This specification establishes requirements for a coupling for use with low pressure, low and medium high temperature, air ducts.
Types - Couplings shall be of two types as follows:
Type I. - 450 Deg. F., NAS520; Type II. - 250 Deg. F., NAS521
Sizes - Couplings shall be of the sizes specified on the applicable NAS drawing.
AIA NAS522 History
More Standards PDF
AIA NASM21094:2024
$27.00 $55.00
AIA NAS595
$26.00 $53.00
AIA NAS500:2024
$27.00 $55.00
AIA NASM27954
$26.00 $53.00








