L&J has had the privilege of working on various projects at New York City Hall for more than 15 years.  We have worked with various Architects and projects have ranged from the renovation of the Governor’s Suite to the present major renovations to the entire building.

The services for this 76,000 SF historic landmark building built in 1812 included the engineering and design of a new chiller and boiler plant, and air-conditioning system; the upgrade of the existing air distribution system complete with hot water heating and ventilation systems, new electric service and distribution, and new emergency power distribution system; the replacement of A/C units; the transfer from a “cooling only” to dual temperature system; a smoke exhaust system; Identification of critical loads and the recommendations of optional loads; and the design of 800 KW of emergency power using auto transfer switching.

Various options for standby chiller and boiler plant were examined.  City Hall requires 24/7 cooling for certain areas with high heat load.  L&J designed a modular chiller plant and boiler plant to be operational on an emergency basis.  The entire City Hall MEP system design included adequate standby capacity to support City Hall activities in an emergency situation.

The scope also included replacing steam radiators, window air conditioners and split system air conditioners with fan coil units supplied by dual temperature water service from a remote central plant in the Municipal Building.

The electrical equipment/systems included new 120/208V electric service with new underground service feeder, new below grade electric service room adjacent to City Hall Building, new 120/208V emergency distribution system from Tweed Building emergency generator plant (two 400 kW paralleled diesel driven engine generators) with new underground emergency feeders (life safety and optimal standby), new below grade emergency electric room adjacent to new electric service room, reconfiguration of Tweed building emergency distribution board and new normal and emergency power distribution systems in City Hall Building.

During the design stage, several electric service/distribution options were examined to anticipate the potential effect on the site.  One of the solutions that developed out of these options was the use of micro-tunneling to install duct banks at 12-15 FT below grade and avoid disturbing the site.

L&J also designed gas driven Fuel Cell to generate 100 kW of power.  This power will be utilized as a base load to reduce carbon foot print. Design of a 9.5kw photovoltaic solar system was also implemented on the roof of City Hall.

The City Hall building did not have sprinkler coverage.  During this renovation, the entire building was provided with wet sprinkler coverage.

The entire project was produced and coordinated using AutoCAD and converted to AutoCAD MEP Revit model with Navis clash detection.

The project was built while City Hall building was occupied by three successive mayors (Giuliani, Bloomberg & DiBlasio).  All work was completed in phases without interruption to the Mayor’s operations.  City Hall is equipped with dual source of electric power, cooling and heating energy.

This project received both the Lucy B. Moses Preservation Award from the New York Landmarks Conservancy and the Project Excellence Award Preservation League of New York State.


NYC Department of Design & Construction


Beyer Blinder Belle Architects


76,000 SF


Mechanical Engineering
Electrical Engineering
Plumbing Engineering
Fire Protection Engineering

Construction Cost

$152 Million

Completion Date



Silver Certified


Mr. Salvatore Cali
Project Executive
30-30 Thomson Avenue
Long Island City, NY 11101
O: (212) 788-3060
M: (646) 210-4501

Mr. Richard Southwick
Beyer Blinder Belle Architects
120 Broadway
New York, NY 10271
(212) 777-7800