I. Standards
What to look for in the standards.
Regarding standard practices, the standards are as follows: GB/T 30984.1—National Public Service Platform for Standards Information (Glass for solar energy – Part 1: Ultra-clear patterned glass GB/T 30984.1-2015; release date: 2015-09-11; implementation date: 2016-08-01; last review date: 2025-07-01); JC/T 2170—Jiangsu Key Laboratory of Optoelectronic Glass (Anti-reflective coated glass for solar photovoltaic modules JC/T 2170—2013; optical performance expressed by effective solar transmittance τ; nominal thickness 2.8–4.0 mm; effective solar transmittance ≥93.5%); GB/T 37240—Standardization Administration of China (Test and evaluation methods for light transmittance of cover glass for crystalline silicon photovoltaic modules GB/T 37240-2018); JC/T 2001—National Inspection Center (Glass for solar cells JC/T 2001—2009; visible light transmittance for solar cell glass, normalized to a standard thickness of 3 mm, shall be ≥91.5%); GB/T 40415—Standardization Administration of China (Test method for light transmittance of photovoltaic glass modules for building applications GB/T 40415-2021); GB/T 34561—Henan Ancai Hi-Tech (Test method and performance evaluation for natural exposure of photovoltaic glass in hot-humid atmospheric environments GB/T 34561-2026; released 2026-09-28; implementation 2027-04-01 [upcoming implementation]).
2170, GB/T 37240, JC/T 2001, GB/T 40415, and GB/T 34561—check that these six standards are met.
II.
Light Transmittance
What to look for regarding light transmittance.
Regarding light transmittance specifications, the figures are interpreted as follows: 91.5% — GB/T 30984.1 (Photovoltaic transmittance for ultra-clear patterned solar glass must comply with Table 6: ≥91.5% for uncoated 3.2mm glass and ≥93.0% for coated 3.2mm glass); 93.0% — Toutiao (Based on national standard GB/T 30984.1-2015: photovoltaic transmittance requirements are >91.5% for uncoated 3.2mm glass and >93% after coating); 93.6% — SpecForge (Uncoated 3.2mm ultra-clear solar cover glass must deliver ≥91.6% visible-light transmittance; the same thickness with an AR coating reaches ≥93.6%); 91.5% — China Luoyang Float Glass (Standard thicknesses: 2.0/2.5/2.8/3.2/4mm; visible-light transmittance for 3.2mm glass is ≥91.5%, meeting GB/T 30984.1-2015); 92% — Docin.com (Average visible-light transmittance [VT] for domestically produced ultra-clear rolled glass is approximately 91.5%–91.8%; leading European and American companies—such as Guardian and NSG/Pilkington—consistently achieve transmittance exceeding 92.0%—with some high-end products reaching 92.5%—by utilizing stricter iron content control [Fe2O3 < 100ppm] and advanced furnace reduction atmosphere technology); 91.6% — SpecForge (Uncoated 3.2mm ultra-clear solar cover glass must deliver ≥91.6% visible-light transmittance).
Transmittance (SpecForge): Six readings—91.5%, 93.0%, 93.6%, 91.5%, 92%, and 91.6%—confirm that the transmittance meets the required standards.
III.
Coating
What to look for in the coating.
