Χτύπησε ο συναγερμός πυρκαγιάς, με αποτέλεσμα να αρχίσει η εκκένωση.

That is a very common question.

Χτυπάω / χτυπώ does literally mean to hit, but it is also used for things that ring, sound, or go off.

So:

• χτυπάω την πόρτα = I knock on the door
• χτυπάει το τηλέφωνο = the phone is ringing
• χτύπησε ο συναγερμός = the alarm went off / sounded

In this sentence, χτύπησε is the natural verb for an alarm sounding.

Because Greek word order is more flexible than English.

Both are possible:

• Χτύπησε ο συναγερμός
• Ο συναγερμός χτύπησε

Starting with the verb often sounds natural in narration and puts focus on the event happening. It is a bit like saying:

• The alarm went off rather than
• The alarm is what went off

So Χτύπησε ο συναγερμός is very normal Greek.

Πυρκαγιάς is the genitive singular of πυρκαγιά.

Greek often uses a noun in the genitive to describe another noun, especially in combinations like this:

• συναγερμός πυρκαγιάς = fire alarm
• literally: alarm of fire

This is similar to how English uses noun + noun, as in fire alarm.

So:

• συναγερμός = alarm
• πυρκαγιάς = of fire

Together: fire alarm.

Because συναγερμός πυρκαγιάς is being used as a set type of expression, like a category: fire alarm.

If you said ο συναγερμός της πυρκαγιάς, it would sound more like:

• the alarm of the fire
• or the fire’s alarm

That is not the normal way to say fire alarm.

So:

• συναγερμός πυρκαγιάς = the standard compound expression
• συναγερμός της πυρκαγιάς = a different, less natural meaning in most contexts

Με αποτέλεσμα means:

• as a result
• with the result that
• resulting in

It connects a cause to its result.

So in this sentence:

• Χτύπησε ο συναγερμός πυρκαγιάς = the fire alarm went off
• με αποτέλεσμα να αρχίσει η εκκένωση = resulting in the evacuation beginning

It is a fairly neutral or slightly formal way to express consequence.

Because in Modern Greek, after expressions like με αποτέλεσμα, the result is often expressed with να + verb.

So the pattern is:

• με αποτέλεσμα να + verb

Here:

• με αποτέλεσμα να αρχίσει = resulting in ... beginning

This να introduces a dependent verb form. English often uses an infinitive or a different structure, but Modern Greek normally uses να.

A good way to think of it is:

• with the result that the evacuation began
• resulting in the evacuation starting

Because να αρχίσει presents the beginning as a single complete event.

Compare:

• να αρχίσει = to begin / to start, viewed as one whole event
• να αρχίζει = to be beginning / to begin repeatedly or as an ongoing process, depending on context

Since the sentence refers to one specific result, the aorist-type form αρχίσει is the natural choice.

Why not άρχισε?

Because after να, Greek does not use the normal past tense form. It uses the να-form instead:

• άρχισε = it began
• να αρχίσει = to begin / that it begin

So με αποτέλεσμα να αρχίσει is the correct structure.

Εκκένωση means evacuation.

It comes from the verb εκκενώνω = I evacuate / empty out.

Greek uses the definite article much more often than English, especially with nouns that refer to a specific event or concept already understood in the situation.

So:

• η εκκένωση = the evacuation

In this sentence, it refers to the specific evacuation that started because the alarm went off, so the article is natural.

Yes, με αποτέλεσμα να αρχίσει η εκκένωση sounds a bit more formal or written.

More everyday alternatives might be:

• Χτύπησε ο συναγερμός πυρκαγιάς και άρχισε η εκκένωση.

  • The fire alarm went off and the evacuation started.

• Χτύπησε ο συναγερμός πυρκαγιάς, οπότε άρχισε η εκκένωση.

  • The fire alarm went off, so the evacuation started.

Your original sentence is absolutely correct; it just has a slightly more polished, report-like tone.

Yes, often it could.

• να αρχίσει η εκκένωση
• να ξεκινήσει η εκκένωση

Both can mean for the evacuation to begin/start.

A small difference in feel:

• αρχίζω = begin, start
• ξεκινώ = start, set in motion, get underway

In many contexts they are interchangeable, but αρχίσει is a very straightforward and natural choice here.