Lead equivalent is guaranteed by the company-supplier in accordance with GOST 3514-57 with
at least 1.753 and the thickness of the plates
More detail of thickness:
Nominal thickness
plates
for glass grade TF-5*
in mm: Lead equivalent at a voltage of 180-200 kV
in mm, not less
10 : 2,5
15 : 4,0
25 : 6,5
50 : 13,5
*Article of this glass is TF-5