Classification of Z-girts

Not all continuous insulation Z-girts are created equal. They are categorized into three distinct classes based on key performance criteria, including structural capacity, structural performance, fastener connections, thermal efficiency, and fire resistance.

Classification of Continuous Insulation Z-Girts

Continuous insulation Z-girts are categorized into three distinct classes based on their ability to meet key performance criteria. These criteria include structural capacity, structural performance, thermal efficiency, fire resistance, and the durability of connections over the building’s lifecycle. Each class represents a different level of performance, allowing designers, contractors, and installers to select the most suitable system for their project’s specific demands and requirements.

Class I continuous insulation Z-girts provide the highest thermal performance, strongest structural capacity, and permanent connections. Additionally, these systems eliminate thermal bypass and pass fire safety standards like NFPA 285, ensuring long-term reliability.

Class II continuous insulation Z-girts provide moderate performance in thermal efficiency and structural strength. They ensure permanent connections and comply with NFPA 285, but do not resolve thermal bypass.

Class III continuous insulation Z-girts prioritize thermal performance but can only accommodate moderate structural loads in a temporary capacity. They suffer from unavoidable connection failures that limit their long-term reliability and effectiveness.

CODE-COMPLIANT
Thermally Broken Systems
NOT CODE-COMPLIANT
Legacy System
CLASS I
Composite metal hybrid Z-girts
CLASS II
Perforated thermal metal Z-girts
CLASS III
FRP Z-girts
Steel Z-girts

HIGH

Structural capacity

MODERATE

Structural capacity

LOW

Structural capacity

HIGH

Structural capacity

LONG-TERM

Structural performance

LONG-TERM

Structural performance

TEMPORARY

Structural performance

LONG-TERM

Structural performance

PERMANENT

connections

PERMANENT

connections

UNAVOIDABLE FAILURE

at connections

PERMANENT

connections

HIGH

static thermal performance

MODERATE

static thermal performance

HIGH

static thermal performance

LOW

static thermal performance

YES

eliminates thermal bypass

NO

eliminates thermal bypass

NO

eliminates thermal bypass

NO

eliminates thermal bypass

PASS

NFPA 285

PASS

NFPA 285

MODERATE

NFPA 285

PASS

NFPA 285
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Performance criteria:

Structural capacity

The engineered ability of Z-girts to support and distribute loads effectively, accommodating demanding, heavyweight cladding or building materials with stability and ease. This includes resistance to bending, deflection, and failure.

Structural performance

The engineered ability of a continuous insulation system — including the Z-girts, their connections, and corresponding fasteners — to consistently maintain their intended strength, stability, and functionality over the lifetime of a building. Unlike systems that degrade, loosen, and lead to failure over time.

Connections

The ability of a fastening system to create durable, permanent interfaces between cladding and the continuous insulation sub-framing system. Designed to carry specified loads without degradation and “unavoidable failure,” permanent connections ensure reliable, long-term performance throughout a building’s lifecycle.

Static thermal performance

The ability of continuous insulation Z-girts to minimize thermal bridging, minimize the use of conductive materials, and sustain consistent insulation efficiency over time, resulting in thermal performance levels in the upper 90% range.

Thermal bypass

The unintended movement of energy through gaps, cracks, or voids in a building’s wall assembly, often stemming from design flaws, material inconsistencies or tolerances, and/or improper installation that leads to significant energy losses.

NFPA 285 compliance

Systems compliant with NFPA 285 meet rigorous standards for fire resistance in multi-story buildings, ensuring that facade materials effectively contain and limit flame spread, thereby enhancing the building’s overall safety.

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