EN 14351-1:2006+A2:2016 is the harmonised product standard a window or external pedestrian doorset must be tested and documented against before it can carry CE/UKCA marking in the EU and UK, with the Declaration of Performance (DoP) issued by the manufacturer under AVCP System 3 for these residential and commercial facade products [S1][S2][S6]. The standard's six core characteristics, wind load, water tightness, air permeability, thermal transmittance, acoustic performance, and load-bearing capacity of safety devices, plus radiation properties, define what a specifier has to read on the DoP before signing off a facade package.
For an aluminium or aluminium-clad system on the European market in 2024-2026, the most visible data points on a DoP are a Uw figure between 0.77 and 1.29 W/m²K depending on glazing, a wind-load class of C4 (1600 Pa) for fixed and single-leaf casement types, water tightness of 9A (600 Pa), and air permeability of Class 4 (±600 Pa) [S1][S2][S3][S4]. Numbers like these are the specifier's decision inputs, not the marketing copy.
What the DoP actually lists: six essential characteristics
Under EN 14351-1:2006+A2:2016 Annex ZA, the manufacturer must declare, for each opening function tested, a row of essential characteristics, each tied to a classification standard, a test standard, a notified body, and a test report [S1][S2][S4]. The characteristics are clause 4.2 resistance to wind load, 4.5 water tightness, 4.6 air permeability, 4.8 dangerous substances, 4.11 acoustic performance, 4.12 thermal transmittance, 4.13 radiation properties, and 4.14 load-bearing capacity of safety devices, with additional clauses 4.5 and 4.6 (impact resistance and ability to release) added in the A2 amendment [S1][S2][S3][S4][S6].
Each declared value is paired with a classification standard (for example EN 12210:2016 for wind load) and a test standard (EN 12211:2016), with the work done by a notified body such as NB 1235 (Danish Technological Institute) or NB 0402 (RISE Research Institutes of Sweden) [S1][S2]. When the characteristic is not measured, the DoP carries "NPD" (No Performance Determined), which is a legal status, not a failure to test, and is the only correct way to leave a line blank [S1][S2][S3][S4][S5]. For an aluminium window and door system on a tall facade, leaving water tightness as NPD is a red flag for the specifier.
Reading the numbers: wind, water, air, and Uw on real 2024-2026 DoPs
On the 23 January 2025 Rationel FORMA (double-glazed) and FORMAPLUS (triple-glazed) DoPs, the 1-leaf casement door (CDO) and fixed casement (FC) both declare wind load Class C4 (1600 Pa) per EN 12210:2016, water tightness Class 9A (600 Pa) per EN 12208:2016, and air permeability Class 4 (±600 Pa) per EN 12207:2016 [S1][S2]. The 2-leaf CDO-2 steps down to wind load Class B4 (1600 Pa), reflecting the larger tested size of 1900 mm × 2000 mm, while the FC was tested at 2500 mm × 2000 mm [S1][S2].
The thermal transmittance line shows the glazing effect directly: FORMA double-glazed is 1.27 W/m²K, FORMAPLUS triple-glazed is 0.80 W/m²K, and the FORMAPLUS FC drops to 0.80 W/m²K with g 0.53 / LT 0.74 versus the FORMA FC at 1.27 W/m²K with g 0.64 / LT 0.82 [S1][S2]. The 27 August 2024 UK AURAPLUS double-glazed DoP carries 1.28 W/m²K (CDO), 1.28 W/m²K (FC), and 1.29 W/m²K (FL fixed light) with the same g 0.64 / LT 0.82 radiation set, while the AURAPLUS triple-glazed DoP of 23 January 2025 sits at 0.79 W/m²K (CDO, CDO-2) and 0.77 W/m²K (FC) [S3][S4]. Across the four DoPs the consistent g/LT pair for triple-glazed (0.53/0.74) and double-glazed (0.64/0.82) is the radiation property block specifiers should match to the building's shading strategy.
AVCP System 3, notified bodies, and the test report chain
Every EN 14351-1:2006+A2:2016 DoP in the research declares AVCP System 3, meaning the manufacturer does factory production control, but the type-testing (ITT) is done by a notified laboratory, and no third-party FPC certification body is involved for these residential/commercial facade products [S1][S2][S3][S4][S6]. The notified bodies carrying the work are NB 1235 (Danish Technological Institute, Denmark), NB 0402 (RISE, Sweden), and on the older UK AURAPLUS DoP, NB 1314 (Chiltern Dynamics / BMT) [S1][S2][S3][S4].
The test report numbers link the declared value back to a physical specimen: DTI/268669-6/2024-Okt. and DTI/268671-2/2024-Nov. are the October-November 2024 reports from DTI for FORMA/FORMAPLUS wind, water, and air tests, while acoustic radiation-property reports dated 2016 (0108/678451R, 0108/682833R, 0108/959384R) are reused across the new 2024-2025 DoPs because the ITT window for acoustic and radiation was already covered [S1][S2][S4]. For a system window and door project, the report numbers and the tested size (WxH) on the DoP are what a building physics reviewer checks first when validating the declared Uw for a specific frame size.
