How to spec a commercial unit skylight by opening size
Logistics Lighting is a national commercial/industrial distributor and specifier - not a manufacturer - under Skylight Sherpa(SM). We stock VELUX Commercial, Sunoptics, Kingspan Light + Air, Birdview, AES, Curbs Plus, and related smoke vents, curbs, and screens across 16 storefront opening families. Inch codes such as 4896 mean a 48" x 96" curb ID; Sunoptics 4080 means 4'-0" x 8'-0" for the same nominal opening. VELUX model 3612 is the 3' x 10' family (36120 in CSI/curb notation). Measure existing Curb Outside Dimension (COD) - including flashing or membrane - before you pick a model; wrong COD is the most common fit failure. Then match CID (for screens), glazing, warranty-as-sold, and code. The LL storefront range includes common 4x8 / 5x6 openings and 3x10 (36120 / 3612).
Last updated: 2026-09-17
How to read size codes
Inch notation (VELUX, Kingspan, Taylon, Birdview, AES, Curbs Plus) concatenates width x length in inches: 4896 ~ 48" x 96" curb ID; 4848 ~ 48" x 48"; 6072 ~ 60" x 72". Sunoptics uses feet-inches without separators: 4080 = 4'-0" x 8'-0", 5060 = 5'-0" x 6'-0" - marketing equivalents of the matching inch family, not a different hole size until you confirm COD/CID on the roof. VELUX Dynamic Dome size code 3612 is Nominal Size 3' x 10'; product data and drawings show curb 36x120, fabricated-to-fit COD 39x123, NFID 40.5x124.5. CSI Spec lists the same opening as [36120]; AES and Curbs Plus curbs use 36120. Spec sheets: Skylight Specification Sheets. Terminology: COD / CID / NFID.
| Nominal opening | Inch / CSI code | Sunoptics ft code | VELUX model note |
|---|---|---|---|
| 4x4 | 4848 | 4040 | CMD2 4848 |
| 4x6 | 4872 | 4060 | CMD2 4872 |
| 4x8 | 4896 | 4080 | CMD2 4896 |
| 5x6 | 6072 | 5060 | CMD2 6072 |
| 5x8 | 6096 | 5080 | CMD2 6096 |
| 5x5 | 6060 | - | CMD2 6060 |
| 3x10 | 36120 | - | CMD2 3612 (= 36120) |
How to measure a curb
Critical fit dimension is existing Curb Outside Dimension (COD), including any flashing or membrane on the curb (Curb Measurement Guide; Terminology). Skylights are typically fabricated about 1" larger than COD for expansion and install clearance, so COD maps into the unit's Net Frame Inside Dimension (NFID). Also record Curb Inside Dimension (CID) when safety screens attach to the top of the curb, and curb height if curbs are replaced or added. Verify all roof curbs on the job share the same dimensions. Typical minimum curb height is about 8" above the roof, though final height is set by the architect/engineer, geography, building type, and roofing membrane provider (Ask Our Experts).
Master table - all 16 storefront opening families
Sixteen distinct opening families are sold on the Logistics Lighting storefront (linked inch/ft notations counted once). Example product links are representative SKUs currently listed - confirm stock and options on quote.
