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BE AWARE THAT MANUFACTURERS INSTRUCTIONS
ARE ALWAYS TAKEN AS CORRECT
IN WHICH CASE THE CALCULATORS MAY NOT BE REQUIRED
1 SELECT THE TAB AT THE BOTTOM VENTILATION OR 
PIPE SIZING OR PURGING ETC
2 FILL IN THE DETAILS IN THE YELLOW BOXES ONLY
IF INFORMATION IS PLACED IN A WRONG BOX THE PROGRAM
WILL TELL YOU
3 THE INFORMATION YOU REQUIRE WILL APPEAR IN THE 
BLUE BOX
any questions email enquire@gb-gas.co.uk or visit www.gb-gas.co.uk
    AIM TO PASS WITH GB GAS  
this is a free domestic gas calculator all calculations are deemed to be correct. Using this calculator will be covered by the disclaimer www.gb-gas.co.uk/disclaimer_5.html for more details
     
HEAT INPUTS            
METRIC METER
IMPERIAL METER
AMOUT OF GAS 
TIME FOR  (1FT3) ONE
USED IN TWO MINS
REVOLUTION IN SECONDS.
first reading
second reading
               
           
           
 
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GAS RATE   m3/hr
     
HEAT INPUT NET   kW
     
HEAT INPUT GROSS   kW
METRIC METER GAS RATES
0.001 > 0.03
>
>
>
>
m3 / two mins gas rate kw net kw gross   m3 / two mins gas rate kw net kw gross   m3 / two mins gas rate kw net kw gross   m3 / two mins gas rate kw net kw gross   m3 / two mins gas rate kw net kw gross
0.001
0.031
0.061
0.092
0.152
0.002
0.032
0.062
0.094
0.154
0.003
0.033
0.063
0.096
0.156
0.004
0.034
0.064
0.098
0.158
0.005
0.035
0.065
0.1
0.16
0.006
0.036
0.066
0.102
0.162
0.007
0.037
0.067
0.104
0.164
0.008
0.038
0.068
0.106
0.166
0.009
0.039
0.069
0.108
0.168
0.01
0.04
0.07
0.11
0.17
0.011
0.041
0.071
0.112
0.172
0.012
0.042
0.072
0.114
0.174
0.013
0.043
0.073
0.116
0.176
0.014
0.044
0.074
0.118
0.178
0.015
0.045
0.075
0.12
0.18
0.016
0.046
0.076
0.122
0.182
0.017
0.047
0.077
0.124
0.184
0.018
0.048
0.078
0.126
0.186
0.019
0.049
0.079
0.128
0.188
0.02
0.05
0.08
0.13
0.19
0.021
0.051
0.081
0.132
0.192
0.022
0.052
0.082
0.134
0.194
0.023
0.053
0.083
0.136
0.196
0.024
0.054
0.084
0.138
0.198
0.025
0.055
0.085
0.14
0.2
0.026
0.056
0.086
0.142
0.202
0.027
0.057
0.087
0.144
0.204
0.028
0.058
0.088
0.146
0.206
0.029
0.059
0.089
0.148
0.208
0.03
0.06
0.09
0.15
0.21
IMPERIAL METER GAS RATES
12 > 41
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>
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>
secs / 1ft3 gas rate kw net kw gross   secs / 1ft3 gas rate kw net kw gross   secs / 1ft3 gas rate kw net kw gross   secs / 1ft3 gas rate kw net kw gross   secs / 1ft3 gas rate kw net kw gross
12
42
72
102
162
13
43
73
104
166
14
44
74
106
170
15
45
75
108
174
16
46
76
110
178
17
47
77
112
182
18
48
78
114
186
19
49
79
116
190
20
50
80
118
194
21
51
81
120
198
22
52
82
122
202
23
53
83
124
206
24
54
84
126
210
25
55
85
128
214
26
56
86
130
218
27
57
87
132
222
28
58
88
134
226
29
59
89
136
230
30
60
90
138
234
31
61
91
140
238
32
62
92
142
242
33
63
93
144
246
34
64
94
146
250
35
65
95
148
254
36
66
96
150
258
37
67
97
152
262
38
68
98
154
266
39
69
99
156
270
40
70
100
158
274
41
71
101
160
278
  FLUED APPLIANCES                 VENTS WITH RECTANGULAR HOLES        
  HEAT INPUT IF MORE THAN ONE APPLIANCE IS FITTED ,INSERT THE TOTAL HEAT INPUT           HOLE SIZE 1 LENGTH (MM)   WIDTH (MM)   NO# OF HOLES    
  NET or            GROSS                    
41.2
        TO OUTSIDE TOP VENT   BOTTOM VENT       HOLE SIZE 2 LENGTH (MM)   WIDTH (MM)   NO# OF HOLES    
  OPEN FLUED IN A ROOM         CM2            
  OPEN FLUED COMPARTMENT TO OUTSIDE     CM2     HOLE SIZE 3 LENGTH (MM)   WIDTH (MM)   NO# OF HOLES    
  OPEN FLUED COMPARTMENT VIA ROOM   CM2            
TOP VENT
BOTTOM VENT
  ROOM SEALED COMPARTMENT TO OUTSIDE     CM2       VENT SIZE     cm2    
  ROOM SEALED COMPARTMENT VIA ROOM     CM2                    
  DFE FIRES IN ON ROOM ENTER HOW MANY FIRES ARE FITTED IN THE SAME ROOM      
 
