Building Envelope Systems Comparison
| Feature / Benefit | SMARTci® | GreenGirt CMH™ | Steel Z-Girt (16-gauge) | Perforated Thermal Metal Z-Girt | FRP-only Z-Girt |
|---|---|---|---|---|---|
| Fire tests compliance with NFPA 285 and ASTM E84 | Yes | Yes | Yes Generic steel Z-girts are typically tested and compliant with NFPA 285 and ASTM E84.2 |
Yes Perforated metal Z-girts are typically tested and compliant with NFPA 285 and ASTM E84.2 |
Limited Tested only in limited combinations of cladding and insulation; not certified for all commercial wall configurations.2 |
| Permanent fastener retention | Yes GreenGirt CMH continuous insulation profiles use steel-reinforced flanges to deliver permanent steel-to-steel fastening. No creep, no loosening over service life.3 |
Yes Same steel-reinforced-flange design as SMARTci. Steel-to-steel fastening for permanent retention.3 |
Yes Steel Z-girts provide permanent fastener retention.3 |
Yes Perforated thermal metal Z-girts provide permanent fastener retention where the steel is intact.3 |
No |
| Free of halogen, bromine, and any Red-List materials | Yes The GreenGirt CMH framing component meets Declare Label, Living Building Challenge Red List Free, and EPD requirements and is halogen- and bromine-free with naturally-sourced fire retardants. These attributes apply to the GreenGirt CMH component specifically; rigid insulation selected for a SMARTci assembly varies and may not meet all of these criteria.4 |
Yes Same standards as SMARTci. Declare Label, Red List Free, EPD.4 |
Yes Generic steel is halogen-, bromine-, and Red List Free.4 |
Yes Perforated metal Z-girts are halogen-, bromine-, and Red List Free; confirm with manufacturer’s listing.4 |
No FRP-only Z-girts are not free of halogen, bromine, or Red List materials and may not meet green-building standards.4 |
| Eliminates both material and fastener creep | Yes Designed and tested to ASTM D2990 to eliminate material and fastener creep.5 |
Yes Same ASTM D2990 testing as SMARTci.5 |
Yes Steel Z-girts maintain structural integrity and fastener retention without creep.5 |
Varies Susceptible to creep under extended loading and force concentrations at the polymer break. GreenGirt Steel maintains structural integrity and fastener retention without creep.5 |
No FRP-only Z-girts are susceptible to creep from extended loading and force concentrations.5 |
| Each order includes finite element analysis and expert engineering review/support | Yes Every project receives a single-source FEA and engineering review tailored to the wall assembly.6 |
Yes Every project receives a single-source FEA and engineering review tailored to the wall assembly.6 |
No Generic manufacturers do not include project-specific FEA or engineering review.6 |
Varies Some manufacturers do not include project-specific FEA or engineering review. GreenGirt Steel does include FEA and expert engineering review/support.6 |
No FRP-only manufacturers do not include project-specific FEA or engineering review.6 |
| Highest thermal efficiency available on the market | Up to 99% Eliminates through-insulation metal and through-fasteners; achieves up to 99% thermal efficiency across the building’s service life.7 |
Up to 99% Same composite metal hybrid platform; up to 99% lifetime thermal efficiency.7 |
No Highly conductive; creates thermal bridging that reduces effective R-value.7 |
~70–80% Steel Z-profile remains the primary load path; thermal performance typically falls in the 70–80% range.7 |
High FRP-only Z-girts do not provide the highest thermal efficiency compared to other systems on the market. |
| Installs twice as fast with stack-and-go installation process | Yes Progressive installation with steel-reinforced flanges and integrated fastener retention eliminates cantilevering and additional insulation retention tools, and reduces field measuring/fabrication. 8 |
Yes Same progressive, stack-and-go installation as SMARTci, with integrated fastener retention.8 |
No Generic steel Z-girts do not feature a progressive installation system. No integrated fastener retention.8 |
Varies No integrated fastener retention; stack-and-go pattern not supported. GreenGirt Steel offers progressive installation with overlapping metal Z-girts and integrated fastener retention eliminating cantilevering, additional insulation retention tools, and reduces field measuring/fabrication.8 |
No FRP-only Z-girts do not feature a progressive installation system. No integrated fastener retention.8 |
| Eliminates the need for insulation retention fasteners | Yes SMARTci, utilizing GreenGirt CMH Z-girts, includes ThermaLock insulation retention technology that holds rigid or mineral wool insulation without stick pins.9 |
Yes GreenGirt CMH Z-girts include ThermaLock insulation retention technology that holds rigid or mineral wool insulation without stick pins.9 |
No No integrated insulation retention; stick pins or supplemental fasteners required.9 |