| Opening | Notation | CID / COD summary (typical) | Brands / product types on LL | Example product |
|---|---|---|---|---|
| 2448 | 2448; 2'x4' | CID 24x48; COD fit ~27x51; NFID 28.25x52.25 | VELUX CMD2 | CMD2 2448 P1C2 |
| 3636 | 3636; 3'x3' | CID 36x36; COD fit ~39x39; NFID 40.25x40.25 | VELUX CMD2 | CMD2 3636 P1C2 |
| 3648 | 3648; 3'x4' | CID 36x48 (cage) | Kingspan Gladiator cage only | 3648 SCAGE |
| 3696 | 3696; 3'x8' | CID 36x96; COD fit ~39x99; NFID 40.5x100.5 | VELUX CMD2 | CMD2 3696 P1C2 |
| 36120 | 36120; VELUX 3612; 3'x10' | CID 36x120; COD 39x123; NFID 40.5x124.5 | VELUX CMD2 3612; AES / Curbs Plus 36120; screens | CMD2 3612 P1C2 |
| 4848 | 4848; Sunoptics 4040; 4'x4' | Inch COD fit ~51x51; Sunoptics COD fit ~50x50 | VELUX; Sunoptics SMD; Kingspan KT11; Birdview; curbs/screens | CMD2 4848 P1C2 |
| 4860 | 4860; 4'x5' | CID 48x60; COD fit ~51x63; NFID 52.5x64.5 | VELUX CMD2 | CMD2 4860 P1C2 |
| 4872 | 4872; Sunoptics 4060; 4'x6' | Inch COD fit ~51x75; Sunoptics ~50x74 | VELUX; Sunoptics SMD; AES; screens | CMD2 4872 P1C2 |
| 4896 | 4896; Sunoptics 4080; 4'x8' | CID ~48x96; COD ~51x99 typical | Dominant: skylights, smoke vents, curbs, screens | CMD2 4896 P1C2 |
| 6060 | 6060; 5'x5' | CID 60x60; COD ~63x63; NFID 64.5x64.5 | VELUX CMD2; Kingspan SVAA; AES/CPC; screens | CMD2 6060 P1C2 |
| 6072 | 6072; Sunoptics 5060; 5'x6' | CID 60x72; COD ~63x75 (inch); Sunoptics COD fit ~62.375x74.375 | VELUX; Sunoptics SMD; Kingspan SVAM; AES/CPC | SMD 5060 C2W1 |
| 6096 | 6096; Sunoptics 5080; 5'x8' | CID 60x96; COD fit ~63x99 (VELUX); Sunoptics SVT2 COD fit ~62x98 | VELUX CMD2; Sunoptics SVT2 5080; 6096 screen | CMD2 6096 P1C2 |
| 7272 | 7272; 6'x6' | CID 72x72; COD fit ~75x75; NFID 76.5x76.5 | VELUX CMD2 | CMD2 7272 P1P2 |
| 4689 | 4689 (Alumilite) | NFID 50.5x93.75; COD fit 49.25x92.5 - != 4896 | Kingspan Alumilite KT12; screen | 4689 KT12 |
| 5596 | 5596 (melt-out) | Frame ~52.9x94.9; SCAGE CID 55x96 | Kingspan ASLDOUL; SCAGE | 5596 ASLDOUL |
| 55102 | 55102 (melt-out) | Frame ~52.9x100.9; SCAGE CID 55x102 | Kingspan ASLDOUL; SCAGE | 55102 ASLDOUL |
Full catalog: Products.
4x8 - 4896 / Sunoptics 4080
For a standard 4x8 commercial curb opening, three units dominate quotes: VELUX CMD2 4896, Sunoptics SMD 4080, and Kingspan 4896 KT11. Inch code 4896 = 48" x 96" curb ID; Sunoptics 4080 = 4'-0" x 8'-0" for the same nominal opening. Typical fabricated-to-fit COD on LL product pages is 51x99; VELUX NFID 52.5x100.5, Sunoptics NFID 52.25x100.25. Birdview 4896 TBCM is also listed for the same family.
| Brand | Model | Size notation | COD fit / NFID (LL fields) | Warranty-as-sold-by LL (from /warranties/) | Best-fit use | Example |
|---|---|---|---|---|---|---|
| VELUX Commercial | CMD2 4896 (Dynamic Dome) | 4896 | COD 51x99; NFID 52.5x100.5 | Standard 15-yr LuxGuard/LuxGuard Plus PC; project purchase through LL to +5 on skylights (20-yr total) | Low-angle morning/afternoon harvest; long roof+skylight warranty story | CMD2 4896 P1C2 |
| Sunoptics | SMD 4080 | 4080 | COD 51x99; NFID 52.25x100.25 | Standard 15-yr Signature PC / SVT2; exclusive +5 available for specific customers to up to 20 yr | High-volume industrial prismatic diffusion | SMD 4080 C2W1 |
| Kingspan Light + Air | 4896 KT11 | 4896 | COD 51x99; NFID 52.5x100.5 | 10-yr transferable when installed per guidelines; optional +5 (15 total) with documented annual inspection/repairs | Spec-driven transferable warranty path | 4896 KT11 |
| Birdview | 4896 TBCM | 4896 | COD 51x99; NFID 51.5x99.5 | See brand warranty docs linked from product page | Alternate polycarbonate dome option on same opening | 4896 TBCM |
Always re-read Warranties before quoting live bid terms. Proof: Tradepoint Atlantic used 276x VELUX Dynamic Dome 4896 (case study).
