Maximum K-Value by Bioclimatic Zone — Argentina (IRAM 11605)🇦🇷
See step-by-step calculation
IRAM 11605 sets the maximum thermal transmittance (K-value) that walls of habitable buildings must meet in each Argentine bioclimatic zone. The colder the zone, the lower the K-limit — meaning better insulation is required. Select your zone to instantly see the compliance ceiling (Level C, winter condition), which is what Buenos Aires Province Law 13059 and most Argentine provincial building codes enforce.
Under IRAM 11605 Level C (Argentina's mandatory building code minimum), the maximum wall K-value by bioclimatic zone is: Zone I-II (warm) = 1.20 W/m²K, Zone III (temperate, Buenos Aires) = 1.00 W/m²K, Zone IV-V (cold, Neuquén/Mendoza) = 0.85 W/m²K, Zone VI (very cold, Patagonian Andes/Ushuaia) = 0.74 W/m²K. A standard 18 cm solid brick wall (K ≈ 2.0) fails in every zone — added insulation is mandatory.
When to use this calculator
- Architect verifying a wall assembly complies with IRAM 11605 before submitting a building permit in Buenos Aires Province (Law 13059)
- Civil engineer selecting the minimum EPS or mineral wool thickness needed to bring a Zone IV-V wall into compliance
- Construction student checking whether a hollow-block + air-gap assembly meets the requirement for a Zone III project
- Building inspector or energy auditor confirming the declared K of an existing wall against the zone's legal ceiling
Worked Example — Zone III (Buenos Aires, La Plata, Rosario)
- Project location: City of Buenos Aires (Zone III per IRAM 11603)
- Standard applied: IRAM 11605, Level C (minimum compliance), winter condition
- Select Zone III in the calculator
- Result: K_max = 1.0 W/m²K
- Typical 18 cm solid brick wall: K ≈ 2.0 W/m²K → FAILS (K is too high)
- Adding 3 cm EPS (λ = 0.033 W/m·K) lowers K to ≈ 0.79 W/m²K → PASSES with margin
How it works
2 min readK-Value Compliance Table — All Argentine Zones (IRAM 11605 Level C)
This is the single reference table you need for wall thermal compliance in Argentina:
| Zone | Description | Representative Cities | K_max Wall (Level C) |
|---|---|---|---|
| I-II | Warm / Sub-tropical | Formosa, Resistencia, Corrientes, Posadas, Misiones | 1.20 W/m²K |
| III | Temperate | Buenos Aires (CABA + GBA), La Plata, Rosario, Córdoba, Santa Fe, Mar del Plata | 1.00 W/m²K |
| IV-V | Cold | Mendoza, San Luis, Neuquén, Bariloche (city), NW Patagonia | 0.85 W/m²K |
| VI | Very Cold | High Andean Patagonia, Ushuaia, high-altitude Andes | 0.74 W/m²K |
Source: IRAM 11605 (1996), Table 1, Level C, horizontal heat-flow, winter condition.
What Is Thermal Transmittance (K or U)?
Thermal transmittance — written K or U — measures the rate of heat flow through one square metre of a building element (wall, roof, floor) per degree Celsius difference between inside and outside. The unit is W/m²K. A lower K = better insulation: K = 0.50 W/m²K lets through half the heat of K = 1.00 W/m²K.
How IRAM 11605 Works
IRAM 11605 defines maximum K-values (K_max) for opaque envelope components of habitable buildings. Three comfort levels exist:
Buenos Aires Province Law 13059 (2003, in force since 2010) requires Level C compliance for all new construction and major renovations. Several other provinces have adopted similar requirements.
How to Calculate K of a Multi-Layer Wall
Use thermal resistances in series (IRAM 11601):
R_total = R_si + Σ(e_i / λ_i) + R_se
K = 1 / R_totalInsulation Thickness Needed to Comply
Starting from an 18 cm hollow ceramic block (K ≈ 1.4 W/m²K), here is roughly how much EPS you need per zone:
| Zone | K_max | EPS Needed (λ = 0.033 W/m·K) |
|---|---|---|
| I-II | 1.20 | ~0 cm — hollow block barely passes |
| III | 1.00 | ~2.5–3 cm EPS |
| IV-V | 0.85 | ~4–5 cm EPS |
| VI | 0.74 | ~6–7 cm EPS |
Typical Material Conductivities (λ)
| Material | λ (W/m·K) | K per 10 cm of thickness |
|---|---|---|
| Solid brick | 0.72 | 7.2 W/m²K |
| Hollow ceramic block | 0.45 | 4.5 W/m²K |
| Expanded polystyrene (EPS) | 0.033 | 0.33 W/m²K |
| Mineral wool (rock wool) | 0.040 | 0.40 W/m²K |
| Concrete | 1.63 | 16.3 W/m²K |
| Air gap (> 2 cm, sealed) | — | ≈ 0.18 m²K/W (fixed) |
Important Notes
This calculator returns wall K_max. Roofs have different (usually stricter) limits — typically 0.83 W/m²K in Zone III, Level C. Floors over unheated spaces have their own table. For permit submission or energy certification, consult the full IRAM 11605 standard and a licensed architect or engineer.
