Modifications are only eligible when referenced and described in both the third-party certification and the manufacturer’s published instructions.
SDI recommends type A, both A40 and A60, over type G due to the superior primer adhesion qualities. A60 is superior to A40 for rust inhibiting.
SDI Technical Data Series 100 has been republished as an ANSI Standard, A250.8.In addition, please see our Technical Data Series 112 “Zinc-Coated Standard Steel Doors and Frames.” The difference in the A and G designations are explained. Table 1 of that document gives coding designations for A40, A60, G60 and G40.
Some Architectural Specifications require steel frames to be back-coated with a “bituminous” product for corrosion protection and sound control. The term “bituminous” is defined as an asphalt or tar material obtained as a residue from heat refined petroleum. For years it was not recommended by the Steel Door Institute for frames to be factory back-coated due to issues with packaging, shipping and handling. This procedure was more effectively accomplished at the jobsite by the contractor or appropriate trade immediately prior to installation of the frame.
Modern materials now offer manufacturers the opportunity to back-coat frames with a more user and environmentally friendly product. Some of these coating s are VOC (Volatile Organic Compounds) free and do not present the handling issues common to bituminous products. Today, multiple SDI manufacturers offer the option of factory back-coated frames which utilize these newer materials.
Per SDI-100-1991 the cores were listed as follows:
A – Kraft Honeycomb
B – Polyurethane
C – Polystyrene
D – Unitized Steel Grid
E – Mineral Fiberboard
F – Vertical Steel Stiffeners
These are now archaic references and should be treated as such.
The type of frame is up to the specifier’s discretion. To answer the question directly, knock down (K-D) frames are not standard for all openings, as many are specified as welded frames.
All frames shall be stored under cover. Assembled frames shall be stored vertically. The units shall be placed on at least 4″ (102 mm) high wood sills or in a manner that will prevent rust or damage, even if they are galvanized or primed. The use of non-vented plastic or canvas shelters that can create a humidity chamber shall be avoided.