Varies No integrated insulation retention; stick pins or supplemental fasteners required. GreenGirt Steel Z-girts include insulation retention locks that hold rigid or mineral wool insulation without stick pins.9 |
Limited Some FRP products retain insulation; many do not. Refer to manufacturer literature.9 |
| Air- and water-tight without the use of caulk or tape | Yes Only system that achieves an air- and water-tight assembly without caulk or tape, when specified with foil-faced polyiso.11 |
No Does not provide a self-sealing air- and water-tight assembly at the framing; air and water control is handled by the wall’s separate barrier system.11 |
No Does not provide a self-sealing air- and water-tight assembly at the framing; air and water control is handled by the wall’s separate barrier system.11 |
No Does not provide a self-sealing air- and water-tight assembly at the framing; air and water control is handled by the wall’s separate barrier system.11 |
No Does not provide a self-sealing air- and water-tight assembly at the framing; air and water control is handled by the wall’s separate barrier system.11 |
| Highest true R-value per inch of wall system | Yes Highest in market due to custom-profiled insulation. Eliminates through-insulation metal and through-fasteners (DrJ TER 1501-06).13 |
High Eliminates through-insulation metal and through-fasteners but does not achieve SMARTci’s full pressure-sealed R-value per inch.13 |
No Through-insulation metal and through-fasteners reduce effective R-value.13 |
Varies Through-insulation metal reduces effective R-value. GreenGirt Steel eliminates through-insulation metal but does not achieve SMARTci’s full pressure-sealed R-value per inch.13 |
No Connection failures and creep over time reduce effective R-value.13 |
| Eliminates gaps, cracks, and thermal bypass: product design, installer, and insulation manufacturer gaps fixed | Guaranteed SMARTci adds a pressure-sealed assembly, GreenGirt CMH Z-girts plus custom-profiled rigid insulation sealed on all four sides, that closes the air pathways around and behind the insulation. This stops the wind-washing and stack-effect air movement that causes thermal bypass, performance the GreenGirt CMH Z-girt alone does not provide. A2P guarantees thermal bypass elimination on SMARTci specifically.1410 |
Partial GreenGirt CMH removes the conductive thermal bridging through the sub-framing, but the Z-girt alone does not create the continuous air seal that stops convective thermal bypass. Full elimination requires SMARTci’s custom-profiled, pressure-sealed rigid insulation; GreenGirt CMH with mineral wool does not close all air pathways.1410 |
No No air seal; allows wind washing and stack-effect air movement behind insulation.14 |
No No air seal; thermal bypass is unresolved.14 |
No No air seal. Some perforated FRP products add additional thermal loss from stack-effect air movement.14 |
| Connection durability standard (ASCE) | Yes Connections are steel-to-steel through steel-reinforced flanges, not self-tapping screws into FRP, so the durability concern ASCE raises for pultruded FRP does not apply.15 |
Yes Same steel-reinforced-flange (steel-to-steel) connection design as SMARTci; the ASCE pultruded-FRP fastening concern does not apply.15 |
Yes Steel-to-steel connections are not subject to the ASCE pultruded-FRP fastening concern.15 |
Yes Steel cross-section is fastened steel-to-steel where intact; not subject to the ASCE pultruded-FRP fastening concern.15 |
Not recommended The ASCE Design Guide for FRP Composite Connections (page 19) does not recommend self-tapping (sheet-metal) screws for fastening into pultruded FRP, identifying bolted, adhesively bonded, or combined connections instead. Sheet-metal-screw retention in FRP therefore cannot be relied on for permanent durability, what A2P characterizes as “unavoidable failure.”15 |
* GreenGirt Steel™, A2P’s steel-based continuous insulation system, is not shown as a separate column above. It delivers the highest thermal efficiency available in a steel-based system and shares GreenGirt CMH’s stack-and-go installation, insulation retention, and steel-to-steel, ASCE-compliant connections. See the GreenGirt Steel system.
Citations & Source References
- A2P engineering reports on NFPA 285 compliance and configuration coverage: GreenGirt and NFPA 285 (Use of Composite Metal Hybrid for NFPA 285 Fire-Rated Continuous Insulation Systems); and GreenGirt & SMARTci NFPA 285 Compliance, CMH 1b Wall Configurations. Multi-configuration approval is supported by an Engineering Judgment from Priest & Associates Consulting (NFPA 285-approved products from Atlas, Rmax, Hunter, Carlisle, and Dow, mineral wool, and high-pressure laminate claddings) and validated by DrJ TER 1501-06.
- A2P Engineering Best Practices: Fire Resistance. greengirt.com/engineering/best-practices/fire-resistance/.
- A2P engineering brief: A2P3001 — Fastener Failure in FRP vs. Permanent Fastening Steel. Supporting article: Short-term Fastening (FRP) vs. Permanent Fastening (Steel CMH).
