Evacuation policies and technologies for high-rise residential buildings

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High rise buildings

Ron Alalouff

As part of the FIREX Connect 2021 online event, a panel of experts discussed fire safety issues in high-rise residential buildings, focusing on evacuation strategies and warning systems. evacuation.

FireSafety-Building-20Session moderator Gerry Dunphy, Director of Events for IFSEC and FIREX International, opened the discussion by stating that while the fire safety challenges for tall buildings have existed for many decades, the fire in Grenfell Tower 2017 revealed the complexity of maintaining a building alongside such a building evacuation strategy in an emergency. An event of this magnitude poses many questions regarding building control, public safety, construction methods and emergency response, and the government has responded with sweeping horizontal reviews, guidelines and legislation. .

Such a discussion, he said, encompasses the impact on building control, potential changes in legislation, new codes of practice and approaches to emergency evacuation from a standpoint. technological and operational. It will examine current approaches to evacuating high-rise buildings, the challenges faced by fire safety professionals, technological solutions to address these challenges, and the impacts of potential changes in legislation.

EAS – Evacuation alert systems

Andy Scott, Chairman of BSI’s Committee on Alarm Devices, Voice Alarm Evacuation Subsystems and Emergency Voice Communications and Director of Manufacturer C-Tec, discussed the implications of BS 8629 : 2019, an important standard that introduces a new technological solution for evacuation. warning systems for use by fire and rescue services in apartment buildings.

He said the word “alert” has been used deliberately to differentiate conventional fire alarms because the main difference between the two is that evacuation alert systems do not have a sensing element. They are legally required in new residential buildings over 18m in Scotland, but in the rest of the UK at present the installation of evacuation warning systems is a risk assessment decision , although it has been suggested that they will enter building regulations in due course.

The Grenfell Tower investigation recommended that evacuation warning systems be installed in all new and existing high-rise residential buildings, Andy Scott said. Checks are carried out manually by the fire and rescue services if they believe that a suspension policy is no longer viable. As the operation of the evacuation alert systems is the responsibility of the fire and rescue services, they have contributed immensely, work on the standard having been led by BSI’s FSH / 17 committee, which oversees the standards for the response. fire protection and firefighter equipment.

Richard Clark, senior fire engineer at the National Council of Fire Chiefs, turned to evacuation policies and explained the theory behind the “stay put” policy. “Stay in place” has been part of building design codes since the 1960s. This means that if you have a fire in your apartment you must evacuate, but the compartmentalization must allow other people in that building to stay in their apartment. apartment without being immediately negatively affected by the fire.

Following the Grenfell Tower fire, watch systems – which are like a human version of a fire alarm – have been introduced in some residential buildings. But these, he said, should only be used as a short-term measure, and only for buildings where the coating poses a risk of rapid fire spread.

“Staying in place” is by far the most common approach for people living in high-rise residential buildings, said Russ Timpson, general manager of the Tall Buildings Fire Safety Network. But there are differences in the world. In Germany, for example, the decision to evacuate or not is left to the occupants of the building.

Changes in evacuation strategies

When designing a building, said Russ Timpson, evacuation policy is taken into account when designing and specifying aspects such as stairs. So, if evacuation strategies end up changing, some aspects of a building may not be suitable for that change and which were designed for a small number of departures at any one time. If a lot of people have to leave suddenly, then there are question marks. In this country, we build a lot of large residential buildings with one staircase, he said, but that would not be allowed in some other countries.

Russ Timpson went on to say that there is a certain gap between the expectations of residents and the reality of actual fire safety in buildings. Other high-rise buildings operate a gradual evacuation where you evacuate only two or three floors in the event of a fire. Simultaneous evacuation can also affect the assumptions that have been made for stairs protected by pressurization systems, as these are built on the principle that only a limited number of doors opening onto the stairs are opened during evacuation. .

In addition, when keeping in place turns into a simultaneous evacuation, there is a risk of congestion on the stairs and of misreading with the firefighters trying to climb them. We know there is going to be a need to change the escape strategies, he said, so we need to implement this change process and BS 8629 is an integral part of that process. But these evacuation systems must be implemented and installed as part of a change process involving all stakeholders.

Compared to other high rise fires around the world, he said, we have to ask ourselves why the Grenfell Tower result was so different from these.

Consideration should be given to changing evacuation strategies when:

  • A fire risk assessment may reveal inherent design or construction failures
  • There is a major change in the structure of the building, the geometry or the profile of the occupants
  • A fire occurs that does not comply with the design fires upon which the fire strategy was based (many of our codes and standards are based on a 5 MW fire and fires that occur in a compartment – if a fire does not start in a compartment the codes do not necessarily correspond).

“There have been countless examples of fires that did not stay in the original compartment or floor,” Russ added. We also need to take human behavior into account, he said, especially with social media. “As fire engineers, we sometimes have to put ourselves in the shoes of the locals and not necessarily see this as a sterile engineering activity.”

After Grenfell, he said, it is predictable that you may need to change your escape strategy during a fire. This adaptability should be taken into account and facilities such as BS 8629 should be provided to enable it. It’s a major change and it’s predictable, and we should factor that into risk assessments.

Adapted to the objective and competence

On how to ensure that installed systems are fit for purpose, Andy Scott said BS 8629 is a code of practice that gives recommendations and nothing is mandatory in it. It is therefore recommended to use a competent installation and maintenance company, and BAFE provides a method for measuring competence. “If you are in charge of fire safety and you used a local guy who could do it for less, then hopefully you will reap the consequences if something were to go wrong,” he said.

“What I don’t understand is why we’re going from no draining to emptying the whole building all at once. Evacuation alert systems don’t do this – they do it floor by floor. Automatic alarm systems don’t need to do this either. This is called a gradual evacuation, but it does not seem to be the order of the day. There may be cases where it is not appropriate, but I do not understand why it is not discussed.

Russ Timpson added, “We need to recognize human behavior in this area. Despite phasing systems and phased evacuation signals – despite all the technology and intentions of the designers and firefighters – you may well end up with a simultaneous evacuation due to human behavior.

Regarding the behavior of people, one of the new requirements of the Building Safety Bill is to have a tenant engagement strategy. But if you are going to live in a high-rise residential building, you will need to accept some collective responsibility for your behavior, such as not barbecuing on a balcony or having a tendency to hoard.

Richard Clark concluded that the new building security regime will place additional requirements on these buildings, such as the security record and the establishment of building security managers who should oversee security in these buildings. For example, if a contractor comes to install a satellite dish, there will be proper routes to oversee this kind of work, be aware of it and make sure it is going well, and residents will have a point of contact to communicate. of their problems resulting in the overall liability of the building.

To watch the full High Rise Evacuation webinar, click here or simply watch below.

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