## Fire resistance

Based on these facts the following component resistances result for the basic constructions:

1. 30 minutes fire resistance REI30
2. 60 minutes fire resistance REI60
3. 90 minutes fire resistance REI90

## Residual section after fire load

All the following information and calculations are based on the assumptions stated here:

• one dimensional charring
• charring rate β1 at the layers = 0.8 mm/min
• charring rate β2 at the webs around the insulation
• layer accounting for loss of strength dred = 7 mm

β1 = 1.6 mm/min for rockwool
β2 = 0.9 ⋅ √ (450/ρIso) mm/min for wood fibre
ρIso = density of wood fibre

## Effective charring depth

def = dchar + dred

def = 31 mm for REI30 = 30 min ⋅ 0.8 mm/min + 7 mm
def = 55 mm for REI60 = 60 min ⋅ 0.8 mm/min + 7 mm
def = 79 mm for REI90 = 90min ⋅ 0.8 mm/min + 7 mm

## Effective charring depth

def = dchar + dred

Example:
ti = 25 mm
def = 31 mm for REI30 = 30 min ⋅ 0.8 mm/min + 7 mm

Example:
ti = 40 mm, wood ρIso = 40 kg/m3
def = 77 mm for REI60 = 50 min ⋅ 0.8 mm/min + 10 min ⋅  3.0 mm/min + 7 mm

## Residual section of acoustic element after fire load

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

AAkustik (mm2) = perforation area
dAkustik (mm) = perforation area
bAkustik (mm) = position of perforation in relation to the timber web
ti (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 = AAkustik / dAkustik . 103 / (bAkustik 1.5 . ti)

β1 = 0.22 ⋅ k + 0.72

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

β2 = 0.9 . √(450 / ρAbsorber)

## Effective charring depth

def = dchar + dred

Example:
Acoustics type 2, ti = 31 mm, hi = 40 mm, ρAbsorber = 110 kg/m3, AAkustik = 707 mm2, dAkustik = 75 mm, bAkustik = 25 mm => k = 2.43, β1 = 0.22 ⋅ k + 0.72 = 1.26 mm/min
def = 48 mm for REI30 = 24 min ⋅ 1.26 mm/min + 6 min ⋅ 1.82 mm/min + 7 mm

## Effective charring depth

def = dchar + dred

Example:
Acoustics type 2, t= 31 mm, hi = 40 mm, tii = 33 mm, ρAbsorber = 110 kg/m3, AAkustik = 707 mm2, dAkustik = 75 mm, bAkustik = 25 mm => k = 2.43, β1 = 0.22 ⋅ k + 0.72 = 1.26 mm/min
def = 89 mm for REI60 = 24 min ⋅ 1.26 mm/min + 22 min ⋅ 1.82 mm/min + 14 min ⋅ 0.8 mm/min + 7 mm

## Joint detail under fire load

Basic boundary conditions for space-enclosingand heat insulation effects must be met in theevent of fire. LIGNATUR floors and roofs withfire resistance class REI30, REI60 and REI90 haveto be installed according to ETA-11 / 0137 withthe appropriate joints, shown on the right. Theyalready reach EI30, EI60 or EI90, so that floorand roof structures can be chosen freely withoutfurtherrequirements.