How the Contractor MEP Market is built

Every line on these charts is derived from New York City Department of Buildings records — no surveys, no estimates of activity that didn't get permitted. This page documents exactly how the numbers are produced so they can be checked and trusted.

1. What it measures

The MEP market is the volume of mechanical (HVAC), plumbing, and sprinkler/standpipe work moving through NYC over time. Each trade can be viewed two ways:

• Physical scope — the actual equipment and components installed: HVAC equipment units, plumbing fixtures & components, sprinkler heads, and standpipe outlets. These are counts, not dollars.
• Man-hours — an estimate of the field labor required to install that scope, split into union, open shop, and other / unknown.

2. Data sources

All figures come from DOB filing and permit systems, queried from BuildNYC's database (never from a live public API at read time):

• DOB NOW scope of work — the structured equipment, fixture, and sprinkler schedules submitted with mechanical, plumbing, and sprinkler/standpipe filings.
• DOB NOW & BIS permits — the issuance records that tell us a job is real and when it started.

3. Only issued permits count

A filing is just an application. We count a job only once it has an issued permit — the point at which work is legally authorized to proceed. Filed-but-not-issued and withdrawn jobs are excluded. This is the single most important filter: it keeps the market measure tied to real construction rather than paperwork.

4. Each job is counted once

In DOB NOW a job number carries multiple filings — an initial filing and later subsequent (S) and post-approval (P) revisions. Revisions restate the same scope; they do not add to it. Summing across them would double- or triple-count the same equipment.

We collapse every job to a single canonical filing — the most complete revision — so a job that installs 40 sprinkler heads contributes 40, no matter how many times it was amended.

5. When work is placed in time

Physical scope and labor are timed differently, on purpose:

• Physical scope is anchored to the job's permit-issuance month — a point-in-time event. The equipment for a job shows up in the month construction was authorized.
• Man-hours are time-phased across the project's construction window rather than dropped in a single month, because a job's labor is spent over months, not on day one. Hours that extend past today are shown as projected (the shaded region on each chart).

6. How man-hours are estimated

Man-hours are synthesized from the installed scope using published trade labor-estimating standards — the MCAA (Mechanical Contractors Association of America) labor-estimating units for mechanical, plumbing, and piping work, and NECA (National Electrical Contractors Association) units for electrical work. The union / open-shop split is inferred from the permittee and licensing signals on each permit; where that signal is absent the hours are reported as other / unknown rather than guessed.

7. Contractor attribution

When you slice the market to a single contractor, a job is attributed to the licensed permittee on the issued MEP permit — the firm legally responsible for that mechanical, plumbing, or sprinkler work. Contractor identities are entity-resolved, so filings under spelling variants and affiliated license numbers roll up to one firm.

A contractor's chart therefore shows the scope and labor on the MEP jobs they pulled the permit for — issued only, de-duplicated, and timed exactly as the city-wide market.

8. Units of measure

9. Coverage & limitations

• DOB NOW was phased in by work type through roughly 2021; the earliest years reflect that adoption ramp, not a smaller market.
• Scope completeness depends on what each applicant entered; obvious data-entry outliers are capped per line item so a single mis-keyed quantity can't distort a month.
• Man-hours are an engineering estimate, not payroll. They are designed for relative comparison across firms, trades, and time — not as a certified labor count.