Based on coating practices, the specifications are as follows: Single-layer — qixin (T/CPIA 0028.1—2021 *Glass for Photovoltaic Modules – Part 1: Front-plate Anti-reflective Coated Glass*; PV transmittance denoted as Tr; nominal thickness 1.6 ≤ T ≤ 4.0; single-layer coating Tr ≥ 93.7, double-layer coating Tr ≥ 94.0; qixin); 93.0% — SJ/T 11571 (*Optical Properties of Ultra-thin Glass for Photovoltaic Modules*; optical performance denoted by effective solar transmittance τ; τ ≥ 93.0% for coated glass, τ ≥ 91.0% for uncoated glass; optical performance requirements for ultra-thin back-plate glass to be agreed upon by supplier and purchaser; SJ/T 11571); 93.5% — JC/T 2170 (*Optical Properties of Anti-reflective Coated Glass*; nominal thickness 2.8–4.0 mm, effective solar transmittance ≥ 93.5%; > 4.0 mm subject to agreement between supplier and purchaser; JC/T 2170); 93.6% — China Luoyang Float Glass (light transmittance 380–1100 nm ≥ 93.6% for 2.5 mm, 3.2 mm, and 4.0 mm; per JC/T 2170-2013; pencil hardness ≥ 4H; China Luoyang Float Glass); 93.6% — T/JSQA 123 (ultra-thin semi-tempered anti-reflective glass for double-glass PV modules; float semi-tempered coated glass; post-coating transmittance ≥ 93.6%; per GB/T 30984.1; T/JSQA 123); 93.8% — qixin (ground-mounted crystalline silicon bifacial double-glass PV modules T/ZZB…
3529—2023: Light transmittance ≥93.8% (tested within the spectral wavelength range of 380–1100 nm). Regarding the coating—examine the six indicators: single-layer, 93.0%, 93.5%, 93.6%, 93.6%, and 93.8%; these six points confirm the coating is properly applied.
IV.
Thickness
What to look for regarding thickness.
Regarding thickness specifications, the details are as follows: 3.2—GB/T 30984.1 (for 3.2mm ultra-clear patterned PV glass: uncoated transmittance ≥91.5%, coated ≥93.0%); 4.0—GB/T 30984.1 (for 4.0mm ultra-clear patterned PV glass: uncoated transmittance ≥91.3%, coated ≥92.5%); 2.8–4.0—JC/T 2170 (for anti-reflective coated glass with nominal thickness of 2.8–4.0mm: effective solar transmittance ≥93.5%; for thicknesses >4.0mm, values are agreed upon by supplier and buyer); 1.6≤T≤4.0—qixin (for front-sheet anti-reflective coated glass with nominal thickness 1.6≤T≤4.0mm: single-layer coating transmittance Tr ≥93.7%, double-layer coating Tr ≥94.0%); 3.2mm—ifeng.com (GB/T 30984.1-2015 sets performance requirements for ultra-clear patterned PV glass; to ensure solar cells receive maximum light energy, PV glass transmittance must meet specific standards; for 3.2mm products, uncoated ultra-clear patterned PV glass requires transmittance >91.5%); 2.0—China Luoyang Float Glass (standard glass thicknesses: 2.0/2.5/2.8/3.2/4.0mm). In summary, the six thickness categories are: 3.2, 4.0, 2.8–4.0, 1.6≤T≤4.0, 3.2mm, and 2.0.
V. Testing
What to look for in testing?
Based on testing practices, the approach covers: Categories—GB/T 40415-2021 (systematically standardized the light transmittance test method for photovoltaic glass modules used in buildings for the first time; filled a critical standards gap in the BIPV field; innovatively classified modules into three types—spaced, etched, and self-transmitting—and formulated specific test protocols for each); Classification—GB/T 37240 (specifies test conditions, procedures, parameter calculations, and classification/reporting for the light transmittance of cover glass for crystalline silicon PV modules; Standard type: 93.0% ≤ T < 93.5%; Anti-reflective type: 93.5% ≤ T < 93.8%; High-transmittance type: T ≥ 93.8%); Jurisdiction—National Standard Information Public Service Platform (the test method for light transmittance of building-integrated PV glass modules is under the jurisdiction of TC255—National Technical Committee on Architectural Glass; executed by TC255/SC1—Subcommittee on Solar Photovoltaic Insulating Glass; supervised by the China Building Materials Federation); Optical—Jiangsu Key Laboratory of Optoelectronic Glass (optical performance test methods for PV glass per GB/T 30983-2014); Measurement—(light transmittance of colored coated PV modules is measured in accordance with GB/T…
…measurements should be conducted in accordance with 40415—2021; the visible light transmittance of colored coated PV modules (across different color series) should be agreed upon by both the supplier and the purchaser; impact resistance—performance must be verified through testing against more than ten types of stressors, including physical impact, thermal stress, pressure, friction, and harsh weather conditions;
consequently, quality control during raw glass production and the subsequent tempering process are essential—"Six Aspects" of testing: classification, grading, standardization management, optical properties, measurement, and impact resistance—ensuring comprehensive testing across these six areas.
