QA Acceptance Criteria
QA Acceptance Criteria
QA Acceptance Criteria
Table of Contents
1.
2.
3.
3.1.
3.2.
Document precedence....................................................3
Scope............................................................................3
Definitions.....................................................................4
Lot....................................................................................4
Random sample.................................................................4
x
2. Scope
CED Document no. 7.1-ST-02, Quality requirements for Engineering and Construction works
specify the quality requirements for Contract 4600008152, Package 10, enabling/construction site
facilities, to ensure that the Employer has confidence in the Contractor conforming to the Works
Information and that an acceptable level of quality of the Works is achieved. The Contractors
Quality Management System shall conform to the requirements of ISO 9001.
The Employer monitors the quality of the Works through a standard quality acceptance control
system that ensure that the Works is constructed in accordance with the Works information.
Acceptance control consists of the testing of certain parameters of products, materials or portions
of the Works for compliance with the requirements of the Works Information. Acceptance control
normally is done according to a quality plan with provisions for the parameters that will be
monitored, the tests that will be applied, size of lots for testing, number of samples per lot and the
acceptance range around the required value that is specified for the parameter in the Works
Information. Acceptance control can be done by:
Statistical methods based on a rational and consistent approach where the risk of faulty
judgement is reduced with benefits to both Employer and Contractor.
The use of statistical methods for acceptance control is covered by this specification.
Acceptance of materials and/or portions of the Works based on the statistical methods described
herein does not constitute acceptance when materials and/or portions of the Works will be
rejected due to other characteristics (not controlled by statistical method) failing to meet the
requirements of the Works Information or there are other causes for rejection such as obviously
defective and excessively non-uniform material, excessive variation due to any assignable cause,
visible signs of poor workmanship and similar causes which due not require further testing and
constitute sufficient grounds for rejection.
The Project Manager/Supervisor reserves the right to carry out such tests as may be considered
necessary on any localised portion of a lot which appears to be defective.
The defects in the localised portion shall be rectified before it is included in the lot for general
acceptance control. The results of tests done on localised portion shall not be included as part of
the random tests required for statistical acceptance control of the lot.
Where statistical acceptance control plans are utilised strict adherence to the plan shall be
observed and decisions based on the plan shall not be altered in order not to distort either the
Contractors or Employers risks.
3. Definitions
3.1. Lot
A lot is a portion of the Works or material produced, which is assessed as a unit for acceptance
control according to the statistical methods described here. The size of each lot and the number
of samples and tests thereon shall be as specified in Table 7, Section 6.3. Each lot shall be
selected to represent as far as possible material or work produced under conditions which did not
vary significantly during the process of production.
x
n
S
Where:
x
n
n xn
n 1
3.5. Outliers
When 1 test result in a sample differs significantly from the other values, this difference may be
due to an assignable cause and the result should be discarded as an outlier in the assessment of
the test.
To
Where:
And
x
n
x x
S
o
xo is the test result with the biggest difference from the mean
Compare the value of To with the value of T from Table 1 for the applicable number of results or
measurements n.
Number of observations n
Critical value T
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
30
35
40
45
50
60
70
80
90
100
Table 1 Outlier determination
1.46
1.67
1.82
1.94
2.03
2.11
2.18
2.23
2.29
2.33
2.37
2.41
2.44
2.47
2.50
2.53
2.56
2.58
2.60
2.62
2.64
2.66
2.75
2.82
2.87
2.92
2.96
3.03
3.09
3.14
3.18
3.21
mean
x
n 1
x
n
and the standard deviation Sn-1 must be calculated from the remaining n-1 test
results provided that the final number of test results used in the assessment shall not be less than
4.
of values representing an acceptable parameter is allowed to lie. The specification limit is a single
lower limit denoted by Ls.
3.10.
Resubmission
When a lot is resubmitted for valid reasons based on engineering judgement or when a
conditionally accepted (rejected) lot is resubmitted after reworking, a new random sample of n
x
n2
determined.
When the lot has not been reworked or the reworking did not lead to a significant change in the
parameter according to the judgement of the Project Manager/Supervisor, the means and
standard deviations of the first and second submissions can be combined to determine the
x
2n
x2 n
S
2n
x x
n
n2
2
2
n2
S S
2
Where the reworking of the lot leads to a significant change in the parameter according to the
judgement of the Project Manager/Supervisor, the reworked lot shall be regarded as a new lot
and judged as for a first submission.
3.11.
ka and kai
These are factors used in the calculation of the acceptance limit L a for the first and second
submissions respectively and is calculated as follows:
k k
k
k
k k 2n
k
i
2
r
is based on values achieved in practice and can be estimated according to the indicative values
in Table 2 below.
