Table 21 Inside Surface Resistance (Table A3.5 CIBSE Guide)

 
 
Surface resistance (m²K/W)
 
Building element
Heat flow
High emissivity
Low emissivity
 
 
factor
factor
Walls
Horizontal
0.12
0.3
 
 
 
 
Ceilings or roofs,
Upward
0.1
0.22
flat or pitched
 
 
 
floors
 
 
 
 
 
 
 
Ceilings and floors
Downward
0.14
0.55
 
Notes:
 
1.                   High emissivity factor assumes ε 1 = ε 2 = 0.90 (most building materials),
     Low emissivity factor assumes ε 1 = 0.90, ε 2 = 0.05,
2.           Surface temperatures are 20°C
3.           Air speed at the surface is assumed to be less than or equal to 0.1 m/s