Gas piping must be
sized to give the correct volume flowrate and pressure for the appliances
being served. We recommend the following method of calculation. - Calculate the gas demand in kW at each piping
system outlet.
N.B. It is important
to use the
appliance kW input rating not the output
rating.
- Measure the length of piping from the gas
meter or service regulator to the
most remote outlet in the building.
- Using the appropriate table, select the column
showing that distance or the next
longer
distance if the table does not give the exact length.
- Starting at the most remote outlet, find
in the column the gas demand for that
outlet. If the
exact figure of demand is not shown,
choose the next larger figure in
the column.
- Opposite this demand figure, in the first
column at the left, read the correct
size of gas
piping.
- Proceed in a similar manner for each outlet
and each section of gas piping.
For each section of piping, determine
the total gas demand supplied
by that section.
- When it is anticipated that the gas supplied
to the piping system will be changed
from LP-gas to Natural Gas, size
the piping system
to provide sufficient capacity for future use with Natural Gas.
- Supply piping should not be smaller than ½" pipe.
The capacity tables include an
allowance for an ordinary number
of fittings. In large, complex
installations it may be
desirable to add some 'equivalent' length to
compensate for fittings.
Note:These tables
and method are adapted from the AGA Gas Engineers Handbook.
Maximum Capacity of Pipe in kW -
Natural Gas
(based on a pressure drop of 1.25 mbar and Natural gas
(G20) |