a.

Upper and lower surface of suspended ceiling, between plastic panels, to comply with paragraph 6.1

b.

No restriction on Class 3 rooflights in small rooms

Minimum classification of lower surface

Use of space below the diffusers or rooflight

Maximum area of each diffuser panel or rooflight (1)

Max total area of diffuser panels and rooflights as percentage of floor area of the space in which the ceiling is located

Minimum separation distance between diffuser panels or rooflights (1)

TP(a)

Any except protected stairway

No limit(2)

No limit

No limit

Class 3(3) or TP (b)

Rooms

5 sq. m

50

3m

Circulation spaces except protected stairways

5 sq. m

1.

Smaller panels can be grouped together provided that the overall size of the group and the space between one group and any others satisfies the dimensions shown.

2.

Lighting diffusers of TP(a) flexible rating should be restricted to panels of not more than 5 sq. m each.

3.

There are no limitations on Class 3 material in small rooms.