Should a lamp that penetrates a ceiling be fire rated ?
The building regulations see the plaster board as means to delay the spread of fire to the under side of the floor above long enough for people in the room above to become aware of the fire and escape before the floor collapses.. . Where there are exposed beams or joists then these have to be of sufficient cross section to remain able to support the floor for that period of time even when burning. The time is normally 30 minutes but can be reduced. In 1980 when we built our house the time was quoted as,
Half hour ( modified 15 minutes ).
To achieve this with the exposed joists we had to fit sacrificial timber to the joists to delay the fire reaching them. We could have used larger joists but that presented other problems.
Some people are saying that fire rated fittings are not needed unless the ceiling forms a fire barrier between two separate accommodations.
This is because if a fire occurred one would alert one's own family and get them out in ( hope fully ) less than 15 minutes. But in the rush to get one's own family to safety it is possible to over look or be unable to alert the other families in separate accomodations in the building.
Hence the protection between accomodations has to delay ( preferably prevent ) the spread of fire for a much longer period and therefore lamps that permit fire to pass through the ceiling cannot be fitted.
There is also the very real hazard of toxic fumes passing through the lamp fitting and then through the floor boards and carpets into the room above in sufficient concentration to affect the people in that room before the fire is discovered.
The building regulations see the plaster board as means to delay the spread of fire to the under side of the floor above long enough for people in the room above to become aware of the fire and escape before the floor collapses.. . Where there are exposed beams or joists then these have to be of sufficient cross section to remain able to support the floor for that period of time even when burning. The time is normally 30 minutes but can be reduced. In 1980 when we built our house the time was quoted as,
Half hour ( modified 15 minutes ).
To achieve this with the exposed joists we had to fit sacrificial timber to the joists to delay the fire reaching them. We could have used larger joists but that presented other problems.
Some people are saying that fire rated fittings are not needed unless the ceiling forms a fire barrier between two separate accommodations.
This is because if a fire occurred one would alert one's own family and get them out in ( hope fully ) less than 15 minutes. But in the rush to get one's own family to safety it is possible to over look or be unable to alert the other families in separate accomodations in the building.
Hence the protection between accomodations has to delay ( preferably prevent ) the spread of fire for a much longer period and therefore lamps that permit fire to pass through the ceiling cannot be fitted.
There is also the very real hazard of toxic fumes passing through the lamp fitting and then through the floor boards and carpets into the room above in sufficient concentration to affect the people in that room before the fire is discovered.
