As cities continue to grow, the way we construct and manage buildings has never been more critical to global economic and social development. Gert Rohrmann, Technical Manager for the solutions team of Siemens Building Technologies UK, looks at the trends in tall buildings and the challenges these environments present.
Increasing urbanisation in recent decades has meant an upturn in the construction of high-rise and tall buildings worldwide, particularly in emerging economies.
The key economic driver for the growth of tall buildings is the lack of space in densely urbanised parts of the world, and this is particularly true for residential developments. The rising population in cities has also meant that mixed-use buildings are gaining greater importance and high-rise construction is no longer restricted to the financial and business sectors. It is becoming an accepted global model for managing the increasing number of city dwellers as more than one million people on our planet move to cities each week.
Branding via buildings
The competition for constructing the tallest building has also created another driver for the growth of tall buildings worldwide – over the past 20 years there has been a move towards creating iconic constructions that become major landmarks within the city. There are over 4 million high-rise buildings across the globe, with a further 3.5 million proposed.
New York-Newark has the highest number of proposed high-rise projects of buildings taller than 150 metres, followed by Toronto, Dubai, Miami, London, Melbourne, and Chicago.
In 2017 there were more buildings constructed that were greater than 200 metres high than in any other previous year, with a total of 144 completions. This represented the fourth consecutive year of increased high-rise construction, almost doubling the 2013 figure of 74 buildings completed. 2017 was also the most geographically diverse year for tall buildings, with completions spanning 69 cities across 23 countries.
China is still the world leader in skyscraper construction, representing 53% of the total, followed by the United States. London has plans for a further 455 towers, with Canary Wharf and the Docklands areas being particular focal points for construction.
10 of the tallest
The ten tallest buildings completed in 2017 were:
1. Ping An Finance Center, Shenzhen, China 599 metres (1,965 ft)
2. Lotte World Tower Seoul, South Korea, 555 metres (1,819 ft)
3. Marina 101, Dubai, United Arab Emirates, 425 metres (1,394 ft)
4. The Address Boulevard, Dubai, United Arab Emirates 370 metres (1,214 ft)
5. Ahmed Abdul Rahim Al Attar Tower, Dubai, United Arab Emirates, 342 metres (1,122 ft)
6. Wilshire Grand Center, Los Angeles, United States 335 metres (1,100 ft)
7. Yuexiu Fortune Center Tower 1, Wuhan, China, 330 metres (1,083 ft)
8. Hon Kwok City Center, Shenzhen, China 329 metres (1,081 ft)
9. Yantai Shimao No. 1 The Harbour, Yantai, China 323 metres (1,060 ft)
10. Zhuhai St. Regis Hotel & Office Tower, Zhuhai, China 322 metres (1,056 ft)
Mini-cities stack up
The key driver for high-rise construction is, of course, to save space and accommodate more occupants, compared to lower density buildings. This approach is much more economical, as buying a smaller plot of land and constructing a tall building is more affordable than purchasing widespread terrain.
With the rise in urbanisation, tall buildings provide a variety of options for housing and offices, allowing a city to grow without expanding its boundaries or infringing green space or farmland.
Tall buildings are increasingly designed as mixed-use structures incorporating housing, offices, fitness and lifestyle amenities, cultural spaces, apartments, hotel rooms, and retail and event spaces.
These ‘mini cities’ can create a sense of community while also promoting the larger community around the building with pedestrian street traffic that benefits local businesses. High-rise construction can also be beneficial to the environment, not only because it takes up less space but because systems like water, heating, cooling and waste are more cost-efficient when they are being managed across a smaller area, with less distance to travel.
However, the sheer scale of these modern facilities, density of occupation and growing user demands also present specific challenges for safety, security and energy management.
Even within the same building, the needs of different locations will vary considerably and priority must be given to ensure appropriate safety and security measures taken are relevant to the threat, rather than a ‘blanket approach’. A full risk assessment should be undertaken to uncover potential vulnerabilities, understand the impact of intrusion, attack or fire, and identify the optimum response.
The increased number of occupants and height above ground means that conventional evacuation procedures are inappropriate for high-rise buildings. Should an incident occur, the simultaneous evacuation strategies adopted for low-rise applications must be replaced with phased evacuation, as limited stair capacity makes the length of time needed for full evacuation impractical. A phased approach involves a small number of floors being evacuated at a time, with priority given to those perceived to be at greatest risk from the specific incident identified and occupants on other floors remaining in place.
