Project Brief

The High School for Environmental Studies occupies a former news studio building on West 56th Street in Manhattan that was converted for school use. It is heated by two 300 boiler horsepower fire-tube, low-pressure steam boilers that feed steam-to-hot-water heat exchangers for perimeter heating. After more than three decades on No. 4 oil, the burners and controls had reached the end of their life and the boilers had leaking and plugged tubes and damaged insulation. KeRi was the prime consultant for this NYC School Construction Authority boiler conversion, from the scope report through the bid documents.

Nondestructive testing showed that the boiler shells had about 30 more years of service life, so the design keeps both boilers and rebuilds them with new refractory, fire tubes, jackets, pressure controls, low water cutoffs and control panels. The No. 4 oil burners are replaced with modulating burners rated for No. 2 oil, B20 and B100 biofuel. The existing fuel oil tank is cleaned and converted for B100, with new distribution piping, heated transfer pumps, a fuel oil polisher and leak detection.

The rest of the plant is renewed around the boilers: a new boiler feed system and chemical feed, a new vacuum condensate pump, new combustion air fans interlocked with each boiler, new breeching and a stainless steel chimney liner with a smoke opacity alarm, new chain-operated valves on the existing 14 inch steam header, and new heat exchangers with variable-speed hot water pumps. A new 400 A boiler room panel, a new sump pump and floor drains, code-compliant pit stairs and boiler access platforms complete the work.

The school stays in operation throughout. One boiler remains in service while the other is rebuilt during the heating season, the auxiliary equipment, fuel system and heat exchanger changeovers are scheduled between May and October, and the contract carries an allowance for temporary boilers in case the plant is not finished before heating season begins.

MEP Engineering Scope

What We Engineered

Heating plant upgrade and biofuel conversion:

• Two 300 BHP steam boilers refurbished with new refractory, fire tubes and controls
• New modulating burners for No. 2 oil, B20 and B100 biofuel
• Fuel oil tank converted for B100 with new transfer pumps, polisher and leak detection
• New boiler feed, chemical feed and vacuum condensate systems
• New breeching, chimney liner and combustion air fans
• New heat exchangers, variable-speed hot water pumps and a 400 A boiler room panel

The Challenge

Two aging No. 4 oil boilers with failing burners, controls and tubes had to be converted to biofuel in an occupied high school that cannot go without heat.

Our Solution

KeRi kept the sound boiler shells, rebuilt them with new biofuel burners and controls, converted the fuel system for B100, renewed the plant auxiliaries, and phased the work so one boiler stays in service through the heating season.