Product Technical Guides : US-EN Direct Fastening - Volume 1 Edition 22 | Page 124

Thermal efficiency Example for insulation material ( EPS or mineral wool ) with a thermal conductivity λ = 0.03 W / mK
Insulation thickness ( inch )
1
2
3
4
5
6
7
8
Hilti insulation fastener
X-IE-G 25
X-IE-G 50
X-IE-G 75
X-IE-G 100
X-IE-G 120
X-IE-G 150
X-IE-G 180
X-IE-G 200
Thermal conductivity λ [ W / mK ]
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
Thermal resistance R [ m 2 K / W ]
0.85
1.69
2.54
3.39
4.23
5.08
5.93
6.77
Thermal transmittance U [ W / m 3 K ]
1.181
0.591
0.394
0.295
0.236
0.197
0.169
0.148
Point thermal transmittance x [ W / K ]
0.002
0.002
0.002
0.001
0.001
0.001
0.001
0.001
Uc = U + n * x [ W / m 2 K ] for n = 1
1.183
0.593
0.396
0.296
0.237
0.198
0.170
0.149
Thermal efficiency = U / Uc
99.8 %
99.7 %
99.5 %
99.7 %
99.6 %
99.5 %
99.4 %
99.3 %
λ
Thermal conductivity [ W / mK ]
R
Thermal resistance [ m 2 K / W ], R = d / λ with d = thickness of inslation or component
U
Thermal transmittance [ W / m 3 K ]
Up = x
Point thermal transmittance x [ W / K ] per single fastener
Uc
Corrected thermal transmittance [ W / m 2 K ]
1
Fastening quality assurance Fastening inspection
x
L h ET
Insulation thickness t I [ mm ] 1
25 / 30
40
50
60
70
75
80
90
h ET
= 12-19 mm
x min
[ mm ]
3
14
24
34
44
49
54
64
x max
[ mm ]
10
21
31
41
51
56
61
71
t I
Insulation thickness t I [ mm ] 1
100
120
130
140
150
160
180
200
h ET
= 12-19 mm
x min
[ mm ]
74
94
104
114
124
134
154
174
x max
[ mm ]
81
100
111
121
131
141
161
181
1 Dimensions are provided in millimeters for accurate field measurement .
124