21 Dec Regulations regarding car parks need reviewing
Following the major fire at the Kings Dock car park of the Echo Arena in Liverpool, UK, on 31st December 2017, Merseyside Fire and Rescue Service (MF&RS) investigated the incident and commissioned a report, just published, which considered the fire protection issues influencing the incident and makes recommendations which may impact on the protection of car parks globally.
Kings dock car park, an 8 level, open-sided construction, comprising a ground and seven upper floors, the seventh being roof top parking. The footprint of 4930m² had a maximum capacity of 1600 cars. The construction method was concrete columns and beams, with tied in reinforced pre-cast ribbed concrete floors.
At the scene attending fire crews reported rapid lateral fire spread, running fuel fires, vertical fire spread from level of origin and a “waterfall” of fire from the ceiling of level 3. It was initially thought that fire spread was via the central ramps, but upon further investigation it is considered that the drainage system was the likely cause of vertical fire spread.
The resulting blaze led to the loss of approximately 1,150 vehicles and so severely affected the fabric of the building that demolition is the likely outcome. A visiting contingent from the Building Research Establishment (BRE) likened the fire to a petrochemical fire; due to the heat generated and the behaviour of the concrete structure (evidence of explosive spalling, floor failure and structural element damage).
Fire spread in car parks
In 1968, The Ministry of Technology and Fire Offices’ Committee Joint Fire Research Organisation researched and concluded that fire spread from one vehicle to others would not occur and that if it did, the Metropolitan Brigades would invariably be in attendance within 3 to 4 minutes.
In 2006, the Department for Communities and Local Government (DCLG) commissioned the Building Research Establishment to carry out a 3 year project titled “Fire Spread in Car Parks” (BD 2552). Although there had been few deaths or injuries recorded to that date in the UK, there were concerns regarding new and emerging risks from modern cars and alternative fuels.
This research demonstrated, amongst other things, that:
• sprinklers are effective in both controlling a developing and fully developed fire
• running fuel fires spread the fire
• current methods to calculate ventilation openings from open-sided car parks and mechanical ventilation in enclosed car parks needed to be considered
• the ease with which a car fire in a car park spread to nearby cars and once a very severe fire has developed, fire will spread to other cars separated by an un-filled parking bay, and
• fire conditions in partial and fully closed car parks are much more severe than in open sided car parks.
The Kings Dock report concluded that the current fire resistance recommendations for car parks in the UK’s Approved Document B (ADB) needed to be kept under revision and that calculations for smoke control and smoke clearance need to be carefully considered. But also recorded that the active and passive fire protection measures within King’s Dock complied with regulatory requirements and performed beyond the required standard during the incident.
The report does however recommend designers should seriously consider sprinkler provision to avoid multiple vehicle fires, resulting in huge insurable losses and the possible loss of life. And that serious consideration should be given to the implications of drainage design that could aid fire spread between levels.
In endorsing that current building regulations for car parks be reviewed in light of this incident, the report makes several pointed observations regarding ADB, Volume 2 (buildings other than dwelling houses) 2010, section 11.2 which gives the general principles for buildings used for parking cars and makes several recommendations :
• ADB states: “the fire load is well defined.” This is based on out-dated research on old vehicles and requires further consideration.
• ADB states: “Where the car park is well ventilated, there is low probability of fire spread from one floor to another.” This was clearly not the case at this incident and requires revision.
• Current methods for calculating ventilation openings for smoke clearance from open-sided car parks should be reviewed.
• Under current guidance in ADB, there is no requirement for sprinklers within an open-sided car park. Serious consideration should be given to the provision of sprinklers.
• The more modern the vehicle, the higher calorific potential. Further research on modern vehicles should be commissioned, in order to ascertain conformity to current fire resistance standards under building regulations.
• Spacing of vehicles and ceiling height in car parks should
be reviewed.
• Rapid spread of fire, once two or more vehicles are fully involved will occur. Fire will “leap” across empty bays, due to its intensity, in particular the temperature of the smoke/ceiling jet (BD2552 p.39). In the Kings Dock car park incident crews reported that additional vehicles became involved “every 30 seconds”. The rate increased exponentially up to rapid fire development on level 4, just after the crews withdrew. Sprinklers will delay fire development and prevent fire spread to multiple vehicles before the attendance of the Fire and Rescue Service.
• Early firefighting intervention, or automatic suppression is imperative to controlling fire spread.
The car park was designed incorporating a drainage system built into the floor which takes away any excess surface water and this is considered as the likely cause of initial fire spread between level 3 and 4. This effect was captured on external CCTV which appeared to show vertical walls of fire at equidistant positions along the length of the level.
Running fuel fires were witnessed by BA crews and this undoubtedly led to fire spread through the drainage system,
down ramps and along the rib slab floor and designers should consider the likelihood of running fuel fires, when designing floor layouts and ramping systems that incorporate vehicle parking.
