The fourth article of Law 3/1985, of March 18, of Metrology, establishes that the obtaining, conservation, development and dissemination of the basic units of measure is the responsibility of the State and therefore the patterns of the units These are the basic principles of the law of the European Union, which are, in fact, the basis of the Treaty of European Union. By Royal Decree 648/1994 of 15 April, declaring the national standards of measurement of the basic units of the International System of Units, the national patterns of length, mass, time, current intensity were determined electrical, thermodynamic temperature and light intensity, with their corresponding technical characteristics. The long elapsed time since the approval of the royal decree cited above and the technological progress produced since then, have made some of the technical characteristics of the national patterns of the basic units obsolete, it is necessary to update them. In particular, experience has shown that, except in the case of the mass pattern, the value of which is related to the third verification of national standards carried out at the International Bureau of Weights and Measures (Bureau International des Poids et al. In 1992, it is not appropriate to include declarations of uncertainty of measurement in a legal standard which, predictably, will maintain a long period of validity, since the normal development of the metrological activity represents a continuous improvement of uncertainties. In addition, the approval of the Mutual Recognition Arrangement (MRA) of the Calibration and Measure Certificates issued by the National Institutes of Metrology, of the International Committee of Weights and Measures (Committee) International des Poids et Mesures, CIPM) has modified the procedure with which the Calibration and Measurement Capabilities (CMC) of the National Institutes of Metrology are demonstrated and published in a way that the uncertainties recognised and published internationally are better than those declared in the definitions in force. By the order now approved, the Annex to the said Royal Decree 648/94 of 15 April 1994, which includes the technical characteristics of the national standards for the measurement of the basic units of the International System of Units corresponding to the magnitudes of length, mass, time, electric current intensity, thermodynamic temperature and luminous intensity, adapting the definitions of these patterns to technical progress. The final provision of Royal Decree 648/94 of 15 April 1994, which is currently authorised, authorises the Minister for Industry, Tourism and Trade to amend the technical definitions contained in the Annex to that regulatory rule to the extent possible. in which technical progress demands it. For the elaboration of this order, the autonomous communities have been consulted and the mandatory hearing has been carried out for the interested parties. In its virtue, I have:

Single item. Amendment to the Annex to Royal Decree 648/1994 of 15 April 1994 declaring the national standards for the measurement of the basic units of the International System of Units.

The Annex to Royal Decree 648/1994 of 15 April is replaced by the following.

Single end disposition. Entry into force.

This order will take effect the day following your publication in the "Official State Bulletin".

Madrid, July 20, 2006. -Minister of Industry, Tourism and Trade, José Montilla Aguilera.

ANNEX

1. National pattern corresponding to the magnitude length.

The national pattern corresponding to the magnitude length, whose unit is the meter (m), is maintained, preserved, guarded and disseminated by the Spanish Metrology Center and consists of a coherent light monochromatic radiation whose frequency value has been established by the International Committee on Weights and Measures (ICRP), considering the value of 299 792 458 m/s for the speed of light in a vacuum, according to the Resolution of the 17th General Conference of Weights and Measures (GFCM). The preservation of the pattern is performed by stabilized helium-neon lasers on a component of the hyperfine structure of the 11-5 R (127) transition of the iode 127 molecule. These lasers are regularly compared to the international standard maintained by the International Bureau of Weights and Measures (Bureau International des Poids et Mesures, BPM) and to the national employers of other States. 2. National pattern corresponding to the mass magnitude. The national pattern corresponding to the mass magnitude, whose unit is the kilogram (kg), is maintained, preserved, guarded and disseminated by the Spanish Metrology Center, is the copy number 24 of the Kilogram International Prototype deposited in the BPM. It was built in 1889 in alloy of platinum-iridium, with 10% of iridium. It is engraved on its surface, at two-thirds height, number 24. It is preserved and maintained according to the criteria indicated by the CPM. The national pattern mass is 0.999 999 890 kg, with a typical combined uncertainty (for k = 1) associated with 2.3 micrograms. This value has been determined with two prototypes of BIPM's platinum-iridium during the third International Comparison that ended in May 1993. 3. National pattern corresponding to the time scale. The national pattern corresponding to the magnitude of time, whose unit is the second (s), is maintained, preserved, guarded and disseminated, under the supervision and coordination of the Spanish Metrology Center, by the Laboratory of the Real Institute and Observatory of the Navy in San Fernando (ROA). It is performed by means of a set of oscillators permanently referred to the frequency of the quantum transition of the cesium atom, established in the XIII GFCM as the definition of the second. It is materialized by means of a set of atomic clocks of cesium and its relative uncertainty and traceability refer to the data published by the Circular T of the Time Section of the BIPM. Based on the national pattern corresponding to the time scale, the Royal Navy Observatory in San Fernando (ROA) develops and maintains the National Time Scale that has by name UTC (ROA). The absolute value of the difference between the UTC scale (ROA) and the Coordinated Universal Time (UTC) is maintained within a margin of one hundred nanoseconds, as established by the Advisory Committee Recommendation for the Definition of the Second (The Committee Consultatif pour la Definition de la Seconde, CCDS), adopted in its twelfth Assembly in 1993. 4. National pattern corresponding to the magnitude of electric current. The national pattern corresponding to the magnitude of electric current, whose unit is the ampere (A), is maintained, preserved, guarded and disseminated by the Spanish Metrology Center. It is carried out from the national patterns of electrical tension and electrical resistance, through the law of Ohm. The national pattern of electrical tension has been established in accordance with Recommendation 1 (Cl-1988) of the CPM, which adopts, by convention for the constant Josephson, the value of KJ-90 = 483 597.9 GHz/V. The national pattern of electrical resistance has been established in accordance with Recommendation 2 (Cl-1988) of the CPM, which adopts, by convention for the constant of von Klitzing, the value of RK-90 = 25 812,807 Ω. This pattern is compared periodically with those of other National Metrology Institutes. 5. National pattern corresponding to the heat-dynamic temperature. The national pattern corresponding to the magnitude thermodynamic temperature whose unit is the kelvin (K) is maintained, preserved, guarded and disseminated by the Spanish Center of Metrology, through the realization of the International Scale Temperature of 1990 (EIT-90), in accordance with Recommendation 5 (CI 1989) of the CPM, which is periodically compared to the Scales of other National Metrology Institutes. The EIT-90 is materialized and maintained by fixed temperature points. Platinum resistance thermometers up to 1235 K and black body, radiation thermometers and lamps are used for temperatures above 1235 K. The Scale is materialized and disseminated from 83 K to 2500 K using interpolation thermometers. 6. National pattern corresponding to the intensity of light intensity. The national pattern corresponding to the intensity of light intensity whose unit is the candela (cd), is maintained, preserved, guarded and disseminated, under the supervision and coordination of the Spanish Metrology Center, by the Department of Metrology of the Institute of Applied Physics, under the Higher Council of Scientific Research. It is performed by means of an Absolute Cryogenic Radiometer (Absolute Cryogenic Radiometer, ACR) of electrical substitution that allows to measure the optical power in watts. The derivation of the luminous intensity is obtained from the illuminance, applying the definition of the candela approved by the GFCM in 1979. The pattern is embodied and preserved by a group of filament lamps, which are compared periodically with those of other National Metrology Institutes through participation in Key Comparisons (Key Comparisons, KC). organised by the Advisory Committee for the Fotometry and Radiometry of the ICPM and by the Technical Committee for the Photometry and Radiometry of the European Metrology Organisation (European Organization of Metrology, EUROMET)