How to
SPECIFY BRICK
When referencing
ASTM C 216, be
sure to identify the
specification’s version
and year
Figure 1. Type FBX brick were used in this project and should be specified
where a uniform, monolithic appearance is desired.
By Christine A. Subasic
he specification of brick begins with identifying its usage.
Most brick manufactured and
used are facing brick, commonly
specified by reference to ASTM C
216 Standard Specification for Facing Brick. Other uses for which
brick may be specified include:
■ Pavements—ASTM C 902 Specification for Pedestrian and Light
Traffic Paving Brick and C 1272
Specification for Heavy Vehicular Paving Brick
■ Sewers and manholes—ASTM C
T
32 Specification for Sewer and
Manhole Brick
■ Reinforced masonry—ASTM C
652 Specification for Hollow
Brick
Although the following information is specific to facing brick,
many aspects are common to the
specification of other types of
brick as well.
The most recently published
version of ASTM C 216 is ASTM C
216-95a Standard Specification for
Facing Brick (Solid Masonry Units
Made from Clay or Shale) (Reference). In the project specifications, it is important to note which
version (including the year) of the
standard specification is being
referenced, as changes are made
periodically. Revisions to an ASTM
standard specification during a
project would not affect the project specifications if the year is
referenced. The tables and data
included h e re i na re t a k e nf ro m
ASTM C 216-95a.
Appearance
Facing brick used in veneer or
structural brick masonry walls is
widely preferred over other siding
materials because of its desirable
appearance. As a result, most
Tolerances on dimensions
Maximum permissible variation, inches (mm), plus or minus from:
Specified dimension
or average brick size
in job lot sample,
inches (mm)
3 (76) and under
Over 3-4 (76 to 102) incl
Over 4-5 (102 to 152) incl
Over 6-8 (152 to 203) incl
Over 8-12 (203 to 305) incl
Over 12-16 (305 to 406) incl
Column A
(for specified dimension)
Type FBX
Type FBS
⁄16 (1.6)
⁄ 32 (2.4)
1
⁄8 (3.2)
5
⁄ 32 (4.0)
7
⁄ 32 (5.6)
9
⁄ 32 (7.1)
⁄32 (2.4)
⁄8 (3.2)
3
⁄ 16 (4.8)
1
⁄4 (6.4)
5
⁄16 (7.9)
3
⁄8 (9.5)
1
3
Column B
(for average brick size in job lot sample) A
Type FBX
Type FBS
smoothB
Type FBS
roughC
⁄16 (1.6)
⁄ 16 (1.6)
3
⁄ 32 (2.4)
3
⁄32 (2.4)
1
⁄8 (3.2)
3
⁄ 16 (4.8)
⁄16 (1.6)
⁄ 32 (2.4)
3
⁄ 32 (2.4)
1
⁄8 (3.2)
3
⁄16 (4.8)
1
⁄4 (6.4)
⁄ 32 (2.4)
⁄8 (3.2)
3
⁄16 (4.8)
1
⁄4 (6.4)
5
⁄16 (7.9)
3
⁄8 (9.5)
3
1
1
1
1
3
3
1
Lot size shall be determined by agreement between purchaser and seller. If not specified, lot size shall be understood to include all
brick of one size and color in the job order.
B
Type FBS smooth units have relatively fine texture and smooth edges, including wire-cut surfaces. These definitions relate to dimensional tolerances only.
C
Type FBS rough units have textured, rounded, or tumbled edges. These definitions apply to dimensional tolerances only.
Copyright ASTM. Reprinted with permission. Source: ASTM C 216-95a (Reference)
A
Figure 2. Dimensional tolerances for facing brick.
