Is it wrong to refer to 18:00hs as "eighteen hours" while in a 24-hour clock country? [duplicate]

Possible Duplicate:
How should one say times aloud in 24-hour notation?

I was wondering if you could help me out with a matter that is bugging me.

Do you think it is wrong to refer to 18:00hs as "eighteen hours" while reading a time-table in a 24-hour clock country?

I mean, is it really necessary to convert the 24-hour clock times to 12-hour clock in order to speak proper English?

I had an argument yesterday regarding this issue, because someone was trying to correct me, as he was expecting to hear 6 PM instead of the way I was reading it (eighteen hours).

Doesn't it eventually depend on your situational context?

It's not the same case for a 24-hour clock European citizen traveling to England than the other way round. If going to England, I should try to adapt to the local system, since I know they are 12-hour based and they may not understand me if I start talking in 24-hour clock.

But if an English person goes to a country with a different time setting (24-hour clock based), the situation is different. Because times will be written in 24-hour clock formats, time-tables will be printed in 24-hour clock formats, etc. He will need that skill in order to fit in. He should be able to understand that 18hs (or eighteen hours) refers to 6 PM, and in that context, not even an English native speaker, IMO, should be in position to tell anyone that "eighteen hours" is wrong.

Since mine is a 24-hour clock based country, would you consider it wrong, then, for someone to read a time-table in this fashion?

Here is an interesting article on how many Europeans, for example, that live in a 24h-hour clock country (like mine), refer verbally to their 24-hour based times when expressing themselves in English.

In written form they just write the time in their local 24-hour form (of course), but when speaking, however, they might use either the 24-hour-clock number, or a 12-hour-clock number followed by the phrase (in local lingo) "in the afternoon" (we also use that form but informally) —so at 3pm, they may say "it's fifteen o'clock" (or, more usually, just "it's fifteen") or they might say "it's three in the afternoon."

Full article: http://www.reidsguides.com/t_pt/t_pt_timezones.html

If the convention in your country is to use a 24-hour clock then you would be perfectly justified to say to an English-speaking visitor "dinner is at nineteen hours" if this is a direct translation of how you would express the time in your native language. Your guest may look a little confused but should quickly understand that you meant, in her terms, seven pm.

Many English speakers are familiar with 24-hour clock notation from watching war movies and trying to comprehend bus timetables. But you may be better understood if you said "nineteen hundred hours". Strictly speaking, "nineteen hours" sounds to an English speaker more like a duration ("the flight took nineteen hours") than a time ("the flight lands at nineteen hundred hours").

Usually when I see such times written, they are written as 1800h, without the hour-minute colon separator. Even when they have a colon, the time is pronounced as Eighteen-hundred. The time 0900 I have heard pronounced as Oh-nine-hundred.