Curtain Wall Systems
Stick · Semi-Unitized · Unitized · Framing & Material Criteria — ASTM E330 / E1996 / EN 13830 / IS 8147
A — Framing Deflection Limits (Mullion / Transom)
| Parameter | System Type | ASTM Limit | EN 13830 Limit | IS 8147 Limit | Code Reference | Notes |
|---|---|---|---|---|---|---|
| Horizontal (wind) | Stick / Semi-Unit. | L/175 or 19mm max | L/200 | L/200 | ASTM E330 / E283 | Whichever is lesser governs |
| Horizontal (wind) | Unitized | L/175 or 19mm max | L/200 | L/200 | ASTM E330 | Panel-to-panel tolerance critical |
| Vertical (gravity) | All Types | L/360 | L/300 | L/300 | AISC / ASTM E1300 | Dead load + live load combination |
| Seismic (inter-story) | Unitized | ±38mm (typ.) | Per EN 1998 | IS 1893 drift | ASTM E2353 | Movement accommodation joints required |
| Thermal movement | All Types | Free movement | Free movement | Free movement | AAMA 501 | Joints to accommodate ΔT = 80°C range |
| Differential settlement | All Types | ±12.5mm vert. | — | — | AAMA CW-DG-1 | Building structure tolerance |
B — Frame Material Stress Limits
| Material | Grade | Allowable Bending Stress | Allowable Shear Stress | Code Reference |
|---|---|---|---|---|
| Aluminium Alloy | 6063-T6 | 115 MPa | 69 MPa | ADM / AA-ASM-35 |
| Aluminium Alloy | 6061-T6 | 150 MPa | 90 MPa | ADM 2020 |
| Steel (mild) | ASTM A36 | 165 MPa | 100 MPa | AISC 360 |
| Steel (high-str.) | A572 Gr50 | 207 MPa | 124 MPa | AISC 360 |
| Stainless Steel | 316 / 304 | 138 MPa (304) | 82 MPa | ASCE 8 / EN 1993-1-4 |
C — Curtain Wall System Types Comparison
| System | Deflection Criterion | Water Penetration Test | Air Infiltration | Structural Test Pressure | Code |
|---|---|---|---|---|---|
| Stick System | L/175 ≤ 19mm | ≥720 Pa (ASTM E331) | ≤0.3 L/s·m² | 1.5× design wind | ASTM E330/E331/E283 |
| Semi-Unitized | L/175 ≤ 19mm | ≥720 Pa | ≤0.3 L/s·m² | 1.5× design wind | ASTM E330/E331 |
| Unitized System | L/175 ≤ 19mm | ≥720 Pa | ≤0.3 L/s·m² | 1.5× design wind | AAMA 501 / ASTM E330 |
Stick System
Semi-Unitized
Unitized
All Systems
Glass — Deflection & Stress
Annealed · Heat Strengthened · Toughened · Laminated — ASTM E1300 / EN 12150 / EN 14449 / IS 2553
A — Maximum Allowable Deflection
| Glass Type | Specification | Max Deflection (ASTM E1300) | Max Deflection (EN) | Condition | Code Reference |
|---|---|---|---|---|---|
| Annealed (AN) | Float / Clear | L/60 (≤ 19mm) | L/65 | Under lateral wind load | ASTM E1300 / EN 16612 |
| Heat Strengthened (HS) | ASTM C1048 Cond. A | L/60 (≤ 19mm) | L/65 | Under lateral wind load | ASTM E1300 / EN 1863 |
| Toughened / Tempered (FT) | ASTM C1048 Cond. B | L/60 (≤ 19mm) | L/65 | Under lateral wind load | ASTM E1300 / EN 12150 |
| Laminated (AN/AN) | PVB / SGP interlayer | L/60 (≤ 25mm) | L/65 | Post-breakage retained | ASTM C1172 / EN 14449 |
| Laminated (FT/FT) | Tempered + PVB/SGP | L/60 (≤ 25mm) | L/65 | Post-breakage retained | ASTM C1172 / EN 14449 |
