Fire completely devastated the automated Andover warehouse of on-line supermarket Ocado on 6 February 2019, despite attendance by 200 firefighters and 20 fire engines. The cause of the fire is not so far disclosed. The warehouse is reported to have contained sprinklers, which raises important points about the use of sprinklers in large open spaces full of combustible items. Sprinklers should not be in isolation, but advisedly used in compartmented zones, part of a holistic fire protection strategy.
The fire in Ocado’s flagship robotic warehouse killed nobody.But it serves to remind us that fire can cause major disruption and costs in the destruction of property and building contents. The blaze lasted at its height for 48 hours, destroying a £45 million state-of-the-art modern handling facility, temporarily wiping £1 billion off the retailer’s stock market value. 100 local residents had to be relocated because of the risk of a pressured tank exploding and concerns over fall-out from the smoke plume, down-wind for 1.6 km. Stock worth £6 million is reported lost, along with the hundreds of robots used throughout the facility for the assembling of orders (at around 30,000 orders per week).
Dr Jim Glocklin, Technical Director of the Fire Protection Association (on behalf of the insurance industry), reported in the specialist on-line news portal IFSEC Global, observes that the intended function of sprinklers is to stop the growth and development of a fire – to hold fire at a manageable size so that it can be more easily extinguished by the fire and rescue service when they arrive.
Dr Glocklin emphasized the importance of holistic fire safety design.He draws attention to the need for sprinklers to be designed within a compartmented structure, i.e. with the building divided into control zones intended to restrict the ability of fire to spread very far, very fast, by the use of robust barriers that are fire resistant, to prevent the physical movement and transfer of fire.
It’s implicit that the use of a sprinkler system should be designed carefully with the characteristics of the protected space in mind, especially including considerations on what the maximum compartment size should be.It would also be sensible, as part of the holistic approach, to give thought to the ability of the compartmentation boundaries to remain in one piece under fire conditions where there is the chance of water impingement, not just from sprinklers but also from firefighter hose streams. That applies particularly to glazed partitions and glass vision panels or internal glazed ribbons assemblies, which can be so important in large internal compartmented spaces to provide natural lighting and allow through vision from one side of a compartment to another.Standard glass products have no significant resistance against fire: traditional glass is notoriously vulnerable to thermal shock and stress.Ceramic glass, however, is exceptional in its immunity to thermal stresses.