04 May Fire Strategies for Scientific Buildings
Alexander Emery, Associate, BuroHappold Engineering explains that before undertaking a fire strategy for a scientific building, or simply diving into following prescriptive design codes, the fire engineer needs to engage proactively with the end users and client team to appropriately respond to their needs.
At no point in recent history have the endeavours of the scientific community to overcome the global pandemic been so vital to everyday life. Scientific buildings are full of valuable assets, ranging from physical items such as MRI equipment and CT scanners, to biological assets such as test organisms, vaccine samples and live experiments. Then there are the knowledge based assets of human researchers and their data sets.
While life safety remains the priority for any fire and life safety engineer around the world, scientific buildings present an equal challenge to offer the highest levels of property protection and business continuity. As fire engineers on such projects, there are a series of key aspects that need to be considered and addressed.
Every building is ultimately designed for an end-user. Whether it is to maximise the views within a residential apartment, provide a focal spot within a shopping mall, or to guide visitors around a museum, designing for the end user is crucial to project success.
Before undertaking a fire strategy for a scientific building, or simply diving into following prescriptive design codes, the fire engineer needs to engage proactively with the end users and client team to truly interrogate their needs. This will not simply be a case of understanding where staff refreshment areas need to be, but is far more comprehensive.
The fire engineer needs to understand the need for rooms to be protected against contaminants (often based upon Biosafety Levels 1-4), what access can and cannot be given, what personal protective equipment (PPE) must be worn in certain areas, what chemicals and equipment will be used, and what level of flexibility the building needs to incorporate to accommodate changing research and working methods.
This may seem obvious, or it may seem over the top, but these fundamental questions will dictate how an effective fire strategy can be developed.
Nothing in, nothing out
Some of the worlds most crucial experiments must be carried out under strict laboratory conditions. This often means that temperatures, humidity and pathogens must be strictly controlled to not skew or mislead experiments. Often laboratories are accessed by way of airlocks and pressure differentials, which serve to create a buffer between the outside air conditions, and the inside air conditions.
Airlocks will have only one door open at a time, to prevent through flow of air, but this can impact the fire strategy. With the need to have the airlock doors open one at a time, this restricts the ability and speed of occupants to evacuate a particular space, unlike a more traditional lobby door arrangement. With this in mind, designers need to factor in such arrangements that can delay the time it takes occupants to evacuate a particular space. A simple solution may be to limit the travel distances in such areas to compensate for this delay to evacuation time. Alternative measures may be to have emergency egress doors directly to outside the building, bypassing the airlock, but such a measure is often not possible without the luxury of such spaces being located on the ground floor.
Of equal importance is where the contents of certain biosecure rooms are of significant risk to the outside world. Such rooms will often require full decontamination procedures to be carried out on both entry and exit, which must be considered in the evacuation sequence and timeline. Decontamination procedures could potentially add minutes to the potential evacuation time for occupants, which should be considered and addressed by the fire safety design.
Understanding what PPE is needed by occupants to protect experiments from contaminants, and occupants from experiments, must be considered in the fire strategy. A requirement to have a simple face mask to enter a space is very different from having to wear a full pressurised hazardous materials protective suit with breathing apparatus.
Where heavy PPE requirements are present, the fire design must factor in the ability for occupants to hear fire alarms, their ability to respond to the alarm, their potentially reduced walking speeds and their ability to escape around the building furniture and exit doors.
The fire engineer can work with the end user to examine these aspects and look for practical solutions and enhancements to adopt. These may be simple concepts such as using much larger and wider corridors and exit doors to facilitate movement in large protective pressurised suits, as well as active measures such as incorporating radio communications into the suits / clean rooms that enable people outside of the room to communicate, calm, and direct people within the room on what they need to do to safely escape the building.
Protecting the work
The research work being carried out in scientific buildings is the primary reason for their existence. Protecting the building and its assets needs to be tailored to the expected needs of the building.