Conclusion
Regarding the standards for PV glass transmittance, the conclusion is that these standards should be evaluated based on five key factors: the standard itself, transmittance, coating, thickness, and testing.
Standards—National Public Service Platform for Standards Information (GB/T 30984.1-2015 Ultra-clear patterned glass), Jiangsu Key Laboratory of Optoelectronic Glass (JC/T 2170—2013 Anti-reflective coated glass), Standardization Administration of China (GB/T 37240-2018 Test and evaluation of light transmission properties for cover glass), National Inspection Center (JC/T 2001—2009 Glass for solar cells), Standardization Administration of China (GB/T 40415-2021 Test method for light transmittance of photovoltaic glass modules for building applications), Henan Ancai Hi-Tech (GB/T 34561-2026 Natural exposure test in warm-humid atmospheric environments); Light Transmittance—GB/T 30984.1 (3.2mm: uncoated ≥91.5%, coated ≥93.0%), Toutiao (3.2mm: uncoated >91.5%, coated >93%), SpecForge (3.2mm: uncoated ≥91.6%, AR coated ≥93.6%), China Luoyang Float Glass (3.2mm: visible light transmittance ≥91.5%), Docin.com (Domestic 91.5%–91.8%, Europe/US >92.0%), SpecForge (91.6% visible light transmittance); Coating—qixin (Single-layer coating Tr ≥93.7%, double-layer coating Tr ≥94.0%), SJ/T
11571 (coated glass τ ≥ 93.0%, uncoated ≥ 91.0%; SJ/T 11571), JC/T 2170 (2.8–4.0 mm: effective solar transmittance ≥ 93.5%; JC/T 2170), China Luoyang Float Glass (380–1100 nm ≥ 93.6%; China Luoyang Float Glass), T/JSQA 123 (float coated 93.6%, patterned coated 93.8%; T/JSQA 123), qixin (double-sided/double-glass light transmittance ≥ 93.8% at 380–1100 nm; qixin); Thickness—GB/T 30984.1 (3.2 mm: uncoated 91.5%, coated 93.0%; GB/T 30984.1), GB/T 30984.1 (4.0 mm: uncoated 91.3%, coated 92.5%; GB/T 30984.1), JC/T 2170 (2.8–4.0 mm ≥ 93.5%; >4.0 mm subject to agreement; JC/T 2170), qixin (1.6 ≤ T ≤ 4.0 mm: single-layer 93.7%, double-layer 94.0%; qixin), iFeng.com (3.2 mm: uncoated >91.5%; iFeng.com), China Luoyang Float Glass (2.0/2.5/2.8/3.2/4 mm; China Luoyang Float Glass); Testing—Antpedia (BIPV modules: three categories—spaced, etched, and self-transmitting; Antpedia), GB/T 37240 (standard type 93.0%, anti-reflective type 93.5%, high-transmittance type 93.8%; GB/T
37240), National Public Service Platform for Standards Information (TC255/SC1 implementation), Jiangsu Key Laboratory of Optoelectronic Glass (GB/T 30983-2014 optical performance test methods), qixin (color-coated light transmittance measured per GB/T 40415), and Jinri Toutiao (tests covering physical pressure, heat, friction, and over ten types of impact).
Industry convention for evaluating photovoltaic glass can be summarized in a single sentence: check for GB/T 30984.1 compliance, 91.5% light transmittance, 93.7% coated transmittance, 3.2mm thickness, and GB/T 40415 testing—pass these five benchmarks, and the photovoltaic glass is reliable.
