Project Brief

For more than a century, Kearfott Corporation has been showing aircraft, spacecraft and missiles where they are. The New Jersey company became one of America's pioneers of inertial navigation, moving from floated gyroscopes to its GYROFLEX tuned rotor gyros and then to monolithic ring laser gyros. Singer-Kearfott KT-70 inertial measurement units flew aboard the Space Shuttle orbiters, Kearfott ring laser gyro systems navigate the Global Hawk unmanned aircraft, and its motion control products have logged millions of hours on the Boeing 737, 747 and 777, the Airbus A320, and the CFM56 and CF6 engines. More than 100,000 Kearfott inertial systems have been built, and its technology supported Blue Origin's flight into space.

When Kearfott brought its headquarters and Guidance & Navigation Division together in Pine Brook, the center of the move was a new cleanroom for assembling, coating, aligning and testing ring laser and fiber optic gyroscopes. KeRi was the MEP and fire protection engineer to Poskanzer Skott Architects for the suite and its support spaces.

The rooms step down in cleanliness from an ISO 5 assembly room, fed through a full HEPA ceiling at 240 air changes an hour and held at +0.09 in. w.c., through ISO 5 and ISO 7 cleanrooms, two coating rooms, a blackout room and a dark room, to an ISO 8 gown-in. Every room is held at 65 to 68°F and no more than 35 percent relative humidity, with return air through the raised floor.

KeRi's moisture calculations showed a standard DX system could not reach that dew point and would let the rooms drift on an estimated 14 to 20 days a year, so Kearfott chose active desiccant dehumidification. A Munters desiccant unit dries all 8,625 CFM of outdoor air before it reaches three mezzanine air handlers totalling 114,000 CFM. The two large units have N+1 fan walls and redundant VFDs, four roof condensing units supply 189 tons of cooling, hot water reheat trims each room, and electric steam humidifiers on an RO/DI skid hold the lower humidity limit.

Plumbing distributed compressed air and vacuum to the benches, with oil-less vacuum pumps and sealed cleanroom penetrations. Electrical added a 225 kVA transformer, an 800 A distribution panel, two 600 A, 480 V power panels and UPS-backed power for the coaters, tied into the existing fire alarm.

MEP Engineering Scope

What We Engineered

MEP and fire protection for the gyroscope cleanroom suite:

• ISO 5, ISO 7 and ISO 8 cleanroom suite with a cascading pressure plan
• Active desiccant dehumidification and steam humidification, 65 to 68°F and 35% RH maximum
• Three mezzanine air handlers, 114,000 CFM, with N+1 fan walls and a HEPA ceiling
• Four roof condensing units and hot water reheat for room-by-room control
• Compressed air and vacuum distribution to the cleanroom benches
• New 225 kVA transformer, 800 A distribution, UPS-backed coater power and sprinkler work

The Challenge

Ring laser and fiber optic gyroscopes are assembled in air that must stay nearly free of particles and very dry, and a standard DX system could not reach the dew point the rooms required.

Our Solution

KeRi paired a desiccant dehumidifier with three redundant air handlers and a HEPA ceiling, cascading pressure from the ISO 5 assembly room down to the plant floor.