Flower power

As Dubai aims to become the world's distribution hub for flowers, Christopher Sell visits the Dubai Flower Centre to find out what it takes to bring them fresh.

Those thinking a visit to the new Dubai Flower Centre is akin to a stroll down to London’s New Covent Garden Flower Market could be in for a slight shock.

While one offers a plethora of horticultural species from around the world, be it your Gladioli, Orchid or Viburnum, the other appears somewhat more stark, with cavernous warehouses storing cargo in a state of transition, awaiting the next move on its global journey.

Yet the name, Dubai Flower Centre is a slight misnomer, as it operates across a broad spectrum of products from flowers and plants from Holland, to fresh and frozen meat from Ethiopia.

The Dubai Flower Centre has been designed as a trans-shipment hub, with daily connections to and from almost any global destination, and with processes designed to ensure the most rapid transit times possible.

And it has undoubtedly been doing a very good job during the first month of operations, in July this year, Dubai Flower Centre handled approximately 5000 tonnes of flowers, fruits and vegetables that had been transported between different regions.

Once the facility if fully operational, this figure could increase to 180,000 annually.

As Sydney D’Souza, project manager at Thermo – the MEP contractor for the project explained, the key to successful perishables logistics is an unbroken, high-quality cool chain.

To that end, the Dubai Flower Centre contains one of the world’s most advanced cool chains, in any weather.

To deliver this, a number of technologies are used in this project.

Key to the building is its ability to moderate and sustain varying temperatures compliant with the numerous functions each area supports.

“The temperature is important as the flowers need to be kept between two and six degrees, it is not like any other job where you can treat each room the same,” said D’Souza.

“Here, each zone is different and you have to make sure you seal it right.”

For storage, D’Souza explained, segregated storage chambers, each with varying temperature ranges, ensure that individual products are catered for.

The zones are supplemented with rapid cooling and hermetically-sealed bays for ethylene producing products, while eight loading docks for full-sized refrigerated trucks allow non-interrupted access to the local market of destinations throughout the Middle East.

To achieve this, 156 air cooler units have been installed to ensure the temperature range remains within 2-6ºC.

A total of 28 air handling units (ahus) serve the storage racks at different temperature zones that range from 2-18ºC, with a humidity range of 35% to 95%.

D’Souza stressed that while storing flowers, it is not only temperature that is important, but also the humidity of the storage facility. Due to changes in atmospheric conditions humidity inside the Flower Centre changes.

A humidification system is used to maintain humidity levels of 85%, 75% and 65% at three locations to meet specific product requirements.

Humidity sensors linked to a humidification spray control panel determine the level of air water mixture that must be sprayed through the nozzles until the desired humidity levels are achieved.

The water air mixture is sprayed at 2.5bar pressure.

A total of 137 nozzles are provided to achieve this range in different humidity controlled zones in storage racks.

Furthermore, five dedicated intelligent humidity control panels are provided for each zone, with the compressed air and water being supplied by two compressors and one reverse osmosis plant respectively.

These air handling unit systems are equipped with ethylene filters and are monitored by a central building management system (bms).

The low temperature ahus and air cooler are served by glycol water at –3ºC through six sets of pumps.

The chilled and glycol water is supplied from the central plant area (CUC-4) that is designed to provide a maximum cooling load of 1300TR for glycol systems and 800TR for the chilled water system.

Ensuring the produce is brought down to the relevant temperature is achieved through a blast cooler, which cools down any inventory from the ambient temperature to storage temperature within 30 minutes.

Power for the Dubai Flower Centre is fed from CUC-4, with the substation comprising six 2000kVA transformers.

Additionally, there are six ringmain units in the substation, which are monitored and controlled by the bms via a SCADA system.

The low voltage (lv) system of the project consists of six lv panels that receive mains power from the six transformers of a rating 11/6.6/0.4kV and 2000/2600kVA in 100% redundancy principle.

Bus couplers are used to couple two lv panels together to transfer power from one to another in the event of a power failure.

There are eight motor control centres (mccs), which are fed from lv panels installed in different locations within the Dubai Flower Centre.

These supply power for the hvac equipment such as ahus, chilled water pumps, glycol pumps, defrost heaters, humidification systems, staircase pressurisation fans and sump pumps.

Somewhat astutely, given the proximity of the flower centre to the airport, the building has been fitted with 12 aircraft warning lights, while 994 smoke/heat detectors, 88 pull stations and 78 sounders providers in various locations offer further safety features.

The entire building is also protected by a sprinkler system as per NFPA 13.

Moreover, the storage racks and lv room are protected by a preaction system, with the substation protected by a deluge system.

The cold storage facility, (measuring 32,000m2) presented the biggest challenge during construction for numerous reasons said D’Souza.

Not only do the lower temperatures require more durable, toughened materials, but they also yielded very little in terms of structural assistance, thereby forcing the contractors to look elsewhere to attach the various cables, pipework and so forth.

“You have to be very careful in the cold areas when it comes to installation.

You cannot just install pipes and so on, the materials must be an epoxy or stainless steel.

With the electrics and wiring you have to be careful.

Everything is cladded, it isn’t like a normal job we had to have galvanised materials for the finish to electrical systems,” explains D’Souza.

“The big challenge was the insulating wall to keep the temperatures down to 6ºC.

Because we have these panels, anything we wanted to fix to the wall we couldn’t fix directly onto the panels because they could not support the weight.

That was the hardest thing about it.”

Complications aside, the Dubai Flower Centre has put together a process system that could in the future rival more established perishable distribution hubs such as Holland.

The cool chain process as outlined by D’Souza involves the rapid handling of perishable goods with automated handling equipment, such as refrigerated dollies, which can carry entire airline pallets, ensuring the products are protected and avoiding exposure to weather anomalies.

“To segregate all the different temperature levels is difficult,” conceded D’Souza.

“It is not easy to ensure each room is airtight and remains secure from room to room air doesn’t care where it goes, it will just move around.”

Recent figures published by the International Air Transport Association (IATA) state that the Middle East led an increase of 5.7% in global air cargo traffic.

And the Dubai Flower Centre, with its location near the airport and unique process facility is well placed to secure its position as the perishable hub of the Middle East.

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