Design, build & occupy

Design, build & occupy

James Daniels, Fire Safety Manager at Warringtonfire, looks at incorporating fire safety in the design phase of mixed-use buildings and goes on to discuss the fire safety considerations required during the construction stage then deliberates the ongoing fire protection measures required during the occupied life of these challenging structures.

The first place to start when discussing mixed-use buildings is to establish exactly what sorts of buildings fit into this category and what they are used for. Mixed-use, or complex buildings, are typically larger buildings that will be occupied in numerous ways. This may include shopping centres that have retail outlets, food and drink establishments, underground parking, and various entertainment areas such as cinemas. Other mixed-use buildings include office buildings with lower level retail outlets; residential buildings with office or retail space; and many transportation hubs, which often include retail and food outlets as well as office space.

When designing the fire safety for mixed-use buildings, every end use must be considered. The order of movement is crucial as not every occupier may need to evacuate in every circumstance, and therefore the notification and alarm systems vary by occupation zone. For example, an alarm triggered by smoke in a restaurant in one end of a building should not necessarily signal evacuation in the retail space at the other end of the building if the proper compartmental protection has been included; especially in very large complex buildings such as airports or megamalls.

This is where experienced consultants can bring value to the project. Fire consultants have specific expertise in the area, extensive knowledge of building codes and regulations, and technical modelling capabilities to determine the potential passage of flames, heat and smoke and the ability to assess and determine the optimal evacuation routes and management plans. Including them throughout the design phase ensures that every detail is considered from the outset and no unnecessary time or expense goes to correcting any errors in the construction phase.

Some of the most common mistakes consultants see at the design phase are:

  • Insufficient consideration of virtual smoke zones that can be formed through creative use of the natural architecture.
  • Lack of understanding of local code-based requirements such as the minimum active fire protection measures and
    alarm systems. 
  • Sprinkler citing design based on the assumption that tenanted units will be provided with ceiling voids less than 800 mm, in line with NFPA 13, but then the ceiling is not fitted while shell-and-core. Or, as part of the tenant fit out, they take down the ceiling but don’t move the sprinklers up to the underside of the slab.
  • Incorrect or incomplete compartmentation.

The creation of a complete fire strategy at the design phase provides an overall outlook at all scenarios where fire can affect a building and its occupiers, and prevents any of these common mistakes from impacting the construction phase. The strategy considers: compliance with all local fire legislation, the objectives of all occupiers, and ensures any requirements outlined for insurance purposes are fulfilled. It is a key component in every building design and can save time and costs in the long run, and most importantly, can save lives.

Construction & phased occupation 

The fire safety measures of mixed-use, or complex, buildings require special consideration during the construction phase. Not only do all systems need to be correctly installed to protect the building structure and human life during occupation and escape, but special consideration needs to be incorporated where there is a client requirement for partial occupation while construction carries on.

As many mixed-use buildings are constructed in phases, there are additional fire risks that don’t exist in the fully occupied phase. It is imperative that correct, effective compartmentation is installed to protect the occupied units from those under construction.

This can become particularly complex when there is additional connectivity to the building. In regions with extreme climates, either very cold or very warm, buildings are often connected through passageways, many of which are subterranean. Here in Qatar, and across much of the Gulf Region and South East Asia, it is possible to travel between dozens of buildings without stepping outside. Many of these connective passageways also include additional retail or food outlets. The escape routes and compartmentation of all these joining components must also be fully considered.

We see a variety of common mistakes during the construction of mixed-use buildings and recommend that a construction phase fire strategy should be developed to identify fire risks and mitigating factors to minimise the potential for, and impact of, a fire during the construction phase. This is often an afterthought and follows a fire incident on site. 

Other common mistakes include:

  • Product approval and certification is not provided.
  • Coordination between the installers of fire systems is inadequate resulting in contractors working in silos and not integrating fire systems in accordance with the fire strategy.
  • Underdeveloped or inadequate cause and effect matrix; improper alarm notification in occupied spaces in the event of detection in the unoccupied spaces.
  • Lack of understanding that where escape routes are shared by multiple occupancies, the most onerous occupancy code requirement applies. Typically corridor fire rating is not correctly provided.
  • Passive fire stopping missing or incorrectly specified and installed. This can include IT rooms on adjoining floors not being properly sealed around the cable trays floor openings, for example. 

