The top spot in the list again goes to EMCOR Group Inc., whose California revenue fell 7% in 2010 to $744.41 million, from $800.55 million in 2009. The Norwalk, Conn., company reported $5.1 billion in worldwide 2010 revenue, and it is busy winning contracts all over California, thanks to its army of mechanical and electrical subsidiaries.

One of EMCOR's biggest 2010 contracts, won by its Dynalectric unit, calls for the installation of electrical systems at the new 19-gate Bradley West concourse terminal at Los Angeles International Airport.

Dynalectric Takes Charge

Dynalectric's scope of work for the airport project includes providing and installing the switchgear, light fixtures with lighting control system package and emergency uninterruptible power source. Dynalectric also will provide automatic transfer switches for the emergency system as well as the structured cabling, data, WiFi and electronic display systems for flight control and for customs/border patrol.

EMCOR's University Mechanical & Engineering Contractors subsidiary in California was awarded a contract this year to install HVAC, mechanical and plumbing systems at the U.S. General Services Administration's San Ysidro Land Point of Entry, the busiest such site in the world, located in San Diego. Dynalectric was also awarded the contract for the complete installation of electrical systems as part of the initial phase of the Long Beach Middle Harbor redevelopment, which will include building wharves, dredging one slip and filling another.

Most of this year's top 10 firms landed in almost the same spots they held on last year's roster. But one firm did break into the top 10. KHS&S, Anaheim, a specialty interior/exterior contractor, climbed to ninth this year, from 18th, as its 2010 revenue rose 35.6% to $118.3 million, compared with 2009's $87.09 million.

Soon after KHS&S was founded in 1984, it struck gold with a $22-million contract to complete the facades at Paris Las Vegas Casino. At the time, KHS&S had no office, no staff and, according to the company, no immediate idea of how it would accomplish the task. Now KHS&S has 20 locations and 650 employees worldwide and offers clients a range of preconstruction services, from performing value engineering to working in a design-assist capacity with owners and architects.

Earlier this year, KHS&S unveiled its communication, collaboration and control (C3) software system, called Scenario Virtual Project Delivery. The system allows design and construction team members 24/7 access to live, integrated project data and automatically integrates with leading AEC software, such as Revit, AutoCAD and Navisworks.

KHS&S recently completed some high-profile projects in California, including the UC Davis Surgery & Emergency Services Pavilion, a three-story, 470,000-sq-ft building in the campus medical center, and the Children's Hospital of Los Angeles, which features prefabricated medical headwalls. The company also worked on UCLA's Terasaki Life Sciences Building, handling the engineering for the exterior framing for the brick cladding and the joist ceiling system, interior framing and drywall.