Author Archives: Barrie Harmsworth

Smoke Ventilation vs. General Ventilation

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The Hurricane® Plus is a roof mounted static cylindrical ventilator ideal for large scale general ventilation and fully compliant with the latest sustainable energy codes.

If you want to buy the Hurricane® Plus or just find out more about is spec, visit: www.greenenergysolutions.ae/products/hurricane-plus-natural-ventilator/

Smoke Ventilation

With the new editions of Uniform Fire and Life Safety Codes throughout the AGCC the difference between smoke ventilation and natural ventilation needs to be clarified. In the Code, only relatively small compartments can have natural ventilation as the smoke ventilation method. Above these sizes the smoke ventilation requires electrical driven force draft fans that are approved by Civil Defense. Larger compartment sizes require fully engineered smoke ventilation systems.

Smoke purging for single storey industrial buildings usually involves a roof mounted extract fan that is rated for high temperature operations and often the manufacturers offer a dual speed fan and claim they can used for general ventilation purposes. Other systems for multi storey buildings are much more complex and involve ducting and special fan controls.

The requirements for smoke ventilation are determined by the various codes and are calculated using mathematical algorithms that are based on the different types of incidents that could occur. Primarily smoke ventilation is designed to remove as much smoke and heat that is possible during a fire incident. Other factors may impinge on this requirement such as sprinklers and local codes.

Whatever the requirements, as these are for life and fire safety, the fans must be fully operational at all times and be maintained to operate at their designed capacity. Often the fans are supplied through a dedicated poser supply since in a typical industrial building the normal poser supply will be cut automatically through the circuit breaker to prevent electrocution of the fire firefighters.

General Ventilation

All industrial buildings in this region (the Arabian Gulf) require ventilation for their day to day operations. In this environment, the extract system must be capable of withstanding high temperatures, humidity, very fine abrasive dust, pollutants such as oil mists and from time to time VOC’s and mildly corrosive atmospheres. Experience has clearly demonstrated that unless specialized fans fitted with HEPA filters are used, electrically driven forced draft fans are expensive to use and require considerable maintenance to perform to their full capacity.

Ventilation rates for general purpose ventilation are often determined by experience as the flow is subject to the law of diminishing returns. In other words there is a limit the amount of internal comfort that can be achieved and that is determined by the temperature of the outside air that is being supplied to provide the ventilation.

The preferably ventilation system for this type of application is natural ventilation using roof mount ventilators. There are many types of these ventilators that include ridge, rotating (wind driven) and now cylindrical static (Hurricane® Plus). The advantages of using this system is its low running and maintenance costs.

Can Dual Speed fans be used for General Ventilation?

Probably not. Despite the recommendations from the suppliers of these fans, smoke ventilation extract fans are a dedicated life and fire safety apparatus. Use of these fans for general purpose ventilation is costly in both electrical consumption and maintenance particularly as the maintenance must be carried out by approved fire and life safety maintenances companies.

Failure of these fans due to incorrect use in a fire incident could jeopardize life and any insurance cover.

Sustainable Energy Codes

Obviously the use of any electrically driven forced draft fan when natural ventilation can be used effectively is not in accordance with any sustainable energy policy or codes. Community Social Responsibility (CSR) requires the use of sustainable energy devices whenever possible.

Advertisement

The Hurricane® Plus is a roof mounted static cylindrical ventilator ideal for large scale general ventilation and fully compliant with the latest sustainable energy codes.

If you want to buy the Hurricane® Plus or just find out more about is spec, visit: www.greenenergysolutions.ae/products/hurricane-plus-natural-ventilator/

Dubai Muscat Race

When it rose in the East, the Sun dawned with a golden glow over a steel gray sea. It was my 71st birthday. Above flew the white spinnaker contrasting against the pale purple sky still dotted with waning twinkling stars and the odd planet. We were doing just over nine knots on the second day of the Muscat Khasab race, the return event of the Dubai Muscat race.

A little shorthanded on crew, I was still at the helm after three hours and steering by the spinnaker. Not as fast but it allowed my inexperienced crew to doze on watch. The other two from the earlier watch were down below one of them snoring for Germany, his home country.

Our boat, a 44 ft sloop, weighing eight tons and locally built, was ultimately headed for Dubai. This was my 18th or 19th Dubai Muscat race, so many of them that in my dotage I am starting to lose count. I have been on nearly all since the race started in 1991 and although this was the 22nd year, two races had not been completed, one of which was cancelled by the Omani authorities on a political whim only 48 hours before the start.

