Automatic detection is what turns a manual alarm system into one that works when nobody is looking. The law does not require it everywhere: it requires appropriate detection where the risk assessment shows people would not otherwise be warned in time. That is a question about your building and its occupants rather than a rule you can look up.
When automatic detection is needed
The trigger is whether a fire could start and develop far enough to threaten people before anybody notices it. Sleeping occupants, unoccupied areas, areas with no line of sight from where people are, and places with a fast fire growth rate all push towards automatic detection. A small open workshop where everyone can see everything can be adequately served by manual call points alone.
What it has to cover
Coverage is expressed as a category, and the category comes from the risk assessment or from Building Regulations guidance for new work. The category is what makes the system auditable: without one, nobody can say whether a detector missing from a room is a defect or a design decision. Insist that the specification states the category and lists any areas deliberately excluded.
Integration with other systems
An integrated system does more on activation than sound: it releases door holders, recalls lifts, shuts down ventilation, closes dampers, stops a process or signals a monitoring centre. Each of those is a line in the cause and effect matrix, and each has to be proved during commissioning and re proved during maintenance. A system with interfaces that nobody has tested since installation is integrated on paper only.
The document that ties it together
The cause and effect matrix is the one document that says what the building does when each device operates. It is what a commissioning engineer tests against, what a maintenance visit should be sampling, and what an assessor reads after a change of use. If it does not exist, the honest position is that nobody can demonstrate the system does what the design intended.
Questions people ask about automatic fire detection system
Is automatic fire detection a legal requirement?
The Fire Safety Order requires appropriate detection where the risk assessment shows it is needed, rather than requiring it everywhere. For new building work, Building Regulations guidance sets expectations by building type.
What is an integrated fire alarm system?
One that operates other building systems on activation, such as door holders, lifts, ventilation and dampers. Each interface has to be listed in the cause and effect matrix and tested, not assumed.
Who tests the interfaces to plant?
The commissioning engineer at handover and the maintenance contractor periodically thereafter. Ask explicitly whether your service visit exercises the interfaces, because many contracts quietly cover detectors only.