As the property sector expands, older and unfit structures often need to be taken down
A drive around the neighbourhood of Karama in Dubai offers a glimpse of several old buildings erected decades ago, none of them over three storeys high. Now, however, Karama seems to be undergoing a facelift of sorts as older buildings are razed to make way for newer structures, and the community – popular among tenants looking for affordable options – gears up to accommodate growing residential demand.
This is by no means unique to the area. As demand for housing picks up in the UAE and wider GCC, new developments will have to be built not just in uninhabited areas, but also in place of existing buildings that are, in many instances, no longer fit for use.
Enter demolition contractors. These firms play a vital role in taking down buildings that are old and often structurally unsafe or dangerous.
While it’s tempting to think of demolition as just destroying buildings, it’s more complicated than that. Big Project ME decided to speak to companies carrying out this work, to garner some insight into the process and the challenges and risks involved.
Goldline Building Demolition, a subsidiary of the UAE-based Goldline Group, was established in 1999 and has carried out work for clients including Meraas, Juma Al Majid, DEWA and Al-Futtaim Carillion.
So how does the demolition process work? Once an agreement has been reached for a particular project to be taken down, the firm first has to obtain a series of permits from various entities, explains Mirza Munnawar, project manager at Goldline Building Demolition, at the firm’s Karama office.
“First of all, we need to get permission from Dubai Municipality, [for which] we have to process certain NOCs. Once the demolition permit is approved, we have to apply for a fencing NOC. After that, we have to take an entry-and-exit NOC from RTA and start the work.”
NOCs (no-objection certificates) are issued by entities like Etisalat, the Dubai Electricity Water Authority (DEWA) and the Roads and Transport Authority (RTA). This is typically to alert the firm of the locations of underground utilities that need to be accounted for when demolition work is being carried out.
Although most of the company’s clients are contractors or government entities like Dubai Municipality or DEWA, sometimes private landowners also approach the firm when looking to redevelop their land.
After obtaining the permit to demolish, the company may also need to apply for a permit to remove and transport hazardous substances like asbestos. Some demolition contractors, like Al Rasheed Demolitions, often hire specialised firms to carry out asbestos removal if the contract requires them to do so, says Mohammed Yaghoub, manager at the firm. “The demolition we do ourselves, but for the removal of asbestos, sometimes we hire other companies that we have an agreement with.”
In addition to the regular permits from Etisalat, DEWA and the like, contractors also need to approach the municipality for permission to take down old buildings that may have historical aspects, particularly in areas like Deira or Bur Dubai, says Biju John, project manager at PKD Demolition. If the buildings are historical, permission would be denied, he says.
The actual demolition process, as one would expect, entails a significant degree of planning.
“We first secure the site,” Munawar says, explaining that fencing and scaffolding is erected for safety purposes. “Generally we’ll put scaffolding in a crowded area, just to control dust and to control the flying debris. We’ll put scaffolding, we’ll cover it with cloth, and we’ll start demolition.”
In terms of equipment, crawler cranes are often deployed where possible, and are a faster and easier means of carrying out demolition work without the use of explosives. However, space constraints in crowded neighbourhoods may prevent their use, forcing firms to use smaller machines like excavators or undertake manual demolition with jackhammers.
So how has the industry evolved over the years in the UAE? Munawwar and Yaghoub agree that regulation has grown a lot more stringent with regard to the safety of the pedestal and neighbouring structures.
Currently, a significant portion of the projects being taken down in the region are under 12 storeys high. Firms like Goldline have a G+12 permit, allowing them to take down buildings of up to 12 floors.
The above mentioned methods are generally a viable option for projects of this height or for those in densely populated areas. But for the high-rise buildings and towers increasingly becoming the norm, other options may be more feasible.
Maryland-based Controlled Demolition (CDI) has decades of expertise in the use of explosives to carry out demolition work, both in the US and internationally. Explaining how the process works, Mark Loiseaux, president of the firm, says it all starts with a site assessment and examining blueprints, if available, of the structure to be taken down.
After determining whether a project is technically and commercially viable for controlled demolition, the firm works with local contractors to approach regulatory authorities, utility companies and even adjacent property-owners to discuss their concerns.
Once that is done, CDI comes up with an implosion plan, which includes preparation of the structure as well as taking into account how to protect surrounding properties and utilities. The equipment and labour required is procured locally, or as locally as possible for international projects, Loiseaux says.