Maximum permissible extent of chippage from the edges and corners
of finished face or faces onto the surface
Chippage in inches (mm) in from
Type
FBX
FBSB (smooth)
FBSC (rough)
FBA
1
1 3
5% or less
⁄8-1⁄4 (3.2-6.4)
⁄4- ⁄8 (6.4-9.5)
95% to 100%
0-1⁄8 (0-3.2)
0- 1⁄4 (0-6.4)
1
3
10% or less
⁄4- 5⁄16 (6.4-7.9)
⁄8-1⁄ 2 (9.5-12.7)
90% to 100%
0- 1⁄4 (0-6.4)
0-3⁄8 (0-9.5)
5
1
15% or less
⁄16 -7⁄16 (7.9-11.1)
⁄ 2- 3⁄4 (12.7-19.1)
85% to 100%
0- 5⁄16 (0-7.9)
0-1⁄2 (0-12.7)
to meet the designated sample or as specified by the purchaser, but not more restrictive than Type FBS (rough)
Edge
Corner
Percentage
allowed A
Chippage in inches (mm) in from
Percentage
allowedA
Edge
Corner
Percentage of exposed brick with chips allowed in the wall, measured the listed dimensions in from an edge or corner.
Smooth texture is the unbroken natural die finish.
C
Rough texture is the finish produced when the face is sanded, combed, scratched, or scarified or the die skin on the face is entirely
broken by mechanical means such as wire-cutting or wire-brushing.
Copyright ASTM. Reprinted with permission. Source: ASTM C 216-95a (Reference)
A
B
Figure 3. Chippage limits for facing brick.
brick is chosen on the basis of its
color and texture. Brick colors
vary widely from light tans and buff
colors to deep reds and oranges.
Color choices are further expanded
by considering brick with surface
colors created by a glaze, slurry, or
sand, or by flashing.
Color and texture should be
specified by indication of a particular manufacturer’s color or blend
and/or by approval of a brick sample panel that includes the full
range of brick colors and textures.
ASTM C 216-95a specifies that the
general color and texture should
match that of an approved sample (8.1 and 8.2). (All numbers in
parentheses refer to the section
numbers in ASTM C 216-95a.)
In the case of brick with a surface color, ASTM C 216-95a specifies that such coatings must be
durable in a freeze/thaw environment to ensure the color stability
(7.1 to 7.3).
Other appearance characteristics covered by ASTM C 216-95a
include dimensional tolerances,
chippage, warpage and out-ofs q u a re . The Specification provides three Types of brick classification depending upon the degree
of permissible variation of these
characteristics (4.1):
■ Type FBS covers brick for general use in masonry.
■ Type FBX covers brick for general use in masonry where requirements call for a higher
deg re e of p re c i s i o n and low-
er p e rm i s s i b l e variation in
size than permitted for Type
FBS.
■ Type FBA covers brick for general use in masonry selected
to produce characteristic architectural effects resulting
from nonuniformity in size
and texture of the individual
units.
When the Type is not specified,
the requirements of Type FBS
govern.
For a project where a uniform,
monolithic appearance is desired,
Type FBX should be specified
(Figure 1). Relatively little variation
in dimensional tolerances is permitted for Type FBX units (9.1) (Figure
2—Table 4 from ASTM C 216). Nor
is much chippage (7.4) or distortion (9.2) allowed (Figure 3—Table
3 from ASTM C 216; and Figure
4—Table 5 from ASTM C 216).
On the other hand, when an
old-world appearance is the desired effect, Type FBS or FBA brick
are a better choice (Figure 5). Not
all brick colors and textures are
available in all Types or sizes.
Size
When specifying the brick size,
t h ew i d t h ,h e i g h t ,a n dl e n g t hs h o u l d
be specified—in that order. Reliance on only a brick name to
denote a size is not a complete
specification. Names usually are
regional in nature and may have
d i ff e re n t meanings in d i ff e re n t
parts of the country. The
specified size is used to determine whether the brick meets the
dimensional tolerance requirements.
ASTM C 216 specifies that in a
sample of 10 brick selected to represent the extreme range of sizes
of brick to be supplied, no brick
shall depart from the specified
size by more than the individual
tolerance shown in Column A of
Figure 2.
In addition, the average size of
this 10-brick sample shall be determined, and no brick in the lot
delivered to the
job can vary from
Tolerances on distortion
this average size
by
more than the
Maximum permissible
distortion,
inches
(mm)
tolerances
given
Maximum dimension,
inches (mm)
Type FBX
Type FBS
in Column B of
the same table.
