The Impact of 2022 NYC Mechanical Code on Future Building Design

The AEC industry is ever evolving to meet the requirements of new legislation, ensure that best practice standards are current, and improve building safety. As of November 7, 2022, the 2022 NYC Building Codes were put into effect. Any application filed on or after that date must follow the 2022 version of these codes. Highlighted below are notable revisions to the Mechanical Code Chapter 4 – Ventilation, which have major impacts on future building designs within New York City.

Revisions to Chapter 4–Ventilation

Chapter 4 of the 2022 NYC Mechanical Code presents one of the most significant changes that will impact both consultants and architects. Section 401.2 explicitly states that mechanical ventilation shall be provided for all occupiable and habitable spaces that are air conditioned. Per section 401.3, the ventilation system should operate whenever the spaces are occupied. Further, the 2022 code revision added a provision that the ventilation system must be in operation if a gas appliance is running. For installations with gas water heaters, stoves, furnaces, or gas dryers, this means the space will be required to be ventilated by a mechanical means as long as that appliance is in operation.

Design Changes as a Result of Code Changes

If you have ever worked on a renovation project in an older New York City building looking to provide and/or update air conditioning, you might have discovered that ventilation is often provided by operable windows. Natural ventilation as a means for outside air is common in older buildings including schools, residential and other occupancy types, and even some older office buildings. When these buildings were built, air conditioning was a technology of the future and not widely available. Architects and engineers designed their buildings with lower ceiling heights and smaller shaft spaces. These common characteristics of older buildings create challenges for today’s HVAC systems requiring complex ductwork.

With the removal of natural ventilation as an option, individual tenants now have to use mechanical ventilation to condition occupiable spaces. As per the 2020 NYC Energy Conservation Code, any system operating over 8,000 hours per year and providing greater than 40 CFM will also need an Energy Recovery Ventilator (ERV). Outdoor air must be supplied by central equipment or may need to be brought in through local louvers within the building. As a result, design teams should be prepared to dedicate more ceiling space to accommodate outdoor air fans, ERVs, and outdoor air ductwork distribution which must be directly ducted to all occupiable rooms. Please refer to Figure 4.

What Are the Driving Factors Behind This Change?

Considering the additional equipment

“ The Impact of 2022…” continued on pg. 5 required to meet the revised mechanical codes, owners will likely experience increased costs, both in terms of construction and on-going maintenance. These owners might ask what the driving factors of the changes are. In other words, they will want an explanation. The primary explanation is the desire to improve indoor air quality. Traditional natural ventilation,