In particular, with high-rise buildings fire rescue is often impossible from the outside. This puts additional pressures on the resilience and reliability of internal life safety systems and procedures. The speed of fire detection is crucial as it enables building managers to intervene at the earliest possible opportunity and prevent further escalation. Robust detection is essential to ensure there is no opportunity for a false fire alarm. The effect that false alarms have on a tall building is immense, as lost working hours and the upheaval of evacuating premises adds up to significant financial loss.
Critically, information and data from multiple sources across high-rise facilities needs to be shared to create maximum efficiencies and performance from the investment in building infrastructure and building systems.
Smarter building management
Technology can help with managing the unique challenges posed by tall, multi-purpose buildings.
Centralised command and control platforms manage critical situations and enhance security and safety operations, whilst reducing risks. This is particularly relevant in tall buildings where it is difficult to investigate an incident physically due to the size of the building – this is where technology can help to support the life safety strategy. Building managers are immediately prompted to take the correct action and the software will automatically set in motion a sequence of pre-agreed activities to ensure the right procedures are adhered to, as well as distributing essential information across multiple agencies.
Capitalising on synergies between core sub-systems, such as integration with building management, electronic security, fire safety and power, will provide higher levels of performance from all systems and also create a fully automated approach to task handling and incident management, should there be a critical event. Integration of multiple technologies into a single platform will provide instant situational awareness, improve ‘cause & effect’, distribute information, coordinate responses both internally and also with external services such as the fire service, and manage all of these resources. By combining systems and creating a logical sequence, it is possible to limit potential damage.
The following scenario within a high-rise facility illustrates the benefits of technology integration and how this maximises safety across the building:
• Detectors automatically sense the presence of smoke
• Video surveillance cameras verify and record the situation
• Ventilation systems adjust to prevent smoke from spreading
• Fire protection dampers close
• Positive air pressure is generated in other smoke-free areas to prevent the infiltration of smoke • Appropriate emergency lighting is instigated
• Escape route control is activated and communicates with the access control system to confirm who is on site
• Live messaging using the local PAVA system or mass notification tools alerts occupants for safe, orderly evacuation and wayfinding instructions ensure safe exit
• Senior management teams are immediately made aware of the incident
• The access control system creates a roll call of occupants on site and cameras monitor the external roll call
• All video compiled into an incident record and a full incident report is generated for distribution
Inputs from multiple devices are now synchronised so that building managers can quickly master each situation and to mitigate human error, decision-making is more systematic and a logical workflow is followed. Management are automatically updated about the scope of the issue, quickly identifying key parameters such as people in danger and hazardous materials, and providing an audit trail for every action.
Deep integration enables identification and analysis of unusual behaviour and anomalies to facilitate proactive, rather than reactive, decision-making. By combining a wide variety of building and infrastructure systems, and creating a logical sequence, it is possible to limit the escalation of damage.
An important area of integration is to enhance energy efficiency and subsequent cost savings. Integration with security systems has a major role to play in this process as this provides vital information relating to the occupancy of a building. The installation of presence detection to determine room occupancy, combined with the integration of heating, ventilation, air conditioning and lighting, maximises energy efficiency across all floors. This is further enhanced by the command and control platform’s ability to operate the heating and cooling systems on a demand basis, ensuring that these systems are only in use at the appropriate time, including automatically reducing or dimming lighting in line with the concentration of occupancy, whilst still maintaining suitable levels for an efficient environment.
Onwards and upwards
Siemens estimates that the current trend towards IoT (Internet of Things) connectivity will mean that by the year 2030, there will be 50 billion networked devices. According to further predictions, 65% of users will require access to their data at all times, 60% will expect greater transparency in their business processes, and 52% will view digitalisation as a way to optimise their systems.
Intelligent systems and devices supply a wealth of data -- the potential of which has so far been virtually untapped. It is already possible to analyse and convert this data into transparent information, using big data applications, which can in turn be fed into linked performance indicators, and in real time. Intelligent algorithms and techniques such as AI (Artificial Intelligence) can assess trends and detect patterns in user behaviour or consumption, making informed decisions, predictive strategies and continual optimisation possible. Effectively creating even smarter building.
The building world is changing to an ever-greater degree, and new, innovative technologies, particularly around digitalisation, offer increasingly clearer insights into how workplaces are used. We are poised on the threshold of a future that will revolutionise how we work, control our environment, enhance safety and use energy resources.
Digitalisation will give building owners valuable information on how their buildings are being utilised throughout the day and how usage changes with the seasons whilst at the same time automatically adjusting and adapting to provide an ideal and safe working and living space for occupants and employees.