8 (203) and under
⁄ (1.6)
⁄ (2.4)
Nor
shall any indiOver 8-12 (203 to 305) incl
⁄ (2.4)
⁄ (3.2)
vidual brick in the
Over 12-16 (305 to 406) incl
⁄ (3.2)
⁄ (4.0)
lot delivered to
Copyright ASTM. Reprinted with permission. Source: ASTM C
the job fall out216-95a (Reference)
side the dimensional tolerances
Figure 4. Distortion tolerances for facing brick.
of Column A (9.1).
1
3
16
32
1
8
3
32
1
5
8
32
Warpage
Warpage refers to the distortion
of the surfaces or edges of an individual brick from a plane surface or
from a straight line. Warpage can
be measured by aligning a plane
surface with the surface or edge under question and measuring the difference from plane. Tolerances
shall not exceed the maximum values shown in Figure 4 (9.2).
Figure 5. This tumbled brick is Type
FBA, used when an old-world appearance is desired.
Out-of-square
Physical properties
The maximum permitted dimension for out-of-square of exposed face of the brick, as specified in ASTM C 216, is 1⁄8 inch for
Type FBS brick and 3⁄32 inch for
Type FBX brick. Tolerances for
Type FBA brick must be specified
by the purchaser, but generally
are not more stringent than for
Type FBS brick (9.3).
Efflorescence
Efflorescence refers to the white
chalky deposits that sometimes
occur when masonry becomes
saturated with water. Salts in the
masonry are carried to the surface by the evaporating water.
Most often, efflorescence is unsightly but not harmful itself. Its
presence can indicate a problem
with water absorption or water
penetration.
ASTM 216 requires that brick
units be tested for efflorescence
and be rated “not effloresced.”
This ensures that the brick do not
contain soluble salts that could
contribute to e ff l o re s c e n c e . It
does not, however, guarantee that
efflorescence will not occur. Mortar and concrete masonry materials may contain efflorescing salts,
but they are not tested for efflorescence.
The 95a revision of ASTM C 216
reorganized section 5 on physical
properties and changed the language of the requirements. The
properties measured and specified include compressive strength,
absorption,andfreeze/thawweight
loss. The absorption and freeze/
thaw waivers found in previous
editions were changed to alternates in the 95a version to better
describe the nature of these requirements (5.1.2 and 5.1.3).
The Grade of brick is used to
specify the physical properties required for the purpose of ensuring freeze/thaw durability. Grade
SW brick are intended for use
“where high and uniform resistance to damage caused by cyclic
freezing is desired and where the
brick may be frozen when saturated with water.” Grade MW brick
may be used “where moderate resistance to cyclic freezing damage
is permissible or where the brick
may be damp but not saturated
with water when freezing occurs.”
ASTM C 216-95a differs from previous versions in that a note was
added to clarify what saturated
means in these definitions. In this
standard, saturated refers to “the
condition of a brick that has ab-
sorbed water to an amount equal
to that resulting from submersion
in room-temperature water for 24
hours” (3.1).
ASTM C 216 contains a table to
guide the user in selecting the
proper Grade based on the face
exposure of the units in place
(5.1.4). In regions of negligible
weathering (where the weathering index is less than 50), Grade
MW brick are suitable for all exposures, except nonvertical surfaces in contact with earth (where
Grade SW should be specified).
These regions include southern
Florida, parts of southern Texas,
and p o rt i o n s of California and
Arizona. In most of the United
States, the weathering index is 50
or greater, and Grade SW should
be specified in all exposures—
above and below grade.
The limitations on the physical
properties depend upon which
Grade is specified. Figure 6 (Table
1 from C 216) contains the physical requirements found in ASTM C
216 for Grade SW and Grade MW
brick. Values for compressive
strength, 5-hour boiling-water absorption, and saturation coefficient are specified. The combination of these properties is felt to
be a good predictor of the durability of brick masonry in place.
Because of the more severe exposure category, the requirements
of Grade SW are more restrictive
than for Grade MW. As a result,
Grade SW brick are generally accepted in lieu of Grade MW (5.1).
