ASK Corporation.  Hydraulic Accessories and Measuring Instruments

Top > Products Info > Unit and Accuracy

Unit and Accuracy of Pressure Gauges in conformance with New JIS

JIS (Japan Industrial Standards) B 70505, pertaining to the Bourdon tube pressure gauge, was revised on April 1, 1994, and the new JIS took effect on April 1, 1995.
The major revisions are found in three points; pressure indication unit (SI unit), pressure range and pressure gauge accuracy. Especially notable is that the exclusive use of the SI unit started on October 1, 1999. Pressure gauge manufacturers are allowed to manufacture only equipment based on the SI unit. If you want to purchase a new pressure gauge, we recommend a product with indication in MPa units.

image

Pressure indication unit (SI unit)
The pressure indication unit of the pressure gauge is integrated to indicate in units of MPa alone. Since October 1, 1999, we cannot manufacture, sell or exhibit pressure gauges with indication units of kgf/- only nor a double indication units of both kgf/- and MPa as in our former products. Pressure gauges in current use based on the conventional units can be used during the period of validity. It must be noted, however, that they cannot be used for certification of business transactions or certification of pressure gauge calibration. For certification of business transactions or calibration, use a pressure gauge based on the SI unit.
Pressure indication range
The new provisions of JIS on pressure range are based on the ISO Standards. Some models cannot be manufactured conforming to the former pressure range. Select the pressure range using the Old/New comparison table.
Pressure accuracy and grade
Pressure accuracy and grade in conformance to the new JIS provisions are based on the ISO Standards. It should be noted that pressure accuracy and grade are different according to the sizes of the pressure gauge. For details of pressure accuracy and grade, see the Old/New comparison table.
ASK started sales of the glycerin pressure gauge in conformance to the new JIS provisions as a standard product on October 1, 1999. During the period from April 1, 1999 to September 1, 1999, pressure gauges with indications in both kgf/- and MPa were sold as optional, but were not kept in stock. You are recommended to change your pressure gauge to one based on the SI unit. The glycerin pressure gauge indicating in both MPa and Psi sold both in Japan and abroad corresponds to the glycerin pressure gauge indicating in both MPa and kgf/-. However, since the Psi unit is excluded from the Si unit, this pressure gauge cannot be used in Japan. We will accept a special order for this product only for export. A manufacturer having manufactured and sold a pressure gauge based on units other than the SI unit is subject to penal provisions. Therefore, if you want to order one, you are requested to submit a certificate (there is no particular specified format) to ASK, verifying that the product is an export item destined for an end user outside Japan. Contact our Sales Department for details.

Old/New Comparison Table

  Former JIS product New JIS product
Pressure accuracy grade
(Standard Item)
±1.5%
ø39  :  ±3%
ø60  :  ±1.6%
ø75  :  ±1.6%
ø100  :  ±1.6%
Pressure range
0.2 MPa/kgf/cm²
0.6 MPa/kgf/cm²
1 MPa/kgf/cm²
1.5 MPa/kgf/cm²
2.5 MPa/kgf/cm²
3.5 MPa/kgf/cm²
5 MPa/kgf/cm²
7 MPa/kgf/cm²
10 MPa/kgf/cm²
15 MPa/kgf/cm²
25 MPa/kgf/cm²
35 MPa/kgf/cm²
50 MPa/kgf/cm²
70 MPa/kgf/cm²
100 MPa/kgf/cm²
0.25 MPa
0.6 MPa
1 MPa
1.6 MPa
2.5 MPa
4 MPa
6 MPa
10 MPa
16 MPa
25 MPa
40 MPa
60 MPa
100 MPa

Pressure translation table

bar MPa atm kgf/cm² Ibf/n²(psi) mHg InHg mAq(mH2O) KPa
1 0.1 0.9869233 1.0197162 14.503729 0.750064 29.530079 10.179162 100
10 1 9.8692327 10.197162 145.03729 7.50064 295.30079 101.97162 1000
1.01325 0.101325 1 1.0332275 14.695904 0.76 29.92126 10.332275 101.325
0.980665 0.0980665 0.9678411 1 14.2233 0.7355592 28.959025 10 98.0665
0.0689476 0.0068948 0.068046 0.070307 1 0.051715 2.0360222 0.7030717 6.8948
1.33322 0.133322 1.31579 1.359506 19.336662 1 39.370079 13.59506 133.322
0.0338638 0.0033864 0.0334211 0.0345315 0.4911538 0.0254 1 0.3453145 3.3864
0.0980665 0.0098067 0.0967841 0.1 1.42233 0.0735561 2.8959105 1 9.8067