwork such as doors, door frames, window sashes and frames."

That is the path. On Sedgwick, a Type I building in the Bronx, the design team needed the Department of Buildings to confirm it. The steps were these:

1. Vistaza commissioned a fire protection engineering judgment from Intertek, signed by Intertek's fire protection engineer. It reviewed the Vi6 fixed and operable windows and the in-swing doors against the New York City Building Code.
2. The engineer's conclusion: "considering the discrete amounts of uPVC used in the sashes and frames of each window or door unit (even those ganged together), we believe that their use would not jeopardize life safety or building fire performance."
3. The architect filed the report with the Department of Buildings as a construction code determination.
4. The Borough Commissioner approved it, finding that "the proposed uPVC based window assemblies comply pursuant to BC 603.1(6)."

The ruling says the windows are permitted as combustible millwork. It does not say they are non-combustible, and it does not make them fire-rated. Intertek issued the same judgment for Vistaza on an earlier project in Queens, so this is a route we have been down more than once, and we can supply the same package to your design team.

Permitted is not the same as rated. Know which one your opening needs.

Where a rated assembly is still required.

Some openings need a fire-protection-rated assembly: a window in a rated corridor wall, an opening too close to a lot line, an opening in a rated shaft or stair enclosure. A standard window of any material, uPVC, aluminum or wood, is not that product. A rated opening needs a tested, labeled fire window or fire-rated glazing in a rated frame.

Mark those openings on the schedule early. We will tell you plainly which ones a Vistaza window can fill and which ones need a rated product from a specialist.

What to ask for.

1. The ASTM E84 report, with its report number, and the sample it was run on.
2. For a Type I or Type II building, the engineering judgment and the record of the determination.
3. A schedule that separates ordinary exterior openings from openings that need a fire-protection rating.

Related reading: what uPVC is, and how a frame is built and safety glazing.