Every figure here carries its unit, the standard it came from and the condition it was measured under; a number without those three is not drawn.
Drawing notes: how a figure is read onto a sheet
rev Aissue 04rev Adrawn by The Transom Set (a named set, not a person)
Where the figures come from
Every number on this set is one of four things: a U-value in W/m²K, an air leakage rate in m³/h per m² at a stated pressure, a water test pressure in pascals, or a condensation figure on a named scale. A figure missing its unit is not drawn here. A figure missing the standard it came from is not drawn here either.
Units and the trap that goes with each
| Quantity | Unit | The trap |
|---|---|---|
| U-value | W/m²K | the route and the area convention change it by fifteen per cent |
| Air leakage | m³/h·m² | quoted at a stated pressure, and it does not scale linearly |
| Water penetration | pascals | a test pressure is not a design pressure and not a wind speed |
| Condensation | index or °C | an index is a rating and a temperature is a reading |
How a document is admitted
A document is used only if it is a specific publication that supports a specific sentence on the sheet, and only if it can be opened. Standards, code text, national-laboratory work and peer-reviewed measurement are preferred, because each publishes its method. Maker material is admitted only where the maker is describing its own product or its own practice, and never for a comparative claim.
What is measured here and what is not
This set reports what documents print and what a test returns. It does not rank products, does not compare frames on price, and does not accept advertising. Where a sheet quotes a maker's figure it says so and names the document. Where a sheet quotes a test it gives the specimen, the condition and the result.
The figures published in the revisions are single-assembly observations. They are published because the method is stated and can be repeated, not because they describe every window of that type.
Documents this sheet is drawn from
- 1NGA's GANA Glazing Manual (2022 Edition)supports the glazing practice manual the set's drawing conventions follow
- 2NGA Publishes Updated GANA Glazing Manual (IYOG Edition)supports the publication history of that manual and the edition in force
- 3Analysis of U.S. Commercial Building Envelope Air Leakage Database to Support Sustainable Building Design (NIST)supports the measured envelope air leakage data the set's targets are drawn from
Each line points at one specific document, with its own title as the link text. No line is a home page and no line is a search result.
Sign the sheet and stop Sign the sheet and stop once you know which unit a figure is in. Every other sheet assumes it.