Catering for change
Behind every neatly packaged tray of food served on an aeroplane is a carefully co-oriented operation involving cleaning, cooking and transportation. Alison Luke investigates the MEP services making the process possible at the new Emirates Flight Catering facility in Dubai.
The increase in flights through Dubai International Airport has also raised the demands on supporting services. Inflight catering is one such area, with larger passenger figures meaning greater numbers of meals being needed on a daily basis. To cope with these changes Emirates Flight Catering (EFC) has increased its capabilities by investing in a US $120 million (AED441 million) purpose-built catering facility alongside its existing Dubai premises.
In July the new Emirates Flight Catering Facility became fully operational, providing dedicated catering for Emirates Airlines flights, with a capacity of 115,000 meals per day. An existing, adjacent facility will continue to provide meals to other airlines served by EFC.
With demands on airline schedules to be maintained, it is essential that every part of the operation runs as required 24 hours a day. A delay in the supply of in-flight meals could mean the late take-off of a plane and have a knock-on effect to entire schedules. The MEP services system is integral to ensuring the success of this operation. "We call them the heart of the building because they are giving services to [all operations]," comments Raad Hulow, EFC senior engineering manager.
Trans Gulf Electro-Mechanical was nominated to install the MEP services by the client, having successfully completed several previous projects for EFC, including the adjacent facility. "Normally we nominate our subcontractors because we have found that they are specialists...usually in this environment we are not just looking to the costs, but to the criteria," explains Hulow. "We don't consider [Trans Gulf] as a contractor; we are [working as] partners here. They know our work profile...it is hard to bring a firm in and educate them in the [specific] needs of catering; [Trans Gulf] is available and know exactly the meaning of catering, how it works and the requirements of the systems," he adds.
The building includes one of the most advanced automation systems in the world for such a facility; this has been fully integrated into a centralised building management system (bms). "Manual handling will affect the working profile: you cannot control the time, you cannot control the quality of delivery, plus the hygiene requirements - you can cover all these points by using an automated system," explains Hulow. "We have reduced the manual handling by 90% [using this system]."
Trans Gulf started on site in April 2005, with initial work involving the approval of equipment. "Our total responsibilities on this project are greater compared to other projects as it was a design and build contract. We had to design everything [involved in the MEP services system] as well as co-ordinate with other services," explained Trans Gulf Electro-Mechanical project manager Gopi Krishnan.
There are two main plantrooms serving the building. The roof level plant area comprises largely of air handling plant. The main boilers and electrical rooms are located at basement level. As uninterrupted 24/7 operations are vital, redundancy has been included in the major systems and two 100kVA uninterruptible power supply systems back up the essential services such as the bms, control panels and production area computers. The sheer volume of electrical supply required in the facility is evident from the 17 transformers each of 1,500kVA capacity that serve the systems.
Rooftop cooling towers provide cold water to five 810TR chillers, which operate with one on standby. Five 2,500A busbars individually supply each of the chillers with power from the ground floor electrical room via secondary distribution boards and each chiller is served individually by a cooling tower. In the event of any problem or maintenance work, the bms will automatically divert the supply of cold water from another cooling tower.
"We can always turn off one cooling tower, chiller or pump to allow maintenance," explains Krishnan. "During peak hours we are expecting four of the chillers to be operating; if there was a problem with one cooling tower the system would automatically transfer to the next tower and the chiller will operate as normal."
The chillers cool the water to 5.5Ãƒâ€šÃ‚Â°C for distribution to 59 air handling units (ahu) located throughout the building. In case of fire the ahu are automatically switched off and an exhaust fan removes any smoke from the building. "We are using the system's exhaust ductwork to vent any smoke at roof level," explains Krishnan. All stairwells are pressurised to ensure safe evacuation is possible.
Two oil-fired boilers generate 6,000kg of steam for cleaning and hot water as well as production equipment. Again a backup is provided, in this case by a diesel-fired boiler which will serve essential equipment such as firefighting pumps and cctv systems.
