Watford High-Rise Sprinkler Activation

• Fire Rescue Service: Hertfordshire
• Incident: Secondary Fire
• When: 12 July 2022
• Time of call: 4:50 am
• Time of stop: 06:20
• Location: Abbey View, Garsmouth Way, Watford
• Occupancy: 17 Storey High-Rise Residential Block
• Number of dwellings: 94
• Automatic fire suppression System: Fire Sprinklers

Image credit Watford Observer

Hertfordshire Fire & Rescue Service (HFRS) have reported the above-mentioned incident resulting in the activation of the premises’ residential sprinkler system.

Background

In 2019, Watford Community Housing invested £1.5 million upgrading various fire safety measures in two of their high-rise residential blocks, providing a further layer of safety from fire for its most vulnerable residents which included the installation of:

• Residential sprinkler system (retrofit)
• Grade D LD1 detection and alarm systems

Incident

• External secondary fire located on the ground floor adjacent to a storage area involving combustible material which had been fly-tipped – the items were scheduled for removal later on that morning.
• 8 pump fire requiring the attendance of over 60 firefighters
• Due to the intensity of the fire, the fire spread

1. Within the ground floor storage area,
2. vertically to the upper floors.

• Fire damage was sustained to the flats with extensive damage sustained to the UPVC frame/glazing
• Superficial damage to the building façade.
• No injuries were reported
• Police have arrested two persons in connection with arson

Activation, Residential Sprinkler System

The residential sprinkler system activated within the: –

• Ground floor storeroom
• Two flats directly above the seat of the fire, the activation of the sprinkler heads was accelerated due to the flat windows directly above the seat of the fire being in the open position, allowing the hot gases, radiant heat to actuate the sprinkler head(s). The sprinkler system activated as designed to contain and limit the spread of fire.
• Due to an unforeseen event, with the fire being an external incident, the sprinkler feed pipe was damaged – however, this was after the system had effectively discharged.

The Benefits of sprinklers

This incident clearly justifies the approach taken by Watford Community Housing to retrofit sprinklers in their two high-rise residential buildings

• Internal fire spread within the two apartments was contained/controlled, preventing further fire spread to the communal areas, demonstrating the effectiveness of the fire compartmentation and overall fire strategy
• Rapidly reducing the rate of production of heat and smoke
• The integrity of the means of escape was maintained
• Two compartment fires, with restricted fire growth. This allowed firefighters to carry out search and rescue operations with limited fire development, which significantly reduces the risks to firefighters.

Observations

• Looking at the attached image the external pipework appears to be chlorinated poly-vinyl chloride) (CPVC) covered with a foil faced mineral fibre.
• This was industry-standard and flame-retardant.
• To further improve the integrity of the system, we are replacing these with steel pipes.
• The secondary fire was due to unauthorised disposal of waste, demonstrating how relatively small fires can rapidly develop, putting residents in danger, causing significant damage and resulting in a major cost to the housing provider

Conclusion

• This incident clearly identifies the importance of designing/installing a residential sprinkler system in accordance with the guidance contained in BS9251:2021, with specific attention to sprinkler pipework which could be compromised by a fire, although in this case the system held until after it had discharged successfully.
• Positively, the fire was contained/controlled by the sprinkler system before the arrival of HFRS.
• Housekeeping is paramount, the dangers of external secondary fires cannot be underestimated, highlighting how a small fire can spread rapidly to the external façade of a building.

Further guidance

• BS9251:2021; Fire Sprinkler Systems for domestic and residential occupancies- Code of practice
• LFB Fire Safety Guidance Note 84; Fires in Communal Areas-Information for external partners

Links

• British Automatic Fire Sprinkler Association, Sprinkler Saves Annual Review 2021/22
• Hertfordshire Fire & Rescue Service
• LFB Fire Safety Guidance Note84; Fires in Communal Areas-Information for external partners
• Watford Observer