How can smoke from a shared corridor get into a flat?

01

The doorway and hidden connections are different possibilities

Opening a flat’s door connects it directly with the corridor for that moment. EPA and CDC also describe smoke travelling through doorways, wall cracks, electrical routes, ceiling spaces, ventilation and plumbing-related connections. These are possible paths in buildings, not a checklist proving that each exists in yours.

A shared service void is a space around building services, not the same thing as a corridor or necessarily a ventilation duct. Smoke may reach a room through such a connection without first crossing the front doorway. Conversely, a smell noticed at the entrance does not establish a hidden route. The building’s actual layout has to be assessed, rather than treating every pipe or grille as an air connection.

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02

Air movement does not follow a fixed rule by floor

NIST’s 2015 multizone-airflow framework describes room-to-room movement driven by mechanical systems, wind pressure and buoyancy from temperature differences. Air moves through available connections under those pressure conditions. Wind, indoor–outdoor temperature differences and operating equipment can change the situation even when the corridor looks the same.

This explains why ‘the smoke must have come from below’ or ‘a shut door means no air passed’ is not a reliable conclusion by itself. It does not mean every fan draws corridor air into every flat, or that a particular service shaft carries smoke. The historical framework is not a simulation of your building; direction and routes require appropriate assessment.

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03

Worked example: an empty corridor is only one observation

Fictional example: you open your front door to bring in groceries and notice a tobacco smell in the corridor. Nobody is there. You close the door, then notice the smell inside the entrance. The manager replies: ‘Nobody was smoking in the hallway when I checked.’ That answer describes one observation, but it does not explain where the smoke began or how the home connects to shared spaces.

A follow-up can be: ‘Can you review the smoking arrangement for the shared areas and have the relevant doorway and shared-space connections assessed?’ State the ordinary doorway event and affected area without naming a suspected resident. The sequence is not proof that the doorway was the only route; there is no need to hold it open, create smoke or follow people to demonstrate a path.

04

A source question and a building question both remain

Ask the responsible manager or landlord to distinguish the building’s smoking rules from the condition of relevant doors, shared spaces and ventilation. Local housing or public-health contacts can explain available local routes; a US EPA example does not establish a landlord’s duties elsewhere. If a technical assessment is needed, it belongs with the responsible building professional.

Ventilation or air cleaning cannot completely control secondhand smoke. Opening a corridor window or adding a fan is therefore not proof the problem is resolved. Do not prop fire doors open, cover required vents, remove grilles or alter service voids to investigate. Keep any private communication to the location and ordinary circumstances; people’s photographs, smoking histories and health details are unnecessary. For personal health concerns, contact a qualified local health professional.

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05

What to keep in mind

• A corridor can be an intermediate space, not the original source.
• Doorways and hidden building connections are possibilities to distinguish, not assume.
• Ask for responsible review of smoking arrangements and building connections without testing smoke paths yourself.