250 Klug Circle, Corona, CA 92880 Phone (951) 245-9525 Fax (951) 245-9653

March 3, 2015

Fasteners and Connectors in Preservative-treated and Fire-retardant-treated wood.

Z4 Continuous Rod Tie-Down System material requirements in compliance with 2012 IBC §2304.9.5.4 Fasteners and connectors in contact with preservative-treated and fire-retardant-treated wood. Summary: Hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper coatings are not required for components in the Z4 Continuous Rod Tie-Down System. Tie-down rods used in this system are not in contact with treated wood. For Plate Washers (PW) in contact with treated wood, protection from corrosion is provided by powder coating. The lag screws used to attach the Cinch Nuts to the wood framing are coated with a Yellow Zinc Dichromate finish. With the Z4 system, plain carbon steel is not in contact with treated wood. . When tie-down rods pass through wood framing (wood plates, sills, beams, etc) Z4 detailing requires holes to be oversized. Since the rods are not designed to connect directly to the wood and are not used as fasteners to attach or connect other wood members, oversized holes are specified to minimize or eliminate contact, and are provided to prevent binding. This detailing (oversized holes) is required so that the surrounding wood structure can move (due to shrinkage and settlement) independent of the stationary rod. The rod is not meant to directly fasten to or penetrate into the wood structure, but to pass by it. IBC §2304.9.5.4 pertains to Fasteners and Connectors which are typically composed of light gauge steel material, nails, screws, staples, spikes, and clips. The application of the section to structural steel in a dry environment, such as with the Tie-Down rods, is not intended. Similarly, per IRC §R317.1 one-half-inch (12.7 mm) diameter or greater steel bolts are exempt from being hot-dipped galvanized. Regardless, if the plain carbon steel of the tie-down rod is in contact with SBX/DOT and zinc borate preservative-treated wood in an interior, dry environment it shall be permitted per section 2304.9.5.1 exception. The following information is provided as reference and supporting evidence to the above-mentioned summary.

250 Klug Circle, Corona, CA 92880 Phone (951) 245-9525 Fax (951) 245-9653

2012 IBC / 2013 CBC Code language: 2304.9.5 Fasteners and connectors in contact with preservative-treated and fire-retardant-treated wood. Fasteners, including nuts and washers, and connectors in contact with preservative-treated and fire-retardant-treated wood shall be in accordance with Sections 2304.9.5.1 through 2304.9.5.4. The coating weights for zinc-coated fasteners shall be in accordance with ASTM A 153. 2304.9.5.1 Fasteners and connectors for preservative-treated wood. Fasteners, including nuts and washers, in contact with preservative-treated wood shall be of hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Fasteners other than nails, timber rivets, wood screws and lag screws shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B 695, Class 55 minimum. Connectors that are used in exterior applications and in contact with preservative-treated wood shall have coating types and weights in accordance with the treated wood or connector manufacturer’s recommendations. In the absence of manufacturer’s recommendations, a minimum of ASTM A 653, type G185 zinc-coated galvanized steel, or equivalent, shall be used. Exception: Plain carbon steel fasteners, including nuts and washers, in SBX/DOT and zinc borate preservative-treated wood in an interior, dry environment shall be permitted. 2304.9.5.3 Fasteners for fire-retardant-treated wood used in exterior applications or wet or damp locations. Fasteners, including nuts and washers, for fire-retardant-treated wood used in exterior applications or wet or damp locations shall be of hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Fasteners other than nails, timber rivets, wood screws and lag screws shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B 695, Class 55 minimum. 2304.9.5.4 Fasteners for fire-retardant-treated wood used in interior applications. Fasteners, including nuts and washers, for fire-retardant-treated wood used in interior locations shall be in accordance with the manufacturer’s recommendations. In the absence of manufacturer’s recommendations, Section 2304.9.5.3 shall apply. ICC-ES Reports investigated: Chemco – FRX and Thermex-FR Viance – D-Blaze Arch – Dricon Hoover – Pyro-Guard This letter subject to revision after 2015.