| Laminated (HS/HS) | HS + PVB | L/60 (≤ 25mm) | L/65 | Post-breakage retained | ASTM C1172 / EN 14449 |
| IGU (Double Glazed) | AN+AN / FT+AN | L/60 per lite | L/65 per lite | Load sharing between lites | ASTM E1300 / EN 16612 |
B — Allowable Design Stress (Surface Tensile Stress)
| Glass Type | Modulus of Rupture (MOR) | ASTM Allowable Stress | EN Allowable Stress (Char. Bending) | Safety Factor | Code |
|---|---|---|---|---|---|
| Annealed (AN) | 41 MPa | 23.3 MPa | 45 MPa (EN 16612) | 1.6–2.5 | ASTM E1300 |
| Heat Strengthened (HS) | 70 MPa | 46.6 MPa | 70 MPa (EN 1863) | 1.6 | ASTM E1300 / EN 1863 |
| Toughened / FT | 120 MPa (min) | 93.1 MPa | 120 MPa (EN 12150) | 1.3 | ASTM E1300 / EN 12150 |
| Laminated (AN+AN / PVB) | 41 MPa (each) | 23.3 MPa per lite | 45 MPa per lite | 1.6–2.5 | ASTM C1172 / EN 14449 |
| Laminated (FT+FT / PVB) | 120 MPa (each) | 93.1 MPa per lite | 120 MPa per lite | 1.3 | ASTM C1172 / EN 14449 |
| Laminated (HS+HS / PVB) | 70 MPa (each) | 46.6 MPa per lite | 70 MPa per lite | 1.6 | ASTM C1172 / EN 14449 |
C — Glass Surface Compressive Prestress (Toughening Level)
| Glass Type | Surface Compressive Stress | Fragmentation (50×50mm) | EN Designation | ASTM Designation |
|---|---|---|---|---|
| Annealed | <24 MPa | Large irregular shards | AN | ASTM C1036 |
| Heat Strengthened | 24–52 MPa | Larger pieces, holds in frame | EN 1863 | ASTM C1048 Kind HS |
| Fully Tempered | ≥69 MPa (ASTM) / ≥90 MPa (EN) | ≥40 pcs / 50×50mm | EN 12150 | ASTM C1048 Kind FT |
Windows — Sliding & Casement
Framing Deflection · Performance Criteria — AAMA 101 / ASTM E330 / EN 14351
A — Deflection Limits (Frame Members)
| Window Type | Member | ASTM / AAMA Limit | EN 14351 Limit | Load Case | Code |
|---|---|---|---|---|---|
| Sliding Window | Head / Sill | L/175 ≤ 19mm | L/200 | Design wind pressure | AAMA 101 / ASTM E330 |
| Sliding Window | Vertical jamb | L/175 ≤ 19mm | L/200 | Design wind pressure | AAMA 101 |
| Casement Window | Sash frame | L/175 ≤ 12.7mm | L/200 | Design wind pressure | AAMA 101 |
| Casement Window | Fixed frame | L/175 ≤ 19mm | L/200 | Design wind pressure | AAMA 101 |
| Top-Hung / Awning | Hinge side | L/175 ≤ 12.7mm | L/200 | Sash weight + wind | AAMA 101 |
B — Performance Classification (AAMA / EN)
| Performance Criteria | AAMA Class R (Residential) | AAMA Class LC (Light Comm.) | AAMA Class C (Commercial) | EN Class | Code |
|---|---|---|---|---|---|
| Structural Wind Load | ±25 psf (1.2 kPa) | ±35 psf (1.68 kPa) | ±55 psf (2.63 kPa) | Class 1–5 | AAMA 101 |
| Water Resistance | 15% design pressure | 15% design pressure | 15% design pressure | Class 1A–E4 | ASTM E331 / EN 12208 |
| Air Infiltration | 0.3 cfm/ft² | 0.3 cfm/ft² | 0.3 cfm/ft² | Class 1–4 | ASTM E283 / EN 12207 |
| Forced Entry | Optional | Optional | Optional | RC1–RC6 | ASTM F588 / EN 1627 |
Shop Fronts
Aluminium Framed Glazed Entrances & Storefronts — ASTM E330 / AAMA SFM-1