Management of the building
There are some complexities regarding the management of the premises, the fire risk and the fire evacuation strategy within the premises however….
• MF&RS were appropriately consulted in the construction of this car park and were able to contribute effectively to ensure public and firefighter safety. This demonstrates the importance of good consultation between developers and the Fire and Rescue Service in ensuring that appropriate safety measures are implemented.
• The close proximity of the serviced apartments to the southern and eastern elevations of the car park meant that aerial appliance access was very limited and firefighters faced extremely difficult conditions in order to save these buildings from fire. Designers and approved inspectors should give due regard to firefighter safety when considering design requirements of their buildings.
Risk assessments (FRA)
Kings Dock Car Park had 4 separate fire risk assessments completed on it by different stakeholders, two of which are for the day to day running of the car park and two are for the car park during the Liverpool International Horse Show which was on at the Echo Arena at the time of the fire. A suitable and sufficient FRA is an analysis of hazards and associated risk within a premises but, the report comments, having more than one can potentially complicate matters.
On a positive note it is recorded that the FRAs and fire strategies for the event were detailed and comprehensive. Co-operation and co-ordination between the responsible persons were fairly robust, with pre-event planning and table top exercises taking place prior to the event.
This pre-planning extended to an emergency planning meeting and one of the scenarios was how to deal with fire in the stables. During the incident, the evacuation of people from the car park was prioritised and a co-ordinated plan was in place to evacuate the horses.
The plan, combined with considerable pressure from worried horse owners, had the potential to lead to an uncontrolled evacuation of horses into oncoming fire appliances and adversely affect firefighting operations but, although tensions were raised at this critical time, the reports praises all the staff for managing a well-controlled and co-ordinated evacuation of the horses, as per the pre-planning.
Alarm system
The report confirms that the car park was served by a combination of a manual and an automatic fire alarm system, complying with BS5839-1 with manual call points on all levels of the car park, adjacent to protected stairwell exits and there were good examples of the effectiveness of the passive fire protection measures in place and how well they performed, despite the severity and intensity of the fire. However the report recommends:
1. An audit of fire escape doors at all parking locations, to check compliance to BS5839-3 and BS7273-4.
2. Correctly labelled addressable detectors and call points help the responsible persons and Fire and Rescue Services to reduce the time taken to identify the specific location of alarm actuation. A delay to locating a fire can lead to an escalated incident and potentially more severe fire.
3. Where CCTV is used as part of a fire strategy for detecting a fire, it should fulfil the requirements of BS EN 6276 and BS8418 and have adequate numbers of staff to monitor it. If this is not achievable, then alternative and/or additional detection should be considered.
Firefighting access and facilities
The gross floor combined area exceeds 24,000m² and consequently requires 100% perimeter access for pumping appliances and high rise appliances. MF&RS insisted on firefighting shafts so that a fire could be fought internally, in a safe environment because the apartments, constructed on the south and east sides, restrict 50% of the access area, consequently reducing firefighter appliance and aerial appliance access to 50% of the building.
On the night of the fire, aerial appliance access proved very difficult and the grilles across the open sides hindered external firefighting. As a consequence, the report recommends access and facilities for firefighters at car parks should be reviewed.
Human behaviour
Interestingly the report explores the probability that human behaviour and reaction to the fire may have led to fire development prior to MF&RS arrival and may also have caused initial attending crews and incident commanders to have been distracted from commencing an immediate weighted attack on the fire on level 3. The report’s theory is based on the fact that there were many witnesses to the fire in its initial stages and presumably had the ability to dial 999 (mobile phone technology), however very few calls were received by MF&RS Fire Control in the early stages of the incident and this would appear to indicate that members of the public displayed reactions to fire that go against all fire situation training and advice.
Also CCTV footage showed several pedestrians and persons in vehicles witnessing the fire but not making an emergency call and although some did drive down to ground level and report the incident to LCC staff, others did nothing. One particular driver stopped their vehicle in the roadway for 30 seconds, immediately next to the vehicle of origin when it was well alight and then proceeded to park their vehicle on the ramp from level 3 to level 4, without raising the alarm.
MF&RS, LCC, ACCL and WH Management staff all cited members of the public not following instruction to evacuate, distracting staff from performing their duties, and interfering with prescribed fire strategies that had been agreed between the responsible parties.
The report recommends that event organisers should seriously consider the limitations of private emergency response teams who should make every attempt, as far as is reasonably practicable, to ensure that their personnel, equipment and vehicles are not mistaken for emergency services.
Merseyside Fire & Recue Service would also advocate more public information as to what their actions should be upon discovering a fire and the potential positive and negative effects of members of public recording and streaming live emergency incidents and the impact this has on the emergency services and any potential victims.
View the full report here: bit.ly/2G9L0hA
Featured image courtesy of Merseyside Fire and Rescue Service (MF&RS)