UKCA versus CE: the GB market's split-path reality
For the UK market after Brexit, the 2024 AURAPLUS DoP is issued as BS EN 14351-1:2006+A2:2016 with UK representative DOVISTA (UK) Ltd. in Huntingdon/Cambridge, and uses the W-EY-UK-20240901 number, while the 2025 AURAPLUS triple-glazed document reverts to the EN reference under DOVISTA A/S in Horsens, Denmark [S3][S4]. This split (one document on the UK DOP register, the next on the EU CPR path) reflects the parallel CE and UKCA regimes that facade contractors have to keep on file for a single residential block delivered to a GB client in 2025-2026 [S3][S4][S7].
On the lower-volume fabricator end, a UK window assembler can issue a Declaration of Conformity rather than a full DoP for limited production runs, as the 6 January 2026 Garrard Windows document does for Liniar / VEVO System 3: it lists thermal transmittance at 2.5 W/m²K (ER Certification Ltd, NB 121) with all other essential characteristics marked "npd" against BS EN 14351-1:2006+A2:2016 Annex ZA, and explicitly states the declaration covers the worst-case product, so the fabricator's other sizes perform equal to or better than the declared number [S5]. That is a defensible route for small-trade fabrication, not for a commercial tower with U-value targets below 1.0 W/m²K.
Comparing the four 2024-2025 Rationel DoPs side by side
Across the four signed Rationel/DOVISTA DoPs published 27 August 2024 and 23 January 2025, the comparison matrix for specifiers comes down to four criteria: glazing line, declared Uw on the smallest test specimen (CDO 1-leaf at 970 × 2000 mm), wind class on the FC (2500 × 2000 mm), and acoustic evidence. [S1]
FORMA double-glazed: Uw 1.27 W/m²K, FC wind C4 (1600 Pa), acoustic test 0108/678451R (2016-01-08) [S1]. FORMAPLUS triple-glazed: Uw 0.80 W/m²K, FC wind C4 (1600 Pa), acoustic test 0108/682833R (2016-02-10) plus SS-EN ISO 10140-1:2021/2:2021 evidence for the FC at NB 0402 [S2]. AURAPLUS double-glazed (UK): Uw 1.28-1.29 W/m²K, FC wind NPD (only the FL fixed light at 2490 × 2400 mm carries C4/1600 Pa), acoustic test 0108/682833R (2016-02-10) [S3]. AURAPLUS triple-glazed: Uw 0.77-0.79 W/m²K, FC wind C4 (1600 Pa), acoustic test 0108/959384R (2020-12-09) with the same 10140-2 chain at NB 0402 [S4].
The takeaway: moving from double to triple glazing saves roughly 0.48 W/m²K on the same test specimen (1.27 to 0.79 W/m²K on CDO FORMA vs AURAPLUS) and reduces the solar heat gain coefficient g from 0.64 to 0.53, a fact a facade engineer should price into summer cooling loads before specifying the higher-transmittance double-glazed unit on a south elevation [S1][S4]. For a door, window and curtain wall package that mixes fixed lights and operable casements, the AURAPLUS triple-glazed FC at 0.77 W/m²K is the strongest declared number in the set, while the UK-only AURAPLUS DoP's NPD wind class on the FC is a gap the specifier has to close with a project-specific ITT before installation [S3][S4].
Limitations and what the DoP does not cover
A EN 14351-1:2006+A2:2016 DoP only declares performance for the tested specimen size and the opening function listed; a 970 × 2000 mm CDO result does not automatically cover a 1900 × 2000 mm CDO-2, which on the FORMA DoP is reclassified to wind B4 instead of C4 even though both use the same profile [S1][S2]. It also does not cover fire resistance or smoke leakage, which are explicitly excluded from the standard's title for these facade products, and any claim of "fire-rated" requires a separate EN 16034 or national approval [S1][S2][S6][S7].
The DoP is issued under the sole responsibility of the manufacturer (DOVISTA A/S in three of the four documents, Garrard Windows Ltd in the fifth) and the type-testing is done at the system level, not on the assembled site unit, so a project-specific Uw calculation per EN ISO 10077-2 is still the specifier's job for the actual frame size on the facade [S1][S2][S3][S4][S5]. Watch for the "NPD" stamp: it is the manufacturer's right to leave a characteristic undeclared, but it also means the specifier cannot use that line in a thermal or acoustic model without project-specific evidence [S1][S2][S3][S4][S5].
Tracking the next signals
Two developments are worth watching through the rest of 2026. First, the Anglian Home Improvements DoP reference document dated August 2026 is now circulating under BS EN 14351-1:2006+A2:2016 with the same clause structure, suggesting UKCA DoPs continue to mirror the EN 14351-1 numbering without a separate UK-only standard [S7]. Second, the 2025 Rationel DoPs are leaning on 2016 and 2020 acoustic test reports (0108/678451R, 0108/682833R, 0108/959384R) alongside 2024 wind/water/air reports, so the next refresh will likely either reissue acoustic evidence or formally extend the ITT validity window per the system-3 rules. For specifiers buying aluminium-clad facade systems in late 2026, the two numbers to check first on any incoming DoP are the FC Uw at the project-relevant size and the wind class of the largest test specimen, because that is where the specifier's actual facade sizing lands.
Related analysis: NFPA 660 Replaces NFPA 652: What Changes Inside a Plant.