If the brick are used in an environment with a weathering index
less than 50, the 5-hour boilingwater absorption and saturationcoefficient requirements given in
Figure 6 d on o ta p p l y. However, the
Physical requirements
Minimum compressive strength
psi (MPa), gross area
Maximum water absorption by
5-hour boiling %
MaximumsaturationcoefficientA
Designation
Average of
5 brick
Individual
Average of
5 brick
Individual
Average of
5 brick
Individual
Grade SW
Grade MW
3000 (20.7)
2500 (17.2)
2500 (17.2)
2200 (15.2)
17.0
22.0
20.0
25.0
0.78
0.88
0.80
0.90
The saturation coefficient is the ratio of absorption by 24-hour submersion in cold water to that after 5-hour submersion in boiling water.
Copyright ASTM. Reprinted with permission. Source: ASTM C 216-95a (Reference)
A
Figure 6. Physical requirements for facing brick.
minimum-compressive-strength
requirement of 2500 psi does apply (5.1.4).
Alternate requirements
In addition to the combinations
specified in Figure 6, the Specification provides alternate means
of satisfying the physical property
requirements for durability. The
Absorption Alternate applies to
units where the cold-water absorption of any single unit of a
random sample of five brick does
not exceed 8%. In this case, the
saturation coefficient requirement
does not apply (5.1.2).
The Freezing and Thawing Alternate is specified as an alternative only when brick do not conform to either the requirements in
Figure 6 for maximum water absorption and saturation coefficient, or to the requirements of
the Absorption Alternate. In this
case, the requirements for 5-hour
boiling-water absorption and saturation coefficient do not apply,
provided a sample of five brick,
meeting the strength requirements of Figure 6, passes the
freezing and thawing test with a
weight loss not greater than 0.5%
of any individual unit (5.1.3). The
criteria for passing this test are
described in the Rating Section of
the Freezing and Thawing test
p ro c e d u re s of ASTM C 67 Standard Test Methods of Sampling
and Testing Brick and Structural
Clay Tile.
Initial rate of absorption
The measurement of the initial
rate of absorption (IRA) is specified in ASTM C 216, but the value
is not. IRA is not a measure of a
brick’s durability. This property is
measured to assist the specifier in
selecting a m o rt a r compatible
with the brick.
Knowledge of the IRA also is valuable during construction. When
brick and mortar do not have adequate moisture, incomplete bond
and low bond strength may result.
Such assemblages may have little
resistance to water permeance.
Too much moisture can cause the
units to “float” on the mortar, resulting in poor bond as well. ASTM
C 216 recommends that brick
units with an IRA of more than 30
grams/(minute)(30 inches2) be
wetted prior to laying (5.3).
Putting it together
The specification of masonry is
covered in Division 4 of the project specifications. Section 04200
covers brick masonry units. Part
I—General of this section contains the general requirements including the specification of necessary testing and samples. Brick
sample panels should be specified here. In Part II—Products,
the size, Type, Grade, and color of
brick should be specified. Installation techniques are covered in
Part III—Execution, which includes items such as filling mortar joints, lapping flashing, etc.
Guide specifications, such as
the American Institute of Architect’s MasterSpec or Brick Institute of America’s Technical Notes
on Brick Construction—11 Series,
can be especially helpful as aids
in writing a complete product
specification. By following a guide
specification, the specifier can
feel more confident that the masonry is specified in the proper
sections and that all items are in-
cluded.
Looking ahead
The next revision to ASTM C
216 will incorporate “mandatory
language” in the standard. This
change was sought by representatives of the model building codes
to comply with their policy of
mandating specifications to be
free of language that makes suggestions or makes the specification optional.
Words like “should,” “may,” and
“might” are replaced with “shall”
and “must.” These changes have
been reviewed and approved by
ASTM Committee C 15 (on Manufactured Masonry Units). A new
edition should be published within the year.
Christine A. Subasic, P.E., is a consulting
architectural engineer based in Olney, Md.
Reference
ASTM C 216-95a, Standard Specification
for Facing Brick (Solid Masonry Units Made
from Clay or Shale), June 1995, ASTM, 100
Barr Harbor Dr., West Conshohocken, PA
19428.
PUBLICATION #M970181
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