Look at IEC 61730 solar panel standard

Commonly used tempered and plate glass

Thin film solar panels often have a standard glass because they are cheap.

In crystalline solar panels, a 3 to 4mm thick solar glass is often used. The thicker the glass in the crystalline solar panels, the more stable are they. Solar panel glass on cheaper modules may be as thin as 2.5mm.

The solar panel glass (in the crystalline solar panels) is not standard glass it has a rough surface. This is necessary to make the EVA film bond well to the solar panel glass during the lamination process. Smooth glass can lead to the delamination.

Thank you, Max Mittag, Vitalii Opryshko, and Mohamed Azab for your valuable suggestions. Can you share with me the standard "IEC 61730"?

]Dear Mr. Manoj Kumar Sharma

for the solar panel you must to employ the glass with low thermal conductivity, or you can use commercial glass BK7 but at this situation you must to use tracking system because the BK7 refraction the solar if it is not vertical to the glass or double glass with air gap (air gab must be given Nu number less than 3 to prevent convection inside gap and the heat transfer still conduction with low thermal conductivity of air dap)

also for testing you can use thermal acrylic sheets with (zero color, 000 color) the thermal conductivity for acrylic low than for BK7 glass) but it have on problem it can be scratch. also the a solar transmission for it bigger than for BK7, and its approaching to 78%, and you can make a test directly for it by using solar intensity meter before and after the BK7 and acrylic sheets.

by the way you can find both of Bk7 and acrylic with different thickness, but the the references advised to 4mm in thickness for single or double glass with air gap

with my respect

Dear Dr. Ali Dawood Salman

Can you explain the varieties of the glasses which are used in the commercial Silicon PV panels?

Thanking you.

Dear Mr. Manoj Kumar Sharma

In my answer I don't mean the photo voltaic panels

my answer refer to the solar air chimney or solar chimney panels for water heater

so its not mean PV, I am sorry about this missed understood,

so if you need any information about the solar water panels or solar air chimney I ready to help..

with my respect

Thank you Dr. Ali Dawood Salman for the clarification.

Manoj Kumar Sharma you can google it, couse I have an old one

Dear Dr. Vitalii Opryshko

Thank you for sharing the document for IEC61730-2. But, it did not fulfill my need as I was told by you that IEC61730 describes the glass characteristics used for the top surface covering of the PV panel. I request you to go through the question and help me accordingly.

Thanks in advance.

Manoj Kumar Sharma I'm not an expert in this field, but there lot of glass manufactures that can be googled. Hope this brochure will help you. Good luck.