A — Frame Deflection Criteria
| Member | Loading | AAMA / ASTM Limit | EN 13830 Limit | Remarks | Code |
|---|---|---|---|---|---|
| Head / Sill | Wind pressure | L/175 ≤ 19mm | L/200 | Controls glass seal | AAMA SFM-1 / ASTM E330 |
| Vertical Mullion | Wind pressure | L/175 ≤ 19mm | L/200 | — | AAMA SFM-1 |
| Door Frame | Operating + wind | L/360 vertical | — | Sill/threshold deflection | AAMA SFM-1 / ASTM A36 |
| Door Leaf | Wind + person load | ≤ 6mm at hardware | ≤ 6mm | Maintains hardware function | AAMA 907 |
B — Performance Criteria
| Test | ASTM Test Method | Minimum Requirement | EN Equivalent |
|---|---|---|---|
| Air Infiltration | ASTM E283 | ≤ 0.3 cfm/ft² at 75 Pa | EN 12207 Class 3 |
| Water Resistance | ASTM E331 | 720 Pa (no leakage) | EN 12208 Class 7A |
| Structural (wind) | ASTM E330 | 1.5× design wind; defl. ≤ L/175 | EN 13830 / EN 12210 |
| Forced Entry | ASTM F842 | Grade 10–40 (project-specific) | EN 1627 RC2–RC3 |
Spider Glazing
Point-Fixed Structural Glazing — ASTM E1300 / ETAG 002 / EN 13022
A — Glass Deflection at Point Fixings
| Support Configuration | Glass Type Required | Max Panel Deflection (ASTM) | Max Panel Deflection (EN) | Fitting Rotation | Code |
|---|---|---|---|---|---|
| 4-Point Fixed (corners) | FT Laminated | L/60 (≤ 25mm) | L/65 | ≤ ±3° | ASTM E1300 / EN 13022 |
| 2-Point Fixed (edge) | FT Laminated | L/60 | L/65 | ≤ ±3° | ASTM E1300 / EN 13022 |
| 1-Point Fixed (corner) | FT Lam. (min 2 lites) | L/60 | L/65 | ≤ ±3° | ASTM E1300 |
B — Fitting / Spider Arm Stress Criteria
| Component | Material | Allowable Stress | Bearing Stress at Hole | Safety Factor | Code |
|---|---|---|---|---|---|
| Spider Fitting (casting) | 316L SS / Cast A4 | 138 MPa (tensile) | ≤ 207 MPa (bearing) | 2.5 | ASCE 8 / EN 1993 |
| Spider Arm (tube) | 316 SS | 138 MPa (bending) | — | 2.5 | EN 1993-1-4 |
| Glass Hole Stress | At countersunk bolt | ≤ 50 MPa local (FT) | — | 2.4 | ASTM E1300 Note |
| Bushing / Sleeve | Delrin / EPDM | Contact pressure ≤ 5 MPa | — | 3.0 | Mfr. data / ETAG 002 |
C — Mandatory Glass Specification for Spider Glazing
| Application | Minimum Glass Build-Up | Interlayer | Reason | Code |
|---|---|---|---|---|
| Overhead (skylight) | FT + FT Laminated | SGP (SentryGlas) | Post-breakage support | ASTM E1300 / CPSC 16 CFR 1201 |
| Vertical façade | FT + FT Laminated or FT monolithic | PVB or SGP | Safety glazing requirement | ASTM C1172 / EN 14449 |
| Balustrade / Barrier | FT + FT Laminated | SGP preferred | Structural post-break integrity | IBC 2021 / BS 6180 |
Railings & Balustrades
Glass Railing — 1-Sided · 2-Sided · 3-Sided · 4-Sided Supports — IBC / ASTM E2353 / EN 12600 / BS 6180
A — Design Loads (IBC / ASCE 7)
| Location | Horizontal Load (ASCE 7) | Vertical Load | Concentrated Load | Code |
|---|---|---|---|---|
| Residential | 0.44 kN/m (30 plf) | 0.73 kN/m (50 plf) | 0.89 kN (200 lb) | ASCE 7 §4.5 / IBC 1607.8 |
