ANALYSIS OF MSL TG-13 PRESSURE GAUGE CALIBRATION METHOD

ANALYSIS OF MSL TG-13 PRESSURE GAUGE CALIBRATION METHOD

ANALISIS METODE KALIBRASI PRESSURE GAUGE MSL TG-13 Adindra Vickar Ega and R. Rudi Anggoro Samodro

Pusat Penelitian Metrologi LIPI, Kompleks Puspiptek Serpong Gedung 420, Tangerang, Banten adindravickar@gmail.com

ABSTRACT

Analysis of MSL TG-13 method by performing calibration of a 0.6% class-ranged 4,000 kPa pressure gauge had been conducted. The calibration was done by using a 0.1% class-ranged 40 bar test gauge as a standard. The purpose of the analysis was to verify the MSL TG-13 method with the widely used standard method Deutscher Kalibrierdienst (DKD-R 6-1). Parameters for the analysis were Error number (En) for the degree of equivalence of both methods, maximum error value according to the requirement in reference document BS en 837-1:1988 for each accuracy class. The result showed that MSL TG-13 method was consistent and complying with the widely used standard methods DKD-R 6-1, proven by En values ≤ 1 in each pressure point. The maximum error of pressure gauge, by using both methods, also complied with the requirement stated in BS En 837-1:1998, which was less than ± 0.6%. Therefore, MSL TG-13 method had been analyzed and could be implemented for pressure gauge calibration.

Keywords: DKD-R 6-1, MSL TG-13, Pressure Gauge, max error, En, accuracy ABSTRAK

Telah dilakukan analisis terhadap metode MSL TG-13 dengan cara melakukan kalibrasi pressure gauge rentang 4.000 kPa dan kelas akurasi 0,6%. Kalibrasi pressure gauge dilakukan dengan menggunakan tes gauge rentang 40 bar dan kelas akurasi 0,1% sebagai standar. Analisis dilakukan untuk pengujian metode MSL TG-13 terhadap metode baku Deutscher Kalibrierdienst (DKD-R 6-1) yang sudah digunakan secara luas. Parameter-parameter analisis tersebut adalah nilai error number (EN) untuk melihat tingkat kesesuaian hasil pengukuran kedua metode serta nilai maksimum error sesuai persyaratan acuan BS EN 837-1:1998 untuk tiap-tiap kelas akurasi.

Hasil analisis menunjukkan bahwa metode MSL TG-13 konsisten dan bersesuaian dengan metode baku DKD-R 6-1, dibuktikan dengan nilai error number (EN) ≤ 1 pada tiap titik ukur. Kesalahan maksimum pressure gauge yang diperoleh dari kedua metode tersebut juga bersesuaian dengan persyaratan BS EN 837-1:1998, yakni tidak lebih dari ± 0,6%. Dengan demikian, metode MSL TG-13 telah dianalisis dan dapat diimplementasikan untuk kalibrasi pressure gauge.

Kata kunci: DKD-R 6-1, MSL TG-13, Pressure Gauge, max error, En, akurasi

1. INTRODUCTION

In industrial sector, metrology takes an im- portant role in the improvement of industrial product quality through measuring instruments which have been calibrated regularly, so that the need of accurate measurement in industry can be achieved.

Research Center for Metrology LIPI as National Metrology Institute of Indonesia has the responsibility to maintain the traceability of measuring instrument in Indonesia.^[1] Effective and efficient calibration process in terms of time and effort is necessary in order to improve the

capacity of calibration services and dissemina- tion to many calibration and industry laboratories in Indonesia. The quality of calibration results is also important because it relates with the quality of industrial products.

Pressure gauge is the most commonly used measuring instrument in industry to monitor the pressure value in production process and also in safety system. In pressure gauge calibration pro- cess, Research Center for Metrology LIPI used the standard method DKD-R 6-1 (Deutscher Kalibrierdienst), which is the international refer- ence.^[2] However, National Metrology Institute

of New Zealand, Measurement Standards Laboratory of New Zealand (MSL), claimed that their pressure gauge calibration method, MSL Technical Guide 13 (MSL TG-13), was easier and faster than the standard method.^[3]

Based on SNI ISO/IEC 17025:2008 clause 5.4.5.2 about method validation, laboratory shall validate non-standard method to confirm the validity of the method.^[4] Research regarding method validation process has been done before in the scope of length metrology, which is validation of bending measurement absolute method with self-calibration principle.^[5] In case of non-standard pressure gauge calibration method prepared by MSL, there is no statement that proves if the method has been validated with the standard method DKD-R 6-1. Besides, there is no scientific publication or citation regarding the method validation.