As with the design phase, expert consultants can play a vital role during construction. These consultants can advise on not only the correct procedures and implementation of the fire strategy, but they are often part of third party testing and certification bodies as well. 

Product certification assures that the fire performance result of the product that was tested, is repeatable if installed in exactly the same way as the tested and certified sample. The use of properly certified products is a generally accepted and adopted practice, however, many contractors misunderstand that properly certified products are enough to satisfy compliance with the building codes. They may not appreciate the need for the correct installation in accordance with the certification listing and approved design, which, if done incorrectly, could deem the product or system’s fire performance entirely ineffective.

Additionally, third party site-based destructive and non-destructive testing, which should also be witnessed by a third party inspector, ensures compliance across all areas. The third party should be accredited to ISO 17020, an internationally recognised standard for the competence of inspection bodies. This provides reassurance to clients that the inspection body has demonstrated competent, suitably qualified and experienced personnel to inspect the installation of fire protection measures and confirms whether or not they meet performance requirements in the event of a fire. 

Site inspection can be done in existing premises or on construction sites in one day, over the course of several days, or on an ongoing basis, depending on what is required. Safety should be at the heart of every building’s lifecycle and testing and certification are key components in ensuring the safety and protection of the lives of all occupiers.

Occupation 

Ideally, the longest phase of a building’s lifecycle is its occupation. Apart from ensuring the fire safety systems, including sprinkler and alarm systems, are in working order, many people don’t consider the longer term fire protection measures that need to be upheld. This is especially true in mixed-use buildings, where we often see renovations or refurbishments to various outlets and spaces, which introduces fire risk associated with construction activities.

Even when no renovations are underway and a building is being ‘normally occupied,’ it is not enough for fire safety systems to be installed if these measures are not monitored and maintained. The individual responsible for upholding the standard of any fire safety measures can vary across mixed-use buildings and it is crucial these roles are understood and the people with the responsibility for fire safety are competent in their role and empowered to rectify any identified issues within their remit. While neglect would most certainly have ramifications to the safety of inhabitants, those individuals who have responsibilities to maintain the measures could also face legal implications.

With this in mind, it is essential to consider the fire strategy we discussed in the design phase as a living document, which continues to outline requirements and responsibilities. All fire strategies should outline the fire protection measures provided and state the standard to which regular third-party testing and maintenance should be undertaken.

 In complex buildings in particular, attention should be paid to making any changes that might disconnect the cause and effect of existing measures, which may in turn compromise escape routes and the overall safety profile within the premises. Building licences also require regular renewal across the Gulf Region and these involve regular inspections. Failure to pass these inspections may result in fines or licence revocation, and ultimately the closure of many businesses.

It is also important to keep in mind the evolution of a building’s occupation, as end use may change over time. A challenge can be the ongoing differences between the objectives and needs of a building’s owner and those of the occupiers; and differences between multiple occupiers. The needs of a small retail outlet are not the same as a business occupying two floors of office space, nor does it match someone living in a residential apartment. The fire strategy should be adapted to these changes as new occupiers move in and the needs of the building develop. In the Gulf Region, unlike in many other geographies, when such changes do occur the Authority Having Jurisdiction takes an active role in the process and requires notification of such changes in order to provide approval.

Other key fire safety measures to consider during a mixed-use building’s occupation include:

  • Robust fire safety management.
  • Tenant fire safety training and awareness.
  • Central management system – who is notified and what happens in the event of an alarm.
  • Correct storage of materials, particularly in relation to storage near to potential ignition sources.
  • Develop a fire risk management programme, in particular where uses permeate with unclear demarcation.
  • Consideration for occupiers with reduced mobility, and with sight or hearing impairment.
  • Accommodation for language barriers, typically in tourist attractions and transit buildings.

Fire safety should never be a tick box exercise. The risk to both life and livelihood is not something that should be taken lightly. Businesses of all kinds, across multiple industries and countries, strive to find value for money and efficiencies, but correct, complete and compliant fire protection is not something that should ever be compromised. A fire not only endangers lives, but it can also impose significant rebuild costs; disrupt operations; pollute the environment; and cause insurmountable reputational damage.

An investment now can bring long term benefits. If a business, builder or contractor has any questions or doubts about the fire protection measures in place, now is the time to make enquiries; there is always a solution. Warringtonfire can undertake the full service offering across testing, inspection, consultancy and certification and can discuss any requirements you may have.  



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