4x4 - 4848 / Sunoptics 4040
A 4x4 opening is written 4848 in inch notation and 4040 in Sunoptics feet-inches - same nominal 4'x4' marketing opening, with slight COD variance by brand. On LL storefront fields, VELUX/Kingspan/Birdview typically fabricate to COD 51x51; Sunoptics SMD 4040 lists COD fit 50x50 and NFID 51.25x51.25. Confirm COD (including flashing) before swapping brands on a reroof.
| Brand | Model | Notation | COD fit / NFID (LL fields) | Notes | Example |
|---|---|---|---|---|---|
| VELUX Commercial | CMD2 4848 | 4848 | COD 51x51; NFID 52.5x52.5 | Dynamic Dome family; LuxGuard PC warranty path per /warranties/ | CMD2 4848 P1C2 |
| Sunoptics | SMD 4040 | 4040 | COD 50x50; NFID 51.25x51.25 | Signature Series; FM-rated option on listed SKU | SMD 4040 C2W1 FMRTG |
| Kingspan Light + Air | 4848 KT11 | 4848 | COD 51x51; NFID 52.5x52.5 | Quasar-class KT11; Kingspan 10+optional5 warranty path | 4848 KT11 |
| Birdview | 4848 TBCM | 4848 | COD 51x51; NFID 51.5x51.5 | Same opening family | 4848 TBCM |
AES/CPC curbs and safety screens are also stocked in this family - see Products.
4x6 - 4872 / Sunoptics 4060
For 4x6, use inch code 4872 or Sunoptics 4060 (4'-0" x 6'-0"). VELUX CMD2 4872 on LL lists COD fit 51x75 and NFID 52.5x76.5; Sunoptics SMD 4060 lists COD fit 50x74 and NFID 51.25x75.25. Do not assume interchangeability without a COD check - the ~1" difference is enough to mis-fit a flashed curb.
| Brand | Model | Notation | COD fit / NFID (LL fields) | Notes | Example |
|---|---|---|---|---|---|
| VELUX Commercial | CMD2 4872 | 4872 | COD 51x75; NFID 52.5x76.5 | Dynamic Dome; CSOS smoke-vent pairing available in family | CMD2 4872 P1C2 |
| Sunoptics | SMD 4060 | 4060 | COD 50x74; NFID 51.25x75.25 | Signature Series clear-over-white prismatic PC on listed SKU | SMD 4060 C2W1 |
AES ARC6 curbs and screens (e.g. 4872 SSCRN) support the same opening family on the storefront.
5x6 - 6072 / Sunoptics 5060
A 5x6 opening is 6072 in inch notation and 5060 in Sunoptics feet-inches. VELUX CMD2 6072 lists COD fit 63x75 / NFID 64.5x76.5; Sunoptics SMD 5060 lists COD fit 62.375x74.375 / NFID 63.625x75.625; Kingspan 6072 SVAM lists ID frame 64.25x76.25 (note: that SKU's Nominal Size field incorrectly says 4'x6' - trust model code + CID 60x72). Fairburn, GA used Sunoptics Signature Series Model 5060 with Curbs Plus 5x6 curbs and safety screens (case study).
| Brand | Model | Notation | COD fit / NFID (LL fields) | Warranty-as-sold path | Example |
|---|---|---|---|---|---|
| VELUX Commercial | CMD2 6072 | 6072 | COD 63x75; NFID 64.5x76.5 | LuxGuard PC: 15-yr standard; LL project +5 to 20 yr | CMD2 6072 P1C2 |
| Sunoptics | SMD 5060 | 5060 | COD 62.375x74.375; NFID 63.625x75.625 | Signature: 15-yr standard; exclusive +5 for specific customers | SMD 5060 C2W1 |
| Kingspan Light + Air | 6072 SVAM | 6072 | NFID 64.25x76.25 (CID 60x72 family) | 10-yr transferable; optional +5 with inspection docs | 6072 SVAM |
5x8 - 6096 / Sunoptics 5080
5x8 is inch 6096 or Sunoptics 5080. On the LL storefront, VELUX CMD2 6096 covers the skylight opening (COD fit 63x99, NFID 64.5x100.5); Sunoptics SVT2 5080 is listed as a smoke vent in this size (COD fit 62x98, NFID 63.25x99.25); 6096 SSCRN is the safety-screen listing. Slight COD variance by brand is expected - measure the curb, do not substitute by nominal size alone.