The purpose of this paper is to describe the pressure gauge calibration standard method DKD-R 6-1, and the MSL TG-13 pressure gauge calibration method, to analyze the MSL TG-13 method regarding the calibration result, uncertainty budget, error number (En) and max error, then compare it with the standard method DKD-R 6-1 calibration results, as the imple- mentation of SNI ISO/IEC 17025:2008 clause 5.4.5.2. If the validation result is satisfactory, the MSL TG-13 method can be implemented by Research Center for Metrology and other calibration laboratories to increase the pressure gauge calibration capacity and for practical calibration purposes.

2. THEORY

2.1 The Standard Method DKD-R 6-1 DKD-R 6-1 gives the specific guidance of pres- sure gauge calibration, for example number of preloadings, load change, waiting time, number of measurement point and series based from the accuracy class, as shown in Table 1.

The measurement process begins with pre-loadings, which increases the pressure from minimum scale (0%) to maximum scale (100%) and decreases to minimum scale of the pressure gauge, as shown in Figure 1.

The purpose of pre-loadings are to char- acterize the bourdon tube elasticity regarding with the needle scale indication of the pressure gauge. Besides, pre-loadings are useful to check if the installation of pressure gauge in the compression pump is correct or not. Improper installation of the pressure gauge will cause pressure medium leak so that it will be difficult to make the reading.

In Table 1, for example, pressure gauge calibration with accuracy class less than 0,1%, would take three pre-loadings, then measure- ment was done at nine measurement point with two times measurement series up and down.

Waiting times for each maximum and minimum

Table 1. DKD-R 6-1 Calibration Sequence

Calibration sequence

Measurment uncertainty

aimed at

Number of measurement

point (with zero)

Number of pre- loadings

Load change + waiting

time

Waiting time at up-

per limit Number of mea- surement series

in % of span up/down Seconds Minutes Up Down

A < 0,1 9 3 > 30 2 2 2

B 0,1 ~ 0,6 9 2 > 30 2 2 1

C > 0,6 5 1 > 30 2 1 1

Figure 1. DKD-R 6-1 Calibration Step^[2]

Figure 2. MSL TG-13 Calibration Step

measurement point was 2 minutes before doing next calibration cycle, except for bourdon tube pressure gauge which took 5 minutes waiting time. The number of measurement cycle could be added another cycle, if the unit under test (UUT) was re-installed with different torque, to check the effect from reproducibility.

2.2 The MSL TG-13 Method

In the MSL TG-13 method, measurement could be done nonsequentially so that the two mea- surement series up and down could be done for just one measurement series, as shown in Figure 2. For example, when calibrating measurement point to 40% of full scale, the first reading was taken from rising pressure, where the pressure increased from 0% to 40%.

After the first reading, the pressure increased until maximum pressure, and then decreased until the desired point 40%, where the second reading was taken from falling pressure. After the second reading, the pressure was decreased until 0%, and the calibration could be continued to the next calibration point or cycle at the same point.

The MSL TG-13 method could make pres- sure gauge calibration easier, especially when using Dead Weight Tester (DWT) as a reference standard. Pressure gauges are usually calibrated with test gauge as a standard, which is traceable to DWT with accuracy class in parts per million (ppm), repeatability measurement at the same measurement point that can be done without unloading the DWT weight so that it will reduce time and also help the operator in doing the calibration. This method also allows the operator to measure zero deviation and hysteresis effect through deviation in every measurement point.

Even though, since the method was not validated yet, it was necessary to compare the calibration results with the standard method to see the conformity of both methods.

2.3 Uncertainty Calculation 2.3.1 DKD-R 6-1

3

, 1

mean ind mean standard i

i

p p p δp

=

∆ = − +

∑

...(1)

Equation (1) is general equation model in calibration, where is error of pressure reading, is mean pressure reading from U U T, is pressure reading or pressure value generated by the standard used in the calibration, corrected by height reference level difference between standard and UUT. Besides both factors, there were other components which give uncertainty contribution, noted with which come from repeatability, zero deviation, and hysteresis.Reproducibility could also be included if there was variation or different treatment in calibration, like reinstallation with different torque.

b) Zero deviation (f₀)

