Fire classification

To complete the facility, light and ventilation are needed for the rooms. Those installations require cut outs (recess) in the ceiling elements, which concern the ceiling
fire classification.

A recessed unit has to be constructed from approved non-combustible materials in
accordance with relevant requirements of SOLAS Ch.II-2Reg.3 and intention of 31
and 47.

The lighting fixture as a separate unit cannot be fire approved. It is the complete installation with the covering of the installed unit that have to withstand the fire load.
When completing the installation you have
to have in mind:
- Fire rating for ceiling installation
- The maximum allowed size of recess in the actual ceiling
- Maximum weight of fixtures/units
- Minimum allowed distance between recesses
- Recess construction
- Method of fixing
- Type of panels the lighting fixture will be
accepted onto:
Width and length of panel
Thickness of panel, thickness of steel
plate, etc.

The installation on a vessel or a rig will never be exactly as the laboratory test installation. In practice there will be a mixing of cut out for lighting and ventilation as
well as ceiling hatches. It is therefore very important to have in mind the minimum
allowed distance between recess for the actual ceiling, as well as the maximum allowed
load for each ceiling element.

For B0 there is no temperature reduction requirements, but no tongue of fire is allowed
to enter the unexposed side during the test period of 30 minutes. This means that,
even the fixture is made of steel with no hole or slots in the body, the area between
fixtures and ceiling is very important to keep in mind, in order to avoid any gap where the fire can enter.

For other B- and F-classes (B15/B30) there is requirement for insulation. This means
that the insulation covering the fixture/ recessed unit must have the same rating
as the ceiling element. Insulation boxes or matting are to be used. A ceiling element
will bend down very much when exposed to high temperatures. A stiff insulation
cap will not follow the same form, and therefore the area between ceiling and
covering insulation also in this aspect is very important to keep in mind.

According to IMO Res.A.754(18), the
performance criteria to “A”,”B”and “F” class
ceilings are:

Criteria	A-class	B-class	F-class
Testing duration	60    minutes	30   minutes	30  minutes
Insulation/Temperature  rise:Average	140°C	140°C	140°C
Maximum	180°C	225°C	225°C
Class description	0, 15, 30, 60	0, 15, 30	30

Integrity: The following requirements shall also be satisfied for the test duration.
- Flaming: There shall be no flaming on the unexposed face
- Cotton wool pad: There shall be no warm gases that can ignite a standardised cotton wool pad
- Gap gauges: By use of a gap meter, control that no gap more than 6 mm wide and 150 mm long, or single opening with diameter more than 25 mm exist