Armstrong Loudspeaker perforations
Type 10.1
rectangular or square field with perforation Rd 5540, free area 40 %
in unperforated ceiling panel, field size and position as required
(standard field size 198 x 198)
Type 10.2
rectangular or square field with perforation Rd 5540, free area 40 %
in standard perforated ceiling panel, field size and position as required
(standard field size 198 x 198)
Type 10.3
rectangular or square field with perforation Rd 5540, free area 40 %
in unperforated field of a standard perforated ceiling, field size and position as required
(standard field size 198 x 198)
Type 20
square field with perforation Qg 8846, free area 46 %, field size and position as required
(standard field size 198 x 198)