Richard Wood asks:
"How do you determine the size and location of openings in the side
and top of the fire enclosure to prevent the spread of flames?"
Clause 5.4.9 of the standard addresses this issue - "During the tests
of 5.4.4 c), 5.4.5, 5.4.6, 5.4.7 and 5.4.8: - if a fire occurs it
shall not propagate beyond the equipment;"
No matter what the size of the openings on the top of the unit, if you
can pass the abnormal tests above without flame spreading from the
unit, can a regulatory agency deny approving the construction ?
(assuming of course the enclosure meets all other requirements for
enclosing electrical/mechanical hazards etc.) I don't think so. Rich
Nute mentions that he has received different interpretations from
various regulatory agencies regarding top enclosure openings. Rich,
do you think there would be differing interpretations if the abnormal
test passes ?
Best Regards,
Kendall Wilcox
[email protected]
