Count Plumbing Fixtures

Fixture counts are arithmetic over a table, and the arithmetic is easy. What goes wrong is the inputs: an occupant load carried over from a different calculation, a table from the wrong code, and a rounding rule applied from memory.

Inputs the command needs

1. Occupant load, with how it was derived and whether it is the egress figure or a separately computed one.
2. Use group, as the fixture table names it, which may differ from the building code occupancy classification.
3. The fixture table, pasted, with its source, edition, and its notes.
4. The sex split assumption and where it comes from.
5. Provided fixtures, by type, if a comparison is wanted.

If the table is not supplied, say so and stop. There is no default table.

Workflow

Step 1 — Read the inputs back

State the occupant load, its derivation, the table's source and edition, and the use group row being used. Quote the row.

Flag immediately if the occupant load was derived for egress and is being reused here without a stated reason.

Step 2 — Apply the split

Apply the sex split as the table directs, before applying any ratio. Show the split as arithmetic.

If the table's notes address all-gender rooms, single-occupant rooms, or substitution of one fixture type for another, quote the note and say whether it is being applied.

Step 3 — Apply each ratio and round as directed

One line per fixture type per sex, formula above the arithmetic:

water closets, female    <ratio quoted>    <occupants> / <ratio> = <raw>    rounded <as table directs> = <required>

Never round before the table says to. Never round the same figure twice.

Step 4 — Report

Fixture type	Sex	Required	Provided	Difference	Table row quoted

Then:

• Shortfalls named individually.
• Any note in the table that was not applied, and why.
• What was assumed rather than quoted, counted.
• The reminder that drinking fountains, service sinks and accessible fixture counts are separate requirements in most tables and are only covered here if they were in the paste.

Step 5 — Save, if asked

Ask whether to write the count to a file and where.

Rules

• Never supply a ratio, a factor, or a rounding rule.
• Never proceed without the table. No default exists.
• Quote the table row used, verbatim, in the output.
• Read the table's notes and say which were applied and which were not.
• Show the split before the ratios.
• Never reuse the egress occupant load without stating that it was reused.
• Quoting a table found by web search is not quoting the code. Search identifies the document; it does not verify the text.

Anti-patterns

• Recalling a fixture ratio for an occupancy because it is common.
• Applying a rounding convention from memory.
• Ignoring the table's notes because the numbers are in the columns.
• Producing a count when no table was supplied.
• Treating the egress occupant load as automatically the fixture occupant load.
• Reporting a total without the per-sex breakdown the table required.