Must the Shul Menorah Burn for 30 Minutes?

Questions:
Is the Shul Menorah, that has been lit before Ma'ariv with a B'rachah, required to burn the entire 30 minutes?

What if no one can stay there, does safety permit extinguishing it before the 30 minutes are over?

Answer:
It may be extinguished.
Source: Rivevot Ephraim 5:29.

Courtesy of -
Rabbi Ari N. Enkin

Addendum see:
http://hebrewbooks.org/pdfpager.aspx?req=46444&st=&pgnum=236
nitei gavriel

rav harpenes
http://hebrewbooks.org/pdfpager.aspx?req=9663&st=&pgnum=147


Kol Tuv,
RRW