Looking down from above

WHETHER COMPOSED of flats and apartments, retail and entertainment spaces, offices, or for mixed-usage, today’s multi-story structures and tall buildings have unique challenges that need to be addressed by security professionals. Effective surveillance of tall buildings begins with an understanding of the threat environment and the intended use of the structure, then designing an appropriate security system design. Use of modern surveillance technologies is the key to success in this vertically-deployed environment.

A tall multi-story building is a microcosm of the situations a surveillance system needs to address, compressed into a single but complex structure. Like any village or town, a tall building can include multiple tenants or owners such as in shopping concourses, offices, or flats. It can feature many entrances and exits for vehicles, pedestrians, and public transit, as well as via car parks and street level lobbies. A multi-story building can be completely restricted in entry and access, or be a varied mix of uncontrolled and highly secured areas. And it can require varying degrees of situational awareness throughout the structure, service corridors, and rooftop areas.

Security and surveillance of entry areas of a tall, multi-story building will vary greatly based upon the contents and usage of the structure itself. For an office tower or hotel, the lobby or car park may be the only area where the public is allowed access. In other tall buildings, such as a medical centre or hospital, the environment can be a mix of public and secure areas on multiple floors of the facility.

In urban environments, the structure may have multiple points of access from street level entries to multi-storied carparks or sub-surface tube and rail access. The tallest buildings, regardless of general purpose, often feature rooftop entertainment areas such as restaurants, bars, and observation areas that are provided with their own controlled-access entrances and exits.

Starting at a building lobby or reception area, complete surveillance coverage is typically desired. Rather than employing dozens of cameras that result in high purchase cost, installation complexity, and ongoing support challenges with an overt presence, this is an ideal environment for the use of megapixel cameras. Such devices combine affordability, reliability, and high definition megapixel video that is superior in resolution and coverage to legacy analog camera imagery.

A four-sensor 180^o panoramic megapixel camera can replace multiple fixed view or PTZ (pan/tilt/zoom) cameras for non-stop surveillance of a wide coverage area. An adjustable-view, omnidirectional 4-sensor multi-sensor megapixel camera provides even better customised surveillance of an entire open space. In both cases, multi-sensor technology will reduce the number of cameras required and lessens the overt security presence for visitors, staff, or residents.

Legacy PTZ cameras remain popular with security professionals for specific applications, but the lower cost and reduced maintenance that multi-sensor cameras offer continues to shrink PTZ use in new projects. The uninterrupted situational awareness and total coverage that a multi-sensor brings, even when zoomed into a specific scene by an operator, is also a strong benefit of multi-sensor technology.

Advanced light management technologies such as wide dynamic range (WDR) are often required when designing a surveillance system for a multi-story structure. In a typical high-rise building lobby or multi-level car park, varied lighting conditions are common. Interior spaces may be illuminated by a mix of natural light plus LED, fluorescent, or incandescent lighting. Entrances and exits may be more brightly illuminated by outdoor illumination and backlighting, resulting in challenges to older camera technologies. These devices are often unable to effectively capture usable video when these two lighting extremes are encountered simultaneously. Enter WDR technology to save the day.

With WDR, both interior and exterior spaces can be effectively monitored simultaneously. This results in key features such as people’s faces or vehicle registration plates being effectively captured in varied lighting, even through windows and doorways. This capability reduces the number of cameras needed both inside and outside a structure. IR technology can also be used, integrated into the camera or installed as separate infrared illumination, to improve the imagery that the camera can capture. Advanced colour technology can also be used by the best megapixel cameras to add more useful data to the images captured.

When a tall building is connected to public transit for coaches or rail, access to the building from subterranean, surface, or above ground levels can often be effectively monitored from controlled access choke points. A single megapixel camera with a fixed view may suffice for such areas, or a multi-sensor panoramic or adjustable view omnidirectional devices may be required for entry through multiple entrances, turnstiles, baffle gates, or other access points.

Multiple entrances    

Most tall buildings also have a mix of secondary entrances, ranging from loading docks to employee and service entrances that the customer, office worker, or resident never sees. Depending upon the building, usage will vary as greatly as the surveillance requirement. A single-sensor fixed view megapixel camera may be all that is needed to monitor a solitary indoor or outdoor entrance, or a dual-sensor device may be appropriate for corners and long corridors. Loading bays may require a multi-sensor camera to cover numerous approaches from a single device, rather than adding the expense and complexity of using multiple single-sensor devices.

Security departments often deploy multi-sensor cameras today to monitor street level approaches to their building for both pedestrian and vehicle traffic. This monitoring may be necessary for high security environments to identify potential threats and for crowd monitoring activities for retail or entertainment areas.

In many tall, multi-story structures, retail, entertainment, and dining spaces are often found in a mix of underground, street, or lower levels. Individual shopkeepers may have their own interior space under surveillance, but this is typically independent of the overall building’s security and surveillance systems.

Large pedestrian traffic flows as well as high volume car park or transit access can result in increased security challenges. Key is the monitoring choke points, and any large open areas such as concourses and galleries for situational awareness.

On the floors of a tall building between the entrance levels and the rooftop areas, surveillance will vary greatly depending upon the use of the structure. In any area of flats or condominiums, the residents are unlikely to welcome surveillance cameras in public areas such as hallways. The main lobby, the elevator lobby on each floor, as well as entrances/exits to stairways may be the only exceptions in monitoring above street level, if any is permitted at all. In an office building, however, surveillance may be more visibly present as the organisations involved may wish to monitor more of the activity underway around the clock.

Tourism and related revenue generating activities can also be a factor in tall buildings. Restaurants, outdoor patios, lounges, and bars, plus pool decks, rooftop observation areas, and more complex entertainment areas can often be found at the upper levels of tall buildings. These have the benefit of controlled access for surveillance purposes, yet can present all the same challenges as any other retail or public space for crowd monitoring and surveillance of activity for potentially dangerous, malicious, or illicit behaviour.

Surveillance systems need to be up to the task, and the cameras need to be intelligently deployed to be the most effective in a challenging environment like a tall, multi-story building. Technologies like multi-sensor megapixel cameras overall and in particular multi-sensor models can greatly reduce the complexity by lessening the number of cameras required. Megapixel cameras deploy over the same type IP twisted pair cabling used for other modern network infrastructure. Most can draw all needed power from the same network over which they provide high quality streaming video to the video surveillance management system. Use of this cabling requires less of the limited conduit infrastructure space available in a multi-story building than did the legacy analog camera systems of the past that relied on dedicated coax cabling and often external power. In a compressed environment such as tall building, these are all strong benefits.

Tall, multi-story structures can be complex to properly monitor and surveil. Use of modern megapixel camera technology is necessary to meet the expectations of the security department and property owners. A clear understanding of the surveillance objectives, budgets, and adequate pre-planning to deliver a suitable system design are all key factors for the success of any such project.

Jeff Whitney is vice president of marketing at Arecont Vision Costar. For more information, visit www.arecontvision.com