| Brand / type | Model | Notation | COD fit / NFID (LL fields) | Role on LL storefront | Example |
|---|---|---|---|---|---|
| VELUX Commercial | CMD2 6096 | 6096 | COD 63x99; NFID 64.5x100.5 | Unit skylight | CMD2 6096 P1C2 |
| Sunoptics | SVT2 5080 | 5080 | COD 62x98; NFID 63.25x99.25 | UL-listed polycarbonate smoke vent | SVT2 5080 |
| Safety screen | 6096 SSCRN | 6096 | CID field 59.5x95.5 | Fall-protection screen for 5x8 curb | 6096 SSCRN |
Smoke-vent selection (UL vs FM, fusible-link temp) belongs with the fire-system engineer and AHJ (Ask Our Experts).
5x5 - 6060
6060 is a square 5' x 5' opening (CID typically 60x60). VELUX CMD2 6060 lists COD fit 63x63 / NFID 64.5x64.5; Kingspan 6060 SVAA lists NFID 64.25x64.25. AES/CPC curbs and screens are stocked in-family. There is no Sunoptics feet-inch twin listed for 6060 on the LL storefront.
| Brand | Model | Notation | COD fit / NFID (LL fields) | Notes | Example |
|---|---|---|---|---|---|
| VELUX Commercial | CMD2 6060 | 6060 | COD 63x63; NFID 64.5x64.5 | Dynamic Dome square | CMD2 6060 P1C2 |
| Kingspan Light + Air | 6060 SVAA | 6060 | NFID 64.25x64.25 | Operable / smoke-vent family per Series 3200/3300 chart | 6060 SVAA |
3x10 - 36120 / VELUX 3612
3x10 is confirmed on product pages and manufacturer PDFs: VELUX model 3612 = Nominal Size 3' x 10' = curb family 36120. CMD2 3612 P1C2 lists COD fit 39x123 and NFID 40.5x124.5; AES 36120 ARC3 lists CID 36x120 / COD 39x123. Curbs Plus CPC/CPM and Z-frame / screen SKUs use 36120. Do not confuse VELUX size code 3612 with a 36" x 12" opening - the trailing 12 abbreviates 120" length on the Dynamic Dome size grid.
| Brand / type | Model | Notation | Key dims (LL / PDF) | Role | Example |
|---|---|---|---|---|---|
| VELUX Commercial | CMD2 3612 | 3612 (= 36120) | COD 39x123; NFID 40.5x124.5; curb 36x120 | Unit skylight | CMD2 3612 P1C2 |
| AES | 36120 ARC3 | 36120 | CID 36x120; COD 39x123 | Metal building / skylight curb | 36120 ARC3 |
| Curbs Plus | CPC-3 / CPC-4 / CPM-3 36120; CP Z-frame; SCS36120G | 36120 | CID/COD match 36x120 / 39x123 on curb listings | Curbs + screens | Search Products for 36120 |
Drawing evidence: Velux-CMD2-3612-Drawing.pdf; size grid: Dynamic Dome Product Data Sheet; CSI: Spec CM-1224 unit size [36120].
Other openings we stock (listing-only)
These storefront families are single-brand or accessory-proven. Spec from the linked example; ask Skylight Sherpa for multi-brand options if the manufacturer chart offers more than LL currently lists as SKUs.
| Opening | Notation | What LL stocks | CID/COD note | Example |
|---|---|---|---|---|
| 2448 | 2'x4' | VELUX CMD2 only on storefront | COD fit 27x51 | CMD2 2448 P1C2 |
| 3636 | 3'x3' | VELUX CMD2 | COD fit 39x39 | CMD2 3636 P1C2 |
| 3696 | 3'x8' | VELUX CMD2 | COD fit 39x99 | CMD2 3696 P1C2 |
| 4860 | 4'x5' | VELUX CMD2 | COD fit 51x63 | CMD2 4860 P1C2 |
| 7272 | 6'x6' | VELUX CMD2 | COD fit 75x75 | CMD2 7272 P1P2 |
| 3648 | 3'x4' cage | Kingspan Gladiator SCAGE only | CID 36x48 | 3648 SCAGE |
| 4689 | Alumilite specialty | Kingspan 4689 KT12 + screen | COD fit 49.25x92.5 - not interchangeable with 4896 | 4689 KT12 |
| 5596 | Melt-out / dropout | Kingspan 5596 ASLDOUL + SCAGE | Specialty RO path (see MKT-PDS-3500) | 5596 ASLDOUL |
| 55102 | Melt-out / dropout | Kingspan 55102 ASLDOUL + SCAGE | Specialty RO path (see MKT-PDS-3500) | 55102 ASLDOUL |
Proof projects
- Tradepoint Atlantic / Baltimore DC (4x8 / 4896) - Distributor: Logistics Lighting. 276x VELUX Dynamic Dome Commercial Skylights Model 4896, LuxGuard Plus (clear PC over white prismatic PC), VELUX aluminum curbs, Johns Manville white TPO 60-mil. Measured ~76 fc under domes vs 50 fc target. Exclusive 20-year Dynamic Dome warranty path through Logistics Lighting (+5 over standard VELUX skylight warranty on that program). Case study.
