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What is the Design, Installation, Operation and Maintenance Manual (DIOM) for watermist fire protection?

Given the variety of water mist systems and their proprietary nature, it is important to accept that the use of water mist does not follow the same approach adopted for other types of fire suppression systems (eg, sprinklers, gas etc).  As a result, system manufacturers have much more involvement and responsibility in demonstrating suitability and performance, above and beyond what standards may require, which is why the DIOM is a key document in system design.

The DIOM is the document that contains all the key information from the manufacturer of the water mist system. These may vary significantly with application and manufacturer. These documents should be used by the specifier, approver and any other stakeholder to understand how the system works, how it should be installed and maintained and to carry out due diligence. For this reason, it should be made public or available to these stakeholders on demand. It will also detail what are the intended applications, the limits of the application of the system and how it has been tested and validated. The DIOM does not work in isolation, must reference the standard to which the system has been designed, if it states compliance to a standard, with documented evidence of compliance to all clauses (or justifications for variations to clauses), what fire test protocols have been used to test the system, what the results were, what third party laboratories have tested or certified it, if any. The National Annex B to BS EN 14972-1:2020 provides the critical list of items to be included in the DIOM, such as:

  • General Information regarding the type of system
  • Limits of application
  • Description of components and the standards to which they are designed
  • Testing of the specific system/s and details of the protocols against which they have been tested and the results of such tests
  • Approvals and certifications gained in respect of systems and components
  • Declaration of conformity to applicable product safety directives
  • Planning, Design and any specific qualifications or approvals needed by the designer
  • Nozzle maximum and minimum spacings, height, working and standby pressure
  • Minimum design area (AMAO), the minimum number of nozzles in the design area
  • Discharge duration per application
  • Water supply requirements
  • Installation process
  • Testing and Placing in Service
  • Inspection
  • Maintenance
  • Typical Applications
  • Hazard description
  • Sources of ignition
  • Types and sizes of fires covered
  • Recommended protection application rates/flux density
  • Interaction with other fire systems (detection, alarm, smoke control)

Read more - What is the history of water mist for fire suppression?