| 3.Grade Of Plywood
|
(b) Grades B, BB and C*
|
No.
|
Categories of defectst
|
Grade
|
B (face)
|
BB
|
C* (back)
|
1
|
Pin Knots
|
Permitted if
tight and not clustered
|
permitted
|
permitted
|
2
|
Sound intergrown
knots exceeding
3 mm
in
diameter
|
Four permitted
per 3 square metres of the surface of the outer ply, to a maximum individual
diameter of
13mm
(not
closed)
|
Five permitted
per 3 square metres of the surface of the outer ply, to a maximum individual
diameter of
25mm
|
permitted
|
3
|
Partially
intergrown knots, unsound knots and nonadhering knots; also holes due to
borers and parasitic plants
|
Not permitted
|
Permitted to a
maximum individual diameter of
9mm
,
provided their cumulative diameter does not exceed
40mm
per square metre and they are properly filled
|
permitted
|
4
|
Irregularities
in the structure of the wood: sound burls (curely grain)
|
permitted if
smooth
|
permitted
|
permitted
|
5
|
Splits
|
|
|
|
(a) Open splits
(puttied)
|
Two permitted at
each end of a panel, to a maximum individual width of
3mm
and a maximum individual length of 6%
of the panel length
|
Two permitted at
each end of a panel, to a maximum individual width of
5mm
and a maximum individual length of
12.5% of the panel length
|
Eight permitted
at each end of a panel, to a maximum individual width of
15mm
and a maximum
individual length of 40% of the panel length
|
(b) Close splits
(hairline)
|
Three permitted
per panel at the ends and to a maximum individual length of
100mm
|
permitted
|
permitted
|
(c) Compression
failure (cross break)
|
One permitted
per outer ply provided hairline and of a length not exceeding 10% of the panel
width
|
One permitted
per outer ply provided hairline and of a length not exceeding 10% of the
panel width
|
`
|
6
|
Bark pockets
|
Not permitted
|
Permitted if
very slight
|
permitted
|
Resin pockets
|
Not permitted
|
One permitted
per square metre of the outer ply, to a maximum individual width of
4mm
and to a maximum individual length of
100mm
|
permitted
|
Resin exudation
|
Not permitted
|
permitted if
slight
|
permitted
|
7
|
Defects due to
borers, vines and parasitic plants
|
|
|
|
(a) Worm holes
and channels
|
Not permitted
|
Pinworm holes
permitted provided they are occasional, scattered and well puttied. No
discoloration permitted. Worm channels not permitted.
|
permitted
|
(b) Marks of
parasite
|
|
|
|
plants and vines
|
Two permitted
per outer ply, to a maximum individual width of
4mm
and maximum individual length of
100mm
, provided the are
smoothly sanded and leveled
|
permitted if
occasional and smoothly sanded and levelled
|
permitted
|
(c) Chicken
track
|
Permitted if
isolated and slight
|
permitted
|
permitted
|
8
|
Sound
discoloration (natural), stain/mineral streak
|
Permitted if
very slight
|
Permitted if not
excessive
|
permitted
|
9
|
Rot
|
Not permitted
|
Not permitted
|
Not permitted
|
10
|
Open joints
|
Not permitted
|
Three permitted
per outer ply, to a maximum individual width of
3mm
and to a maximum individual length of 10% of the
panel length, if properly filled
|
Permitted to a
maximum individual width of
15mm
and to a maximum individual length of 60% of the panel length
|
Mechanical
defects, e.g. chainmarks, machinery stain, sander burns, metal stain, grease,
oil or colored chalk on face
|
Not permitted
|
Permitted if
slight and occasional
|
permitted
|
14
|
Roughness,
brashness or torn grain
|
Permitted if
very slight and occasional
|
Permitted if
slight
|
Permitted if not
excessive
|
17
|
Inclusion of
metal particles
|
Permitted if
non-ferrous and in inner plies or cores only
|
Permitted if
non-ferrous and in inner plies or cores only
|
Permitted if
non-ferrous and in inner plies or cores only
|
Sanding
|
Smooth
|
Reasonably
smooth
|
No special
requirements
|
18
|
Repairs, boat or
symmetrical patch
|
Not permitted
|
Five permitted
per outer ply, to a maximum individual width of
100mm
and to a maximum individual length of
150mm
, provided they are
well made, are of similar grain and are color matched
|
Permitted
|
|
Shims
|
Not permitted
|
Permitted to a
maximum individual width of
5mm
and to a maximum individual length of
300mm
, provided they are well made, are of similar
grain and are color matched
|
Permitted
|
|
Tape or glue
residue, putty mark
|
Not permitted
|
Permitted if
slight and smoothly sanded
|
Permitted
|
|
Knifemark
|
Not permitted
|
Permitted to a
width of
0.8mm
if
slight
|
Permitted
|
20
|
Other defects
which are not indicated
|
Not permitted
unless they resemble a defect already defined in which case they shall be
considered under that category
|
Not permitted
unless they resemble a defect already defined in which case they shall be
considered under that category
|
Not permitted
unless they resemble a defect already defined in which case they shall be considered
under that category
|
*It is intended
that classification by appearance of tropical hardwood plywood covered by
this table will, in a reasonable time, comply with the grading requirements
for grades and given to the grade descriptions in table 6(a).
|
Numbers cross
reference, where possible, to those in table 5,6(a) and 7.
|
Sometimes
designated CC quality.
|
