ASTM D5462-21 PDF
Standard Test Method for On-Line Measurement of Low-Level Dissolved Oxygen in Water
Standard Test Method for On-Line Measurement of Low-Level Dissolved Oxygen in Water
- Статус документа:
- Действующий
- Формат:
- Электронный (PDF)
- Количество страниц:
- 6
- Дата публикации:
- 1 июня 2021 г.
- Издание:
- D5462
- ICS:
- 13.060.50
SIGNIFICANCE AND USE 5.1 DO may be either a corrosive or passivating agent in boiler/steam cycles and is therefore controlled to specific concentrations that are low relative to environmental and wastewater treatment samples. Out-of-specification DO concentrations may cause corrosion in boiler systems, which leads to corrosion fatigue and corrosion products — all detrimental to the life and efficient operation of a steam generator. The efficiency of DO removal from boiler feedwater by mechanical or chemical means, or both, may be monitored by continuously measuring the DO concentration before and after the removal process with on-line instrumentation. DO measurement is also a check for air leakage into the boiler water cycle. 5.2 Feedwater chemistry guidelines for high-pressure boilers generally require specific feedwater DO concentrations: 5 μg/L or less for reducing all volatile treatment [AVT(R)]; 5–10 μg/L for oxidizing all volatile treatment [AVT(O)]; 50–200 μg/L for oxygenated treatment [OT] (3). 5.3 In microelectronics production, DO can be detrimental in some manufacturing processes, for example, causing undesirable oxidation on silicon wafers. SCOPE 1.1 This test method covers the on-line determination of dissolved oxygen (DO) in water samples primarily in ranges from 0 to 500 μg/L (ppb), although higher ranges may be used for calibration. On-line instrumentation is used for continuous measurements of DO in samples that are brought through sample lines and conditioned from high-temperature and high-pressure sources when necessary. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazards statements, see 6.5. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Abstract
Overview
ASTM D5462-21 is the internationally recognized standard test method for the on-line measurement of low-level dissolved oxygen (DO) in water. Developed by ASTM International, this standard is crucial for industries requiring continuous, accurate monitoring of dissolved oxygen concentrations, particularly in high-purity water applications such as power generation and microelectronics manufacturing. The method is applicable to water samples typically ranging from 0 to 500 µg/L (ppb) of DO but allows for higher ranges during calibration. Measurement is performed via on-line instrumentation capable of delivering real-time data, improving process control, system reliability, and water quality management.
Key Topics
- DO Measurement Principles: Utilizes electrochemical probes-either diffusion-type (galvanic or polarographic) or equilibrium-type-to detect dissolved oxygen using gas-permeable membranes and precise temperature compensation for accurate readings.
- Importance in Power Generation: Low-level DO measurement is essential in boiler and steam cycles to prevent corrosion, corrosion fatigue, and the accumulation of corrosion products, which reduce the service life and operational efficiency of steam generators.
- Microelectronics Manufacturing: Stringent DO control prevents undesirable oxidation, particularly on sensitive materials like silicon wafers.
- Continuous Monitoring: On-line, real-time DO measurement detects process upsets, verifies oxygen removal efficiency, and identifies air ingress, ensuring compliance with industry specifications.
- Calibration and Maintenance: Provides guidance on instrument and probe calibration, periodic maintenance, and quality control to guarantee accurate, repeatable results.
- Sampling Best Practices: Emphasizes selecting appropriate sample line materials (e.g., stainless steel, PVDF, Nylon), maintaining flow rates, and preventing atmospheric contamination.
Applications
ASTM D5462-21 is widely applied in industries requiring precise, continuous measurement of low-level dissolved oxygen:
- Power Plants: Monitoring DO in boiler feedwater and throughout the steam cycle to ensure concentration levels suitable for reducing [AVT(R)], oxidizing [AVT(O)], and oxygenated [OT] treatments.
- Industrial Process Water: Maintaining water chemistry control in systems where DO impacts corrosion rates or process effectiveness.
- Microelectronics: Achieving ultra-pure water conditions to prevent device defects caused by unintended oxidation during manufacturing.
- Quality Assurance: Ensuring DO levels remain within specification for regulatory compliance and system efficiency.
- Leak Detection: Identifying air ingress or system breaches by detecting abnormal increases in DO concentrations.
Practical Benefits
- Enhanced Corrosion Protection: Reduces maintenance costs and extends equipment lifespan by identifying and controlling corrosive oxygen levels.
- Real-Time Process Optimization: Immediate feedback for adjustments in water treatment processes, ensuring efficient chemical usage and system operation.
- Data-Driven Decision Making: Continuous monitoring provides traceable records for operational audits and regulatory reporting.
Related Standards
For effective implementation of ASTM D5462-21, consider its relationship with related ASTM water analysis standards:
- ASTM D1066 - Practice for Sampling Steam
- ASTM D3370 - Practices for Sampling Water from Flowing Process Streams
- ASTM D3864 - Guide for On-Line Monitoring Systems for Water Analysis
- ASTM D1193 - Specification for Reagent Water
- ASTM D2777 - Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
- ASTM D1129 - Terminology Relating to Water
These referenced standards support sampling, analysis, terminology, and calibration, ensuring more reliable and reproducible low-level dissolved oxygen measurements in water.
Keywords: ASTM D5462-21, dissolved oxygen, on-line measurement, water analysis, boiler feedwater, corrosion prevention, power generation water, microelectronics water purity, continuous DO monitoring, water quality standard
Технические детали
- Технический комитет
- D19 - Water
- SKU
- ASTM D5462-21
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