Rinnai M060C Installation And Operation Manual page 46

The gas supply must be capable of handling the entire
gas load required at the location. Gas line sizing is
based on gas type, the pressure drop in the system,
the gas pressure supplied, and gas line type. For gas
pipe sizing, refer to the National Fuel Gas Code, ANSI
Z223.1/NFPA 54, or the Natural Gas and Propane
Installation Code, CSA B149.1
For some tables, you will need to determine the cubic
feet per hour of gas required by dividing the gas input
by the heating value of the gas (available from the
local gas company). The gas input needs to include all
gas products at the location and the maximum Btu
usage at full load when all gas products are in use.
Use the table for your gas type and pipe type to find
the pipe size required. Ensure the maximum input rate
o the DHW system is used for calculating the gas pipe
sizing. The pipe size must be able to provide the
required cubic feet per hour of gas or the required
Btu/hr.
The information below is provided as an example. The
appropriate table from the applicable code must be
used.
Natural Gas
Pressure Drop 0.5 in. w.c.
Information in table
obtained from NFPA 54,
ANSI Z223.1 - 2015.
Length in ft (meters) Capacity in Cubic Feet of Gas per Hour
10 (3)
20 (6)
30 (9)
40 (12)
50 (15)
60 (18)
70 (21)
80 (24)
90 (27)
100 (30)
46
Schedule 40 Metallic Pipe
Inlet Pressure: Less than 2 psi
Specific Gravity: 0.60
Nominal Pipe Size (in.)
1/2 3/4 1
172 360 678
118 247 466
95 199 374
81 170 320
72 151 284
65 137 257
60 126 237
56 117 220
52 110 207
50 104 195
Rinnai M-Series Condensing Boiler Combi Manual
GAS PIPE SIZING CALCULATION WORKSHEET
Instructions: Enter values in empty boxes.
Rinnai Model Gas Input:
A
Additional Appliance Total Gas Input:
B
Heating Value of Gas:
C
Cubic Feet Per Hour (CFH):
(CFH) =
(CFH) =
=
CFH
ANSWER:
Rinnai Model Gas Input:
160,000
A
Additional Appliance Total Gas
Input:
65,000
B
Heating Value of Gas:
C
1 1/4
Cubic Feet Per Hour (CFH):
1,390
(CFH) =
957
768
(CFH) =
657
583
ANSWER:
528
=
486
CFH
452
For this example, the pipe
424
diameter must be at least 3/4 in.
pipe size and 10 ft (3 m) in
400
length.
Btu/hr
Btu/hr
3
Btu/ft
A + B
C
3
FT /HR
EXAMPLE
BTU/HR
BTU/HR
1,000
3
BTU/FT
A + B
C
160,000+65,000
1000
225 3
FT /HR