- Fairburn, GA - Sta-Dry Roofing (5x6 / 5060) - Distributor: Logistics Lighting. Contractor: Sta-Dry Roofing Inc. Vendors: Sunoptics Inc. & Curbs Plus. Products: Sunoptics Signature Series Model 5060 curb-mount skylights and Curbs Plus 5x6 roof curbs with safety screens; 290,000 sf TPO(MA) overlay on occupied facility. Skylights/curbs backed by Logistics Lighting's exclusive 20-year warranty path on that program. Case study.
- 1.3M sf industrial roof + 4x8 skylights - Orndorff & Spaid; 276 four-by-eight VELUX units with prefabricated curbs and one-shipment logistics coordinated through Logistics Lighting. Case study.
Manufacturer size charts (PDF) - appendix (NOT currently separate LL SKUs)
The following 13 openings appear on manufacturer product-data / ordering charts linked from LL spec resources, but are not sold today as separate Logistics Lighting storefront SKUs. Treat as PDF-catalog only - do not imply stock, lead time, or a live LL model number. Ask Skylight Sherpa if a project requires one of these sizes; factory availability is manufacturer-dependent.
| Opening key | Nominal | Source chart | Status |
|---|---|---|---|
| 2496 | 2'x8' | VELUX PDS; Kingspan Series 1200 / Quasar | PDF-catalog / not on LL storefront |
| 24120 / VELUX 2412 | 2'x10' | VELUX PDS (2412); Spec (24120); Series 1200 / Quasar | PDF-catalog |
| 3660 | 3'x5' | VELUX PDS; Spec; Series 1200 / Quasar | PDF-catalog |
| 3672 | 3'x6' | VELUX PDS; Spec; Series 1200 / Quasar | PDF-catalog |
| 4783 | ~47x83 | VELUX PDS (4783); Series 1200 | PDF-catalog |
| 48120 / VELUX 4812 | 4'x10' | VELUX PDS (4812); Spec (48120); Series 1200 / Quasar | PDF-catalog |
| 60120 / VELUX 6012 | 5'x10' | VELUX PDS (6012); Spec (60120); Quasar ALHD | PDF-catalog |
| 4070 | 4'x7' (Sunoptics) | Signature Series PDS; SVT2 ordering | PDF-catalog |
| 5558 | Sunoptics special | Signature Series; SVT2 ordering | PDF-catalog |
| 5555 | Kingspan dropout | MKT-PDS-3500 (RO 48x48) | PDF-catalog (LL sells 5596/55102 only) |
| 5566 | Kingspan dropout | MKT-PDS-3500 (RO 48x60) | PDF-catalog |
| 5578 | Kingspan dropout | MKT-PDS-3500 (RO 48x72) | PDF-catalog |
| 4884 | 4'x7' inch | Kingspan Quasar prismatic spec (ID curb 48x84) | PDF-catalog |
Additional Quasar specialty squares/rects appear on the Quasar prismatic dimensions table and are likewise not LL storefront SKUs. Spec PDFs: Skylight Specification Sheets, Roof Curb Spec Sheets.
Next step - Skylight Sherpa(SM)
Need a quote package with cut sheets, curb fit check (COD/CID), smoke-vent pairing, fall protection, and warranty-as-sold language? Logistics Lighting coordinates quote to order to delivery with a single point of contact. We distribute - we do not manufacture.
Call 844-455-7283 or 307-633-9696 | sales@logisticslighting.com
Last updated: 2026-09-17