For a "B" or "F" class bulkhead or lining, the specimen
should be supported at the top and secured on the vertical sides and
at the bottom in a manner representative of the conditions in service.
The support provided at the top of a bulkhead or lining should allow
for the appropriate expansion or clearance to be used as in practice.
At the vertical edges lateral expansion towards the vertical edges
of the restraint frame should be prevented by ensuring a tight fit
of the specimen within the frame which may be achieved by inserting
a rigid packing between the vertical edges and the frame. If provision
for movement at the edges of a bulkhead or lining is made for a particular
construction in service, the specimen should simulate these conditions.
For a "B" or "F" class ceiling, expansion of the ceiling
members should be prevented at the perimeter edges since the specimen
is intended to simulate a part of a ceiling removed from a much greater
area. Expansion should be prevented by ensuring a tight fit of the
specimen within the frame which may be achieved by inserting a rigid
packing between the ends or edges of ceiling members and the restraint
frame. Only if the ceiling is being tested at full size in one or
more directions is it allowed to incorporate the expansion allowance
at the perimeter edges in the appropriate direction or directions.