This recent fire in Bexleyheath, London was started in a shop with flats above. The fire was believed to have started in an electrical cupboard.
There are implications here for fire risk assessors when assessing shops because you have to consider the escape of the occupants above and whether a fire in the shop could impact upon their means of escape.
The key things to look for are whether adequate separation is provided between the commercial and residential premises and whether an interlinked fire detection warning system is required. What is the construction, age and conversion details. Do the occupants of the flat have to escape down an internal staircase and is that adequately compartmentalized to provide a safe escape for them. Perhaps they have an external rear metal escape staircase which could reduce the risk.
When dealing with a fire incident, fire crews have to consider surrounding properties and whether there is the need for these places to evacuate.
Whether dealing with an actual fire or carrying out a fire risk assessment, we have to consider the building as a whole and not just what we first walk into.
https://www.london-fire.gov.uk/incidents/2022/september/fire-at-shop-with-flats-above/
London Fire Risk Assessments - https://www.whalefire.co.uk/london/fire-risk-assessments-london.aspx