“My desire is to have minimum Western involvement. What I like to do is find a local contractor in the country where the work is going to take place,” says Loiseaux, whose firm has experience handling projects around the world, including the Middle East. CDI can even partner with civil contractors that may not be in the demolition business but have the necessary heavy equipment required to clear debris after the implosion.
“If a civil contractor has the equipment and they also have a concrete crusher, they can become a demolition contractor with my help. I would only send a maximum of two people. We would simply provide the guidance on how to prepare the building to CDI specifications, and then we would handle the explosions, because that’s a very precise operation.”
Safety is naturally a critical element of the process, Loiseaux firmly asserts. “We’re an engineering company involved in the demolition of structures that happens to use explosives as one of our tools. Our primary tool is gravity.”
The energy used to lift the construction materials in place when building the structure is stored within it, so CDI designs the systematic removal of the supports holding up the structure, in order to let gravity have its way with the building, he explains.
“The key is placing the minimum amount of explosives strategically in support columns and walls throughout the building, to generate the collapse mechanism that we need to properly control the building, causing it to fall in the available area.”
Despite the level of careful planning involved, his firm doesn’t work miracles, he notes. “I’m not a magician. Often there’s no room for the debris, so we can’t take the structure down.”
Moreover, protection also needs to be set up around the explosives to ensure that debris does not fly from detonation. Surrounding buildings then need to be protected from what is known as an air blast.
“When you bring a building down, you compress all of the debris, and the air inside the building rushes down at speeds of up to 80-90mph, so the biggest thing to worry about in protecting adjacent improvements is what we call the air blast. That’s the air rushing out of the building as debris falls to the ground.”
To safeguard structures from the air blast, trucks are often parked in the street to take the brunt of the air rushing out of the building. Other means and methods specific to the structure being taken down and the site can be used. Detonation of the explosives is carried out by hard-wiring them to a command post, to prevent human error causing a premature implosion.
“We make sure everything is safe, and then someone pushes the button. You also don’t set off all those explosives off at once. They are set off over what is called an implosion sequence, where the charges are detonated not only over seconds but over microseconds. You have primary implosion delays that control the fall of the building, and you have micro-delays that are installed in the initiation sequence to reduce noise level.”
The process involves a great deal of technical expertise. However, in regions like the Middle East where labour is relatively cheap, it can be tough for specialist firms to compete, Loiseaux admits. Conventional methods can reach a building of up to 10-12 storeys with cranes, a wrecking ball or high-reach excavators. But for projects built higher, it’s worth contractors considering implosions, he says.
A key advantage is time. Conventional or manual demolition techniques might take weeks or months to complete, subjecting surrounding areas to a prolonged period of noise levels and dust.
“The quantity and type of dust that is generated by conventional demolition is the same quantity and type of dust that is generated by an implosion. It is far preferable to have one event that takes five seconds on a morning, that is going to create least inconvenience to traffic and businesses,” Loiseaux concludes.
“You just bring the building down, you clean up the dust, and the community goes back to normal. There’s a tremendous advantage in reducing the impact of demolition of a major building on the community, where implosion is the right method over all the others.”
Demolition safety: A consultant’s perspective
Demolition is risky business and presents its own unique challenges. Accidents in this type of work are more likely to be fatal than in any other industry, says Steve Carpenter, principal consultant – Health, Safety & Risk Management at WSP | Parsons Brinckerhoff.
During the process, the main causes of accident are premature collapse of buildings and structures and falls from workplaces and access routes, he says. “These invariably stem from a lack of planning, resulting in operatives devising their own methods of work and means of access.”
In order to manage the health and safety aspects of a demolition project, WSP | Parsons Brinckerhoff ensures that some measures are implemented across the board. First, thorough structural surveys and assessments are undertaken before any load-bearing parts of the structure are altered. Next, the competencies of contractors are evaluated via a thorough pre-tender health and safety assessment process.
The firm then oversees the preparation of a demolition execution plan which incorporates the approaches to be adopted during the demolition phase, including risk assessment and a detailed method statement. Assessment and monitoring of the arrangements for demolition include the following: establishing exclusion zones and hard-hat areas, clearly marked and with barriers or hoardings; covered walkways; using high-reach machines; reinforcing machine cabs so that drivers are not injured; and training and supervising site workers.
Meanwhile, for the contractor’s part, regular toolbox talks are carried out on-site, and third-party training is also conducted every year, tackling issues like safety and work standards, Munawar says.
“Demolition actually depends upon the planning and coordination between the foreman and the operator. The machine operator should be well experienced,” he adds, noting that all of Goldline’s operators have over ten years of experience.