The variety of processes being carried out in the facility means that adjacent areas may need quite different environmental conditions. "You'll find in the same room different lumen levels in different areas [as these are set] depending on the activity being carried out directly underneath, whether people are working there or it's simply for trolley movement," explains Krishnan.
The temperatures also vary according to the task being carried out and these are closely controlled by the bms. "There is no standard air conditioning temperature throughout," stresses Krishnan. "In the kitchens the temperature requirement is 18Ãƒâ€šÃ‚Â°C, whereas for comfort some other areas are 22Ãƒâ€šÃ‚Â°C." A further demand on the air conditioning system is the need to control air quality and hygiene levels within the food preparation and kitchen areas and to control any smells. "We must always keep a negative variation in the kitchen areas," states Krishnan. "You will not find a food smell in the corridors, even directly outside the kitchens." Within the food preparation areas a further series of air conditioning units directly above the table tops chills the work surface to the required temperature.
With the facility complete and the MEP systems serving the adjacent building also, the thousands of passengers due to travel through Dubai this summer can be assured that their inflight meal will arrive exactly when expected.
On track automation
A sophisticated automation system minimises manual handling of the aircraft food trolleys, crockery and food. Central to this is a monorail conveyor system of almost 2.5km in length. The trolleys are collected on arrival from the flight and transferred automatically through the various stages of emptying, cleaning and refilling via the system.
A continuous busbar system running the length of the monorail provides power and communications to the motorised units that carry the carts. Sensors within the tracks enable full control of the trolley movements via the building management system. The system was installed by a specialist contractor, with Trans Gulf providing power supplies and links to the building management system.
Preparing the scene
The scale and complexity of the MEP installation at the Emirates Catering Facility made co-ordination one of the most challenging parts of the project. "We were working on co-ordination drawings for three to four months [before beginning installations]," reports Krishnan.
As Trans Gulf was responsible for primary MEP services it provided utilities such as power and water to subcontractors installing the specialist equipment, which further increased the co-ordination work needed.
At peak, Trans Gulf had over 1,000 operatives working on site. These were divided by trades, with different teams dedicated to individual areas of the building. "We had six or eight groups operating separately under [dedicated] co-ordinators. Apart from our work we had to co-ordinate with the other nominated contractors as directed by the client; those [were not all] local contractors...as the major kitchen equipment comes from Germany," adds Krishnan.
Many of the products used in the MEP installation are specific to the catering industry; combined with other environmental factors, product procurement meant careful pre-planning. Hanging electrical points in the food preparation areas for example are standard in the catering industry, but are not regularly used on other projects. Much of the equipment had to be imported from the USA and Europe which meant long lead times.
At roof level, the electrical panel had to be specially fabricated to withstand the external conditions, while ductwork required special coatings to be applied offsite after fabrication - a process that meant around three months for sections of ductwork to be completed and installed. In addition, all electrical cabling meets the new cable core colour standards recently introduced in Hong Kong and already established in Europe. Specially requested from Sharjah-based National Cables, the lead time was again around three months.
The volume of MEP services to be installed in the building made co-ordination complex. This challenge was increased by the structure: there are no false ceilings in large sections, so all services had to be directly attached to the structural steelwork. In addition, the support systems for some ground floor services had to be attached to the first floor slab and fed directly through the steel mesh mezzanine floor.
"It was very difficult to hang everything from the structure," stresses Krishnan,"we had to ensure the load was correctly distributed." Trans Gulf designed and manufactured special supports for the system and installed these in consultation with the structural engineers after finalising the MEP systems design to establish the total weight of the equipment.
This design process took around two months to complete. In order to maintain the tight programme set for the project, the installation of services was ongoing simultaneously. "We produced a temporary support from the ground and installed our pipework on this and later put it onto the load on the structure," explains Krishnan.
With most services to be installed at high level, this was completed by fully scaffolding some areas during the process, plus the use of mobile scaffolding. The services were installed according to their final level in the design, with those at the highest levels being finalised first, working down progressively to the lowest hanging services.