"N"
Certificate for Construction of Class 1, 2, 3 & MC
Vessels, Class 1, 2 & 3 Piping Systems, Class 1, 2 & 3
Shop Assembly and as a Material Organization Supplying Ferrous
and Nonferrous Material
"NA"
Certificate for Class 1, 2, 3 & MC Shop Assembly
"NPT"
Certificate for Class 1, 2, 3, MC & TP Fabrication
with and without Design Responsibility for Appurtenances and as
a Material Organization Supplying Ferrous and Nonferrous Material
"NS"
Certificate for Class 1,2,3, & MC Fabrication for
Nuclear Supports
*New
in 2003
"U"
Certificate for Manufacture Pressure Vessels and Heat
Exchangers
"U2"
Certificate for Manufacture of Pressure Vessels and Heat
Exchangers
"U3"
Certificate for the manufacture of pressure vessels at
AIT HQ and Field Sites controlled by AIT
*New in 2003
"R"
Certificate National Board Certificate for Repairs and/or
Alterations
"NB"
Certificate National Board Certificate for Registering
Boilers, Pressure Vessels, or other Pressure Retaining Items with
ASME Stamp(s): U, U2 and U3
"NB"
Certificate National Board Certificate for Registering
Boilers, Pressure Vessels, or other Pressure Retaining Items with
ASME Stamp(s): NPT, NA, N and NS