Nominal concrete cover — EN 1992-1-1 §4.4.1 with the Dutch National Annex
Find the nominal cover c_nom for a reinforcement bar. The calculator determines the structural class from the design working life, concrete class and the modifications you select, takes the minimum cover for durability and for bond, and adds the allowance for deviation from the Dutch NB.
Open this example in the calculator →
What it checks
- Structural class and its modifications (EN 1992-1-1 §4.4.1.2)
- Minimum cover for bond and durability, c_min (§4.4.1.2)
- Nominal cover c_nom = c_min + Δc_dev (§4.4.1.1, §4.4.1.3)
Scope
- Exposure classes X0, XC1–XC4, XD1–XD3, XS1–XS3.
- Concrete cast against formwork, prepared ground or directly against soil.
Not covered (the calculator says NOT COVERED instead of approximating)
- Exposure classes for freeze–thaw (XF) and chemical attack (XA).
- Prestressing tendons.
Worked example
Exposure class XC1, design working life 50 years, C30/37, bar diameter 20 mm, cast against formwork, no slab geometry and no special quality control.
Inputs
| Input | Value |
|---|---|
| Exposure class (governing, Table 4.1) | XC1 |
| Design working life | 50 yr |
| Concrete strength class | C30/37 |
| Slab geometry (bar position unaffected by construction) | no |
| Special quality control of concrete production | no |
| Bar diameter (largest bar against this surface) | 20 mm |
| Concrete cast against | formwork |
Main steps
| Step | Clause | Working | |
|---|---|---|---|
| Minimum cover for durability | EN 1992-1-1 §4.4.1.2(5), Table 4.4N (NB) | c_min,dur = Table 4.4N (S3, XC1) = S3, XC1 = 10 mm | ⚠ |
| Minimum cover | EN 1992-1-1 §4.4.1.2(2), Eq. (4.2) (NB) | c_min = max(c_min,b ; c_min,dur + Δc_dur,γ − Δc_dur,st − Δc_dur,add ; 10) = max(20 ; 10 + 0 − 0 − 0 ; 10) = 20 mm | ⚠ |
| Nominal cover | EN 1992-1-1 §4.4.1.1(2), Eq. (4.1); 4.4.1.3(1)P (NB) | c_nom = c_min + Δc_dev = 20 + 5 = 25 mm | ⚠ |
Outcome
Values only (no unity check)
| Result | Value |
|---|---|
| structural class | 3 S |
| c_min,dur | 10 mm |
| c_min | 20 mm |
| c_nom | 25 mm |
Dutch National Annex values used
| Symbol | Value | Clause | Status |
|---|---|---|---|
| S_rec | S4 | EN 1992-1-1 4.4.1.2(5) (NB) | transcribed ⚠ |
| C_min,ΔS(XC1) | C30/37 | EN 1992-1-1 4.4.1.2(5), Table 4.3N (NB) | transcribed ⚠ |
| S_min | S1 | EN 1992-1-1 4.4.1.2(5) (NB) | transcribed ⚠ |
| c_min,dur(S3,XC1) | 10 mm | EN 1992-1-1 4.4.1.2(5), Table 4.4N (NB) | transcribed ⚠ |
| Δc_dur,γ | 0 mm | EN 1992-1-1 4.4.1.2(6) (NB) | transcribed ⚠ |
| Δc_dur,st | 0 mm | EN 1992-1-1 4.4.1.2(7) (NB) | transcribed ⚠ |
| Δc_dur,add | 0 mm | EN 1992-1-1 4.4.1.2(8) (NB) | transcribed ⚠ |
| Δc_dev | 5 mm | EN 1992-1-1 4.4.1.3(1)P (NB) | transcribed ⚠ |
Clauses used in the worked example
EN 1992-1-1 §4.4.1.1(2), Eq. (4.1); 4.4.1.3(1)P (NB), EN 1992-1-1 §4.4.1.2(2), Eq. (4.2) (NB), EN 1992-1-1 §4.4.1.2(3), Table 4.2, EN 1992-1-1 §4.4.1.2(5) (NB), EN 1992-1-1 §4.4.1.2(5), Table 4.3N (NB), EN 1992-1-1 §4.4.1.2(5), Table 4.4N (NB)
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