The Standard
What Is ASHRAE Standard 62.1?
ANSI/ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality, sets minimum outdoor air delivery rates and system requirements for commercial buildings — offices, retail, restaurants, schools, hotels, and healthcare outpatient facilities. First issued in 1973 and updated on a three-year cycle, the current version is 62.1-2022.
The standard has been adopted by reference into the International Mechanical Code (IMC), which forms the basis of the NYC Mechanical Code. For commercial buildings in New York City, 62.1 compliance is legally required — not optional.
Its demand control ventilation provisions allow a BAS to modulate outdoor air based on CO2 sensor readings — ensuring every occupied zone is properly ventilated based on who is actually there, not worst-case design assumptions.
The two-component formula separates people-based OA (scales with occupancy, addressed by DCV) from area-based OA (addresses building materials off-gassing — cannot go to zero even when unoccupied). A typical office requires 5 CFM per person plus 0.06 CFM per sq ft.
Energy code companion ASHRAE 90.1-2019 Section 6.4.3.8 makes DCV mandatory for spaces over 500 sq ft with design occupancy ≥ 25 people/1,000 sq ft and an economizer or >3,000 CFM design OA. Conference rooms, lobbies, restaurants, and large open offices typically qualify.
ASHRAE explicitly defines CO2 concentration as a proxy for ventilation adequacy — not a direct health hazard indicator. Rising CO2 signals insufficient dilution relative to occupancy. A full IAQ monitoring system also covers PM2.5, VOCs, and CO (a direct safety concern) independent of DCV.
How It Works
DCV: What MJI Programs and Commissions
Each DCV installation follows a documented process — from sensor placement through commissioning and NYC DOB documentation.
Why It Matters
Six Reasons to Implement DCV
Required by Energy Code
ASHRAE 90.1-2019 Section 6.4.3.8 makes DCV mandatory for spaces over 500 sq ft with design occupancy ≥ 25 people per 1,000 sq ft and an air economizer or >3,000 CFM design outdoor airflow. Most VAV systems in commercial buildings qualify.
9–33% HVAC Energy Savings
CO2-based DCV reduces HVAC energy consumption by 9–33% compared to constant-volume outdoor air systems, per ASHRAE Research Project RP-1747. Savings come from reduced heating, cooling, dehumidification, and fan energy on every occupied day.
Scales to Actual Occupancy
Most commercial buildings operate at 30–60% of peak occupancy on a typical day. A fixed outdoor air system conditions for worst-case assumptions all day long. DCV delivers only what's needed — in real time.
Supports LL97 Compliance
For NYC buildings facing Local Law 97 carbon penalties, reducing HVAC energy directly cuts CO2e emissions. DCV is one of the few controls-only strategies that produces measurable, documentable reductions without equipment replacement.
Open Standard, Any Platform
ASHRAE 62.1 DCV sequences are not tied to any manufacturer. MJI programs them on Niagara N4, Johnson Controls Facility Explorer, and any BAS platform that supports modern DDC programming — no new hardware required in most cases.
LEED & WELL Alignment
LEED v5 requires ASHRAE 62.1-2022 compliance as a mandatory prerequisite. WELL Building Standard v2 Option 4 awards credit for demonstrating CO2 levels at or below 900 ppm in occupied spaces — both are supported by proper DCV implementation.