Guidelines for Selecting the Proper Materials and Coatings
Simpson Strong-Tie connectors, anchors and fasteners feature a wide range of materials and coatings designed to meet specific performance criteria. It is important to select a material and/or coating that is suitable for the intended application and environment based upon factors such as corrosion resistance and mechanical properties of the material. For more information on selecting connectors, anchors and fasteners based upon corrosion resistance, please see General Corrosion Risks, Guidelines for Selecting the Proper Materials and Coatings, Materials and Coatings Available – Connectors, and Materials and Coatings Available – Fasteners for more information on selecting products based on corrosion resistance.
Evaluate the Application
Consider the importance of the connection.
Evaluate the Exposure
Consider these moisture and treatment chemical exposure conditions:
- Dry service: Generally INTERIOR applications and includes wall and ceiling cavities, raised floor applications in enclosed buildings that have been designed to prevent condensation and exposure to other sources of moisture.
- Wet Service: Generally EXTERIOR construction in conditions other than Elevated Service. These include Exterior Protected and Exposed and General Use Ground Contact as described by the AWPA UC4A.
- Elevated Service: Includes fumes, fertilizers, soil, some preservative-treated wood (AWPA UC4B and UC4C), industrial zones, acid rain and other corrosive elements.
- Uncertain: Unknown exposure, materials, or treatment chemicals.
- Ocean/Water Front: Marine environments that include airborne chlorides and some splash. Environments with de-icing salts are included.
- Treatment Chemicals: See AWPA Use Category Designations. The preservative-treated wood supplier should provide all of the pertinent information about the wood being used. The information should include Use Category Designation, wood species group, wood treatment chemical, and chemical retention. See appropriate evaluation reports for corrosion effects of treatment chemicals and fastener corrosion resistance recommendations.
- Fire-Retardant-Treated (FRT) Wood: Metal connectors in contact with FRT wood in dry service applications may generally be uncoated, painted or galvanized G90 zinc-coated steel. Refer to the FRT wood manufacturer’s recommendations for fastener and connector protection requirements. The 2015 IBC Section 2304.10.5.4 and 2015 IRC Section R317.3.4 refer to the manufacturer’s recommendations for fastener corrosion requirements. In the absence of recommendations from the manufacturer, the code requires fasteners to be hot-dip galvanized, stainless steel, silicon bronze or copper. Fastener shear and withdrawal allowable loads may be reduced in FRT lumber. Refer to the FRT manufacturer’s evaluation report for reduction factors.
Use the Simpson Strong-Tie Corrosion Classification Table
If the treatment chemical information is incomplete, Simpson Strong-Tie recommends the use of a 300 series stainless steel product. Also if the treatment chemical is not shown in the Corrosion Classification Table, then Simpson Strong-Tie has not evaluated it and cannot make any recommendations other than the use of coatings and materials in the Severe category. Manufacturers may independently provide test results of other product information; Simpson Strong-Tie expresses no opinion regarding such information.
|Corrosion Resistance Recommendations|
|FASTENERS & ANCHORS|
|Phosphate (gray, black),
Clear (bright) zinc (ASTM F1941),
Heavy electro-galvanized (ASTM A641-Class 1),
Yellow zinc (ASTM F1941),
Type 410 stainless steel
|Mechanically galvanized (AS 3566.2-C3, N2000, ASTM B695-Class 55),
Quik Guard® coating,
Hot-dip galvanized (ASTM A153-Class D),
Type 410 stainless steel with protective top coat
|Type 304 stainless steel,
Type 305 stainless steel
|Type 316 stainless steel,
Hot-dip galvanized (ASTM A153-Class C),
Silicon bronze, Copper
|Simpson Strong-Tie gray paint Powder coating Standard G90 zinc coating||ZMAX® (G185) Hot-dip galvanized (ASTM A123)||Type 316L stainless steel||Type 316L stainless steel|
|Corrosion Resistance Classifications|
|Environment||Material to be Fastened|
|Untreated Wood or Other Material||Preservative-treated Wood||FRT Wood|
|SBX-DOT Zinc Borate||Chemical Retention ≤ AWPA, UC4A||Chemical Retention > AWPA, UC4A||ACZA||Other or Uncertain|