The Central Archive Store at Network Rail in York is home to a unique collection of rail-related architectural drawings and documents. Some of the oldest materials date back 200 years, to the first railroad and locomotive designs by George and Robert Stephenson. Fireworks was entrusted to design and install a fire system to protect this historical collection.

Fire protection project requirements

The Central Archive Store is a purpose-built facility with several different storage areas. A requirement of the design was that the fire system can protect each individual storage area separately. It also needs to be able to detect smoke at the very earliest stages. Many of the archive documents are extremely fragile and cannot be exposed to excessive heat, water or smoke. For this reason, the project specifications set out stringent testing requirements for the fire system chosen.

System design – watermist with very early smoke detection

Fireworks designed a bespoke watermist solution for the Central Archive Store, linked and controlled by Very Early Smoke Detection Aspirator (VESDA) detection systems in the archive areas. Heat-activated watermist nozzles were installed in the escape routes, corridors and stairs.

In the event of fire, a watermist pump forces water under pressure through the watermist nozzles in the affected area only. The watermist nozzles emit a fine mist that rapidly cools the heat, suppresses the fire and reduces the spread of smoke. As only very small amounts of atomised water are used, watermist can be used in a wide range of applications where sprinklers are not suitable – including archives, museums and heritage buildings.

Testing and observations

A series of fire tests were designed and carried out by Fireworks in accordance with NFPA750 guidelines and the specific requirements of Network Rail, under the supervision of their designated fire risk consultant.

It was observed during the scale testing that fires started in various positions within a section of a typical archive store were quickly controlled by the watermist system, preventing the fire and smoke from spreading.
Archive documents stored adjacent to the fire source were unaffected throughout the tests and there was no water penetration into the document containers.

In all tests the fires were quickly extinguished by the watermist system.  

The tests proved conclusively to the client and their representatives that watermist is the optimum fire protection solution for archives.