LUKA is an HVAC design convention or standard used primarily in the Benelux countries. LUKA area calculations are supported by some rectangular patterns, such as bends, branches, drop cheek bends, cap ends, grills, radius offsets, reducing radius offsets, roof kerbs, square to rounds, straights, straights with branches, tapers and tees. There are two versions of LUKA area calculations supported: version 1 and version 2. Version 1 follows the original LUKA handbook calculation method. Version 2 only applies to bends, drop cheek beds, and reducing radius offsets. In the Fabrication products, for the patterns that are equipped with LUKA area calculations, you can select which version of the LUKA area calculation method is used; 1 or 2.
Patterns Equipped with LUKA Area Calculations
The table below lists the CID numbers which have LUKA area calculations.
| Pattern Class | CID Numbers |
| RectStraight | 1 25 36 410 411 340 412 |
| RectTaper | 2 27 342 440 441 |
| RectBend | 3 4 17 20 22 23 420 421 430 431 819 354 526 761250 251 |
| RectBranch | 7 417 |
| RectCapEnd | 12 802 401 222 127: |
| RectDropBend | 320 399 801: |
| RectOffset | 5 13 470 471: |
| RectRadiusOffset | 9 330 367: |
| RectRadiusOffsetIn3 | 939: |
| RoofKerb | 971: |
| RectSqrRnd | 8 28 29 34 450 451 324 254: |
| RectStrtBranch | 15 38 760 39 : |
| RectTee | 5 13 470 471 255: |
Applying LUKA Area Calculations
Two options in the Pattern Database, on the Pattern Options dialog, are used to control the minimum area and minimum length allowed in the calculations. For more information, see "Standards Tab" in Pattern Options.
The exact area calculation differs from fitting to fitting, but in general:
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The maximum periphery is multiplied by the greater of the actual length and the LUKA minimum length.
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The area value returned is the greater of the calculated value and the LUKA minimum area.