| Commercial / Assembly | 0.73 kN/m (50 plf) | 0.73 kN/m (50 plf) | 0.89 kN (200 lb) | ASCE 7 §4.5 / IBC 1607.8 |
| Stadiums / Assembly >1000 | 1.46 kN/m (100 plf) | 0.73 kN/m | 0.89 kN | ASCE 7 §4.5 |
| EN (BS 6180) | 0.74–3.0 kN/m (UDL) | 1.0 kN/m² | 1.0 kN point | BS 6399-1 / EN 1991-1-1 |
B — Glass Deflection Limits by Support Configuration
| Support Type | Configuration | Glass Spec (Min) | Max Top Rail Deflection | Max Glass Panel Defl. | Code |
|---|---|---|---|---|---|
| 1-Sided (base clamp / shoe) | Cantilevered from base, no top rail | FT Lam. (min 12+12) | H/65 at top | H/65 | IBC 2308 / ASTM E2353 |
| 2-Sided (base + top) | Base channel + top capping rail | FT Lam. (min 10+10) | H/100 | H/100 | IBC / ASTM E2353 |
| 3-Sided (base + 2 verticals) | Base + two vertical frame members | FT Lam. (min 8+8) | H/100 | H/100 | IBC / EN 12600 |
| 4-Sided (fully framed) | Base + top + two verticals | FT Lam. or HS Lam. (min 6+6) | H/150 | H/150 | IBC / EN 12600 |
C — Glass Impact Classification (EN 12600)
| Drop Height | EN 12600 Class | Performance | Typical Application |
|---|---|---|---|
| 190 mm pendulum | Class 3 | Safe break or no break | Low-risk residential |
| 450 mm pendulum | Class 2 | Safe break or no break | Commercial balustrades |
| 1200 mm pendulum | Class 1 | Safe break or no break | High-risk public areas |
Tile & Stone Cladding
Porcelain · Granite · Ventilated Façade — ASTM C648 / EN 1348 / TCNA / IS 13630
A — Framing / Sub-structure Deflection
| Framing Element | Span Condition | ASTM / IBC Limit | EN Limit | Remarks | Code |
|---|---|---|---|---|---|
| Support rail (horiz.) | Gravity + wind | L/600 or 3mm | L/600 | Critical — prevents cracking | TCNA / ASTM C1242 |
| Vertical carrier (bracket) | Wind suction + gravity | L/360 | L/400 | — | IBC / EN 1996 |
| Anchor bracket | Combined | 3mm max | 3mm max | Differential movement | ASTM C1242 |
| Substrate / wall | All loads | L/360 ≤ 6mm | L/400 | Stiff substrate required | TCNA EJ171 / EN 13888 |
B — Tile / Stone Material Criteria
| Property | Porcelain Tile | Natural Granite | Natural Limestone | Test Method |
|---|---|---|---|---|
| Breaking Strength (min) | 1300 N (ASTM) / 1300 N (EN) | 1800 N | 1300 N | ASTM C648 / EN ISO 10545-4 |
| Modulus of Rupture (min) | 35 MPa (porcelain) | 15 MPa | 8 MPa | ASTM C674 / EN ISO 10545-4 |
| Water Absorption (max) | ≤ 0.5% (porcelain) | ≤ 0.4% | ≤ 3% | ASTM C373 / EN ISO 10545-3 |
| Thermal Shock Resistance | Pass (10 cycles) | Not required | Not required | ASTM C484 / EN ISO 10545-9 |
| Frost Resistance | Pass (100 cycles) | Pass (48 cycles) | Pass (48 cycles) | ASTM C1026 / EN ISO 10545-12 |
C — Anchor / Fixing Stress Limits
| Fixing Type | Material | Allowable Pull-out | Allowable Shear | Code |
|---|---|---|---|---|
| SS Undercut anchor | 316 SS | ≥ 1.0 kN (SFactor=3) | ≥ 0.5 kN | ASTM C1242 / ETAG 034 |