Layer
Property
Fill
Selected subgrade
Subbase
Asphalt base
Asphalt surfacing
Concrete
Relative density
Relative density
Relative density
Cementitious binder content (stabilised)
Relative density
Bitiminous binder content (continuous)
Bitiminous binder content (gap)
Grading < 19.00 mm
< 4.75 mm
< 0.300 mm
< 0.075 mm
Relative density
Bitiminous binder content (continuous)
Bitiminous binder content (gap)
Grading < 9.75 mm
< 2.36 mm
< 0.300 mm
< 0.075 mm
Cube crushing strength
Table 2 Values of
(%)
5
10
10
10
15
10
10
10
10
10
10
15
10
10
10
10
10
10
10
k , kr, kr2 and ka are obtained from the following Table 3 for values of k or k for different values
of or .
or (%)
k or k
0.01
0.1
0.5
1.0
5.0
10
15
3.72
3.09
2.58
2.33
1.65
1.28
1.04
Table 3 Values of k or k for different values of or .
20
0.842
25
0.675
For the purposes of this Contract, a, r and (r)2 will have the following values and corresponding
ka, kr and kr2 values:
description
value (%)
a
5.00
r
1.00
(r)2
0.01
Table 4 and corresponding k values
k description
ka
kr
kr2
k value
1.645
2.326
3.719
Table 5 in Section 3.13 and Table 6 in Section 3.14 contain calculated values of k a and kai for
different values of .
3.12.
kr and kri
These are factors used in the calculation of the rejection limit L r for the first and second
submissions respectively and is calculated as follows:
k k
r
k r k
k k
k 2n
r
2
r
is based on values achieved in practice and can be estimated according to the indicative values
in Table 2.
k , kr and kr2 are obtained from Table 3 for values of k or k for different values of or .
For the purposes of this Contract, r and (r)2 will have the values and corresponding kr and kr2
values contained in Table 4.
Table 5 in Section 3.13 and Table 6 in Section 3.14 contain calculated values of k r and kri for
different values of .
3.13.
= 10%
= 15%
= 20%
= 25%
n
3
ka
kr
ka
kr
ka
kr
ka
kr
ka
kr
0.695
0.302
0.332
-0.061
0.087
-0.307
-0.108
-0.501
-0.275
-0.669
0.822
0.482
0.459
0.118
0.214
-0.127
0.019
-0.321
-0.148
-0.489
0.909
0.604
0.546
0.241
0.301
-0.004
0.106
-0.199
-0.061
-0.366
0.973
0.695
0.610
0.332
0.365
0.087
0.170
-0.108
0.003
-0.275
1.023
0.766
0.660
0.402
0.415
0.157
0.220
-0.037
0.053
-0.205
1.063
0.822
0.700
0.459
0.455
0.214
0.260
0.019
0.093
-0.148
1.097
0.869
0.733
0.506
0.488
0.261
0.293
0.066
0.126
-0.101
10
1.125
0.909
0.761
0.548
0.516
0.301
0.322
0.106
0.154
-0.061
12
1.170
0.973
0.807
0.610
0.562
0.365
0.367
0.170
0.200
0.003
14
1.205
1.023
0.842
0.660
0.597
0.415
0.402
0.220
0.235
0.053
16
1.234
1.063
0.870
0.700
0.625
0.455
0.431
0.260
0.263
0.093
18
1.257
1.096
0.894
0.733
0.649
0.488
0.454
0.293
0.287
0.126
20
1.277
1.125
0.914
0.761
0.669
0.516
0.474
0.322
0.307
0.154
3.14.
= 10%
= 15%
= 20%
= 25%
n
3
kai
kri
kai
kri
kai
kri
kai
kai
kai
kri
1.225
1.051
0.862
0.688
0.616
0.442
0.422
0.248
0.254
0.080
1.281
1.130
0.918
0.767
0.673
0.522
0.478
0.327
0.311
0.160
1.319
1.185
0.956
0.822
0.711
0.576
0.516
0.382
0.349
0.214
1.348
1.225
0.985
0.862
0.740
0.616
0.545
0.422
0.378
0.254
1.370
1.256
1.007
0.893
0.762
0.648
0.567
0.453
0.400
0.286
1.388
1.281
1.024
0.918
0.779
0.673
0.585
0.478
0.417
0.311
1.402
1.302
1.039
0.939
0.794
0.694
0.599
0.499
0.432
0.332
10
1.415
1.319
1.052
0.956
0.806
0.711
0.612
0.516
0.444
0.349
12
1.435
1.348
1.072
0.985
0.826
0.739
0.632
0.545
0.464
0.377
14
1.450
1.370
1.087
1.007
0.842
0.762
0.647
0.567
0.480
0.400
16
1.463
1.388
1.100
1.024
0.855
0.779
0.660
0.585
0.493
0.417
18
1.473
1.402
1.110
1.039
0.865
0.794
0.670
0.599
0.503
0.432
20
1.482
1.415
1.119
1.052
0.874
0.806
0.679
0.612
0.512
0.444
4. Judgement plans
The judgement plan for each parameter of the material or portion of the work shall be applied as
detailed in the sections below.
x
n
Ls is determined from Table 7 or the relevant requirements of the Works Information. k r and kri is
determined from Table 7 or Tables 5 & 6 for different values of or .
