d_ef = d_char + d_red

d_ef = 31 mm für REI30 = 30 min ⋅ 0.8 mm/Min + 7 mm
d_ef = 55 mm für REI60 = 60 min ⋅ 0.8 mm/Min + 7 mm
d_ef = 79 mm für REI90 = 90min ⋅ 0.8 mm/Min + 7 mm

d_ef = d_char + d_red

Example :

t_i = 40 mm, mineral fibre (A2-s1, d0 and melting point ≥ 1000°C)

d_ef = 63 mm for REI60
= 50 Min ⋅ 0.8 mm/Min + 10 min ⋅  3.0 mm/Min + 7 mm

The charring rate β₀ of the acoustic slat can be described based on the following parameters:

A_Akustik (mm²) = perforation area
d_Akustik (mm) = perforation area
b_Akustik (mm) = position of perforation in relation to the timber web
t_i (mm) = thickness of the acoustic slat

The factor k summarises the resulting influence of the parameters. The charring rate β₁ can be calculated depending on the factor k. 

k = A_Akustik / d_Akustik . 10³ / (b_{Akustik ^1.5} . t_i)

β₁ = 0.22 ⋅ k + 0.72

The charring rate β₂ at the webs around the wood fibre absorber depends on the density ρ_Absorber (kg/m³).

β₂ = 0.9 . √(450 / ρ_Absorber)

d_ef = d_char + d_red

Example akustic 2:

• t_i = 31 mm, h_i = 40 mm, ρ_Absorber = 110 kg/m³
• A_Akustik = 707 mm², d_Akustik = 75 mm, b_Akustik = 25 mm
• => k = 2.43, β₁ = 0.22 ⋅ k + 0.72 = 1.26 mm/min

d_ef = 48 mm für REI30
= 24 Min ⋅ 1.26 mm/Min + 6 Min ⋅ 1.82 mm/Min + 7 mm

d_ef = d_char + d_red

Example akustic type 2:

• t_i = 31 mm, h_i = 40 mm, ρ_Absorber = 110 kg/m³
• A_Akustik = 707 mm², d_Akustik = 75 mm, b_Akustik = 25 mm
• => k = 2.43, β₁ = 0.22 ⋅ k + 0.72 = 1.26 mm/Min

def = 89 mm für REI60 =
24 min ⋅ 1.26 mm/Min + 22 Min ⋅ 1.82 mm/Min + 14 Min ⋅ 0.8 mm/Min + 7 mm

Basic boundary conditions for space-enclosing and heat insulation effects must be met in the event of fire. LIGNATUR floors and roofs with fire resistance class REI30, REI60 and REI90 have to be installed according to ETA-11 / 0137 with the appropriate joints, shown on the right. They already reach EI30, EI60 or EI90, so that floor and roof structures can be chosen freely without further requirements.

European Technical Assessment ETA-11/0137