| Kerf / Slot anchor | 316 SS | ≥ 0.8 kN (bearing) | ≥ 0.4 kN | ASTM C1242 |
| Epoxy anchor (chemical) | SS stud | ≥ 2.5 kN | ≥ 1.5 kN | ASTM E488 / ETA |
Aluminium Composite Panel (ACP)
Rainscreen & Cassette Systems — ASTM E330 / EN 1396 / AAMA 2604
A — Sub-frame Deflection Criteria
| Framing Member | Load | ASTM / AAMA Limit | EN Limit | Notes | Code |
|---|---|---|---|---|---|
| Horizontal girt / rail | Wind + panel wt. | L/175 ≤ 19mm | L/200 | Panel joint governs | ASTM E330 / AAMA CW-DG-1 |
| Vertical mullion | Wind | L/175 ≤ 19mm | L/200 | — | ASTM E330 |
| Bracket / cleat | Gravity + wind | 2mm max tip defl. | 2mm max | Critical for flatness | AAMA / project spec |
| Panel flatness (oil-canning) | Thermal + wind | ≤ L/200 panel span | ≤ 3mm over 1m | Aesthetic / visual | ASTM E330 / EN 1396 |
B — ACP Panel Material Criteria
| Property | FR (Fire-Retardant) Core | A2 (Mineral) Core | Test Method | Notes |
|---|---|---|---|---|
| Tensile strength (skin) | ≥ 110 MPa | ≥ 110 MPa | ASTM B209 / EN 485 | Al skin 0.5mm min |
| Peel strength | ≥ 40 N/mm | ≥ 40 N/mm | ASTM D1876 / EN 1396 | Core-to-skin bond |
| Panel bending strength | ≥ 150 N/mm (bending mom.) | ≥ 150 N/mm | EN 1396 | — |
| Fire reaction class | B-s1,d0 (FR) | A2-s1,d0 | EN 13501-1 / ASTM E84 | A2 mandatory for high-rise |
| Coating durability | PVDF 70% resin min. | PVDF 70% resin min. | AAMA 2605 (superior) | AAMA 2604 = commercial grade |
| Panel thickness | 3mm / 4mm / 6mm | 4mm / 6mm | EN 1396 / project spec | 6mm for large panels |
Zinc Cladding
Standing Seam · Cassette · Shingle — EN 988 / DIN 17770 / prEN 14783
A — Sub-frame Deflection Limits
| Sub-frame Element | Load | ASTM Limit | EN Limit | Notes | Code |
|---|---|---|---|---|---|
| Horizontal bearer rail | Wind + cladding wt. | L/200 | L/200 | Zinc panels are flexible — rail tolerance critical | ASTM E330 / project spec |
| Vertical post | Wind | L/200 ≤ 12mm | L/200 | — | ASTM E330 |
| Support bracket | Combined | 2mm tip max | 2mm tip max | Adjust for thermal expansion | EN 988 Commentary |
B — Zinc Panel Material Properties & Criteria
| Property | Value / Limit | Test Method | Code | Notes |
|---|---|---|---|---|
| Minimum thickness | 0.7mm (vertical) / 0.65mm (horizontal) | Calliper / EN ISO 1462 | EN 988 Table 2 | Typical: 0.7–1.0mm for façade |
| Tensile strength | 150–260 MPa | EN ISO 6892-1 | EN 988 | Ti-alloy rolled zinc |
| Elongation at break | ≥ 10% (longitudinal) | EN ISO 6892-1 | EN 988 | Formability requirement |
| Thermal expansion | 2.2 mm/m per 100°C ΔT | — | DIN 17770 | Sliding clips mandatory |
| Min. bend radius | 3× thickness (cold) | — | EN 988 / Manufacturer | Work at > 10°C |
| Panel span (unsupported) | ≤ 600mm centres (typical) | — | prEN 14783 / project spec | Depends on wind zone & thickness |
Silicone — Structural & Weatherseal
ASTM C1184 / C1401 / C920 / ETAG 002 / EN 15434
