Meeting the Challenges

City scapes outlined by super high rise buildings are a common sight throughout the Middle East. These buildings allow for diverse facilities with an endless combination of visitors, residents and staff within the building at any one time some of whom may be physically impaired and find it difficult to exit in a hurry. Alison Cousin’s discusses how technology is overcoming the challenges.

THE SHARD IN the UK, the Burj Khalifa and the planned Nakheel Tower in Dubai are the latest of an ever increasing world of the high rise buildings. Modern technology and learning provides architects with the means to build higher and higher. Such buildings are certainly impressive to see and provide us with a sense of awe and "How is that possible?" type questions.

The scale of these buildings is staggering and their immense amount of floor space allows for great diversity in the type of facilities within – such as residential, commercial, retail or leisure. More often than not they are multi-functional combining, say, shops, bars and restaurants in the lower levels, with offices and accommodation in the upper floors.

With the wide range of facilities there will be a combination of visitors, permanent residents and staff within the building at any one time. Therefore, some will be more familiar with the layout of a building than others. Human nature, being what it is, dictates that we are creatures of habit. This includes our route in and out of a building – we will generally exit the same way we entered – regardless of the fact that it may be the longest route.

Alternative routes

People are busy and are unlikely to look for alternative routes through a building just in case there should there be an emergency, such as a fire.

With the sheer numbers and the mix of people – combined with the fact that few will be aware of best exit routes – it is clear that there is potentially a great risk to life for many during a fire. Standard alarm bells and klaxons do inform of a problem, however, without any instruction or details, people are reluctant to act.

The introduction of the voice alarm system has, regrettably, been due to loss of life during disasters. In particular, in 1987 there was a fatal fire on the underground rail system in London at King’s Cross St Pancras which killed 31 people and in 1989 ‘The Hillsborough Football Disaster’ (England) where 96 people were fatally crushed.

The principal reason for voice alarm is safety - providing people with voiced instruction during the event of an emergency. With the ability to automatically broadcast pre-recorded clear messages and prioritised emergency microphones – people can be informed of a danger and the action they must take. This makes it possible to direct people away from danger and give verbal instructions such as which lifts are operational or which stairwell to use.

Ideally the system is ‘zonal’, thereby capable of broadcasting messages of ‘warning’ to some areas whilst instructing those in immediate danger to ‘evacuate’. The zonal nature of the system is of particular importance with regard to the high rise building.

Under most circumstances, it would be impractical – even dangerous – to attempt to evacuate everyone from a high rise building. With the best will in the world, lifts and stairwells are unlikely to cope with the sheer volume of people – let alone the fact that some may be panicking and acting irrationally. In addition to this, it is often the case that at least some of the lifts will be unavailable – they are programmed to travel directly to ground level upon activation of an alarm system – special fire evacuation lifts are used instead.

Phased evacuation

Automatically activated by the fire alarm system, the voice alarm system responds immediately. A person pressing the ‘fire’ button will indicate the location of the danger and the system will react accordingly. Typically it will be programmed to broadcast a message to evacuate the floors that are in immediate danger (often the one with the fire, the one below and two above; the roof and basement areas are sometimes included) whilst, at the same time, alerting others. When these levels are cleared (or before if necessary) and others are at risk, then further levels are evacuated. This is referred to as ‘phased evacuation’.

The messages (sometimes in more than one language) provide clear, easily understood instruction – ensuring there can be no doubt of the need to take action. At any time, the broadcast of the messages can be overridden by ‘prioritised’ emergency microphones connected to the system. Occupants of the building, using a voice alarm system, can be led to safety effectively and efficiently.

Another factor to be considered is the need of those that are less able to ‘self-evacuate’. People that are physically impaired, not only wheelchair users, but the elderly, those with loss of sight, expectant mothers and so on, could find it difficult to exit in a hurry without assistance. It is also possible that with their slower progress, they will become overwhelmed/knocked over by others – endangering themselves and others.

Refuge areas

The solution has been provided by the introduction of ‘refuge areas’ and ‘emergency voice communication (EVC)’ systems. A ‘refuge area’ is a place near an evacuation lift or somewhere that provides an exit route from a building. The area should be designed in such a way that it is fire resistant and of a size which is suitable to turn a wheelchair – without impeding the path of any other occupants of the building. In the UK the British Standard (BS9999) defines the need and specification for a refuge area.

With an EVC system, each refuge area is fitted with an ‘outstation’ which provides a means of ‘hands free’ communication with building control. Upon arrival to the refuge area the occupant, or assistant, operates the button on the outstation to indicate that the area is ‘occupied’ and calls the operator of the control panel. This provides the ability to reassure the occupant and keep them fully informed. This is a ‘disabled refuge system’.

The concept of disabled refuge areas and emergency voice communication systems was introduced when BS5588-8 was published in 1999, followed by BS5839-9 in 2003. A good EVC system is not limited to the one use, it has added functionality – such as the addition of fire telephones, emergency/steward telephones and disabled toilet alarms.

The fire telephones are an additional aid during the evacuation of a building. They tend to be used by fire officers as a means of communication between the operator of the control panel and different levels in the building. Fire officers will work through the building and typically use the system to report back on a level-by-level basis that an area is clear.

Chris Hartup (Sales Manager for Baldwin Boxall Communications Ltd) on the subject of voice alarm and current trends, commented "The Graphical User Interface is becoming a must on most new builds, particularly where automatic phased evacuation is implemented. This has an added advantage of providing users with detailed activity and fault log information which is time and date stamped, for a comprehensive user audit trial.

"Also, there is a growing demand for systems which are decentralised (i.e. more than one independent system, linked together) on a digital network. Using the digital network facility provides simultaneous audio channels resulting in the need to run less cabling.

"Another trend is towards the integration of a building’s voice alarm with other systems on site (such as security and CCTV). This is achieved with outputs from voice alarm to the ‘building management system (BMS)’."

Baldwin Boxall Communications Ltd is a UK based manufacturer of quality voice alarm and emergency voice communication systems and has experienced the changes in the industry first hand. Baldwin Boxall has been designing and manufacturing public address announcement systems for 28 years.