Back in 1988, I had conceived the idea of this race along with Andy Gibbons of the majestic Bustan Hotel in Oman. We had in mind that the race would go from the Jebel Ali Hotel slightly South of Dubai to the Bustan. Redha Attallah, the manager of the Jebel Ali Hotel Marina at the time was fully supportive and the small fleet of keel boats at Dubai Offshore Sailing Club seemed keen.

Andy and I quickly found out, particularly in those days, that trying to get agreement to sail between two countries both of whom had had a spattering war going between not long before and still had mixed relationships to say the least, was not an easy task. Andy approached the Royal Navy of Oman and their initial reaction was lukewarm as the boats would have to sail through the sensitive Straits of Hormutz, the narrow passage of water between Iran and Oman. The Straits are a magnificent natural wonder with sheer cliffs and swirling tidal currents and the Navy had strong reservations about small yachts sailing through them, particularly at night with little or no navigation aids.

Eventually, after much negotiation, Arab style, over a lot of coffee and tea, agreement was reached but then Saddam invaded Kuwait. This caused a delay but finally it was planned to start in March 1991. By this time Jebel Ali Hotel had got cold feet so I decided to start it at Dubai Offshore Sailing Club. They too were not happy with the risk and made me take it all, in writing. Fortunately I had the support of Saeed Hareb of the newly formed Dubai International Marine Club and Ali Bin Shafar head of Dubai Coastguards.

What excitement when we sailed off from Dubai after the start. On my small 8 metre yacht we felt like Christopher Columbus. We were heading for the great unknown. Few of us had ever sailed so far on an ocean trip and certainly not to Muscat.

On approaching the Straits late in the afternoon, storm clouds gathered over the mountain tops. When the Sun set these clouds were shot with bolts of lightning. The wind and the sea picked up and in our small boat we became very anxious and wished that we had played golf instead. Midnight came and the wind peaked, whistling loudly through the rigging and the reefed main flogged noisily. Suddenly there was an unbelievable cloudburst and our cockpit filled with rain that flattened the sea.

Drenched and cold we stood ankle deep in rainwater and with the wind reduced to a whisper we drifted towards the Straits. The tide took us in the direction of the mystical Lion’s Mouth, a narrow gap between the Island of the Musandam and the mainland. Our hopes were raised as the clouds had disappeared and the night was clear and the sky filled with stars that shone bright.

But our luck did not hold. The tide changed and drove us into a small bay in the lee of the island. We tried to haul ourselves by hand around the island but the tide was too strong. Stuck in the lee of the island we peered down into the deep purple colored water and watched the mayhem below as fish hunted fish illuminated by streaks of phosphorescence.

Just before dawn we had all started to doze off when we were rudely awakened by a loud slapping noise. The tide had changed and small waves were lapping at the rocky overhangs. Around us the water swirled and the tide carried us unceremoniously out of the other end of the island. We were spat out into the Indian Ocean along with all the other flotsam including a half submerged wooden pallet and a dead goat. We were on our way to Muscat.

After that I was hooked. Such an adventure, I had to do it again, and again and now next year will be my twentieth race. No matter how you approach the Straits, they are always threatening if not a little scary but always different. Careful or you might be the recipient of 20 years fucking retribution as I have been.

It could be the dead of night, moonless, the only the eerie flash every ten seconds of the Telegraph Island light with a jet black sea, as smooth as a mirror, that seamlessly merged with the dark sky. Around a rocky crag a village lights up as if it were on fire then disappears as quickly as it came. Or strong winds against the tide, standing waves as high as the gunwale, a reefed main and a blur of spray.

Sailors on the Dubai Muscat race have witnessed whales blowing, sharks, dolphins, turtles, smugglers, pirates, the US Navy aircraft carriers and on one occasion an abandoned half submerged fishing boat. The Indian Ocean off the coast of the UAE and Oman teems with plankton that draws a huge variety of fish. Similarly, the wealth of Dubai draws illegal migrants like a massive magnet, many of them chancing the hazardous trip on small boats operated by people smugglers across dangerous shipping lanes full of giant oil tankers and container vessels. Some don’t make it. Some are captured by the Oman Navy. Some drown after being thrown overboard by the smugglers to avoid capture by the navy. Some do make it. And a very few send back a small fortune to their families in India, enough to lure more on this perilous trip.

Satisfied with the stringent safety requirements and the professional race managers appointed by the Organizers, the Royal Ocean Racing Club has recognized the Dubai Muscat race as one of their qualifiers. Local sailors can benefit from this to gain the sea miles they need to join the RORC, as I have done, filling a long held wish.

If, by chance, you have the luck of passing through Dubai in the month of November and you are an experienced sailor, boats are always looking for crew. You could do a lot worse than spending a couple of weeks on the Dubai Muscat Race.