A common entrance door has to serve several functions: keeping unauthorised people out, letting in those who need to reach the building, and allowing evacuation in line with the requirements applying to the building. There is no single national rule of the kind "all doors must stay open" or "all must be locked". Before changing the system, the problem has to be identified and the project classified in legal terms.
Why is a door that stays open a problem?
Because it removes the first separation between the street and the common parts.
Intrusions, thefts from cellars, criminal damage and unauthorised occupation all become easier.
But before voting on an expensive system, check the cause: a badly adjusted door closer, a faulty strike plate, day-to-day use, a contractor's access, or a genuine access control problem.
Can you simply fit a stronger lock?
Not without looking at evacuation.
The constraints applying to a building door depend in particular on the municipal building regulations, on the building permit, and, depending on the case, on safety requirements or the opinions of the competent services.
What majority is needed to change the system?
It all depends on what is actually being done.
A repair or a like-for-like replacement that counts as maintenance may be voted by the ordinary majority of those present or represented. (loi du 16 mai 1975, art. 15)
The alteration of existing equipment that brings an improvement may fall under article 16 d), and therefore under the majority of the votes of all co-owners, with a second meeting possible. Creating genuinely new equipment may fall under the improvement regime of articles 26 and 17, and therefore under a double majority.
Moving from a mechanical key to a badge should therefore not be classified automatically without looking at the project: is an existing system being replaced, or is new infrastructure being created?
Badge, entryphone or app: does the data matter?
Yes.
A named badge, a video entryphone or a camera may process personal data. The co-ownership then has to comply with the GDPR: informing the people concerned, limited access, a proportionate retention period, and a processing agreement where the system is operated by a contractor.
For video surveillance, the CNPD guidelines are the Luxembourg reference to use.
And access for the postal service or other contractors?
That is a practical need to be dealt with in the design of the system.
There is no single solution imposed on every building. The access requirement is therefore handled in the design of the system, building by building.
An airlock, a letterbox area, an entryphone or controlled access may each answer the need, depending on the building.
Who decides which system is right?
The co-ownership must first define the problem, then classify the project and vote under the right regime.
Buying technology before making that distinction is an elegant way of starting with the invoice.