2,0 1,0 4,0 3,0 6,0 5,0

max{ , ,

fo= x −x x −x x −x ...(6)

( )

3

o fo

u f = ...(7) with :

x_1,0 ..x_6,0 = Zero scale reading at 0% pres- sure point in cycle1~6

3

, 1

mean ind mean standard i

i

p p p δp

=

∆ = ³ − +

∑

, 1

mean ind mean standard i

i

p p p δp

=

∆ = −³ +

∑

, 1

mean ind mean standard i

i

p p p δp

=

∆ = − +

∑

3

, 1

mean ind mean standard i

i

p p p δp

=

∆ = − +∑ ,

a) Repeatability (b’)

b'_up,j = | (x_3,j- x_3,0) - (x_1,j- x_1,0) | ...(2) b'_down,j = | (x_4,j- x_4,0) - (x_2,j- x_1,0) | ...(3) b'_mean,j = max{b'_up,j , b'_down,j} ...(4)

( ') ' 3

u b = b ...(5)

x_1,j ..x₄ = Reading scale value at each pres- sure point in cycle 1~4

x_1,0 ..x₄ = Zero scale reading at 0% pressure point in cycle1~4

Standard uncertainty values for repeatability and zero deviation components were calculated based on Equation (2)–(7).

2.3.2 MSL TG-13

p_ref= p_read+ p_corr ...(8) Mathematical model used by MSL in Pressure gauge calibration was shown in Equation (8), where p_ref is the applied reference pressure, p_read is the pressure gauge reading, and p_corr is the correction. Three main uncertainty compo- nents were from repeatability, resolution, and reference pressure. The calculation of standard uncertainty from repeatability component in MSL TG-13 is different fromDKD-R 6-1, as it used single pooled standard deviation calcula- tion, as shown in Equation (9) :

( )

( )

2

1, 2,1

0

2 0 12,

1 2 2

1 2 2

N

read i read i

N i i

p p

urep N

Diff

urep N

=

=

−

=

=

∑

∑

...(9)

with :

N = Number of rising and falling pressure point in single calibration cycle.

p_read1,i = i^th gauge pressure reading from first calibration cycle

p_read2,i = i^th gauge pressure reading from second

calibration cycle

Equation (9) refered to ISO 5725-3:1994 (Section 8.2, Equation 12).^[6] Constant values 1/√2 arised from two calibration cycle.

The uncertainties from reference pressure, resolution, and hysteresis were calculated in equation (10)~(13):

a) Reference Pressure

std std

u u

= k ...(10) The uncertainty from reference pressure was simply calculated from the uncertainty statement in the reference calibration re- port. The value was divided with coverage factor k.

b) Resolution

res resolution2 3

u = ...(11) The uncertainty calculation from resolution refered to the Joint Committee for Guides in Metrology (JCGM):100 Guide to the Expression of Uncertainty in Measurement and EURAMET EA-4/02 M:2013.^[7,8]The resolution value depended on the smallest scale interval division by the operator. The division values used were between 1/2, 1/4, 1/5, and 1/10, according to the DKD-R 6-1 and BS En 837-1.^[9] The constant value √3 arised from semi-range rectangular distribution.

c) Hysteresis

{

}

üüüüü

4, 3,0 3, 3,0

6, 5,0 5, 5,0

1 ,

, ,

mean j j j

j j

j j

h x x x x

n

x x x x

x x x x

= ⋅ − −

+ − −

+ − −

...(12)

( )

^,

3

mean j

u h = h ...(13)

The combined uncertainty from all compo- nents was expressed in Equation (14) and Equation (15).

For DKD-R 6-1 method,

2 2 2 2 2

c std repeat res hys zero dev

u = u +u +u +u +u ...(14) For MSL TG-13 method,

2 2 2 2

corr ref repeat resolution hys

u = u +u +u +u ...(15) As for the expanded uncertainty, it was calcu- lated using Equation (16),

c . c

U =k u ...(16) where is coverage factor value, which is obtained from the effective degree of freedom

calculation, as shown in Equation (17),

( )

4 4 1

.

eff c

N i i

i i

v u

u c v

=

=

∑

...(17)

with c_i is the sensitivity coefficient from each uncertainty component, which is partial deriva- tive from the equation.

c . c

U =k u

( )

4 4 1

.

eff c

N i i

i i

v u

u c v

=

=

( ) ∑

4 4 1

.

eff c

N i i

i i

v u

u c v

=

=

∑ ^{) (}

4 4

1

.

c eff

i N i

i i

u v

uc

v ⁼

=

∑

2.4 Calculation Method

Based on BS En 837-1 reference, maximum permissible errors (MPE) for each accuracy class pressure gauge was as shown in the Table 2.