Passive fire protection relies on the ability of fire resistance rated construction such as walls and doors to offer a barrier to the spread of fire and smoke in a building, and when properly constructed is a proven, reliable method of fire protection. The passive fire protection strategy for scientific buildings can normally be easily tailored, and may rely on enclosing high risk laboratories from the rest of the building by one or two hours fire resistance rated construction. This is often an area where designers may look to go beyond prescriptive fire safety code requirements and enhance the level of protection offered to certain areas of the building, and can be a quick and cost effective method of improving resilience to a building.
Active fire protection relies on equipment and systems being activated to offer a fire protection benefit. This may be a sprinkler head activating and releasing water over a fire, or a deployable fire curtain being activated by the fire alarm system. Active fire protection measures offer real benefits to buildings, but their inclusion in high risk or high sensitivity areas must be fully evaluated. An example of this may be the provision of sprinkler protection in a building, where accidental activation of a head could result in the loss of an experiment. Alternatively, there may be cases where accidental water discharge in data storage rooms could cause damage or loss of crucial data.
The fire engineering strategy needs to address these aspects, and provide sensible measures to protect the building, its occupants, and its research. Advancements in fire protection technology continue around the world at pace, and the ability to use alternative systems, such as gas suppression in server rooms, offers solutions to such problems.
There will always be a fine balance to strike between the use of passive fire protection and active fire protection methods to overcome certain design challenges, and depending on the use of certain buildings and building areas, it may be possible to trade one method off for another.
Designing a fire strategy for flexibility
Single-purpose buildings are out, as clients request structures that can adapt to accommodate new and changing needs. This shift has been accelerated by the pandemic, which is forcing a re-evaluation of working environments.
Science and technology, in its very nature, changes all the time. Research moves on, funding is diverted and reallocated, and different equipment and environments are needed for different projects. Buildings need to be flexible to accommodate these shifts, and there are many reasons why buildings fail to deliver this. Fire safety is often seen as a barrier to flexibility, particularly in more complex buildings. There are two reasons for this – firstly, a poor understanding of fire safety by management teams and users, and secondly, a lack of planning and forethought during the design of the building.
An example of where Buro Happold’s fire engineering team has accepted the challenge of flexibility and adaptability is the new Research Institute building in London. This is the partial redevelopment of an existing hospital to deliver a world-leading medical research facility. The four upper storeys in this building are designed in the most flexible way: stores and higher risk spaces are located in an inner ring around the central core of the building while the outer ring of laboratory and write-up spaces are designed to be able to change purpose between the two uses.
This flexibility is made possible by considering each storey as a separate compartment and assigning a higher risk profile to the entire floorplate. The risk on each floorplate is reduced through the provision of a sprinkler system and an automatic fire detection and alarm system. These provisions are above the minimum recommendations of local prescriptive guidance; the building is below 30 metres in height, so guidance does not explicitly recommend the provision of sprinklers on compartment floors. However, the inclusion of sprinklers provides the flexibility desired by the client, as floorplates can be changed over between laboratory and write-up space, as research work changes and new funding becomes available.
Nevertheless, a crucial aspect of fire safety needed to allow future flexibility is ensuring that clear and concise documentation exists that is representative of the building. This includes having truly accurate, as built fire strategy reports, plans, and mechanical services drawing layouts which can be used to quickly examine the feasibility to repurpose certain areas of a building.
In summary, scientific buildings present unique challenges to fire and life safety designers around the world. The challenges over biosafety levels for protecting contaminants into and out of secure rooms will always pose a challenge for fire engineers, as ultimately the mechanisms to prevent contamination occurring will delay the time it takes for building occupants to safely escape.
This is a function of aspects such as escape through air-locks, extensive decontamination procedures, or the difficulty in moving in highly sophisticated hazardous materials personal protective equipment.
As fire engineers, it is crucial to understand the needs of the building and its users, and to place ourselves in a position to walk through each escape scenario with the end users and make sure that sensible and effective egress provisions and procedures are made available at the design stage, and followed throughout the lifetime of the building.