Frequently asked questions
What is the maximum K-value allowed for walls in Buenos Aires (Zone III)?
IRAM 11605 Level C sets a maximum of 1.00 W/m²K for walls in Zone III (Buenos Aires, La Plata, Rosario, Córdoba). This is the legal floor under Buenos Aires Province Law 13059. A typical 18 cm solid brick wall has K ≈ 2.0 W/m²K — it fails by a factor of 2 and needs added insulation.
Does an 18 cm solid brick wall comply in any Argentine zone?
No. A standard 18 cm solid brick wall has K ≈ 2.0 W/m²K, which exceeds the maximum of 1.20 W/m²K even in the warmest Zones I-II. Added insulation — EPS, mineral wool, or an air gap — is required in all zones.
What is the difference between IRAM 11605 Level A, B, and C?
Level C is the legal minimum that most Argentine building codes require. Level B offers medium comfort with lower energy bills. Level A is the recommended, most stringent level — often required for passive house or energy-label certifications. This calculator returns Level C values, the mandatory compliance floor.
How much EPS insulation do I need to comply in Zone III (Buenos Aires)?
Starting from a typical 18 cm hollow brick wall (K ≈ 1.4 W/m²K), adding approximately 2.5–3 cm of EPS (λ = 0.033 W/m·K) brings the wall K below 1.00 W/m²K, meeting Zone III Level C. For Zone IV-V you need about 4–5 cm; for Zone VI, 6–7 cm.
Which Argentine cities belong to each bioclimatic zone?
Zone I-II: Formosa, Resistencia, Corrientes, Posadas, NE Salta, Misiones. Zone III: Buenos Aires (CABA and GBA), La Plata, Rosario, Córdoba, Santa Fe, Mar del Plata. Zone IV-V: Mendoza, Neuquén, San Luis, NW Patagonia, Bariloche (city). Zone VI: High Andean Patagonia, Ushuaia, high-altitude Andes throughout.
Do these K limits apply to roofs as well as walls?
No — IRAM 11605 sets stricter K limits for roofs. In Zone III Level C, the roof K_max is approximately 0.83 W/m²K (compared to 1.00 W/m²K for walls). This tool returns wall values only. Roof assemblies require a separate calculation with the roof table from IRAM 11605.
Is thermal insulation compliance legally mandatory in Argentina?
Yes, in Buenos Aires Province under Law 13059 (2003, regulated 2010), IRAM 11605 Level C is mandatory for new construction and major renovations. Neuquén, Mendoza, and Santa Fe have adopted similar provincial ordinances. Nationally enforcement varies by municipality, but it is required for any energy-efficiency certificate or green building rating.
What is the relationship between K-value and R-value?
They are reciprocals in SI units: R = 1/K. A wall with K = 1.0 W/m²K has R = 1.0 m²K/W. U.S. and Canadian codes use R-value in ft²·°F·h/BTU (imperial), but Argentine and European standards express insulation performance as K or U in W/m²K.
Why do colder zones require lower (stricter) K-values?
A larger temperature difference between inside and outside drives more heat loss through the wall. In Zone VI (Ushuaia, Andean Patagonia), winter design temperatures can fall to −15 °C or below, so a poorly insulated wall wastes enormous heating energy. Stricter K limits force better insulation, cutting energy costs and carbon emissions.
Can I use mineral wool instead of EPS to comply?
Yes. Mineral (rock) wool has λ ≈ 0.040 W/m·K — slightly less efficient than EPS (λ = 0.033 W/m·K), so you need a little more thickness for the same K reduction. About 3–4 cm of mineral wool achieves what 2.5–3 cm of EPS does in Zone III. Both are accepted under IRAM 11601 calculations.
Sources and references
- IRAM 11605:1996 — Condiciones de habitabilidad en edificios: valores de transmitancia térmica máxima admisible (IRAM, Argentina)
- IRAM 11603 — Clasificación bioambiental de la República Argentina
- Ley 13059 — Condiciones de acondicionamiento térmico en edificios (Buenos Aires Province)
- Guía de Cálculo de Transmitancia Térmica en Sistemas Constructivos (Ministerio de Obras Públicas, Argentina)
- IRAM 11601 — Aislamiento térmico de edificios: métodos de cálculo