The maximum error or error span was calculated with Equation (18)

U U'= + ∆p ...(18)

Where is the error span or maximum error, is the expanded uncertainty with coverage factor k = 2 and 95% confidence level,

is the correction.

Besides MPE value, Error Number (En) was also used to clarify the conformity of the measurement results from both methods, using the equation (19).

...(19)

Where X_A is the measurement value from method A, X_B is the measurement value from method B, U (X_A) is the expanded uncertainty from method A and U (X_B) is the expanded uncertainty from method B. Both methods reach conformity if .^{[10], [11]}

3. METHODOLOGY

In this research, the calibration was done between the 0.6% accuracy class-ranged 4,000 kPa pressure gauge manufactured by Palmer as the UUT and the 0.1% accuracy class-ranged 40 bar Test Gauge manufactured by Wika as the

standard. As mentioned in BS En 837-1:1996 clause 10.2, the standard used for pressure gauge calibration should have an MPE at least four times better than the pressure gauge under calibration.

Room condition also had to be maintained in temperature between 18^oC and 28^oC. Humidity and ambient pressure also needed to be noted if the air density affected the calibration result.

The instalation of the calibration was shown in Figure 3. Height difference (Δh) between test gauge and pressure gauge reference level should be taken into account of the head correction (Δph=ρ.g.Δh). The pressure reading from the test gauge as the standard then would be cor- rected by the head correction values, depending on the position of the test gauge and pressure gauge. Head correction would be added to the reference pressure if the test gauge was higher than pressure gauge, and vice versa.

The calibration process was done alternately.

First, the calibration was done by using the stan- dard DKD-R 6-1 method. Then, the calibration was done using the MSL TG-13 method. The number of measurement cycle for both methods was two cycles to compare the results.

The measurement results, the correction and the uncertainty, from both methods were then analyzed by using the equation from both methods. For the uncertainty from resolution component, the smallest scale interval division used in the calculation was 1/5. The combined and expanded uncertainties were calculated with Equation (14) until Equation (17). The method validation was then carried out by calculating Table 2. Maximum Permissible Errors Pressure

Gauge^[9]

Accuracy classes Limits of permissible error (% of span)

0.1 ± 0.1 %

0.25 ± 0.25 %

0.6 ± 0.6 %

1 ± 1 %

1.6 ± 1.6 %

2.5 ± 2.5 %

4 ± 4 % Figure 3. Set Up of The Calibration

U U'= + ∆p U U'= + ∆p

U U'= + ∆p

[

^{( )}

] [

^{2 ( )}

]

²

A B

N

A B

X X

E U X U X

= −

+ En

Gauge Reference Height (P1) TG Reference

Height (P2)

the MPE and En values from both methods using Equation (18) and Equation (19).

4. RESULTS AND DISCUSSION

The measurement results from both methods, standard method DKD-R 6-1, and MSL TG-13 method, were shown in Table 3 and Table 4 respectively.

The reference pressure from test gauge as standard was corrected by 0.423 kPa as the results from 0.05 m height difference of refer- ence level, 865 kg/m³ Tellus 22 fluid density, with 9.78137 m/s² local gravity in Pressure Laboratory Research Center for Metrology. In the case of the test gauge position was higher than the pressure gauge in the installation, the head correction was added to the reference pressure value in each pressure point.

From the results, the uncertainty from zero deviation components was zero. The results also showed that the repeatability component for each pressure point in MSL TG-13 was 2.61 kPa, since it used single pooled standard deviation, by assuming that the characteristic of each pressure point was the same. This differed from DKD-R 6-1 method, where the repeatability value for each pressure point was different by assuming that the characteristic of

each pressure point was different so that the number of measurement point cannot represent the number of repeat measurement. In other words, it could not be considered as Type A uncertainty. The uncertainty from hysteresis component in both DKD-R 6-1 and MSL TG-13 methods prevailed in all measurement points, except at first and final measurement point.

Table 5 and Table 6 described the uncertainty budgets of DKD-R 6-1 and MSL TG-13 at 50%

measurement point. The measurement point at 50% of full scale was chosen since it had the biggest expanded uncertainty than the other measurement points. The result showed that expanded uncertainty from MSL TG-13 was big- ger than the DKD-R 6-1 expanded uncertainty value. This was because the contribution of hysteresis effect in MSL TG-13 was larger than DKD-R 6-1, even though the repeatability un- certainty was smaller than DKD-R 6-1 method.