Accept the lot if the sample mean
x
n
or
n2
La.
x
n
or
x
n2
x
n
or
x
n2
rejection limit Lr but is less than the acceptance limit La. Sections 3.9 and 3.10 deal with
conditional acceptance and resubmission.
A spreadsheet data sheet template to determine the lower limit specification acceptance control is
part of the supporting documentation for this specification.
5. Parameters to be controlled
The parameters to be controlled by means of the acceptance plans are listed in Table 7 and/or
derived from the parameters specified for control testing in the Works Information.
6. Lot size
6.1. Road construction layers
The lot sizes will be according to Table 7 or a days production. However the Project
Manager/Supervisor may order a lot of any size if:
The factors affecting the parameters under consideration exhibit abnormal variation
6.2. Concrete
The lot size will be according to Table 7 or a days production. However the Project
Manager/Supervisor may order a lot of any size if:
The lot sizes on concrete structures could vary considerately, particularly in the case of small
structures where it could be necessary to combine samples of the same grade of concrete for
different structures provided that the concrete is obtained from the same plant and is cast in the
same period under consideration.
Rock fill 1
Soil or
gravel fill
Excavations
and natural
subgrade 3
Parameter
1 Relative
density %
2 Layer
thickness
Atterberg
limits and
grading
CBR
Relative
density %2
Layer
thickness
Atterberg
limits
CBR
Relative
density %2
Layer
thickness
Subbase
and
selected
layer
(untreated)
Atterberg
limits
CBR
Relative
Maximum
quantity
1 sample
Maximum
lot size
Min no
of
samples
per lot
process
control
Min no of
samples
per lot
acceptance
control
non
statistical
Min no of
samples
per lot for
acceptance
control
statistical
n
(%)
10 000 m3
20 000 m3
1 layer
20 000 m3
10 000 m3
10 000 m3
2 000 m3
1 layer
5 400
12 000 m3
20 000 m3
1 800
12 000 m3
1 800
12 000 m3
1
-
3
2
4 10
4
10
10
15
10
4 10
10
10
10 000 m2
12 000
30 000 m2
20 000
30 000 m2
2 500 m2
12 000 m2
15
1 layer
12 000 m2
10
6 10
10
10
2 500 m2
2 500 m2
5 000 m2
18 000
22 500 m2
12 000
15 000 m2
9 000
Ls lower
limit
Engineering
Judgement
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
As
specified in
Works
Information,
SANS 1200
ka
kr
kai
kri
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
0.459
0.459
0.118
0.118
0.918
0.918
0.767
0.767
0.214
-0.127
0.673
0.522
0.459
0.118
0.918
0.767
0.459
0.118
0.918
0.767
0.459
0.118
0.918
0.767
0.214
-0.127
0.673
0.522
0.459
0.118
0.918
0.767
0.610
0.332
0.985
0.862
0.459
0.118
0.918
0.767
Structure
Parameter
density %
Layer
thickness
Subbase
and
selected
layer
(treated)
Gravel base
Crushed
stone base
Atterberg
limits
CBR or UCS
Stabilizer
content 4
Relative
density %
Layer
thickness
Atterberg
limits and
grading
CBR or UCS
(not for
crushed
stone)
Compressive
strength
(cement
stabilised)
Stabilizer
content (if
stabilized)4
Relative
density %
Maximum
quantity
1 sample
Maximum
lot size
Min no
of
samples
per lot
process
control
2 500 m2
18 000 m2
9 000
18 000 m2
1 layer
2 500 m2
2 500 m2
2 500 m2
2 500 m2
1 layer
18 000
22 500 m2
12 000
15 000 m2
10 000 m2
9 000
18 000 m2
9 000
18 000 m2
kri
(%)
Ls lower
limit
ka
Min no of
samples
per lot for
acceptance
control
statistical
n
6
10
0.610
0.332
0.985
0.862
10
0.610
0.332
0.985
0.862
6 10
10
0.610
0.332
0.985
0.862
10
0.459
0.118
0.918
0.767
10
18
10
0.894
0.733
1.110
1.039
10
COTO &
Drawings
for each
application
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
0.610
0.332
0.985
0.862
10
0.610
0.332
0.985
0.862
0.610
0.332
0.985
0.862
0.459
0.118
0.918
0.767
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
kr
kai
Min no of
samples
per lot
acceptance
control
non
statistical
3
2 500 m2
9 000
22 500 m2
6 10
10
2 500 m2
12 000
15 000 m2
10
2 500 m2
15 000 18 000 m2
10
0.459
0.118
0.918
0.767
10
18
10
0.894
0.733
1.110
1.039
15
0.365
0.087