  CONSULT MANUFACTURERS INSTRUCTIONS **       CM2       LENGTH  
WIDTH
  FLUELESS APPLIANCES   OPENABLE WINDOW OR SIMILAR REQUIRED      
  COOKER ROOM VOLUME   m3             LENGTH  
  IS A DOOR TO OUTSIDE FITTED X FOR YES     CM2       WIDTH  
  FLUELESS WATER HEATER ROOM VOLUME m3            
            CM2    
  FLUELESS SPACE HEATERS CONSULT MANUFACTURERS INSTRUCTIONS **             VENTS WITH CIRCULAR HOLES      
  INSERT Kw OF THE APPLIANCE         HOLE SIZE 1 DIAMETER (MM)   NO# OF HOLES        
  IN A ROOM MAX 45 W/m3   MAX 90 W/m3   DOES IT CONFORM TO BS EN 449              
  CM2   CM2   X FOR YES                  
VENT SIZE
cm2
  MULTIPLE APPLIANCES                                
  Flueless space heating** open flued space heating** any other appliances      
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CM2 CM2 CM2
                 
  VENT TO OUTSIDE SIZE REQUIRED       CM2      
  space heating is CH BOILER, WARM AIR HEATER, FIRE OR SPACE HEATER **        
                       
  PURGING                             
  INSERT PIPE LENGTHS AND METER TYPE (Purge Calcuation only required if information is placed in orange boxes)                         
  Meter type G4 / U6 0.008 0.01 get-attachment                  
  PUT AN X IN THE BOX BESIDE THE METER TYPE U16 0.025 0.03                    
    E6 0.0024 0.0036                    
  COPPER PIPE LENGTH IN M     STEEL PIPE LENGTH IN M     MDPE PIPE LENGTH IN M          
  15mm 0.00014 15mm     ½ 0.00024 20mm    0.00019        
  22mm 0.00032 20mm     ¾  0.00046 25mm  0.00033        
  28mm 0.00054 25mm      1 0.00064 32mm     0.00053        
  35mm 0.00084 32mm   1¼ 0.0011              
  Total installation volume M3     Total purge volume M3     Data          
      or imperial  ft3              
                           
               
COMBUSTION PERFORMANCE ANALYSIS       
Co2 % Co PPM o2 %
2.8      
  AUTO co/co2 ratio      
OR 
  INSERT CO/CO2 RATIO      
BS 7967-3
APPLIANCE TYPE CO/CO2  RATIO    
Back boiler unit Boiler 0.008
In combination with fire 0.02
Central heating boiler   0.008
Hot water circulator   0.01
Flued space heater (check man instructions) 0.02
Flueless space heater   0.001
Water heater flued and Flueless 0.02
Warm air heater   0.008
Flueless cooker Oven 0.008
Hob Visual inspection of flames  
Grill (CE marked) 0.01
Grill (No CE mark) 0.02
Range oven flued   0.02
Refrigerator (LPG)   0.007
Tumble drier Flued 0.01
flueless 0.001
Gas lights (LPG)   0.02