The 2 kPa standard uncertainty from standard component was obtained from Research Center for Metrology’s test gauge calibration report.^[12]

By using equation (10) with coverage factor k = 2, the value of uncertainty from standard was 1 kPa. The uncertainty from resolution component gives 2.9 kPa. For both methods, DKD-R 6-1 and MSL TG-13, the uncertainty from resolution

Table 3. Pressure Gauge Calibration Result with Standard DKD-R 6-1Method

Measure Point

(%)

Test Gauge M1 (rise) ~

M6 (fall) (kPa)

Pressure Gauge Repeatability

Hysteresis M1

(rise) M2 (fall)

M3 (rise)

M4 (fall)

Zero

deviation Up Down Mean (kPa) (kPa) (kPa)

0 0.423 0 0 0 0

0

0 0 0 0

10 400.423 390 400 390 390 0 10 10 5

20 799.423 800 800 790 800 10 0 10 5

30 1200.423 1190 1200 1190 1200 0 0 0 10

40 1598.423 1600 1610 1600 1610 0 10 10 10

50 1999.423 2010 2010 2000 2010 10 0 10 10

60 2399.423 2410 2410 2410 2410 0 0 0 5

70 2800.423 2810 2810 2800 2810 10 0 10 5

80 3199.423 3210 3210 3210 3210 0 0 0 0

90 3600.423 3610 3610 3610 3610 0 0 0 0

100 4001.423 4010 4010 4010 4010 0 0 0 0

Table 4. Pressure Gauge Calibration Result with MSL TG-13Method

Measure Point

(%)

Test Gauge M1 (rise) ~

M6 (fall) (kPa)

Pressure Gauge Repeatability

Hysteresis M1

(rise) M2 (fall)

M3 (rise)

M4

(fall) Up Down Mean

(kPa) (kPa) (kPa)

0 0.423 0 0 0 0 0 0

2.61

0

10 400.423 390 400 400 400 10 0 5

20 799.423 800 800 800 810 0 10 5

30 1200.423 1200 1190 1190 1200 10 10 10

40 1598.423 1600 1610 1600 1610 0 0 10

50 1999.423 2000 2010 2000 2010 0 0 10

60 2399.423 2400 2410 2410 2410 10 0 5

70 2800.423 2800 2800 2800 2810 0 10 5

80 3199.423 3200 3200 3200 3200 0 0 0

90 3600.423 3610 3610 3610 3610 0 0 0

100 4001.423 4010 4010 4010 4010 0 0 0

Table 5. Uncertainty Budget at 50% of Full Scale Measurement Point with DKD-R 6-1 Method Uncertainty

source Unit Dis- trib

U 2a

Divi- sor vi

Std.

Uncert

Sens.

Coeff c_i.u_i (c_i.u_i)² (c_i.u_i)⁴/ ui ci vi

Standard kPa nor-

mal 2 2 60 1 -1 -1E+00 1.0E+00 1.7E-02

Delta density kg/m³ Rect 86.5 3.46 50 24.97 4.9E-05 1.2E-03 1.5E-06 4.4E-14 Gravity m/s² Rect 4.9E-5 3.46 50 1E-5 4.3E-03 6.1E-08 3.7E-15 2.8E-31

Head corr. m Rect 0.005 3.46 50 1.4E-3 8.46 1.2E-02 1.5E-04 4.4E-10

Zero deviation kPa Rect 0 3.46 50 0 1 0.0E+00 0.0E+00 0.0E+00

Resolution kPa Rect 10 3.46 50 2.89 1 2.9E+00 8.3E+00 1.4E+00

Repeatability kPa Rect 10 3.46 50 2.89 1 2.9E+00 8.3E+00 1.4E+00

Hysteresis kPa Rect 5 3.46 50 1.4 1 1.4E+00 2.1E+00 8.7E-02

Reproducibility kPa Rect 0 3.46 50 0 1 0.0E+00 0.0E+00 0.0E+00

Sums 2.0E+01 2.9E+00

Combined uncert, uc₁ 4.44411

Effective degree of freedom, veff 135.38 Covered factor for CL=95% 1.98

Expanded unc, U(unit) 8.8

Table 6. Uncertainty Budget at 50% of Full Scale Measurement Point (MSL TG-13 Method) Uncertainty.

source Unit Distrib U

2a

Divi- sor vi

Std.

