Guides · The paperwork

Window ratings, decoded — and how to check them yourself.

Every impact window legally sold in Florida sits on top of a public paper trail: a test report, an approval document, a table of tested sizes and pressures. Sellers rarely mention that you can read all of it for free. This guide explains what the ratings mean — then walks you through the public portals so no one can hand-wave you.

Design pressure: the number that actually matters

Design pressure (DP) is the wind load a window assembly is engineered to resist, in pounds per square foot (psf). It always comes as a pair:

  • a positive number — wind pushing the window into the building, and
  • a negative number — suction pulling it outward, which is often the harder load. A rating written as +65/−70 means the unit is engineered for 65 psf pushing in and 70 psf pulling out.

What your opening needs is a separate question from what a product offers. Required pressures are calculated from your building’s location, height, surrounding exposure and even which part of the wall the window sits in — corners see higher suction than the middle of a wall. That calculation belongs to the permit drawings for your project, not to a brochure.

The conversion chart that doesn’t exist: pages that map DP numbers to hurricane categories (“DP 50 = Category 5”) are making it up — and the charts on different sites contradict each other. Pressure grows with the square of wind speed and shifts with height, exposure and wall zone. There is no single mph number hiding inside a DP rating.

One more number worth knowing: in the structural test behind the rating, the unit is held at 1.5 times its design pressure. That safety factor is part of the standard, not a bonus the salesperson negotiated for you.

The two approval systems — NOA and FL number

Florida runs two public product-approval systems, and the difference is geographic:

Miami-Dade NOAFlorida Product Approval (FL #)
Issued byMiami-Dade County Product ControlStatewide system (floridabuilding.org)
Required forThe High-Velocity Hurricane Zone — which is exactly two counties: Miami-Dade and BrowardProducts used elsewhere in Florida
Testing behind itTAS 201 (large missile) · TAS 202 (structural, air, water) · TAS 203 (cyclic)ASTM E1886 / E1996 and related standards
Works in the other system’s territory?Yes — an NOA is accepted statewideNo — an FL number alone does not qualify a product for the HVHZ

The reciprocity is one-way, and it is the single most useful fact in this guide: a product with a current Miami-Dade NOA has passed the strictest path. Palm Beach County and the rest of the state are governed by the wind-borne debris rules of the Florida Building Code — see how that plays out city by city on our local pages.

Look up any product yourself — it takes about three minutes

This is the part almost nobody teaches, and it is the part that protects you. Both approval databases are public, free, and searchable without an account.

On the statewide portal

  1. Ask the seller for the FL number of the exact product on your quote (for example, “FL12345.6”). If they cannot produce one, stop here — that is your answer.
  2. Go to the Florida Product Approval search at floridabuilding.org and search by that number (or by manufacturer).
  3. Open the approval and read three things: the status (current, not superseded), the installation instructions it references, and the evaluation documents listing tested sizes and pressures.

On the Miami-Dade portal

  1. Ask for the NOA number (a file number like “24-0101.02”).
  2. Search the Miami-Dade Product Control database— you can also filter by manufacturer, product category, impact rating and maximum design pressure.
  3. Open the NOA PDF. The next section shows you what to read in it.

How to read the approval document

An NOA or FL approval is a few pages of dense tables, but only five things decide whether it covers your project:

  • Expiration date. Approvals expire and get renewed or superseded. A lapsed document is a red flag on any quote.
  • Maximum tested sizes. The approval covers openings up to the tested width and height — not “whatever fits.” If your opening is larger than the table allows, that product, in that configuration, is not qualified for it.
  • The design-pressure table. DP varies by size within the same series. Find the row that matches your dimensions; that row — not the headline number — is your rating.
  • Glass makeup. The tested glazing (glass thicknesses, interlayer type and thickness) is spelled out. A quote that swaps the glass build is quoting a different, untested product. Our guide on how impact windows work explains what those layers do.
  • Anchoring and installation instructions. The approval belongs to the assembly installed as specified — anchor type, spacing, embedment. This is what the permit inspection verifies; see permits and inspections.
Red flag worth memorizing: “Approved for Florida!” with no number attached is not an approval — it is a sentence. Every real approval has a number you can search in the public portals above, and every impact-rated unit carries a permanent etched mark on the glass identifying it.

Where your required pressure comes from

If you want to see the other side of the equation, the free ASCE 7 Hazard Tool reports the ultimate design wind speed for any address — South Florida sits in the strongest band in the continental United States. Turning that speed into required psf for each opening involves height, exposure category and wall zone, and it is the job of the drawings in your permit package. What you can do as a buyer is simpler and just as powerful: make sure the DP on the approval document covers the DP on those drawings, size by size.

When you build a project with SmartWay, that check is part of the review — every recommendation states its source, verification date and status, and says so when something is not verified yet.

Questions we actually get

What is the difference between a Miami-Dade NOA and a Florida Product Approval?
Both are public approval documents. A Notice of Acceptance (NOA) is issued by Miami-Dade County Product Control and is required for the High-Velocity Hurricane Zone; it is accepted statewide. A Florida Product Approval (an FL number) is the statewide system run through floridabuilding.org. The reciprocity is one-way: an NOA works everywhere in Florida, but an FL number alone is not sufficient inside the HVHZ.
Do I need an HVHZ product outside Miami-Dade and Broward?
The HVHZ itself is only Miami-Dade and Broward counties. Elsewhere, the Florida Building Code still requires opening protection in the wind-borne debris region, but products are qualified through the statewide Florida Product Approval system rather than Miami-Dade NOAs. Many buyers outside the HVHZ still choose HVHZ-tested products; the code does not force them to.
Can a strong window have a low design pressure on my opening?
Yes — DP is per size and configuration, not per product line. The same series that reaches a high DP in a small size may carry a much lower rating at its maximum tested dimensions. That is why the approval document has a table instead of a single number.
Is there a chart that converts DP ratings to hurricane categories?
No honest one. Wind pressure grows with the square of wind speed and depends on your building’s height, exposure and the zone of the wall the window sits in. Two homes in the same category of storm can need very different design pressures. Charts that map “DP 50 = Category X” disagree with each other because each one is invented.
What should I ask a seller to put in writing?
The approval number (NOA or FL) for each product on the quote, the series name, and the tested sizes and design pressures that cover your exact openings. If a quote cannot name its approval numbers, you are not looking at a specified product — you are looking at a promise.

Sources

Last checked: August 20, 2026. Portal links are re-verified when this page is updated; if a link above stops working, the document numbers still search correctly on each agency’s site.

Build your project with verified specs →Next: evaluating brands