01 MARCH 2001

Sensaire Service is one of the leading building engineering services companies in the Middle East with more than 20 years of experience in this specialist market. Typically associated with larger scale construction projects with a broad capability in building services and management and the creation of "intelligent buildings", Sensaire is headquartered in Dubai with offices established throughout the UAE and overseas.

As well as the Al Wasl contract, Sensaire has recently been associated with Dubai Internet City, installing fibre-optic cabling on six floors for a sophisticated building management system, business and first class lounges for Emirates at the new Dubai International Airport terminal, Airport Free Zone offices, Dubai Higher College of Technology for Women and new buildings for Enoc and Emarat, each with variable air volume (VAV) systems to reduce operating loads. A highly prestigious project for Dubai Municipality also is presently under construction, incorporating enhancements designed by Sensaire for energy-efficient variable speed pumping with automatic balancing of dynamic hydronic flow.

Since its establishment in the early 1980s, Sensaire has built a formidable reputation for the quality and execution of its wide range of electrical and mechanical services for the construction sector as well as establishing an ISO 9002-certified sheet metal duct products manufacturing facility.

Today, the company has a workforce of more than 1,500 engaged on a multitude of civil projects, ranging from shopping malls, hospitals, offices, airports and hotels. Certified to ISO 9001, Sensaire provides expert engineering services for the complete installation of electrical and mechanical systems including air-conditioning, ventilation, electrical lighting and power, sanitary and drainage, water distribution, low voltage, stadium floodlighting, and civil defence works for safety such as alarm, detection, sprinklers, dry and wet risers, etc.

All these services are fully supported by an in-house design and engineering team utilising leading edge CAD (computer-aided design) software and networked computer systems.

Al Wasl project

The scope of the project consists of two independent buildings. An office tower comprising basement, ground, mezzanine, 14 floors and lower roof. The office block has a basement, ground, five floors and roof.

Throughout the project, Sensaire's quality management team was involved at all times for the installation, inspection, commissioning and testing of the electrical and mechanical systems.

Electrical: Sensaire installed all the main systems for the two buildings, including mains electrical supply, power distribution, electrical lighting, HVAC (heating, ventilation and air-conditioning) controls and BMS (building management system), fire alarms, public address, CCTV (closed circuit television), and earthing and lightning protection, lighting control, emergency lighting, and telephones. Mains electrical supply of the office block and tower is through eight distribution boards located in the LV room in the basement of the office block. In turn, these MDBs are fed from eight transformers each of 1,500 kVA, with step-downs from 11 kV to 380 V to three phase 50 HZ and feeds to the respective panels. The total connected load of the MDBs exceed 4,000 kW for the office block.

The electrical lighting system provides a permanent lighting system throughout the building and wiring accessories have been installed to provide extensive fire detection coverage in the building. Separate addressable fire alarm systems have been provided to both buildings.

The public address system amplifies the signal from various input devices prior to distributing them via loud-speakers throughout the buildings. A background music system is provided which is based on a high-performance range of pre-mixing and booster amplifiers.

In addition, a CCTV system has been installed to provide visual security surveillance of areas in the buildings.

In the event of a direct strike by lightning, earthing and lightning protection is automatically engaged with emergency light, light control and telephone systems operating. An 800 kVA generator is installed which powers the emergency MDB in the event of power failure.

Air-conditioning: Separate air-conditioning has been provided to each block consisting of eight primary and six secondary chilled water pumps distributing through an immense network of chilled water piping to three "fresh" outdoor air-handing units with heat recovery coils, 16 air-handling units, 249 fan-powered VAVs and 514 fan coil units, thermally insulated ducting and air terminal devices (grilles and diffusers etc.) installed at suitable locations.

According to a spokesman for Sensaire, the latest state-of-the-art building management systems have been utilised for the air-conditioning and ventilation network.

The computer room on the first floor of the office tower is served by a chilled water air-handling unit and, additionally, a DX unit provided for back-up standby.

Life safety systems: The company has installed the latest fire-fighting and protection systems in the office tower and office block, comprising sprinkler and hose reels pumps, breeching inlets, landing valves, sprinkler heads, carbon dioxide and dry powder extinguishers.

The sprinkler heads are connected to a network of hydraulically-designed piping installed in both the buildings as the sprinkler system is interfaced with the fire alarm system through flow switches.

In the event of a fire incident, staircases of the affected building are pressurised by fans located on the roof of the buildings to prevent entry of smoke into these egress routes which thus enhances occupant safety.

Ventilation systems: Exhaust air from toilets and general areas is discharged to the atmosphere through the heat recovery coils located adjacent the extract fans.

The basement and ground floor of the office block comprise car-parking with ventilation provided by two-speed fans operating via a duct network.

Public health installations: Water distribution systems consist of a basement water storage tank, roof water tank, water transfer and booster pumps, water heaters, water hammer arrestors and the water distribution pipe network. The sanitary and drainage system includes discharge of soil and waste water from all fixtures such as water closets, wash basins, urinals, sinks, kitchen outlets points, etc that are finally connected to the external drainage services. PVCu pipes and fittings are used for soil, vent and rainwater pipe systems above ground.

The complete drainage is accumulated in sewage pumps stations and pumped to the final inspection chamber through a break pressure manhole.

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