- A2P Engineering Best Practices: Environmental Impact, with Declare Label / Living Building Challenge / EPD documentation. greengirt.com/engineering/best-practices/environmental-impact/.
- ASTM D2990 — Standard Test Methods for Tensile, Compressive, and Flexural Creep and Creep-Rupture of Plastics. A2P test results.
- A2P engineering brief: A2P3002 — Best Practice Structural Engineering for Composite Substructure Materials (CMH vs. Generic FRP). A2P Engineering overview: greengirt.com/engineering/.
- A2P engineering brief: A2P2001 — Designing with Composite Z Sub-Framing & Fastener Performance for Building Envelope Service Temperature. Independent 3D thermal modeling by Morrison Hershfield/Stantec (ASHRAE and CSA standards): greengirt.com/engineering/thermal-performance/.
- A2P Engineering Best Practices: Ease of Installation. greengirt.com/engineering/best-practices/ease-of-installation/.
- A2P product reference: What is CMH? greengirt.com/what-is-cmh/.
- A2P article: Understanding and Addressing Thermal Bypasses in Building Enclosures.
- A2P third-party report: DrJ TER A2P SMARTci Exterior Wall Continuous Insulation System (TER 1501-06).
- A2P Engineering: FRP’s “Unavoidable Failure.” greengirt.com/engineering/unavoidable-failure/.
- DrJ TER 1501-06 and A2P2001. Effective R-value per inch of wall system, A2P SMARTci platform.
- A2P Engineering Best Practices: Thermal Bypass, and A2P engineering brief: SMARTci Thermal Bypass Elimination Guarantee. greengirt.com/engineering/best-practices/thermal-efficiency/thermal-bypass/. Guarantee terms verified via A2P engineering legal review (Pillar 2 documentation).
- ASCE Design Guide for FRP Composite Connections (American Society of Civil Engineers), page 19, which does not recommend self-tapping screws for fastening into pultruded FRP and identifies bolted, adhesively bonded, or combined connections instead. ASCE Library, DOI 10.1061/9780784406120. A2P summary: greengirt.com/unavoidable-failure-2/.
Comparison Charts
- Comparison #1: Z-Girts
- Comparison #2: Clips
- Comparison #3: Adjustable Clips
- Comparison #4: Perforated Metal Z-Girts
- Comparison #5: GreenGirt Max & GreenGirt Optima
Download the Comprehensive Continuous Insulation Z-girt Comparison Chart
Additional Systems-Specific Comparisons
Looking for additional details, technical resources, and comparisons? The Advanced Architectural Products team has compiled several systems-specific comparisons for various types of continuous insulation and building enclosure systems. Access these resources for comprehensive details and technical insights:
Frequently Asked Questions (FAQs)
GreenGirt CMH and SMARTci systems are stated to achieve 92%–99% thermal efficiency because they eliminate through-insulation metal and through-fasteners, reducing thermal bridging and helping the system maintain that performance over the life of the building.
FRP-only Z-girts are susceptible to creep from extended loading and force concentrations (and perforated metal Z-girts are also described as susceptible).
Yes. All projects that use GreenGirt CMH or SMARTci systems undergo a comprehensive engineering review that includes Finite Element Analysis (FEA) tailored to the project’s requirements, and it contrasts this by saying generic steel, perforated metal, and generic FRP Z-girt manufacturers do not provide that comprehensive FEA-based review.
GreenGirt CMH™ continuous insulation systems eliminate conductive thermal bridging through the sub-framing. SMARTci® building enclosure systems build on GreenGirt CMH by adding custom-profiled, pressure-sealed rigid insulation that closes air pathways around and behind the insulation. A2P guarantees thermal bypass elimination on SMARTci specifically.
Yes. Both systems are compliant with NFPA 285 and ASTM E84. Components consist of non-flammable materials (glass and steel) with naturally-sourced fire retardants, validated by DrJ TER 1501-06 and an Engineering Judgment from Priest & Associates Consulting.
Yes. The GreenGirt CMH framing component meets Declare Label, Living Building Challenge Red List Free, and EPD requirements, and is halogen- and bromine-free. Rigid insulation selected for a SMARTci assembly varies and may not meet all of these criteria.
Yes. SMARTci is the only system in the comparison that achieves an air- and water-tight assembly without caulk or tape, when specified with foil-faced polyiso (DrJ TER 1501-06). The other systems rely on the wall’s separate barrier system.
The ASCE Design Guide for FRP Composite Connections (page 19) identifies bolted, adhesively bonded, or combined connections for pultruded FRP instead of self-tapping screws, because screw retention in FRP cannot be relied on for permanent durability. GreenGirt CMH and SMARTci avoid this by fastening steel-to-steel through steel-reinforced flanges.
Have additional questions? Send us your questions and our technical experts will provide you with the information you seek.
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