Type 2 — A Type 2 product retains 100% of its declared loop tensile strength (cable ties) or declared mechanical strength (fixing devices) after test conditions. The declared maximum operating temperature for products designated and marked as "Type 2" is based solely on performance criteria in
ANSI/UL 62275. The polymeric material comprising the product has not been separately investigated for long-term thermal properties according to
ANSI/UL 746B, "Polymeric Materials - Long Term Property Evaluations."
Type 21 — A Type 21 product retains 100% of its declared loop tensile strength (cable ties) or declared mechanical strength (fixing devices) after test conditions. The declared maximum operating temperature for products designated and marked as "Type 21" is limited to the Relative Thermal Index - Strength (RTI - Strength) at 1.5 mm (0.06 in.) thickness for the polymeric material that comprises the product. The RTI - Strength for the material is determined by separate investigation for long-term thermal properties according to
ANSI/UL 746B, and the declared maximum operating temperature of the product is based on the performance criteria in
ANSI/UL 62275.
Type 2S and Type 21S — Type 2S and Type 21S products meet the same requirements as Type 2 and Type 21 products, respectively, but have been additionally investigated for use as primary support for a flexible conduit, flexible tubing, or cable in accordance with the NEC. Such products may also be marked "Support" in lieu of the "S" designation.