A — Structural Silicone Design Stress (ETAG 002 / ASTM C1184)
| Load Type | ASTM Allowable Stress | ETAG 002 Allowable | Safety Factor Applied | Code |
|---|---|---|---|---|
| Dead Load (gravity, permanent) | 7 psi (0.048 MPa) | 0.007 N/mm² (ETAG) | SF = 10 | ASTM C1184 / ETAG 002 |
| Wind Load (short-duration) | 20 psi (0.138 MPa) | 0.14 N/mm² | SF = 6 | ASTM C1184 / ETAG 002 |
| Tension (wind uplift) | 20 psi (0.138 MPa) | 0.14 N/mm² | SF = 6 | ASTM C1184 / ETAG 002 |
| Shear (in-plane) | 14 psi (0.096 MPa) | 0.10 N/mm² | SF = 6 | ASTM C1184 / ETAG 002 |
| Thermal / movement combined | 12.5% movement capacity | 12.5% joint width | Design joint width | ASTM C920 Class 100/50 |
B — Silicone Bite (Contact Width) Design Formulae
| Design Parameter | Formula / Limit | Minimum Dimension | Code | Notes |
|---|---|---|---|---|
| Bite width (b) | b = (W × a) / (2 × σ_allow) | 6mm minimum | ETAG 002 / ASTM C1184 | W=wind, a=panel width |
| Structural bite (dead load check) | b ≥ (panel wt.) / (0.007 × L × 2 sides) | 6mm | ETAG 002 | Must check both wind & gravity |
| Weatherseal joint width | ≥ 2× max movement + 6mm | 6mm | ASTM C920 / C1193 | Width : depth = 2:1 (max) |
| Joint depth (weatherseal) | Width ≤ 13mm → depth = width; >13mm → depth = 13mm | 6mm | ASTM C1193 | Back-up rod mandatory |
C — Silicone Classification (ASTM C920)
| Type | Grade | Class (Movement) | Use | Typical Application | Code |
|---|---|---|---|---|---|
| S (single comp.) | P (non-sag) | 100/50 (±50%) | NT (non-traffic) | Structural SSG, CW joints | ASTM C920 |
| M (multi comp.) | NS (self-leveling) | 25 (±25%) | NT | Weatherseals, perimeter | ASTM C920 |
| S | P | 25 (±25%) | T (traffic) | Glazed floor joints | ASTM C920 |
| Structural SSG | 2-part | 100/50 | NT (structural) | Unitized CW, spider panels | ASTM C1184 / ETAG 002 |
Quick Reference Summary
Key deflection limits at a glance — all systems
| System | Element | ASTM Deflection Limit | EN Deflection Limit | Governing Code |
|---|---|---|---|---|
| Curtain Wall (all types) | Mullion / Transom (horizontal) | L/175 ≤ 19mm | L/200 | ASTM E330 |
| Curtain Wall (vertical) | Transom (gravity) | L/360 | L/300 | ASTM E330 |
| Glass (all types) | Panel centre deflection | L/60 ≤ 19–25mm | L/65 | ASTM E1300 |
| Windows | Frame members | L/175 ≤ 19mm | L/200 | AAMA 101 |
| Shop Fronts | Mullion / Head | L/175 ≤ 19mm | L/200 | AAMA SFM-1 |
| Spider Glazing | Glass panel | L/60 ≤ 25mm | L/65 | ASTM E1300 |
| Railings — 1-sided | Top of glass | H/65 | H/65 | IBC / ASTM E2353 |
| Railings — 4-sided | Frame + glass | H/150 | H/150 | IBC / EN 12600 |
| Tile Cladding (substrate) | Support rail | L/600 ≤ 3mm | L/600 | TCNA / ASTM C1242 |
| ACP (sub-frame girt) | Horizontal girt | L/175 ≤ 19mm | L/200 | ASTM E330 |
| Zinc Cladding (rail) | Bearer rail | L/200 | L/200 | EN 988 |
| Silicone (structural) | Wind load stress | 0.138 MPa (20 psi) | 0.14 N/mm² | ASTM C1184 / ETAG 002 |