Glossary

On water and its title

• National water — water owned by the Nation, whose use requires a title granted by the authority.
• Concession holder — individual or company holding a concession title to use or extract national water.
• Allocation holder — the equivalent where the holder is a public body, typically a municipal water utility.
• Water use — the specific point where water covered by the title is extracted or used: a well, a spring, an intake.

On the assessment

• Conformity assessment — visually attesting and verifying that the metering system and its operation satisfy the standard.
• Verification Unit (UV) — a company accredited by the Mexican accreditation body and approved by CONAGUA to carry out that assessment.
• Verification report — the document recording the outcome of the assessment.
• Results sheet — the record of what was measured during the verification, which underpins the report.
• Register of Verification Units — CONAGUA’s register where each approval is entered and which enables access to the reports system.

On who may do it

• ema — the Mexican accreditation body, which accredits the unit against the requirements applicable to inspection bodies.
• Approval — the act by which CONAGUA enables an already accredited unit to assess conformity with NMX-AA-179-SCFI-2018. It lasts four years.
• Competence standard — the certification held by the individual carrying out the verification. EC0913 covers spool-piece meters for pressurised pipe.
• CONOCER — the council before which personnel are certified in a competence standard; the certificate is issued by the Ministry of Public Education.

On the equipment

• Spool-piece meter — installed as a section within the pipe, in line with the flow.
• Transit-time ultrasonic system — measures from outside the pipe using ultrasonic waves, without cutting it.
• Measurement standard — the calibrated instrument against which the verified equipment is contrasted.
• UTM coordinates — the system used to record the exact location of the measurement point in the file.

The standard’s definitions sit in clauses 3.22 to 3.26; the unit’s obligations, in clause 10. ^{1 2}