Uncert

Sens.

Coeff c_i.u_i (c_i.u_i)²

(c_i.u_i)⁴/vi

ui ci

Standard kPa normal 2 2 60 1 -1 -1E+00 1,0E+00 1,7E-02

Delta density kg/m³ Rect 86,5 3,46 50 24,97 4,9E-05 1,2E-03 1,5E-06 4,4E-14 Gravity m/s² Rect 4,9E-5 3,46 50 1E-5 4,3E-03 6,1E-08 3,7E-15 2,8E-31

Head corr. m Rect 0,005 3,46 50 1,4E-3 8,46 1,2E-02 1,5E-04 4,4E-10

Zero deviation kPa Rect 0 3,46 50 0 1 0,0E+00 0,0E+00 0,0E+00

Resolution kPa Rect 10 3,46 50 2,89 1 2,9E+00 8,3E+00 1,4E+00

Repeatability kPa normal 2,61 1,00 60 2,61 1 2,6E+00 6,8E+00 7,7E-01

Hysteresis kPa Rect 10 3,46 50 2,89 1 2,9E+00 8,3E+00 1,4E+00

Reproducibility kPa Rect 0 3,46 50 0 1 0,0E+00 0,0E+00 0,0E+00

Sums 2,4E+01 3,6E+00

Combined uncert, uc₁ 4,94823 Effective degree of freedom, veff 167,97

Covered factor for CL=95% 1,97 Expanded unc, U(unit) 9,8

Figure 4. (a) Uncertainty Contribution Graph from DKD-R 6-1Method (b) Uncertainty Contribution Graph from MSL TG-13Method

(a) (a)

gave the biggest contribution to the expanded uncertainty value, as shown in Figure 4. This was because resolution was highly correlated with the pressure gauge accuracy class. The fewer the number of the division scale, the lower the accuracy class of the pressure gauge was, and vice versa. Besides resolution, another component which gave significant contribution to the expanded uncertainty was repeatability and hysteresis.

From the obtained correction and the ex- panded uncertainty, the error span or maximum error, which was the important parameter of the pressure gauge accuracy class conformity based on BS En 837-1, could be calculated.

Figure 5 showed that maximum error of the 0.6% pressure gauge accuracy class calibrated with DKD-R 6-1 and MSL TG-13 method did not exceed the BS En 837-1 MPE requirement, which was ± 0.6% or ± 24 kPa for 0.6% pressure gauge accuracy class.

Figure 5 also informed that the measure- ment results from MSL TG-13 method was in conformity with the standard DKD-R 6-1 method. The expanded uncertainty of DKD-R 6-1 measurement results still covered the MSL TG-13 expanded uncertainty. The conformity of the results from the two methods could be determined from the En values by using equation (19) as shown in Table 7.

Table 7 shows that the En values in each pressure point were less or equal than 1. |Eⁿ| ≤ 1 expressed that the deviation of the measurement results from both methods was smaller than the expanded uncertainty from both methods. Thus, the MSL TG-13 method could be implemented for practical calibration purposes.

5. CONCLUSION

The pressure gauge calibration feasible claimed method MSL TG-13 has been analyzed. The calibration result shows that MSL TG-13 method is consistent and complying with the widely used standard methods DKD-R 6-1, proven by En values ≤ 1 in each pressure point. The maximum error of pressure gauge, by using both methods, also complies with the requirement Figure 5. Conformity Check Error Span Pressure Gauge Calibration Method

Table 7. Error Number (En) between DKD R 6-1 and MSL TG-13 Measurement Results

Nominal (kPa)

En Number DKD-R 6-1 & MSL TG-13

0 0.00

400 0.41

800 0.41

1,200 0.00

1,600 0.19

2,000 0.19

2,400 0.24

2,800 0.41

3,200 1.00

3,600 0.00

4,000 0.00

stated in BS En 837-1:1998, which is less than

± 0.6%. Therefore, MSL TG-13 method has been analyzed and can be implemented for practical calibration purpose.

6. ACKNOWLEDGEMENT

The author wishes to express his gratitude to Research Center for Metrology LIPI manage- ment for the support, as well as for the provided facility and equipment, and also MSL New Zealand for sharing the MSL TG-13 technical guide for pressure gauge calibration.

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