0.740
0.616
2 500 m2
2 500 m2
10 000 m2
6 000
9 000 m2
Structure
Asphalt
bases and
wearing
courses
Aggregate
for asphalt
Aggregate
for seals
Parameter
Layer
thickness
Grading and
binder
content
Marshal
stability, flow
and air voids
Relative
density
Distribution
of rolled in
chippings
Immersion
index 5
ACV and/or
Treton
Sand
equivalent
Flakiness
index
Grading
ACV and/or
Treton
Flakiness
index
Grading
Adhesion
Maximum
quantity
1 sample
1 layer
150 t
1 days
work
Maximum
lot size
6 000
9 000 m2
400 - 800
t
Min no
of
samples
per lot
process
control
Min no of
samples
per lot
acceptance
control
non
statistical
Min no of
samples
per lot for
acceptance
control
statistical
n
(%)
10
10
10
15
2 000 m2
1 days
work
6 000
9 000 m2
2 000 m2
6 000
9 000 m2
10
5 000 m3 6
Stockpile
200 m3 6
Stockpile
1 000 m3 6
1 000 m3 7
Stockpile
Stockpile
2
2
4
4
5 000 m3 6
Stockpile
1 000 m3 6
1 000 m3 6
Stockpile
Stockpile
2
2
4
4
Ls lower
limit
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
As
specified in
Works
Information,
SANS 1200
COTO &
ka
kr
kai
kri
0.610
0.332
0.985
0.862
0.700
0.459
1.024
0.918
0.459
0.118
0.918
0.767
0.365
0.087
0.740
0.616
0.610
0.332
0.985
0.862
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Structure
Parameter
Maximum
quantity
1 sample
Maximum
lot size
Min no
of
samples
per lot
process
control
Min no of
samples
per lot
acceptance
control
non
statistical
Min no of
samples
per lot for
acceptance
control
statistical
n
(%)
R&W 7
Aggregate
for concrete
Concrete
structures
and
pavements
ACV
Flakiness
index
Grading
Organic
content 8
Cement
content 9
Air content 9
Slump
Cube
strength 11
5 000 m3 6
Stockpile
1 000 m3 6
200 m3 6
Stockpile
Stockpile
2
2
4
4
200 m3 6
Stockpile
Per
Per
1
1
4
10
casting of casting of
max 150
max 150
m3
m3
Casting of
0-75 m3
1 casting
3 sets
3 sets
6 sets
10
Casting of
75 -150
m3
1 casting
3 sets
4 sets
8 sets
10
Casting of
150 + m3
1 casting
3 sets
5 sets
10 sets
10
Table 7 - Table of constants to be used in Judgement Plans
Ls lower
limit
Drawings
for each
application
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
As
specified in
Works
Information,
SANS 1200
COTO &
Drawings
for each
application
ka
kr
kai
kri
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
0.459
0.118
0.918
0.767
0.610
0.332
0.985
0.862
0.700
0.459
1.024
0.918
0.761
0.546
1.052
0.956
Notes:
1. Only plate bearing tests and layer thickness measurements are conducted at the discretion of the Project Manager/Supervisor
2. A maximum density must be determined for every field density. Where the maximum density does not vary, the number of density
measurements can be reduced.
3. Soils and gravels in the upper 150 mm below the bottom of selected layers.
4. The upper and lower half of the layer must be sampled separately. This series of tests is intended to evaluate the thoroughness of the
mixing process and not the actual quantity mixed in. At least 4 samples of the material before stabilization must be taken to determine
whether the natural CaO or MgO varies.
5. Is done initially and thereafter only when aggregate or mix design changes.
6. Volume of newly delivered material or change in design.
7. Is done initially and every time the aggregate changes.
8. Includes determination of other deleterious materials.
9. Is done when required but usually at least every 200 m 3.
10. The grading is not normally included in a statistical control plan.
11. One set comprises 3 cubes.
In the case of changes in sample size n, amended values for k a and kai or kr and kri can be obtained from Tables 5 & 6 or calculated from the
formulas in Sections 3.11 and 3.12.
Accept the lot if all the parameters are acceptable in terms of Section 4.
Reject the lot if any 1 or more of the parameters are rejected in terms of Section 4.
Accept the lot conditionally if any 1 or more of the parameters are conditionally
acceptable and all the remaining parameters are acceptable in terms of Section 4.