Work through the four steps with your own numbers. It shows the method and the figures to take to the B149.1 tables.
Why this does not give you a pipe size
Deliberately. The capacity tables are copyright CSA and belong in the code book,
which you should be reading anyway — on the exam and on the job. What this does is
the part people get wrong: establishing the run, rounding the column up correctly,
and adding the right load before you open the table.
The four steps
Longest measured run — meter to the farthest appliance, always
the longest single path.
Column at or above that length, rounding up. Never down.
Total load — every appliance the section feeds, not only the
ones past the tee.
Pipe size — the first capacity meeting or exceeding the load.
Round up again.
Where people lose marks
Rounding the column down because the run is "almost" that length
Counting only the appliances downstream of a tee
Using Annex A for a propane system
Sizing to the load exactly rather than the first capacity above it
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