1.3 To extend the vertical height restriction, it was determined that an FMRC Vertical Duct Fire test would be required. Approved sizes may range from 12 in. Colchester, VT facilities on July 16, 1996. All ducts shall be fabricated from Type 316L stainless steel. Duct joints normally occur at maximum 4 ft.
Security is achieved by bolting together exterior overlying carbon steel companion rings.
The minimum number of holes in the companion ring for the flange connections is one hole for each 6 in. 2.2 Ducts shall be fabricated of identical material to that originally used and tested. 2.5 Elbows and other fixtures are fabricated using the same process. The 12 in. Additionally, the duct and all field-applied joints shall maintain their structural integrity without developing any through openings.